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Comments by Steve M.
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Understanding battery capacity: Ah is not A
- 7 August 2015Jan,
thanks for the help. I called today to see about buying three of those batteries and ended up speaking with Daryl (I think that was his name). Anyway, he advised you haven't quite got those batteries ready to sell so we discussed alternatives. It sounds like, as long as my alternator is producing 24 V constant and 80 or more (adequate amps to equal the draw at any given point in time), the battery capacity really doesn't matter and more importantly, it does not impede either voltage or amps - the load basically skips across the top of the battery and on out to the motors. That was EXACTLY what i was trying to determine. I'm just sorry i wasn't able to by the batteries from you to return the favor for your technical advice and help. I'll keep you posted on how it works out and thanks again.
Understanding battery capacity: Ah is not A
- 25 July 2015Jan, I have read through the posts but don't see anything that addresses my situation - so here goes. I have built a remote (radio) controlled lawnmower (which has now morphed into a snow plow as well) which runs on tracks and is driven by two 500W electric motors for drive power. The first prototype had a 7hp gas motor that drove the blades only and I used 36V motors but the problem was my locomotion was limited to available battery power run time which was about an hour, and then you had to recharge before you could mow again. I decided to go with a bigger gas engine (23 hp Kohler) so I would have enough hp to run the blades and also drive a 100 amp alternator to charge the drive batteries while using the mower, theoretically eliminating my run time limit. I changed to 24V motors (because 24V alternators were much cheaper than 36V alternators) but I still carry three 12V 50ah batteries because I now have two separate electrical circuits; a 24V circuit (two 12V 50ah batteries hooked in series) dedicated exclusively to running the electric drive motors and a 12V circuit dedicated to running accessory items i.e. starter, blade clutch, radio package, snowplow angle, etc. (The third battery for the 12V circuit is charged separately by the internal alternator on the Kohler engine.) Everything works fine except I now can’t climb one bank because of the additional weight added due to the bigger motor, alternator, etc. So I am looking to cut pounds and naturally thought of batteries first as the 12V 50ah batteries weigh about 35 lbs. each. I thought about eliminating the batteries altogether (for the 24v circuit) but the electric motor company says I need a battery between the alternator and the motor controller for a "buffer" (presumably to stabilize current available to the motors?). The 24V electric motors draw about 5 amps ea. under light load and about 40 amps (ea) under full load so I need a current availability of 80 amps to maintain power under full load. If I go to smaller capacity batteries, I can lighten things up considerably but I am not sure how that affects current. In other words, assuming my alternator is putting out up to 100 amps on demand and the motors are calling for 80 amps, if I use a lower ah batteries in between will I limit or restrict available current? And is there anything else I'm not considering that might cause me problem by going the lighter battery route? Thanks for any help you can provide.
PS: here's a link to the first prototype unit in lawnmower mode with electric drive power by battery only. https://www.youtube.com/watch?v=N9A2AMfU1dw (this link also shows the slope I was originally able conquer but I now can't because of increased weight.) And here’s a link to the 2nd prototype (with bigger motor and alternator) in snowplow mode: https://www.youtube.com/watch?v=WWezIfjlNmY