I am looking to connect a series of Lithium batteries in parallel for some devices I am making. These batteries are going to power any device I hook up to the circuit at the battery voltage, that is they are going to be in parallel. What I am looking for is a method of connecting Lithium batteries in parallel that have differences in charges without them trying to charge each other (and subsequently catch fire).

I was going to hook them up in parallel and put diodes to restrict the current flow from any cell in one direction thus preventing one battery from charging any other. The diodes I was going to use had a break down voltage larger then any voltage difference the batteries might see in each other so I think they would be safe. However, I don't like this solution since the constant voltage loss from the diode is something I'd like to avoid.

Is there a better way to do this?

 

One battery discharges before the other and the remaining battery is overloaded and catches on fire.

Don't play with fire, use a bigger battery.

 

to add a diode in series is standard practice but you loose voltage .7v to .3v dependingon what type of diodes you choose. 1n4001 .7 but shackey diodes .3v the laterone have a break down of low voltage but whoo cares they will never see more the .3v difference that will work. the other way is a pain using a very small resistance in series eitherway you will loose unwanted overal power as heat dissipation. on a final note lithium battery are not very friendly [sensitivity] to parameters.

 

if you are not experienced in handling lion batteries avoid them they are too risky to experment with
try nimh or SLA batteries

 

Many of the commercial Lithium batteries packs sold to the R/C crowd use parallel and series combinations. However they use matched and tested cells and most people use special chargers that test for and maintain or correct balance between cells.

Lefty

 

I have experience in dealing Lithium Batteries and I wasn't about to do anything I know to be dangerous. Honestly, I was just asking if anyone knew of any other techniques to hook batteries, potentially those with differing charges, in parallel safely that I could investigate.