# underpower controller???



## everanger (Sep 7, 2009)

wow over 60 views and no ideas? is it that dumb of question?


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## Tesseract (Sep 27, 2008)

Most (note I say MOST) motor controllers translate throttle position into motor current because that directly controls motor torque, which controls acceleration. Top speed, however, is determined by voltage - going from 72V down to 48V will likely prove extremely disappointing. Also, if you are reducing voltage by removing batteries then you will have reduced the range by an equally dramatic amount.


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## everanger (Sep 7, 2009)

Thanks for the reply.I was actually think of running the battries parellel so that should increase range,but with less accel and lower top speed.These are my thoughts and a fun experiment for just moving some cables around.


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## Guest (Oct 31, 2009)

everanger said:


> Thanks for the reply.I was actually think of running the battries parellel so that should increase range,but with less accel and lower top speed.These are my thoughts and a fun experiment for just moving some cables around.



Kinda hard to move batteries in parallel from 72 volts to 48 volts. You could parallel the pack to 36 volts. You should stick with 72 and just have fun. You will soon want more anyway.

Pete


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## MN Driver (Sep 29, 2009)

everanger said:


> Thanks for the reply.I was actually think of running the battries parellel so that should increase range,but with less accel and lower top speed.These are my thoughts and a fun experiment for just moving some cables around.


If you took your 6 batteries and put them in parallel you would get 36 volts from your former 72 volt system, you would need to pull twice the amps to get the same acceleration but your controller will have its amperage draw limits and you will lose in acceleration and even if you pulled twice the amps to get the same acceleration you are still pulling twice the amps but the same would come from the batteries if it worked that way. 36 volts won't give you much for top speed at all and you won't find any more range improvement than you would have gotten from just going slower in the first place.

Remember volts * amps = watts(power) We measure capacity based on kilowatt-hours or kWh, you aren't increasing your capacity, you are only limiting what your system can do. If you paralleled packs to try to get more range you would need to keep the same batteries and buy an identical set to actually get more capacity, but with twice the batteries you might as well increase performance too and just raise the voltage and swap controllers, if of course your other components could handle it too. It's either that or replace your batteries with higher capacity ones.

If your system does what you want it to do, then keep it as it is because to increase range at this point involves spending more money.


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