Deep Cycle ?

[Bluefuzzyone]

I need to replace the 12 volt car battery I have been using to recharge my TP 6000 Lipo Batteries. Should I buy a regular car battery or a Deep Cycle Marine Battery that is used by the fishermen to run thier trolling motors, fish finders ,etc
:?


Tom

[DavidH]

I would get the Deep Cycle Marine battery. It is more suited to having a lot of current drawn from it between charges.

David

[Bluefuzzyone]

Thanks for the quick reply, I was pretty sure that was the way to go but a second expert opinion is always reasuring. :D

Tom

[PDC]

Forget batteries, get a generator.

[Gary JP4]

I would get the Deep Cycle Marine battery.

Yes. Regular 12 volt lead acid batteries do not hold up well to deep cycling. That is what you are doing when you run it down and then charge it back up. Sometimes they fail (have greatly reduced capacity) after only a couple of cycles. Like a car battery going bad after going dead once or twice.

[shagdad]

golf cart battery work great that"s what I use on my alternitve sys on my house and they always come back I also puls them with-- elec desulfator--

[xircom]

What's the capacity you guys are using ? I guess around 20Ah or so ?

[Teej]

20Ah is tiny. That's barely 1 charge on my flight pack. (10s5000)

You want at least a 75 or 100 Ah battery which will cost you $160...maybe $180. Or as someone else said, get a generator. $200 and you can run several chargers off it for hours on 1 gallon of gas (And it reminds you that electric power is not that clean - the pollution just runs somewhere else. ;) )

[kgfly]

Definitely get deep-cycle and you will need at least 100AH depending upon what batteries you want to charge.

Pb batteries are normally rated at 0.1C or 0.05C. So a 100AH deep-cycle battery will deliver close to 100AH at 5A load or less. That means about 30 x 2200 recharges or maybe 15 x 5000.

If you were to use a 20AH battery at 3A you might only get 3 to 5 charges out of it.

[xircom]

oh 100AH is very big ! maybe have to ask how you are using them ? I guess you will use them just for the afternoon or day when you go fly, and for the next time you would not only charge the lipos, but the deep cycle battery as well ?

[Teej]

Pb batteries are normally rated at 0.1C or 0.05C. So a 100AH deep-cycle battery will deliver close to 100AH at 5A load or less. That means about 30 x 2200 recharges or maybe 15 x 5000.


That's more or less true, assuming you're talking about 3s packs.

You'll get about half that on a 6s for a trex600, and I'd get 1/4 of that for my 10s flight packs...and that's assuming it's a spare battery that I don't need to start my car with.

Charging 10s (42v) at 5 amps is going to be pulling 17+ amps out of the source .

[redgiki]

Ouch. I was considering a 90aH deep-cycle marine battery for my field-charging needs, and realized that even my modest requirements would overtax it:

5 charging stations @ 2.1A and 12-ish volts (3S 2100mah packs) = ~11 amps constant, once you figure in losses.

(I use a Great Planes Polycharge 4 and Triton for my small packs)

Discharge is only 0.1C on a 90aH? Wow, that means with all my packs going, I'd be discharging faster than the C rating of the lead-acid battery, and slow down a lot. Looks like I need about 120-150aH for all-day flying.

No wonder most electric flyers don't like to field charge. Up until now, I've only field-charged off a generator, or just 1 or 2 packs off my little 20aH motorcycle battery in my Honda Insight...

[xircom]

about charging from car battery -> it says no charge from running car, why is that ?

[kgfly]

Cars when running are often at over 14V, if your charger is only rated to 12V input then that could be why.

[xircom]

I also heard, that generally charger of car-batteries are using pulsed voltages, maybe the car alternator using the same for charging the battery when running ?

[Pinecone]

But the battery acts as a giant capacitor so it smooths the pulses.

I thought that the prohibition for charging while running was for the simple, cheap, stupid chargers that come with RTF pacakages. Where there is not good voltage regulation, so the high voltage could cause over charged packs.

[xircom]

so are you guys running the car while charging the battery ? the problem of not running it is, that drawing 4 amps or more from an ordinary car battery over hours I guess makes it broken soon, as it"s not deep cycle ???

[kgfly]

Yup, you will quickly kill your car battery using it as a charger power supply for anything but the smallest lipos.