battery power regulator

An advertisement in QST magazine caught my eye and I wonder if some one
has used something similar to this in gliders(we don't need 25 Amps at
12 Volts):
http://www.mfjenterprises.com/Produc...ctid=MFJ-4416B
The idea is to keep the voltage supplied to your electrics constant even
if the battery voltage drops to as low as 9 Volts (in the above example).

Tony LS6-b "6N"

On 7/27/11 7:02 PM, Tony V wrote:
An advertisement in QST magazine caught my eye and I wonder if some one
has used something similar to this in gliders(we don't need 25 Amps at
12 Volts):
http://www.mfjenterprises.com/Produc...ctid=MFJ-4416B
The idea is to keep the voltage supplied to your electrics constant even
if the battery voltage drops to as low as 9 Volts (in the above example).

Tony LS6-b "6N"

Tony

With modern avionics/electronics you really should not need this. Modern
radios, transponders, etc. have built in switch mode power supplies that
effectively do the same as this device does, but usually more
efficiently. These approaches are really only something to consider if
you have some legacy piece of electronics that is very sensitive to
voltage -- and often in those cases a bigger battery (if possible) is a
better solution.

Another minor downside of these type devices is the apparent sudden loss
of power - but that's solved by monitoring the raw battery voltage.

Darryl

On 7/28/2011 3:52 PM, Darryl Ramm wrote:
On 7/27/11 7:02 PM, Tony V wrote:
An advertisement in QST magazine caught my eye and I wonder if some one
has used something similar to this in gliders(we don't need 25 Amps at
12 Volts):
http://www.mfjenterprises.com/Produc...ctid=MFJ-4416B
The idea is to keep the voltage supplied to your electrics constant even
if the battery voltage drops to as low as 9 Volts (in the above example).

Tony LS6-b "6N"

Tony

With modern avionics/electronics you really should not need this. Modern
radios, transponders, etc. have built in switch mode power supplies that
effectively do the same as this device does, but usually more
efficiently.

Thanks, Darrell. The reason that I ask is that after flying for a few
hours with a new 9Ahr battery, the LCDs on my radio (Dittel FSG71M)
blank out when I transmit - which gets out OK. Other than the radio, I'm
only running a Cambridge 302 and an iPaq.

Tony V.

On 7/29/11 4:51 PM, Tony V wrote:

With modern avionics/electronics you really should not need this. Modern
radios, transponders, etc. have built in switch mode power supplies that
effectively do the same as this device does, but usually more
efficiently.

Thanks, Darrell. The reason that I ask is that after flying for a few
hours with a new 9Ahr battery, the LCDs on my radio (Dittel FSG71M)
blank out when I transmit - which gets out OK. Other than the radio, I'm
only running a Cambridge 302 and an iPaq.

Tony V.

Its hard to see what would be drawing so much power to drop the Dittel
below its speced operating voltage. There was a recall/repair on some of
these radios but I though that only affected the RF board, not sure that
could affect the display like this but I don't know. Was yours affected?
- check here http://www.cumulus-soaring.com/dittel.htm Other Dittel
users can comment if they ever see this display problem at reasonable
supply voltages. I've never owned a Dittel radio.

I'd want to check that the 9Ah battery is not faulty or not getting
fully charged (the charger may be faulty or incorrectly sized etc),
something else/hidden is drawing power or the Ditel has a problem.

It would be nice to do a discharge test on the battery after charging it
as you normally would and see exactly what power it is storing. You can
do this maually but much easier with a discharge tester like the West
Mountain Radio CBT III. Improper charging is not an uncommon
problem-check your charger is the right type, and sized for the battery
and if it has indicators for charge/complete or float stage do they show
as expected (and you still need to leave the battery on charge for many
hours after that to top up the last ~10% or so). But if you can't do
that at least measure the current your equipment is drawing and measure
the voltage under load (all avionics on and transmit key pressed) when
the Ditel starts misbehaving. I have numbers for common toys including
the C302 etc. in slides at http://www.darryl-ramm.com/glider-batteries
I think the radios are speced down to 9V and may work even lower, and
with your setup just should not have problem after only a few hours.

You would not be the first person to have something hidden behind the
panel that is consuming power. Some PDAs can suck interesting amounts of
power ( transponder) esp. if they have a large Li extended battery
packs that are connected to the ship when discharged. A poorly designed
PDA chargers might be very inefficient (but most are not). Still noe of
these alone would really explain this. Maybe you have several things
goign on. Certainly measure the current draw with everything turned on
and see if it makes sense with what is in my slides. Also measure the
current of each device.

Darryl

Tony,

I am with Darryl on this, with your seemingly modern electronics and a new
9AH battery, you "should not be having a problem". But of course you do
apparently seem to be having an problem. I say apparently as you say your
Dittel display disappears when you transmit but it still "... gets out
OK...". This seems like a problem with your radio, not with your battery
or wiring. But here are some other ideas.

What is the gauge of your wiring from the battery to your instrument panel?
If you are using small gauge wiring, and drawing considerable amps when
transmitting, then the voltage can drop considerably between the battery
and your radio. I use 12ga wiring. 14ga generally works just fine.
Anything smaller and you are throwing away voltage, which we glider pilots
cannot afford. So measure the voltage of your power system at the radio
when you hit the transmit key. If the voltage drops considerably (i.e.
from 12.5VDC to 11.5VDC) then you either have a wiring/connection issue or
your battery is bad. BTW: Only use Tefzel wiring in aircraft:
http://wingsandwheels.com/tefzel_coa...kers_louds.htm.

Battery Testing - Testing your batteries each year is a good idea. Darryl
mentions a very nice battery tester which does a quick job of determining
good from bad. Unfortunately, it costs $150 which is a bit steep for a
once a year effort. So here is my (slow) poor man battery testing method
that should not cost more than $10-$15:
http://aviation.derosaweb.net/#batterytest

Good luck.


Enjoy, John DeRosa
johnatderosaweb.com

On 7/31/2011 10:58 PM, John Derosa wrote:
Tony,

I am with Darryl on this, with your seemingly modern electronics and a new
9AH battery, you "should not be having a problem". But of course you do
apparently seem to be having an problem. I say apparently as you say your
Dittel display disappears when you transmit but it still "... gets out
OK...". This seems like a problem with your radio, not with your battery
or wiring.

So it appears. When it happened again today, I switched the 302 to the
battery voltage screen and when I was transmitting (with the blank LCD
display), the 302 was registering 11.6 volts. So, it appears that I have
a radio or wiring problem.

What is the gauge of your wiring from the battery to your instrument panel?
If you are using small gauge wiring, and drawing considerable amps when
transmitting, then the voltage can drop considerably between the battery
and your radio. I use 12ga wiring. 14ga generally works just fine.
Anything smaller and you are throwing away voltage, which we glider pilots
cannot afford. So measure the voltage of your power system at the radio
when you hit the transmit key. If the voltage drops considerably (i.e.
from 12.5VDC to 11.5VDC) then you either have a wiring/connection issue or
your battery is bad. BTW: Only use Tefzel wiring in aircraft:
http://wingsandwheels.com/tefzel_coa...kers_louds.htm.

I will be checking the wiring to the radio very closely.

Battery Testing - Testing your batteries each year is a good idea. Darryl
mentions a very nice battery tester which does a quick job of determining
good from bad. Unfortunately, it costs $150 which is a bit steep for a
once a year effort. So here is my (slow) poor man battery testing method
that should not cost more than $10-$15:
http://aviation.derosaweb.net/#batterytest

This is nice. I typically test by putting a 1 Amp load on the battery
(using a 1156 automotive light bulb). My charger is an
accumate(http://www.accumate.com/612/), which IMHO is quite good.

Thanks for the advice!

Tony, LS6-b "6N"

In article Tony V writes:
An advertisement in QST magazine caught my eye and I wonder if some one
has used something similar to this in gliders(we don't need 25 Amps at
12 Volts):
http://www.mfjenterprises.com/Produc...ctid=MFJ-4416B
The idea is to keep the voltage supplied to your electrics constant even
if the battery voltage drops to as low as 9 Volts (in the above example).

Tony LS6-b "6N"


You might want to read the reviews at http://www.eham.net/reviews/detail/7504
first. I would want to test it extensively on the ground before I tried one
in an aircraft.

Unfortunately, in looking for other products that do the same thing, the
reviews I have found have been no better.


Alan

On Wed, 27 Jul 2011 22:02:14 -0400, Tony V wrote:

An advertisement in QST magazine caught my eye and I wonder if some one
has used something similar to this in gliders(we don't need 25 Amps at
12 Volts):
http://www.mfjenterprises.com/Produc...ctid=MFJ-4416B The idea
is to keep the voltage supplied to your electrics constant even if the
battery voltage drops to as low as 9 Volts (in the above example).

Assuming you're using it to maintain 12v off a nominally 12v battery, the
only problem I'd see is that once the battery drops below about 11.5v
there's not a lot left in it. Maintaining 12v out of the black box is
probably going to suck the last juice out of the battery pretty fast. Add
on the 90% efficiency of the thing and merely by fitting it you've just
increased your power drain by 11%. Bottom line: I wouldn't use one this
way because I don't think it would help much.

However, if you want to run a higher voltage device off a 12v battery,
its a good idea.

I carry a 28v R C Allen turn & slip in my Libelle, which uses a solid
state 12v = 28v converter in its power cable. This works perfectly. The
device is tiny - a single PCB inside heat-shrink tube and about 40mm x
15mm, so I haven't seen what on the board. However, I'd lay long odds
that it contains a Maxim step-up voltage switching regulator, say a MAX
1771, a power MOSFET and 6 passive components.

http://www.maxim-ic.com/datasheet/index.mvp/id/1030

The MAX1771 can handle up to 2 amps and costs $US 3.55 - that is a Buy It
Now price on eBay, so I'd guess you could have a working voltage
converter for $8 or less - say 12 bucks if you sprung for input and
output connectors rather than simply soldering the wires on.

At that price I'd also try using one to power a 14v radio off a 12v
battery rather than adding an extra 2v cell.


--
martin@ | Martin Gregorie
gregorie. | Essex, UK
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