If Ive got a 10s4p battery, and I build a 2s4p to match,
And charge only BMS.
Why can I just plug in a s2 pack on my loopkey, to give myself 12s. (and if I can, why should i not?)
charge them independantly
Lay the extra pack on the board or fix it underneath.
Mechanically its only good for those long dedicated cruises not so much A to B or anything.
Purpose: Get 12s feel on demand, while keeping 10s reliability and weight for daily a/b
@pookybear and I were discussing this.
I mean yes it will work but you will need to make sure it drains as often as the main pack or it will be at a higher voltage than the rest of the pack (in terms of per cell) after a ride which isn’t too concerning
You will also need to set the ESC to be configured in the 12s setup and set the voltage cut off to the 10s pack or you will have an unpleasant surprise on occasion
Is It a bad idea to build the 2s pack with an antispark ?
Sounds like a sweet idea! As long as the p groups added have similar capacity and equivalent or higher max discharge currents, it should definitely work. Might have to try that on my 10s board…
I don’t think there’s any problem building with an anti spark. The anti spark just has a resistor at the tip to pre charge the caps so there isn’t a huge influx of current that can harm components.
yeah right? Ok like I felt like this was actually an ok idea.
I have a 10 s board that I love but on the rides with @pookybear and Jason (not that one)
I feel like im missing that 12s punch
What ESC are you using? cheap ones without an over-voltage protection diode tend to die at 12s. Focbox, Unity, Trampa VESC, ESCape (to name a few) should all be good though.
I’ve been putting together one of these myself. I’ve got it halfway wired up. I know that my 2S pack will drain faster than my main pack, as they are 25R vs VTC5A in my main pack. I did this on purpose so that none of my main packs P groups would get too low… I don’t care as much about my little 2S loopkey. But! I care about it enough that I added a little low voltage alarm on it to know to disconnect it and toss it in my bag when I start sagging too low. Also, I plan on having metr profiles setup to apply 12S configs whenever I connect it.
I don’t have current progress pics, but it’s all printed, test fitted, just need to finish the spot welding and solder on the power cables.
Maybe I’ll finish it up tomorrow or Friday.
Yeah that’s basic understanding at this point. I’ve got a unity. Thanks for looking out
I love this approach. It really takes the risk away from the main battery and puts the wear on your booster pack. I’d be curious to hear your long term results!
What is 12s “punch” exactly? You mean available torque?
more voltage = more faster
I know that, but that wasn’t my question.
I mean top speed . But I’ve heard the higher voltage gives more acc off the line as well
Oh, the acceleration goes down the closer to max duty cycle the ESC runs at, with a higher voltage input there is a higher max duty cycle so getting to the same speed will take less time and have more throttle response
Only if you don’t re-gear it though
Not sure what you mean. Duty cycle is a percentage, max can’t be more than 100%.
I don’t think it needs to be that complicated.
Power is proportional to acceleration, and power is V*I so therefore more V, more Power, more acceleration. Really no need to split it apart anymore than that.
I was being sarcastic
That’s not entirely correct though. If all you do is raise the voltage without a proportional increase in gearing, all you get is more top speed but not more acceleration.
My bad, meant erpm. Same duty cycle at higher voltage has higher erpm so you are at a lower duty cycle to have the same erpm. Therefore more room in the throttle and better response at a given speed
Eh I’m just talking about power the motor produces. But yeah, really this is just about getting top speed
