Battery safety in high powered regulated mods

[Chris Cox]

I recently got a sigelei 100 watt (which rocks, btw!) and I'm wondering about battery safety. I have matched pairs of VTC5s and VTC4s that I've been running in it exclusively, and they are all basically new, so I shouldn't have to worry about getting new batteries for a bit. But when the time comes, I'm wondering if using the 20 amp 2500mah LGs will be safe (assuming that VTC5s will be impossible to get by then). I never go below .4ohms on any build, so with ohms law in mind, I should be more than safe with the 20 amp limit on the LGs - even if the mod somehow turned itself up to 100 watts it should only be pulling just under 16 amps (I usually run around 35 watts)... but I've seen a few (vague) posts here and there indicating that only 30 amp batteries should ever be used in mods like this. Is there something I don't know about high power regulated mods, than in some worst case scenario could lead to them pulling amps beyond what the coil would normally pull?

 

[Ryedan]

Check out the battery drain calculator at Steam Engine. Check 'regulated PV', 'power regulation (VW)', 100 watts, chose your battery and for a worst case scenario chose 80% for 'APV efficiency'.

With fully charged batteries at 8.4V you're drawing 14.9A. With drained batts at 6V, you're drawing 20.8A. Keep in mind that with batteries in series, one will drain faster than the other which puts more stress on the more drained cell.

If this were my PV, I would use 30A batteries in it and not worry about what power setting it was on. IMO Sony 30A batteries will be back in a year. If you have enough batts to last that long I wouldn't worry about it. You could also buy some more VTC4 now and put them in your rotation and they will all last longer.

 

[Chris Cox]

Nice, that's exactly the info I was looking for. Thanks!!