What would happen if I ran non matching batteries with different mah and c ratings?
typically thats not a good idea. Whenever possible run identical packs in series or parallel depending on the combination of cells and Mah you are looking for. For exampe, running 2 x 3300 mah 5s packs in parallel gives you a combined 5s output at 6600 mah total capacity. On the other hand, running 2 x 5000 mah 3s packs in series give you a 6s setup with a total of 5000 mah capacity. Bottomline, use identical packs, mixing and matching, especially with C ratings and capcitiies is not a good idea.
basically one will dump sooner than the other and puff the pack. Think of it like comparing a 5000mah 30c pack with a 4000mah 60c pack at 6 cells; your esc is going to look to lipo cut off at 3vots per cell or 18 total volts, infact 18 total volts is all your esc sees, it has no idea what the individual cells are doing even though one or two might be at 2.6V puffing your cells.
Now think if it like a 5liter wine bottle with a half inch spout and a 4liter bottle with a one inch spout. poor both of their liquids out at the same angle at the same time into a bowl and which will empty first? well the 4L with 1inch spout since it will flow faster and has less volume. But the chef (esc lipo cut off) told you are only to stop when there is still 6 total liters still in the bottles. Oops one is already empty! now your wide bottle will puff.
Your question has been pretty much answered. You must run batteries that match both mah and c rating to avoid damaging the batteries.
You can run batteries with the same ratings, but different manufactures, however, this is not recommended since manufactures use different criteria to rate their batteries, so even though the numbers may match, actual performance may not.
You can run batteries with different voltages (cell count) in series, as long as the mah and c ratings are the same. For eg. You could run. 2s battery and a 3s battery in series for a total of 5s provided the batteries have the same mah and c rating. Also preferable they are from the same manufacture and same type. (I.e. preferable not to mix xyz brand platinum series batteries with xyz brand silver series batteries)
A simple rule of thumb for connecting batteries in parallel and series....
When you connect them in parallel the higher voltage battery will attempt to charge the lower voltage battery, probably ruining it. (Batteries are not often connected in parallel for this reason even if they have nominally the same voltage ratings - they are never exactly the same) So do not connect different voltage batteries in parallel.
When you connect them in series, your net voltage will be the sum of the two or three voltages, but the current and current capacity (mAh) available will be limited to that available from the lower amperage battery - when it runs out its internal resistance will raise significantly and thus block use of the other battery.
I obtained the above information from one of my electronics periodicals that I use for teaching at a local junior college... They state it easier than I can in simple form.....
Last edited by orca44; 10-29-2012 at 02:39 PM.
"enjoy your ride"