Quick lipo question

[Trea916]

What's the proper voltage cutoff for 2. 4s lipos running in parellel

[ozzie-crawl]

it remains the same if in parallel as that of a single pack,so around 3.2 volts per cell
so around 12.8 volts on a 4s setup doesnt matter if 1p or 2p

[ED66677]

be aware that some brand (I have had this with HK Rhino's), when the pack is empty, the voltage remains much higher, around 3.6V!!! LVC won't kick then!

[ozzie-crawl]

yea i started a thread some time back on lvc for modern batteries, there not dropping voltage under load as much as they used to with the lower C packs.
i have the esc in my rc truck set to 3.4 volts but if i run to lvc i put back around 5200mah into a 5000 pack

[ED66677]

I'm thinking of getting an external LVC but even the CellShiel from Dimensionengineering can be set to 3.5V max!!! not enough! would be cool if it was 3.6 or 3.7 but think about it... 3.7 is the nominal voltage of a lipo :confused2::crying:

[ozzie-crawl]

yea not sure on that, depends on load,if the batteries are not under high load they will discharge a to a lower voltage,compared to a high load application.
the high discharge that lipos can now take means they just dont drop that voltage as much.
does your lv cut in ? are the cells at 3.6-3.7 volts at rest

[ED66677]

the LVC did not cut and voltage was 3.55V after 20min, 3.65 after 1H30, so could be that under load (8XL in a 29" DF copy) the voltage was below 3.5V when I stopped and realized I was running since too long!

[ozzie-crawl]

what esc and whats the lvc set at
under 2.8 volts i think kills a cell but safer to be 3.2 or above
the nominal voltage is exactly that its nominal not its low point,it wont hurt being under 3.7 volts if thats what your worried about :confused2:
flat 3.2
nominal 3.7
full 4.2

whats the capacity and how many amps did it take to charge

[ED66677]

that's a cheap chinese 100A, LVC is set at 3.2V

the nominal voltage is exactly that its nominal not its low point,it wont hurt being under 3.7 volts if thats what your worried about
flat 3.2
nominal 3.7
full 4.2
agree with that, except that for the Rhino's, they are dead flat when voltage is probably 3.4V or higher, will have to measure directly after the run next time but sure it is way above 3.2!

[ozzie-crawl]

yea i see what your saying,i never used the lvc on my boats,as i used to time my runs.
for the exact reason i dont think lvc work with the batteries we have now
remember capacity and volts are different, i have had cells at 3.7 volts but put in over 5200 mah into a 5000 pack,the turnigy usually have a bit more capacity than stated
but even so if keeping them no less than 80% discharged shouldn't take much more than 4000 mah

[ED66677]

I think I'll try a CellShield, looks like a good equipement to have anyway!