Batteries in parallel C rating?

[Genesius]

Hi, If I wire 2 11.1v 1200mah lipos in parallel I know that I effectively will have a 11.1v 2400mah battery. My question is about the C rating. I know the C rating is the amount of amps that the battery could supply if needed and that the burst C rating only happens in the initial instance of the power delivery again only if needed (ie for initially getting a high torque motor moving) but wired in parallel does it increase?

Both batteries are 20C so will that mean I get 40C? I presume it does but I'm no sparky and some times what I think is logical isn't always correct.

[Genesius]

Re: Batteries in parallel C rating?

Anyone know?

[Proto]

Re: Batteries in parallel C rating?

I'd think so as well, considering it's two charges at the same time, not one+auxillary battery, though like you aptly put it, 'I'm no sparky'.

[Genesius]

Re: Batteries in parallel C rating?

Well at least I'm not the only one think along those lines. I would still like this confirmed more just so I know rather than because I need to know. Also is ther any issue combining 2 batteries if they are in slightly different formats. Both 11.1 both 20c both 3 cell lipos. But one is a 3 stick crane stock battery and the other is a stick lipo. I think as the make up of both matter is is the same, it shouldn't matter. Just wanted to check that it only how they are shrink wrapped that's different.

[Bachelarius]

Re: Batteries in parallel C rating?

Research :/ Done any googling on the subject? Lipos are used outside of airsoft as well and none-airsofters (RC guys and Laptop technicians etc.) tend to have a much better grasp of these things than we do.

I can confirm that adding 2 cells together in parallel will add up the mAh not the C rating. But adding 2 different cells together is an unknown for me. The thing about C Ratings is that it's a bit of a magical number - not very easy to measure, so a seller can slap any old sticker on the cell and claim it's a 20C or 50C or whatever, if your 2 cells are different, there is no guarantee that they are made from the same type of cell.

I would only ever parallel identical cells personally, but that is because I don't fully understand the effects of Different C ratings in parallel and the effects of a lipo becoming unbalanced during use (I know that an unbalanced cell during charge is very bad though - which is why we balance-charge them).

Research, research, research - DO NOT TAKE THIS DECISION LIGHTLY and definitely don't just do it if you don't already know what will happen, there is real risk involved :/

[Genesius]

Re: Batteries in parallel C rating?

yeah i googled it and even youtubed it. i didnt find much useful info and nothing on combining 2 same spec bateries that have a different configuration. all i found was that you shouldnt combine 2 differently rated lipos.

both batteries have the same C rating, same voltage, and are the same manufacturer.

Im pretty sure that a C rating is just a maximum amp draw per hour. As i said it doesnt really matter but i would like to know. I thought the C rating would be worked out by the batteries ability to discharge. The risistance would come from the cells and the wires. double the cells and wires and you should get double the available amps to draw.

11.1v X 1200mah = 13.32 watts
11.1v X 2400mah = 26.64 watts availible.

The voltage stays the same but the availible wattage increases.

just read that the C rating is amps per hour. So yes its a magical number as it would all depend on what was using the power. So C rating is the theoretical max amps per hour. Both my batteries have the same C rating.

OK so from what i can work out...... I know nothing, lol. i think i will run them in parallel for a day and then check the charger to see if its had any negative effects on the balance. if not im good to go!

RC people run lipos in parallel a lot but usually they are exactly the same. im sure though, as its only the way the cells have been divided to fit into a crane stock and the other they are all wrapped together then this will be fine.

No risks involved with lipos unless you stab them, or use a rubbish charger that doesnt switch off. Lipos are in everything, my phone, my ipad, laptop, car radio, sat nav, ok not everything - most things. the devices circuitry stops them over charging as do most decent chargers so im not too worried. if anything does go wrong (which im 99.9999% sure it wont) they will be in a crane stock and not in my hands.

i will post back my finding!

[Caveira]

Re: Batteries in parallel C rating?

if anything does go wrong (which im 99.9999% sure it wont) they will be in a crane stock and not in my hands.

So right by your face then, while you're firing!!!


Seriously, though, while I'm no sparky either I have thought that as they are from the same manufacturer there shouldn't be an issue. The only little niggle I've got in the back of my mind is that the two different configurations would involve different wiring setups, but I can't decide if that will cause enough of a difference in efficency to matter

[Genesius]

Re: Batteries in parallel C rating?

the wiring set up isnt different. OK there will be about 6cm of extra wire on the crane stock variant that will cause resistance but not enough to worry about. And yet the batteries will be inside the crane stock next to my face but 1. batteries are not bombs, if they pop, well they just get hot and pop but more likely just fizzle, so being inside a hard ABS case is probably the best place for them, 2. before they pop batteries get hot so ill notice and my gun will keep me warm on Saturday as its going to be chilly, lol.

Seriously Lipos have got such a bad rep all because - as with ANY battery - if you treat it poorly it will break in either a spectacular or unspectacular way (usually the latter).

Lipos are no more dangerous than the AA's in your TV remote. Throw both on a fire and they will pop, puncture them and they will pop, over charge them and they will pop. use them correctly and they are fine.

As i said above Lipos have been around years and are used in more things than people realise. I cant see the major mobile phone manufacturers putting them in tiny devices right next to your temple if they were likely to explode at any given moment.

However i am fully aware that what i am doing is not 'standard practice'. However after even more research i can confirm that that the only difference between the 2 batteries is how the cells are wrapped. the stick battery has 3 cells on top of each other and then wrapped in plastic film so its all neat and tidy and the 3 leg crane stock one has the 3 cells seperated. same as with 7.4's- 2 cells wrapped together or 2 cells/legs wrapped individually.

Too a lot of research to find out. i have no idea why this is such a grey area in airsoft.