More Battery Milage / Juice ??

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abudabit
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Last seen: 15 years 7 months ago
Joined: Monday, October 6, 2008 - 11:22
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Re: More Battery Milage / Juice ??

If I can add something....

24v at 18 ah = 432 wh (watt hours)

Me, my batteries, and my bike which add up to probably 270 lbs get like 20 mile range (maybe more) with around 600 wh. Simply adding more ah is not the solution. You need to address why your set up is so innefficient. Common things that cause inefficiency:

- demanding a lot of torque out of a motor not designed for it (runs high amps which causes massive heat dissipation). Do your components feel burning hot after use? Like someone mentioned, running very slow can be a major source of inefficiency if the system wasn't designed for it.

- mechanical inefficiency - are you wheels wobbly? are your brakes rubbing? If you turn it upside down and spin each wheel by hand do they keep spinning for a while? Check the wheels on your trailer too.

- hills: do you climb a lot of them? Weight + inclines + poor ratio = bad

The other possibility is that your batteries aren't storing all they are rated for. Are they old? Are you draining them to max? Draining lead acid to max / below 50% will permanently reduce battery capacity.

If your motor is meant for 24v, I doubt it has a high N-m/A performance which means you are drawing lots of current and generating lots of waste for your slow speed high torque application.

I don't know, just some things to look into.

deronmoped
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Last seen: 15 years 6 months ago
Joined: Tuesday, December 25, 2007 - 08:18
Points: 342
Re: More Battery Milage / Juice ??

abudabit

That is what I'm thinking, something is really wrong. If she can draw her batteries down to 50% then puppetplanet has over 200 watts to work with. Now if she can only go a little over 3 miles, that is like 60 watts a mile. She says her trike/trailer load is 250 Lbs, my total bicycle load is 250 Lbs too, yet I figure I was using 12 watts per mile.

I would check tire pressures, rubbing brakes, how tight the drive on the motor is, is the drive out of alignment, bearings on the motor shot, brushes, connections, controller getting really hot, motor getting hot, is the controller cutting off...

Deron.

antiscab
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Last seen: 12 months 1 day ago
Joined: Saturday, July 7, 2007 - 23:55
Points: 1686
Re: More Battery Milage / Juice ??

an 18AH lead acid battery is good for around 14-15AH at 0.5-1C rates when the battery is brand new.
so at 24v thats 360whr (since at 1C most batteries can hold above 12v)
If they are old it will be much less as you have both increased voltage sag and reduced AH capacity.

is your motor hot after these 3 miles? is your controller hot?
if you are blowing through 360whr in 3 miles at low speed, something somewhere will be red hot.

if nothing is noticeably hot, then the old batteries are to blame.

to give you an idea of how little energy you should need, i use 70whr/mile on my emax at 40mph (including accelerations at 5500w).
so its highly unlikely you are using 120whr/mile on your bike.

Matt

Daily Ride:
2007 Vectrix, modified with 42 x Thundersky 60Ah in July 2010. Done 194'000km

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