I am trying to get a firm grasp on batteries. Is the amp hour rating what effects the range? Say you have a 144V pack made of 12 12V batteries with a 50 ah rating and you had another pack made of 12 12v batteries with a 100 ah rating. If everything else was equal (and hypothetically the battery packs weighed the same)- would you have twice the range on the 100 ah pack?

Exactly. Amp hours is how much current you can draw from the battery for how long. You also need to pay attention to the max amps you can draw from the battery, but in the case of say, an Optima yellow top deep cycle battery, it goes like this. The battery is rated for 55Ah, and drawing 55 amps isn’t a problem, so accordingly, I can draw 55 amps for an hour, or I can draw half that for two hours.

Generally amps become torque and volts speed when applied to a motor.

What’s really interesting is that in reality, voltage is most analogous to “electricity pressure”, and amps are a measure of the speed (drift velocity) of the electrons. The more volts you’ve got, the more amps you can pump down the wire.

-Mark

[QUOTE=Wirecutter;1927]

What’s really interesting is that in reality, voltage is most analogous to “electricity pressure”, and amps are a measure of the speed (drift velocity) of the electrons.

-Mark[/QUOTE]

hmmm interesting- I thought that is was the inverse.

Thanks for the input. So in deciding what battery to use the major factors are ah, weight, and cost. In the case of Li-on batteries they have a better weight to ah ratio which ultimately makes a lighter battery pack for an equivalent voltage and Ah rating. But this requires the batteries to have packs in parallel run in series to obtain a decent ah. And because it has batteries in parallel then a BMS is necessary to ensure a balanced charge. Do I have this all correct?

Thanks

the ah rating of automotive batteries is at 20 hour discharge

ie 40 ah =2 amp over 20 hours

traction batteries are at 5 hour rating ie 40 ah = 8 amps at 5 hours.

BUT – discharge a 40 ah battery over 1 hour and you will only get under 20 ah

or 40 amps for 1/2 hour or 20 amps for 40 minutes approx.

how ever the lifepo4 batteries at 10 ah will give nearly all this power at even 30 amp discharge.

so they are very much lighter and give nearly twice the ah of a similar lead acid battery rated the same.

amps and volts. (amps times volts = watts)

likened to a water hose

watts are like gallons delivered

amps are like flow of water (enabled by the pressure )

volts are like pressure in psi

high volts = high amps heaps of energy

high pressure(water) fat hose(fat wire) lots of gallons of water.

high pressure thin hose (high resistance) low current loss of power