K2 vs. StarkPower LiFePo4 batteries

[Fox Two[_2_]]

Are there significant differences between these batteries? Why is there a 50% difference in their cost? I've noticed that some brands have more restrictive low temperature limits - not good for those cold wave flights!

Chris

[[email protected]]

We have been selling the Starkpower battery for more than a year now. Started out very cautiously - selling only a few to a few of our steady customers. We have now sold several hundred with no complaints. They really are great and are exactly the same size as the battery they replace.

One caution is you must use the special charger (inexpensive) that shuts off when the battery reaches a fully charged state.

Tom Knauff
Knauff & Grove, Inc
Ridge Soaring Gliderport

www.eglider.org

[Jim White[_3_]]

At 11:33 03 February 2015, wrote:
>We have been selling the Starkpower battery for more than a year now.
>Start=
>ed out very cautiously - selling only a few to a few of our steady
>customer=
>s. We have now sold several hundred with no complaints. They really are
>gr=
>eat and are exactly the same size as the battery they replace.
>
>One caution is you must use the special charger (inexpensive) that shuts
>of=
>f when the battery reaches a fully charged state.
>
>Tom Knauff
>Knauff & Grove, Inc
>Ridge Soaring Gliderport
>
>www.eglider.org
>
Tom, I want to fit Stark batteries to my ASW27 and am aware of their advice
re charging. Problem is that three years ago I fitted at great expense
Strobl solar panels with their OS4 charge controller. This controller is
designed for two SLA batteries and produces approx. 800ma shared between
the batteries. With SLA this will bring them up to full charge over time
and maintain them at c. 13.6 Volts. The panels have an open circuit max
voltage of 17V.

When flying I draw at least 800ma so the panels are just helping to
lengthen the operating time of my batteries so I do not see this would be a
problem but with the instruments turned off the panels would probably be
trickle charging. What is your opinion? If the internal battery circuitry
is managing the battery would that not shut down the charge when full?

I suppose that I could add a circuit to turn off the power completely at
14.6v but that would be a pain.

Any knowledgeable advice welcome.

Jim

[Dan Marotta]

Not to belittle Tom in any way, but you'd be better served to pose that
question directly to the battery's manufacturer. Perhaps they can point
you to a DC to DC charger which could use the output of your solar cells
and the logic of their smart charger. If you're handy with a soldering
iron, you could possibly make such a device.

I use a Tenergy battery (love it) and, by asking the manufacturer, they
sent me a spec sheet on their smart charger. It settled a lot of my
nerves about using a LiFePO4 battery.

Good luck!
Dan

On 2/3/2015 7:56 AM, Jim White wrote:
> At 11:33 03 February 2015, wrote:
>> We have been selling the Starkpower battery for more than a year now.
>> Start=
>> ed out very cautiously - selling only a few to a few of our steady
>> customer=
>> s. We have now sold several hundred with no complaints. They really are
>> gr=
>> eat and are exactly the same size as the battery they replace.
>>
>> One caution is you must use the special charger (inexpensive) that shuts
>> of=
>> f when the battery reaches a fully charged state.
>>
>> Tom Knauff
>> Knauff & Grove, Inc
>> Ridge Soaring Gliderport
>>
>> www.eglider.org
>>
> Tom, I want to fit Stark batteries to my ASW27 and am aware of their advice
> re charging. Problem is that three years ago I fitted at great expense
> Strobl solar panels with their OS4 charge controller. This controller is
> designed for two SLA batteries and produces approx. 800ma shared between
> the batteries. With SLA this will bring them up to full charge over time
> and maintain them at c. 13.6 Volts. The panels have an open circuit max
> voltage of 17V.
>
> When flying I draw at least 800ma so the panels are just helping to
> lengthen the operating time of my batteries so I do not see this would be a
> problem but with the instruments turned off the panels would probably be
> trickle charging. What is your opinion? If the internal battery circuitry
> is managing the battery would that not shut down the charge when full?
>
> I suppose that I could add a circuit to turn off the power completely at
> 14.6v but that would be a pain.
>
> Any knowledgeable advice welcome.
>
> Jim
>
>

--
Dan Marotta

[[email protected]]

On Tuesday, February 3, 2015 at 7:00:07 AM UTC-8, Jim White wrote:
> At 11:33 03 February 2015, wrote:
> >We have been selling the Starkpower battery for more than a year now.
> >Start=
> >ed out very cautiously - selling only a few to a few of our steady
> >customer=
> >s. We have now sold several hundred with no complaints. They really are
> >gr=
> >eat and are exactly the same size as the battery they replace.
> >
> >One caution is you must use the special charger (inexpensive) that shuts
> >of=
> >f when the battery reaches a fully charged state.
> >
> >Tom Knauff
> >Knauff & Grove, Inc
> >Ridge Soaring Gliderport
> >
> >www.eglider.org
> >
> Tom, I want to fit Stark batteries to my ASW27 and am aware of their advice
> re charging. Problem is that three years ago I fitted at great expense
> Strobl solar panels with their OS4 charge controller. This controller is
> designed for two SLA batteries and produces approx. 800ma shared between
> the batteries. With SLA this will bring them up to full charge over time
> and maintain them at c. 13.6 Volts. The panels have an open circuit max
> voltage of 17V.
>
> When flying I draw at least 800ma so the panels are just helping to
> lengthen the operating time of my batteries so I do not see this would be a
> problem but with the instruments turned off the panels would probably be
> trickle charging. What is your opinion? If the internal battery circuitry
> is managing the battery would that not shut down the charge when full?
>
> I suppose that I could add a circuit to turn off the power completely at
> 14.6v but that would be a pain.
>
> Any knowledgeable advice welcome.
>
> Jim

Call Starkpower. They are very helpful on the phone. Since the LFP charger shuts off at 14V, the 13.6 set point of your regulator is probably fine - but it may depend on how it is regulating.

[Dave Springford]

I'll preface my remarks with the statement that I sell K2 batteries.

The K2's are made in the USA, not Chinese knock-offs. K2 pays a fee to the patent holder while the knock-off's do not. K2 has also had their batteries UL certified and listed.

These items account for some of the price difference.

The K2 also have a higher Watt-hour rating at 123 vs 115 for the Stark and the K2 are rated for 25 amp continuous discharge vs 15 for the Stark. The K2's also have a better temperature range.

In my opinion, the K2 is a superior product and is worth the extra cost.

I sell K2 batteries with the protection module for $150 US and chargers for $30 US and will have some on hand at the Seniors at Seminole Lake. For any one interested in purchasing a K2, contact me at the address below.

Dave Springford
dave at foxonecorp dot com

[son_of_flubber]

On Tuesday, February 3, 2015 at 6:50:28 PM UTC-5, Dave Springford wrote:

> The K2's are made in the USA, not Chinese knock-offs. K2 pays a fee to the patent holder while the knock-off's do not. K2 has also had their batteries UL certified and listed.

This wins my dollar. I'd be concerned that the internals of Starkpower would change from batch to batch. The blatant ripoff of 'Stark Industries' from the 'Ironman' franchise is a red flag.

I also don't buy baby formula that is made in China.

Of course I buy all sorts of non-critical well made components/products from China. And they do a good job on things like the Iphone. But any commodity item like batteries is going to be a 'race to the bottom'.

I've no certainty that K2 is any more robust, but one can hope. UL labs is still a good operation.

[Richard[_9_]]

On Tuesday, February 3, 2015 at 4:20:56 PM UTC-8, son_of_flubber wrote:
> On Tuesday, February 3, 2015 at 6:50:28 PM UTC-5, Dave Springford wrote:
>
> > The K2's are made in the USA, not Chinese knock-offs. K2 pays a fee to the patent holder while the knock-off's do not. K2 has also had their batteries UL certified and listed.
>
> This wins my dollar. I'd be concerned that the internals of Starkpower would change from batch to batch. The blatant ripoff of 'Stark Industries' from the 'Ironman' franchise is a red flag.
>
> I also don't buy baby formula that is made in China.
>
> Of course I buy all sorts of non-critical well made components/products from China. And they do a good job on things like the Iphone. But any commodity item like batteries is going to be a 'race to the bottom'.
>
> I've no certainty that K2 is any more robust, but one can hope. UL labs is still a good operation.

Check the K2 Web Site the K2s are made in Henderson, NV and China. I suspect the cells are made in China and packaged in Henderson.

Richard

[Tango Eight]

http://www.etotheipiplusone.net/?p=1991

No dog in this fight.

T8

[[email protected]]

For Jim White:

Send me your email address and I will respond to your question.

Tom Knauff

[jfitch]

On Tuesday, February 3, 2015 at 3:50:28 PM UTC-8, Dave Springford wrote:
> I'll preface my remarks with the statement that I sell K2 batteries.
>
> The K2's are made in the USA, not Chinese knock-offs. K2 pays a fee to the patent holder while the knock-off's do not. K2 has also had their batteries UL certified and listed.
>
> These items account for some of the price difference.
>
> The K2 also have a higher Watt-hour rating at 123 vs 115 for the Stark and the K2 are rated for 25 amp continuous discharge vs 15 for the Stark. The K2's also have a better temperature range.
>
> In my opinion, the K2 is a superior product and is worth the extra cost.
>
> I sell K2 batteries with the protection module for $150 US and chargers for $30 US and will have some on hand at the Seniors at Seminole Lake. For any one interested in purchasing a K2, contact me at the address below.
>
> Dave Springford
> dave at foxonecorp dot com

I don't believe anyone is building cells in North America for the consumer market. These are all coming from China. It makes no sense at all to build the BMS boards here either. So as a point of differentiation between vendors, there is nothing in it.

[Charlie M. (UH & 002 owner/pilot)]

On Wednesday, February 4, 2015 at 12:08:54 PM UTC-5, jfitch wrote:
> On Tuesday, February 3, 2015 at 3:50:28 PM UTC-8, Dave Springford wrote:
> > I'll preface my remarks with the statement that I sell K2 batteries.
> >
> > The K2's are made in the USA, not Chinese knock-offs. K2 pays a fee to the patent holder while the knock-off's do not. K2 has also had their batteries UL certified and listed.
> >
> > These items account for some of the price difference.
> >
> > The K2 also have a higher Watt-hour rating at 123 vs 115 for the Stark and the K2 are rated for 25 amp continuous discharge vs 15 for the Stark. The K2's also have a better temperature range.
> >
> > In my opinion, the K2 is a superior product and is worth the extra cost.
> >
> > I sell K2 batteries with the protection module for $150 US and chargers for $30 US and will have some on hand at the Seniors at Seminole Lake. For any one interested in purchasing a K2, contact me at the address below.
> >
> > Dave Springford
> > dave at foxonecorp dot com
>
> I don't believe anyone is building cells in North America for the consumer market. These are all coming from China. It makes no sense at all to build the BMS boards here either. So as a point of differentiation between vendors, there is nothing in it.

As an avid "Electric RC'er", while you are likely correct that most cells come from a limited number of places, where they end up can be a case of, "Give me cells" vs. "I don't want seconds/low performers".....
Price is not always a guarantee (there is a "very high priced" LiPO hobby vendor that has performance numbers similar to "mid level" vendors.....), but it can help out as well as "post sale support".

Not saying anything for/against any vendor mentioned here, just a different view.

[Jim White[_3_]]

Reading the blurb referenced it would seem that the A123 batteries (which
are available from http://www.buya123batteries.com) seem to have the best
protection / charging electronics they only rated at 5Ah although this
should provide better performance than a 7Ah SLA.

The higher power batteries do not seem to have all the tricks in the
electronics.

Interesting note: although A123 is a US company using MIT derived
technology, they are owned by the Chinese!


At 17:37 04 February 2015, Charlie M. UH & 002 owner/pilot wrote:
>On Wednesday, February 4, 2015 at 12:08:54 PM UTC-5, jfitch wrote:
>> On Tuesday, February 3, 2015 at 3:50:28 PM UTC-8, Dave Springford
wrote:
>> > I'll preface my remarks with the statement that I sell K2 batteries.
>> >
>> > The K2's are made in the USA, not Chinese knock-offs. K2 pays a fee
to
>the patent holder while the knock-off's do not. K2 has also had their
>batteries UL certified and listed.
>> >
>> > These items account for some of the price difference.
>> >
>> > The K2 also have a higher Watt-hour rating at 123 vs 115 for the
Stark
>and the K2 are rated for 25 amp continuous discharge vs 15 for the Stark.
>The K2's also have a better temperature range.
>> >
>> > In my opinion, the K2 is a superior product and is worth the extra
>cost.
>> >
>> > I sell K2 batteries with the protection module for $150 US and
chargers
>for $30 US and will have some on hand at the Seniors at Seminole Lake.
For
>any one interested in purchasing a K2, contact me at the address below.
>> >
>> > Dave Springford
>> > dave at foxonecorp dot com
>>
>> I don't believe anyone is building cells in North America for the
>consumer market. These are all coming from China. It makes no sense at
all
>to build the BMS boards here either. So as a point of differentiation
>between vendors, there is nothing in it.
>
>As an avid "Electric RC'er", while you are likely correct that most cells
>come from a limited number of places, where they end up can be a case of,
>"Give me cells" vs. "I don't want seconds/low performers".....
>Price is not always a guarantee (there is a "very high priced" LiPO hobby
>vendor that has performance numbers similar to "mid level" vendors.....),
>but it can help out as well as "post sale support".
>
>Not saying anything for/against any vendor mentioned here, just a
different
>view.
>

[Ron Gleason]

On Thursday, 5 February 2015 04:30:04 UTC-7, Jim White wrote:
> Reading the blurb referenced it would seem that the A123 batteries (which
> are available from http://www.buya123batteries.com) seem to have the best
> protection / charging electronics they only rated at 5Ah although this
> should provide better performance than a 7Ah SLA.
>
> The higher power batteries do not seem to have all the tricks in the
> electronics.
>
> Interesting note: although A123 is a US company using MIT derived
> technology, they are owned by the Chinese!
>
>
> At 17:37 04 February 2015, Charlie M. UH & 002 owner/pilot wrote:
> >On Wednesday, February 4, 2015 at 12:08:54 PM UTC-5, jfitch wrote:
> >> On Tuesday, February 3, 2015 at 3:50:28 PM UTC-8, Dave Springford
> wrote:
> >> > I'll preface my remarks with the statement that I sell K2 batteries.
> >> >
> >> > The K2's are made in the USA, not Chinese knock-offs. K2 pays a fee
> to
> >the patent holder while the knock-off's do not. K2 has also had their
> >batteries UL certified and listed.
> >> >
> >> > These items account for some of the price difference.
> >> >
> >> > The K2 also have a higher Watt-hour rating at 123 vs 115 for the
> Stark
> >and the K2 are rated for 25 amp continuous discharge vs 15 for the Stark.
> >The K2's also have a better temperature range.
> >> >
> >> > In my opinion, the K2 is a superior product and is worth the extra
> >cost.
> >> >
> >> > I sell K2 batteries with the protection module for $150 US and
> chargers
> >for $30 US and will have some on hand at the Seniors at Seminole Lake.
> For
> >any one interested in purchasing a K2, contact me at the address below.
> >> >
> >> > Dave Springford
> >> > dave at foxonecorp dot com
> >>
> >> I don't believe anyone is building cells in North America for the
> >consumer market. These are all coming from China. It makes no sense at
> all
> >to build the BMS boards here either. So as a point of differentiation
> >between vendors, there is nothing in it.
> >
> >As an avid "Electric RC'er", while you are likely correct that most cells
> >come from a limited number of places, where they end up can be a case of,
> >"Give me cells" vs. "I don't want seconds/low performers".....
> >Price is not always a guarantee (there is a "very high priced" LiPO hobby
> >vendor that has performance numbers similar to "mid level" vendors.....),
> >but it can help out as well as "post sale support".
> >
> >Not saying anything for/against any vendor mentioned here, just a
> different
> >view.
> >

http://en.wikipedia.org/wiki/A123_Systems as you can read this company started out in Massachusetts and received US Government grants, went bankrupt and was bough by the Chinese.

[6PK]

On Tuesday, February 3, 2015 at 1:47:54 AM UTC-8, Fox Two wrote:
> Are there significant differences between these batteries? Why is there a 50% difference in their cost? I've noticed that some brands have more restrictive low temperature limits - not good for those cold wave flights!
>
> Chris

I purchased a "Bioenno Power" 12v 12ah(LiFePO4) battery and charger and used it for over a year now with no problems. Cost $136.99 which includes the charger.
http://www.bioennopower.com/collections/12v-series-lifepo4-batteries/products/12v-12ah-lifepo4-battery
Any comment on this brand out there?
6PK

[son_of_flubber]

On Monday, February 9, 2015 at 10:58:56 AM UTC-5, 6PK wrote:

> http://www.bioennopower.com/collections/12v-series-lifepo4-batteries/products/12v-12ah-lifepo4-battery
> Any comment on this brand out there?

Found this on bioenno website. Are the ISO certs significant?

"As an OEM, Bioenno Power conducts technology development, product design and markets a variety of products. Our company has engineering, and small scale manufacturing facilities in Santa Ana, CA. For large-scale manufacturing, the company uses overseas contract manufacturers (CMs) to carry out production according to Bioenno Power's designs and requirements. Our CMs have fully implemented the ISO quality management system, and have ISO9001:2008 and ISO14001 certifications, which ensure a consistent process, stable performance, and high reliability."

[Ramy[_2_]]

On Tuesday, February 3, 2015 at 3:33:38 AM UTC-8, wrote:
> We have been selling the Starkpower battery for more than a year now. Started out very cautiously - selling only a few to a few of our steady customers. We have now sold several hundred with no complaints. They really are great and are exactly the same size as the battery they replace.
>
> One caution is you must use the special charger (inexpensive) that shuts off when the battery reaches a fully charged state.
>
> Tom Knauff
> Knauff & Grove, Inc
> Ridge Soaring Gliderport
>
> www.eglider.org

Can one charger charge two identical starkpower batteries in parallel?

Ramy

[Jonathan St. Cloud]

After having two dogs piosoned by Chinese dog food (did not even know the food was made in China) I try very hard not to buy anything made in China. Plus they are well know to steal as much intellectual property as possible.

On Tuesday, February 3, 2015 at 4:20:56 PM UTC-8, son_of_flubber wrote:

> I also don't buy baby formula that is made in China.
>
> Of course I buy all sorts of non-critical well made components/products from China. And they do a good job on things like the Iphone. But any commodity item like batteries is going to be a 'race to the bottom'.
>
> I've no certainty that K2 is any more robust, but one can hope. UL labs is still a good operation.

[JS]

I have used and charged two 10AH LiFePO4 batteries in parallel sans probleme.
Jim

On Tuesday, April 14, 2015 at 2:48:04 PM UTC-7, Ramy wrote:
>
> Can one charger charge two identical starkpower batteries in parallel?
>
> Ramy

[Charlie M. (UH & 002 owner/pilot)]

On Tuesday, April 14, 2015 at 5:48:04 PM UTC-4, Ramy wrote:
> On Tuesday, February 3, 2015 at 3:33:38 AM UTC-8, wrote:
> > We have been selling the Starkpower battery for more than a year now. Started out very cautiously - selling only a few to a few of our steady customers. We have now sold several hundred with no complaints. They really are great and are exactly the same size as the battery they replace.
> >
> > One caution is you must use the special charger (inexpensive) that shuts off when the battery reaches a fully charged state.
> >
> > Tom Knauff
> > Knauff & Grove, Inc
> > Ridge Soaring Gliderport
> >
> > www.eglider.org
>
> Can one charger charge two identical starkpower batteries in parallel?
>
> Ramy

You can, not really recommended. Typical in charging ANY batteries in parallel.

[Ron Gleason]

On Tuesday, 14 April 2015 15:48:04 UTC-6, Ramy wrote:
> On Tuesday, February 3, 2015 at 3:33:38 AM UTC-8, wrote:
> > We have been selling the Starkpower battery for more than a year now. Started out very cautiously - selling only a few to a few of our steady customers. We have now sold several hundred with no complaints. They really are great and are exactly the same size as the battery they replace.
> >
> > One caution is you must use the special charger (inexpensive) that shuts off when the battery reaches a fully charged state.
> >
> > Tom Knauff
> > Knauff & Grove, Inc
> > Ridge Soaring Gliderport
> >
> > www.eglider.org
>
> Can one charger charge two identical starkpower batteries in parallel?
>
> Ramy

Works for me with 2 K2 batteries. I sent you a picture

[Tango Eight]

On Tuesday, April 14, 2015 at 7:29:58 PM UTC-4, JS wrote:
> I have used and charged two 10AH LiFePO4 batteries in parallel sans probleme.
> Jim
>
> On Tuesday, April 14, 2015 at 2:48:04 PM UTC-7, Ramy wrote:
> >
> > Can one charger charge two identical starkpower batteries in parallel?
> >
> > Ramy

Please take questions of this sort to the manufacturer of *your* batteries. The right answer is going to depend on the details of internal construction. And there are going to be some cautions if not an outright admonishment against this.

LFP batteries have very low internal resistance, so batteries in different states of charge will pass a very large current when connected in parallel until their voltage is equalized. If your batteries are fused as they should be (right on the terminal), you stand a fair chance of blowing fuses if you hook together batteries in reasonably different states of charge.

Here's a *great* time to ignore the "well, it worked for me" replies. It'll work acceptably well right up to when it doesn't.

My $0.02.

Evan Ludeman / T8

[Dan Marotta]

....And the chargers are very inexpensive. I have 2 LiFePO4 batteries
and two chargers.

On 4/14/2015 5:44 PM, Tango Eight wrote:
> On Tuesday, April 14, 2015 at 7:29:58 PM UTC-4, JS wrote:
>> I have used and charged two 10AH LiFePO4 batteries in parallel sans probleme.
>> Jim
>>
>> On Tuesday, April 14, 2015 at 2:48:04 PM UTC-7, Ramy wrote:
>>> Can one charger charge two identical starkpower batteries in parallel?
>>>
>>> Ramy
> Please take questions of this sort to the manufacturer of *your* batteries. The right answer is going to depend on the details of internal construction. And there are going to be some cautions if not an outright admonishment against this.
>
> LFP batteries have very low internal resistance, so batteries in different states of charge will pass a very large current when connected in parallel until their voltage is equalized. If your batteries are fused as they should be (right on the terminal), you stand a fair chance of blowing fuses if you hook together batteries in reasonably different states of charge.
>
> Here's a *great* time to ignore the "well, it worked for me" replies. It'll work acceptably well right up to when it doesn't.
>
> My $0.02.
>
> Evan Ludeman / T8

--
Dan Marotta

[Ron Gleason]

On Tuesday, 14 April 2015 17:44:48 UTC-6, Tango Eight wrote:
> On Tuesday, April 14, 2015 at 7:29:58 PM UTC-4, JS wrote:
> > I have used and charged two 10AH LiFePO4 batteries in parallel sans probleme.
> > Jim
> >
> > On Tuesday, April 14, 2015 at 2:48:04 PM UTC-7, Ramy wrote:
> > >
> > > Can one charger charge two identical starkpower batteries in parallel?
> > >
> > > Ramy
>
> Please take questions of this sort to the manufacturer of *your* batteries. The right answer is going to depend on the details of internal construction. And there are going to be some cautions if not an outright admonishment against this.
>
> LFP batteries have very low internal resistance, so batteries in different states of charge will pass a very large current when connected in parallel until their voltage is equalized. If your batteries are fused as they should be (right on the terminal), you stand a fair chance of blowing fuses if you hook together batteries in reasonably different states of charge.
>
> Here's a *great* time to ignore the "well, it worked for me" replies. It'll work acceptably well right up to when it doesn't.
>
> My $0.02.
>
> Evan Ludeman / T8

Damn you Evan, the voice of reason and logic. I just checked K2 website and nothing posted but a charger is only $40. Seems to be cheap insurance for for $125+ battery.

No an excuse but this is the setup that came with the plane I bought. Buy beware but I should have known that.

[Ron Gleason]

On Tuesday, 14 April 2015 17:44:48 UTC-6, Tango Eight wrote:
> On Tuesday, April 14, 2015 at 7:29:58 PM UTC-4, JS wrote:
> > I have used and charged two 10AH LiFePO4 batteries in parallel sans probleme.
> > Jim
> >
> > On Tuesday, April 14, 2015 at 2:48:04 PM UTC-7, Ramy wrote:
> > >
> > > Can one charger charge two identical starkpower batteries in parallel?
> > >
> > > Ramy
>
> Please take questions of this sort to the manufacturer of *your* batteries. The right answer is going to depend on the details of internal construction. And there are going to be some cautions if not an outright admonishment against this.
>
> LFP batteries have very low internal resistance, so batteries in different states of charge will pass a very large current when connected in parallel until their voltage is equalized. If your batteries are fused as they should be (right on the terminal), you stand a fair chance of blowing fuses if you hook together batteries in reasonably different states of charge.
>
> Here's a *great* time to ignore the "well, it worked for me" replies. It'll work acceptably well right up to when it doesn't.
>
> My $0.02.
>
> Evan Ludeman / T8

Damn you Evan, presenting common sense and logic. I looked on the K2 website and nothing mentioned about charging in parallel. However chargers are $50 buck, cheap insurance.

Not an excuse but this setup came with the plane I acquired. Buyer beware, but I should have checked the setup. yup ordered a second charger today. Thanks Evan.

Ron

[Tango Eight]

On Tuesday, April 14, 2015 at 8:23:29 PM UTC-4, Ron Gleason wrote:
> On Tuesday, 14 April 2015 17:44:48 UTC-6, Tango Eight wrote:
> > On Tuesday, April 14, 2015 at 7:29:58 PM UTC-4, JS wrote:
> > > I have used and charged two 10AH LiFePO4 batteries in parallel sans probleme.
> > > Jim
> > >
> > > On Tuesday, April 14, 2015 at 2:48:04 PM UTC-7, Ramy wrote:
> > > >
> > > > Can one charger charge two identical starkpower batteries in parallel?
> > > >
> > > > Ramy
> >
> > Please take questions of this sort to the manufacturer of *your* batteries. The right answer is going to depend on the details of internal construction. And there are going to be some cautions if not an outright admonishment against this.
> >
> > LFP batteries have very low internal resistance, so batteries in different states of charge will pass a very large current when connected in parallel until their voltage is equalized. If your batteries are fused as they should be (right on the terminal), you stand a fair chance of blowing fuses if you hook together batteries in reasonably different states of charge.
> >
> > Here's a *great* time to ignore the "well, it worked for me" replies. It'll work acceptably well right up to when it doesn't.
> >
> > My $0.02.
> >
> > Evan Ludeman / T8
>
> Damn you Evan, presenting common sense and logic. I looked on the K2 website and nothing mentioned about charging in parallel. However chargers are $50 buck, cheap insurance.
>
> Not an excuse but this setup came with the plane I acquired. Buyer beware, but I should have checked the setup. yup ordered a second charger today.. Thanks Evan.
>
> Ron

No trouble!

So the next consideration is switching in flight. Same concerns apply...

I've never been able to figure out a good way to get a back up battery in my 20, so I have just one big honking 12AH battery. But if I had a dual LFP battery system, I'd use (appropriately rated) low voltage drop diodes to prevent back feeding the low battery with some mongo current during switchover. With my luck, I'd blow the fuse on my good battery....

-Evan / T8

[Ron Gleason]

On Tuesday, 14 April 2015 18:41:54 UTC-6, Tango Eight wrote:
> On Tuesday, April 14, 2015 at 8:23:29 PM UTC-4, Ron Gleason wrote:
> > On Tuesday, 14 April 2015 17:44:48 UTC-6, Tango Eight wrote:
> > > On Tuesday, April 14, 2015 at 7:29:58 PM UTC-4, JS wrote:
> > > > I have used and charged two 10AH LiFePO4 batteries in parallel sans probleme.
> > > > Jim
> > > >
> > > > On Tuesday, April 14, 2015 at 2:48:04 PM UTC-7, Ramy wrote:
> > > > >
> > > > > Can one charger charge two identical starkpower batteries in parallel?
> > > > >
> > > > > Ramy
> > >
> > > Please take questions of this sort to the manufacturer of *your* batteries. The right answer is going to depend on the details of internal construction. And there are going to be some cautions if not an outright admonishment against this.
> > >
> > > LFP batteries have very low internal resistance, so batteries in different states of charge will pass a very large current when connected in parallel until their voltage is equalized. If your batteries are fused as they should be (right on the terminal), you stand a fair chance of blowing fuses if you hook together batteries in reasonably different states of charge.
> > >
> > > Here's a *great* time to ignore the "well, it worked for me" replies. It'll work acceptably well right up to when it doesn't.
> > >
> > > My $0.02.
> > >
> > > Evan Ludeman / T8
> >
> > Damn you Evan, presenting common sense and logic. I looked on the K2 website and nothing mentioned about charging in parallel. However chargers are $50 buck, cheap insurance.
> >
> > Not an excuse but this setup came with the plane I acquired. Buyer beware, but I should have checked the setup. yup ordered a second charger today. Thanks Evan.
> >
> > Ron
>
> No trouble!
>
> So the next consideration is switching in flight. Same concerns apply...
>
> I've never been able to figure out a good way to get a back up battery in my 20, so I have just one big honking 12AH battery. But if I had a dual LFP battery system, I'd use (appropriately rated) low voltage drop diodes to prevent back feeding the low battery with some mongo current during switchover. With my luck, I'd blow the fuse on my good battery....
>
> -Evan / T8

Switching in flight is covered, similar to what you describe. I have the opposite situation; currently 2 batteries but ability to add 2 more (front of stick and in tail) that are wired and plumbed.

Thanks Evan

[Dave Leonard]

From the StarkPower website:
"Unlimited packs in parallel at 12V but only with individual 12V chargers on each battery."

http://www.starkpower.com/spnews/energystoragebatt/

On Tuesday, April 14, 2015 at 6:41:54 PM UTC-6, Tango Eight wrote:
> On Tuesday, April 14, 2015 at 8:23:29 PM UTC-4, Ron Gleason wrote:
> > On Tuesday, 14 April 2015 17:44:48 UTC-6, Tango Eight wrote:
> > > On Tuesday, April 14, 2015 at 7:29:58 PM UTC-4, JS wrote:
> > > > I have used and charged two 10AH LiFePO4 batteries in parallel sans probleme.
> > > > Jim
> > > >
> > > > On Tuesday, April 14, 2015 at 2:48:04 PM UTC-7, Ramy wrote:
> > > > >
> > > > > Can one charger charge two identical starkpower batteries in parallel?
> > > > >
> > > > > Ramy
> > >
> > > Please take questions of this sort to the manufacturer of *your* batteries. The right answer is going to depend on the details of internal construction. And there are going to be some cautions if not an outright admonishment against this.
> > >
> > > LFP batteries have very low internal resistance, so batteries in different states of charge will pass a very large current when connected in parallel until their voltage is equalized. If your batteries are fused as they should be (right on the terminal), you stand a fair chance of blowing fuses if you hook together batteries in reasonably different states of charge.
> > >
> > > Here's a *great* time to ignore the "well, it worked for me" replies. It'll work acceptably well right up to when it doesn't.
> > >
> > > My $0.02.
> > >
> > > Evan Ludeman / T8
> >
> > Damn you Evan, presenting common sense and logic. I looked on the K2 website and nothing mentioned about charging in parallel. However chargers are $50 buck, cheap insurance.
> >
> > Not an excuse but this setup came with the plane I acquired. Buyer beware, but I should have checked the setup. yup ordered a second charger today. Thanks Evan.
> >
> > Ron
>
> No trouble!
>
> So the next consideration is switching in flight. Same concerns apply...
>
> I've never been able to figure out a good way to get a back up battery in my 20, so I have just one big honking 12AH battery. But if I had a dual LFP battery system, I'd use (appropriately rated) low voltage drop diodes to prevent back feeding the low battery with some mongo current during switchover. With my luck, I'd blow the fuse on my good battery....
>
> -Evan / T8

[Clay[_4_]]

"So the next consideration is switching in flight. Same concerns apply..."

Yikes, I switched from 2 lead acids to 2 LFPs, and I seriously doubt I have low voltage drop diodes in there. Is this like a Schottky Diode? https://www.sparkfun.com/products/10926. I take it the BMS or whatever it's called in the K2s doesn't manage this. Thanks for the heads up Evan.

[Tango Eight]

On Tuesday, April 14, 2015 at 9:16:30 PM UTC-4, Clay wrote:
> "So the next consideration is switching in flight. Same concerns apply...."
>
> Yikes, I switched from 2 lead acids to 2 LFPs, and I seriously doubt I have low voltage drop diodes in there. Is this like a Schottky Diode? https://www.sparkfun.com/products/10926. I take it the BMS or whatever it's called in the K2s doesn't manage this. Thanks for the heads up Evan.

You want to use components rated for more than one amp :-), but right idea. I don't have specific recommendations, but troll the Mouser(.com) catalog or equivalent.

Trying to get good data on what these bms boards do is tough (or was, last I looked). But most will source quite a bit of current. DC doesn't switch worth a crap either... interrupting a high current DC load is *really* hard on switch contacts and best avoided.

-Evan / T8

[[email protected][_1_]]

Here is my e-mail conversation with the TechRep at K2.


I want to wire two 12v10aH K2 batteries in a parallel circuit to yield a 12v20aH pack. Is this acceptable? Will a single K2 charger charge both batteries simultaneously?

Great product!

Thanks, Mark



Yes, you can wire them in parallel and still use our charger to charge them up. Note, if you are dealing with high amperage, the parallel wiring doesn't mean double the max amperage.


Best Regards,

Mark Stoker

K2 Energy Solutions, Inc.

[Charlie M. (UH & 002 owner/pilot)]

On Tuesday, April 14, 2015 at 11:53:31 PM UTC-4, wrote:
> Here is my e-mail conversation with the TechRep at K2.
>
>
> I want to wire two 12v10aH K2 batteries in a parallel circuit to yield a 12v20aH pack. Is this acceptable? Will a single K2 charger charge both batteries simultaneously?
>
> Great product!
>
> Thanks, Mark
>
>
>
> Yes, you can wire them in parallel and still use our charger to charge them up. Note, if you are dealing with high amperage, the parallel wiring doesn't mean double the max amperage.
>
>
> Best Regards,
>
> Mark Stoker
>
> K2 Energy Solutions, Inc.

Running 2 batteries always connected in parallel is/can be a bit different than having 2 batteries charged off a single charger in parallel.
A lot comes down to the state of charge in each battery when you start charging them as well as what (if any) circuitry is inside the battery.

[Clay[_4_]]

"DC doesn't switch worth a crap either... interrupting a high current DC load is *really* hard on switch contacts and best avoided."

Better to get rid of switch entirely and just install a diode for each battery?

[Tango Eight]

On Wednesday, April 15, 2015 at 1:03:37 PM UTC-4, Clay wrote:
> "DC doesn't switch worth a crap either... interrupting a high current DC load is *really* hard on switch contacts and best avoided."
>
> Better to get rid of switch entirely and just install a diode for each battery?

With diodes on each master circuit, you prevent back-feeding the discharged battery and the high current problem goes away. Keep the switches.

best,
Evan

[Dan Marotta]

I have two LiFePO4 batteries and two toggle switches. When it's time to
switch I simply turn on the second switch and turn off the first.
Click, click - it takes about as long to do it as to say, "click,
click". No problems.

On 4/14/2015 6:41 PM, Tango Eight wrote:
> On Tuesday, April 14, 2015 at 8:23:29 PM UTC-4, Ron Gleason wrote:
>> On Tuesday, 14 April 2015 17:44:48 UTC-6, Tango Eight wrote:
>>> On Tuesday, April 14, 2015 at 7:29:58 PM UTC-4, JS wrote:
>>>> I have used and charged two 10AH LiFePO4 batteries in parallel sans probleme.
>>>> Jim
>>>>
>>>> On Tuesday, April 14, 2015 at 2:48:04 PM UTC-7, Ramy wrote:
>>>>> Can one charger charge two identical starkpower batteries in parallel?
>>>>>
>>>>> Ramy
>>> Please take questions of this sort to the manufacturer of *your* batteries. The right answer is going to depend on the details of internal construction. And there are going to be some cautions if not an outright admonishment against this.
>>>
>>> LFP batteries have very low internal resistance, so batteries in different states of charge will pass a very large current when connected in parallel until their voltage is equalized. If your batteries are fused as they should be (right on the terminal), you stand a fair chance of blowing fuses if you hook together batteries in reasonably different states of charge.
>>>
>>> Here's a *great* time to ignore the "well, it worked for me" replies. It'll work acceptably well right up to when it doesn't.
>>>
>>> My $0.02.
>>>
>>> Evan Ludeman / T8
>> Damn you Evan, presenting common sense and logic. I looked on the K2 website and nothing mentioned about charging in parallel. However chargers are $50 buck, cheap insurance.
>>
>> Not an excuse but this setup came with the plane I acquired. Buyer beware, but I should have checked the setup. yup ordered a second charger today. Thanks Evan.
>>
>> Ron
> No trouble!
>
> So the next consideration is switching in flight. Same concerns apply...
>
> I've never been able to figure out a good way to get a back up battery in my 20, so I have just one big honking 12AH battery. But if I had a dual LFP battery system, I'd use (appropriately rated) low voltage drop diodes to prevent back feeding the low battery with some mongo current during switchover. With my luck, I'd blow the fuse on my good battery....
>
> -Evan / T8

--
Dan Marotta

[Tango Eight]

On Wednesday, April 15, 2015 at 4:21:29 PM UTC-4, Dan Marotta wrote:
> I have two LiFePO4 batteries and two toggle switches.* When it's
> time to switch I simply turn on the second switch and turn off the
> first.* Click, click - it takes about as long to do it as to say,
> "click, click".* No problems.
>

Run your first battery down to 11.5 V, then put an ammeter in line and let us know what the surge looks like when you switch in the second battery (at full capacity). I'm genuinely curious.

-Evan

[JS]

All commercially available "SLA replacement" LiFePO4 batteries have overcharge and over-discharge protection.
From my experience, if run in parallel they will have the same voltage. After a typical 5-hour flight with a full panel running, about 12V.
Charging two similarly discharged batteries in parallel worked well, but the chargers I was using at the time didn't quite have the voltage required for LiFePO4. I now use separate chargers that came with the batteries from Tenergy.
But underneath the workbench the glider batteries charge on, there's a bank of eight AGM batteries running the inverter/UPS on the entire house. They're running at 48V in series/parallel, under constant charge and discharge.
Adding a diode to your batteries will prevent your Strobl Solar system from charging them in flight. Discovered the solar panels unnecessary with LiFePO4.
Jim