Can a battery be charged with another battery?!

[DYORD]

I have an 8.4V 1100 mah batt pack. Just wondering if it can be charged with 9.6V 2400 mah battery.. and how long?!

How about 8.4V 150(one fifty) mah with 9.6V 2400mah?!

Theoretically, i think it's possible... but has anyone done this?

[super_six_four]

? never heard of that. whats wrong with a charger

[ILLusion]

It should be possible, as long as the source has a higher voltage and a higher capacity.

I have portable emergency battery re-chargers that are powered by another battery source

[Dracheous]

Originally Posted by ILLusion

It should be possible, as long as the source has a higher voltage and a higher capacity.

I have portable emergency battery re-chargers that are powered by another battery source

+1, its like any of those motomaster jumpstarter kits. Just ONE big ass battery with jumpers to start your vehicle, just usually has built in charger unit.

The question is why for airsoft? Unless you are using one of those units motomaster carries to charge batteries on the field, the better idea would be to buy extras and keep them charged before games.

[DYORD]

Actually.. 9.6V Sub C batteries can't fit my AK... so I'm bringing me with the extra battery for emergency recharging..

[mopic]

Yes, however the battery doing the charging should be significantly bigger the one receiving the charge. A lot of energy is lost in the transfer overcomming the internal resistance of the dead battery. The Booster pack situation is a little different, you are not fully charging the car battery, simply giving it enough juice to crank over the engine, the alternator charges the battery once the engine is running. The situation you described may be be okay to quickly boost the battery to a useable state for another hundred rounds or so. Keep in mind, such a quick discharge of the larger battery is not great for battery longevity.

[Styrak]

Yeah, a lot of power would be lost to heat and resistance. Might work....not all that well though.

[Kos-Mos]

it will work.

Did it a few times in the past.

You will need a bit more capacity and about 1.2-1.5 volt extra.

Then you will be good to go.

BUT

You better just get an extra battery already charged.

Keep in mind that you have no way to control the charging current. Let's say you use a 9.6v 3000mAh pack to charge a mini-type 600mAh, the large pack will push 35A in your mini... It probably will break.

You are better getting a charger that can run on DC power, and get an alarm system backup battery. They are ACID-GEL type. and can come in capacity from 3.5A to 7A and more (size accoding)

OR

go buy a Motomaster Eliminator backup power (the one with the power oulets and all...) charge it, go to the game, and return it for a refund right after. Charged over 50 1200mAh mini packs on that.

[DYORD]

how do you compute for the time of charging? Let's say I have 9.6V Battery pack (which i think output 35A) to charge 8.4V 1100 mah?

[kalnaren]

I once tried sticking an inverter into a portable 12v battery (24 amp, if I remember correctly). Plugged my battery charger into the inverter. Worked pretty damn good for charging my minis.

[Dracheous]

Originally Posted by mopic

Yes, however the battery doing the charging should be significantly bigger the one receiving the charge. A lot of energy is lost in the transfer overcomming the internal resistance of the dead battery. The Booster pack situation is a little different, you are not fully charging the car battery, simply giving it enough juice to crank over the engine, the alternator charges the battery once the engine is running. The situation you described may be be okay to quickly boost the battery to a useable state for another hundred rounds or so. Keep in mind, such a quick discharge of the larger battery is not great for battery longevity.

Uh, I said that the unit has a built in charger, as in for charging its OWN battery. Also, those units that Motomaster carries usually have plug outlets for operating small appliances in which case you simply plug in your RC battery charger to it and away you go. The wattage and max volt capacity of those units far exceeds anything an RC charger would need,

Personally, I'd never wire one battery to another for "recharging" purposes, I'd foresee something like the thing exploding eventually. Just buy the right battery? And there are mods out there for getting 9.6v batteries into AK's.

[Naglfar]

DO NOT do this unless you put a large enough diode in series with the circuit to prevent any charge from getting back into the larger battery.
Once the system reaches equilibrium you will not be able to charge any further, i.e. it will never fully charge the smaller battery.

I think this is a horrible idea, it would be ten times more efficient and cost-effective to just get a second battery and use a good quality charger as they will prolong the life of your batteries, which I don't want to even think about how much damage recharging off another battery will do.