Hey Guys,

Plan on using this on my car battery for first time tomorrow, whats the most amps I should try with that setup? Wasn't planning on needing more than 10-15 amps, but its for a 6S 5000 mah lipo battery.

Can my car battery handle that?

Thanks,

BK

Originally Posted by bkent100

Hey Guys,

Plan on using this on my car battery for first time tomorrow, whats the most amps I should try with that setup? Wasn't planning on needing more than 10-15 amps, but its for a 6S 5000 mah lipo battery.

Can my car battery handle that?

Thanks,

BK

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Yes, but not for long. . .
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http://www.windsun.com/Batteries/Battery_FAQ.htm
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I killed two truck batteries last year. They don't die until the coldest day of the winter. . .
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YMMV
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Originally Posted by klhoard

They don't die until the coldest day of the year

and usally quite suddenly, far from home. Killed a few regular car batteries in my day. Now I leave the car battery to the car and power the charger some other way, pb battery, DC supply, generator.

BK

Both of the above post gave you sound advise. To charge a 6S 5000 will required approx. 10 AH from your auto battery which is designed to supply perhaps 2Ah at most between charges.

Only way I would use a regular auto starting battery to charge such a relatively large LiPoly would be with the engine running and then I would start the engine before connecting the charger and leave it running during the charge.

Charles

Originally Posted by Gregor99

and usally quite suddenly, far from home. Killed a few regular car batteries in my day. Now I leave the car battery to the car and power the charger some other way, pb battery, DC supply, generator.

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But at least they died in a crowded parking lot, behind the security gate at work, and temps were 15F with blowing snow . . . So I had THAT going for me!! . .
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2 X F-250 diesel truck batteries (installed) - $476.00
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1 X El-Cheapo 1500 Watt Generator from Tractor Supply $199.00 + tax
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Who said that education was cheap?!?!?
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Originally Posted by everydayflyer

. . .<snip>. . .
Only way I would use a regular auto starting battery to charge such a relatively large LiPoly would be with the engine running and then I would start the engine before connecting the charger and leave it running during the charge.

Charles

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Hopefully an automotive professional can back me up here, but I believe you can also damage the alternator on your car if you draw too many amps from it. One thing I AM sure of is that the PL8 is capable of drawing alot of juice if it wants it . . .
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You're using a 12 volt system to charge a 21 volt (5S x 4.2V) battery, so to charge at 5 amps (1C), the PL8 must step up that voltage from 12V to 21V. Since energy doesn't come from nowhere, the PL8 must draw much more than 5 amps on the 12 volt input side to create the 21 volts at 5 amps on the output side to charge your 5S-5000 battery. Now if you're charging at the Auto 3.0C rate (and Parallel charging!!), you can see that the PL8 can start demanding an exponential amount of amperage (in the 1.21 GigaWatt range . . do you drive a DeLorian?) from your poor little alternator that was only designed to top off your auto battery after each start and keep your radio working.
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That is why you will see guys charging the smaller (<12V) LiPo's from their car batteries all day long with no consequences. Their chargers are charging a 2200 Mah LiPo at 2.2 amps, but drawing less than that from their car. However, when you go to a charger that needs to step up the voltage, it must also step up the amperage. . . What do the car guys say: "Cheap, Fast, Reliable - Pick Two"?
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Man, I am just the bearer of good news today, ain't I?
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If you don't want to lug a generator around, another good solution is to get one or two Marine Deep Cycle batteries, then go to a local RV dealer and have them set you up with a charging system that uses your car's alternator to slowly charge the deep cycles but won't allow them to discharge your automotive battery or draw too much off of your alternator except while charging. You can run the deep cycles down to 50% without damage, where your car battery needs to remain at 98% depth of charge.
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Hopefully an automotive professional can back me up here, but I believe you can also damage the alternator on your car if you draw too many amps from it. .

True but not likely with most full size ,fully equiped autos these days. Most have 100 A plus alternators and using the PL8 V2 at approx. 14V means 560 watts output and with approx. 90% effecency appros. 616 watts input or apprxov 44 Amps. My 2001 Blazer Extreme will handle that at idle with the air conditiong running and the stereo cranked up.

My setup which has been posted and linked to numerious times is in fact two each 125 Ah flooded cells deep cycles mounted to a rack I build that is attached to the towing receptacal and yes they are connected thru a relay to the charging system and can be charged at 30 amps while engine is running.

https://www.rcgroups.com/forums/show...4#post15515324

https://www.rcgroups.com/forums/show...&postcount=847



Charles

Originally Posted by klhoard

.One thing I AM sure of is that the PL8 is capable of drawing alot of juice if it wants it .

One thing I AM sure of is you can limit the maximum current that the PL8 will draw from the supply source. You can also set low voltage limit as well so that you don't kill your car battery by draining too low.

Originally Posted by SteveM732

One thing I AM sure of is you can limit the maximum current that the PL8 will draw from the supply source. You can also set low voltage limit as well so that you don't kill your car battery by draining too low.

Bravo Steve!

Tim Marks

Problem is that limiting the max. amp that PL8 can draw IMO makes the likely hood of doing permanate damage to a starting Pb battery worse not better. The slower the Pb is discharged to X voltage the deeper it is discharged percentage wise of total capacity.

Run your car battery down with the starter (high amps. ) and the lights will still work , run it down with the lights and the starter will not even turn over.

The site linked to in post 3107 happens to be one I have linked to many times over the years. There is a very good chart there showing percentage of discharge versus no load voltage . Kind of a fuel % table for a Pb battery.

That chart shows that a Pb at 12.42 V no load is discharged approx. 20% . I bet many are driving vechiles with batteries that are this low after setting ovenight. A short drive to the field applies a surface charge and any charging from it will drop the remaining charge to a really damaging level. Set the PL8 to stop pulling juice at even 11.5 volts and the battery is still being over discharged and any charging at all will trigger the low voltage input limit.

Simple answer was given in post above.

Yes, but not for long. . .
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http://www.windsun.com/Batteries/Battery_FAQ.htm




Snipfrom the linked to battery facts site.:

Starting (sometimes called SLI, for starting, lighting, ignition) batteries are commonly used to start and run engines. Engine starters need a very large starting current for a very short time. Starting batteries have a large number of thin plates for maximum surface area. The plates are composed of a Lead "sponge", similar in appearance to a very fine foam sponge. This gives a very large surface area, but if deep cycled, this sponge will quickly be consumed and fall to the bottom of the cells. Automotive batteries will generally fail after 30-150 deep cycles if deep cycled, while they may last for thousands of cycles in normal starting use (2-5% discharge).

Deep cycle batteries are designed to be discharged down as much as 80% time after time, and have much thicker plates. The major difference between a true deep cycle battery and others is that the plates are SOLID Lead plates - not sponge. This gives less surface area, thus less "instant" power like starting batteries need. Although these an be cycled down to 20% charge, the best lifespan vs cost method is to keep the average cycle at about 50% discharge.

Charles

Can anyone confirm that the FUIM3 interface has a 5 pin mini B type connector?

Thanks.

Yes Standard USB to Mini same as used with numerious other chargers, digital camers,external HDs ,you name it. There are like 6 laying around on / connected to my computers..

Cheers.

I'm not getting an internal resistance measurement any longer (parallel charge)...I did in the past...I've tried it only once with lipo generic high power...I'll try it with others later.

Did a single pack with generic Lipo faster charge and the resistance measurement worked no problem.

Anyone else?

Originally Posted by Tim Marks

Hi:

Check the Tech Docs section of the revolectrix web site:

http://revolectrix.fmadirect.com/downloads.htm

Download the document "PL8 Application Note - Remote Control"

Tim Marks

My SW can now start/stop, choose preset, and monitor the battery.

Those who wish to see the progress can see it here:
http://code.google.com/p/pl8c/

Moving right along....
The tech docs don't cover a lot of things - like reading and setting presets, charger options etc...

Can we get a description of those?