Batteries?

[ElectroGhandi]

I'm most likely going to purchase this motor/speed controller combo:
http://www.electricscooterparts.com/kollmorganinfo.html

Would I be better off getting 2 car batteries from Walmart to power this or should I be looking at purpose-built scooter batteries from electricscooterparts.com?

 

[devino246]

24V scooter batteries would be best. Car batteries are designed to output high amperage for short periods(generally 15 seconds of starting). I would think 2 car batteries would be alot heavier than a scooter battery. Scooter batteries are about the same if not cheaper than car batteries anyway.

 

[ElectroGhandi]

What kind of Ah/Amp hour rating should I be looking at for that motor?

 

[zabac70]

That depends on how long or how hard you want to drive/ride (don't know what you're building). Below 15 AH is pretty useless , because you don't want to drain those batteries (presumably SLA, or any kind of deep cycle batts) more than 50 % DOD (in rare occasions up to 80 % DOD), that is, if you want them to last in average 500 cycles.

 

[ElectroGhandi]

How about charging the batteries? Should I get a 24 volt charger and just attach the wires from the charger directly to the batteries?

 

[zabac70]

That also depends on your choice(or budget). You can use two , cheap, 12 V chargers and charge your batteries separately. You can also use/buy/obtain/build dedicated 24 V charger and there are (basically) two choices: cheap one (same thing as previous) and , so called, smart charger , that monitors level of current , adjusting charging current , monitors temperature of batteries and so on...That is a more expensive solution , but prolongs battery life (you can kill batteries with overcharging them , as well with over discharging them). Really , the first thing that I've mentioned is the cheapest solution and the only hassle is that you should "baby sit" batteries , while charging (checking voltage with multimeter and their temperature). These days even cheap 12 V chargers have some advanced options (like automatic shutdown and variable charging current) - you should "shop around" to see what is the best value for money.

 

[oscaryu1]

What? Under 15aH useless? I can travel a good 5 miles on my 900W 24V scooter overvolted to 48V (which is probably pumping a good 1200W+ at that voltage), I don't know what you're talking about useless. This is on 9/10aH batteries also. And that's 5 miles WOT all the way (very low gearing).

Motor seems to have an integrated ESC... find out what the motor's rated at (amperage, and wattage). IMO find some 10aH batteries (if the motor is below 750 watts) and have fun. Above that, step into the 17aH-21aH if you want some serious range.

 

[zabac70]

Sorry about that. Because I live in a city , I keep forgetting that public transport isn't available everywhere in the world at any time , so 5-6 miles of range can be useful, especially if one can't/doesn't want to walk or use ordinary bike. However , not much fun (time wise) and you use 48 V system that is less thirsty on Amps for the same speed (you've mentioned low gearing). Motor doesn't have integrated ESC , just connector for it. I would have recommended Lithium batteries, but I've assumed that E-Ghandi works on the budget and that this is a start up project (to get familiar with electric propulsion).

 

[oscaryu1]

Increasing voltage doesn't always directly reduce amperage draw, although the motor IS geared low (which makes the biggest difference).

I get an hour of ride time, nonstop on that. That's plenty IMO.

Motor does have an integrated ESC, power at one end and a potentiometer for the throttle. Or am I wrong? :dunno:

If he's on a budget, stick to reliable SLA's or LiFePO4's.

 

[zabac70]

You re right about controller (it is integrated).