passpato said:
Why would range be shorter? 12 amp hours is 12 amp hours lead or lipo.
Unfortunately, that's not really the case, since they are rated by different methods, and work in different ways. Because the Puekert effect with lead chemistries is much more severe than with Lipo or any other common EV chemistry. That means that at the higher current draws (c-rates) we are using, you get at best 70-80% of the rated capacity, and usually more like 50% or less. And that is assuming 100% DOD, which will kill your lead based batteries in far fewer cycles than doing that to most other chemistries. So often you'll only be able to pull perhaps a quarter to a third of the rated capacity from a lead battery, if you want it to last a good number of cycles.
Also note that most lead-based batteries are measured for capacity at a very low current draw--typically 1/20th of their capacity. So a 20Ah SLA is tested for that 20Ah at only 1A! If you draw 20A constant from it, it isn't going to last 1 hour, it is probably only going to last for 20-30 minutes at best. Drawing 40A from it would be less than half of even *that* capacity.
And if I buy a lower amp controller the motor will burn it out. The motor draws the amps from the battery not the controller.The controller in effect switches on and off the power to slow the motor down at lower throttle settings.
Not exactly. The last sentence is essentially true, but the motor shouldn't burn out a lower amp controller (assuming the controller has a current-limit in it to prevent drawing more than it is capable of, which is how most of them are made). The motor simply wont' perform as well, because it can't draw as much power as it "wants" to, so it won't accelerate as hard as it would with a higher current supplied to it.
The lower-amp controller will simply switch on for less time when it hits it's current limit, for each pulse, supplyng the motor with less average voltage and thus less current.
Often enough the lower-amp controllers might be of lesser quality than the higher-amp controllers, less able to shed the heat generated, and so might blow up because of that, but not directly because the motor is trying to pull more amps. It would instead be because the motor is pulling max amps the controller can supply for a longer time, to reach the speeds at whcih current drops because of the faster rotation of the motor, and that longer duration generating heat for a longer time, potentially reaching saturation in the controller and overheating it. If it doesn't have a thermal shutdown, it could cook it and kill it that way.
I already have this motor on my own bike with 10 a/h Ping battery and a 100 amp max 4qd controller and I get 30 killlometers plus.
10Ah Ping with a 100A controller? Does it doesn't pull anywhere near that amount of power from the Ping for any length of time? I ask because Pings are usually rated for 1-1.5C continuous, and maybe 2-3C burst, for best life. It is certainly possible for one to last quite some time (years), but the lower the rate you pull power from it, the longer it will last. See Dogman's various threads about his experiences with different types of Pings for some examples. I'd be interested in details of how long yours has lasted, under what kind of continuous current draw conditions, as well as what the peaks are and how long the peaks last, and how often they occur.
My main concern is that sla batteries would not cope with 33 amps for the ten minutes before the thermister cuts out the motor and that the connectors will burn as do the genuine Heinzmann connectors when used on rickshaws etc.
The right size SLA batteries could indeed handle it, but they would be quite large and heavy. Typically the powerchair batteries like the 31Ah U1 types I have here could probably do it, but their range will be greatly reduced by doing that. 33A continous on a 31Ah SLA is pretty likely to result in less than half, possibly only 1/3 of the actual capacity being available, unless you run them to 100% DOD, which isn't recommended if you want them to last a good number of cycles.
