On board battery(ies) for powering radios/Flarm etc

Just a quick question.
Had a brainstorm the other day, might have hit my head, don't remember, who knows...

What are y'all using for on board power these days?

Last I flew, we were using 6? amp hour gel cells by Hobbico from Tower Hobbies. (The kind that powered the little Powerwheels Jeep your kid/grandkid rode in 20 years ago)

What kind of power capacity are folks using?

I was working my big a$$ Milwaukee 10" chop saw and saw how compact the 18v, 9 amp LiPo was, and how fast it charged on the included rapid charger and got to thinking 1, 2 or 3 of those on a semi-custom mount with built in voltage regulator would be right dandy in these birds, and available at the big orange box store if a replacement is needed in a hurry.

Just a thought. Please return to your regularly scheduled mayhem.

Neal,

I think there are still a lot of pilot using Sealed Lead Acid (SLA) batteries in their glider. It works OK for gliders that maybe have an electronic Vario and a radio.

As you add other electric devices, especially a transponder, the capacity demands go up. You can get SLA batteries with 12-15AH capacity, but many ships are equipped with Lithium/Iron/Phosphate (LiFePo) chemistry batteries.

Most of the sailplane accessory distributors have them in stock, for example:

http://craggyaero.com/lifepo4_battery1.htm

Hope that helps,

Mike

On Monday, October 12, 2020 at 7:26:11 PM UTC-7, Michael Bamberg wrote:
Neal,

I think there are still a lot of pilot using Sealed Lead Acid (SLA) batteries in their glider. It works OK for gliders that maybe have an electronic Vario and a radio.

As you add other electric devices, especially a transponder, the capacity demands go up. You can get SLA batteries with 12-15AH capacity, but many ships are equipped with Lithium/Iron/Phosphate (LiFePo) chemistry batteries.

Most of the sailplane accessory distributors have them in stock, for example:

http://craggyaero.com/lifepo4_battery1.htm

Hope that helps,

Mike

Test Graph is include with every LIFEPO4 Battery sold by Craggy Aero.

Richard
www.craggyaero.com

Thanks for that link. Price is decent, under a $100 for a 10 amp hour battery. I think I could easily over double that capacity with a couple power tool batteries in the same cubic space, however, the cost would be 4 times that.

LiPo tech has come a Looooooong way in the last 5 years. I cannot recall hearing about a LiPo combusting during use in a long time. Even at the ultra high amp draws I use in my chop saw, the batteries dont even get warm.

I was always anti-battery power tool until my first Milwaukee impact driver/hammer drill set 2 years ago. I have spent the last year renovating my house and upgrading all my tools. I am nearly 100% cordless now. I just had a wild idea that perhaps some of this new battery tech can come the way of soaring. I wasn't sure if anyone else was out there doing it.

Neal Alders wrote on 10/13/2020 10:56 AM:
Thanks for that link. Price is decent, under a $100 for a 10 amp hour battery. I think I could easily over double that capacity with a couple power tool batteries in the same cubic space, however, the cost would be 4 times that.

LiPo tech has come a Looooooong way in the last 5 years. I cannot recall hearing about a LiPo combusting during use in a long time. Even at the ultra high amp draws I use in my chop saw, the batteries dont even get warm.

I was always anti-battery power tool until my first Milwaukee impact driver/hammer drill set 2 years ago. I have spent the last year renovating my house and upgrading all my tools. I am nearly 100% cordless now. I just had a wild idea that perhaps some of this new battery tech can come the way of soaring. I wasn't sure if anyone else was out there doing it.

Instrument power is easily and cheaply solved with several brands of LiFe 12 volt batteries.
What we'd really like to see is better batteries for electric sailplanes (aka "traction
batteries"), specially more energy/mass and lower cost. Smaller would be useful, too, but not
nearly so much.

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
- "A Guide to Self-Launching Sailplane Operation"
https://sites.google.com/site/motorg...ad-the-guide-1

Im waiting for Super Capacitors to get perfected. I think LiPo and brushless batteries have made significant strides, and Super Capacitors would further that another generation of capability in electric powered aircraft.

Speaking of which,

Anyone know anything about this side by side self launch 15 meter bird, the Pipstrel Taurus? Electric or gas power?

On Monday, October 12, 2020 at 10:10:18 PM UTC-4, wrote:

What kind of power capacity are folks using?

Most popular are lithium iron phosphate (LFP) batteries in same form factor as those old 6AH SLAs, now typically with 9 - 10 AH capacity. Decent quality examples last for years and years with little change in capacity... and your radio still transmits
from the wave at -20C at 10% state of charge (however, do not recharge until battery warms up).

Modern (Chinese) SLAs are of poor quality, not nearly as good as what we had (at higher cost) from Western manufacturers in 1990s.

(btw, try the search function, works great, will return hours of reading on this very topic)

T8

Yes, I also looked longingly at the tool batteries as well. A 3d printer could make a holder/connector and there are plenty of demo boards around for switching powersupplies to make 12V.

But I decided to go with three K2's. So far I've never used the third K2.

They were already tested and in the physical and electrical form the glider expects.
LiFePo seemed more forgiving than LiIon.
I'd rather not divert the hobby from flying to building battery systems.
It seemed a thing that would be fun and easy to get close, but tricky to get right.

If the K2's didn't work so well, it might be a different story.

On Tuesday, October 13, 2020 at 9:35:47 AM UTC-4, wrote:
Yes, I also looked longingly at the tool batteries as well. A 3d printer could make a holder/connector and there are plenty of demo boards around for switching powersupplies to make 12V.

But I decided to go with three K2's. So far I've never used the third K2..

They were already tested and in the physical and electrical form the glider expects.
LiFePo seemed more forgiving than LiIon.
I'd rather not divert the hobby from flying to building battery systems.
It seemed a thing that would be fun and easy to get close, but tricky to get right.

If the K2's didn't work so well, it might be a different story.

And tricky to keep a home-made kludge safe. Other types of lithium batteries are prone to spontaneous combustion. You don't want a fire in flight! A ready-made LFP battery, with a built-in circuit protecting it from over-current etc, in a proper case that fits in your glider, can now be bought for around $40 - hardly more expensive than an old-tech SLA. It's a no-brainer.

Also keep in mind that AFAIK power tool batteries (certainly the Milwaukee) have no intelligence - all the BMS functions are built into the charger and tools. So you have a volatile, uncontrolled LiPo sitting behind your head.. You can get the same AH in a well constructed, controlled LiFePo4 for the same or less money.
On Tuesday, October 13, 2020 at 7:21:25 AM UTC-7, wrote:
On Tuesday, October 13, 2020 at 9:35:47 AM UTC-4, wrote:
Yes, I also looked longingly at the tool batteries as well. A 3d printer could make a holder/connector and there are plenty of demo boards around for switching powersupplies to make 12V.

But I decided to go with three K2's. So far I've never used the third K2.

They were already tested and in the physical and electrical form the glider expects.
LiFePo seemed more forgiving than LiIon.
I'd rather not divert the hobby from flying to building battery systems..
It seemed a thing that would be fun and easy to get close, but tricky to get right.

If the K2's didn't work so well, it might be a different story.
And tricky to keep a home-made kludge safe. Other types of lithium batteries are prone to spontaneous combustion. You don't want a fire in flight! A ready-made LFP battery, with a built-in circuit protecting it from over-current etc, in a proper case that fits in your glider, can now be bought for around $40 - hardly more expensive than an old-tech SLA. It's a no-brainer..