Amp Hours

G

grouchyolfart

New Member
Sorry. Just couldn't get through a search to find what I wanted. Maybe y'all can help.

I'm in the process of building a couple of 36volt/500watt hub motored bikes. They're for my wife and daughter, but I want to avoid using those hemangoid 12v/12ah batteries in a 36 volt pack and can't afford LiPo.

I saw mention, somewhere, someone is using 3 12v/8ah batteries instead. What does this affect? Range/duration? Speed? They're also a heck of a lot cheaper than the 12ah batts.

We don't do long range riding. Just for fun and a bit of excercise. I use a Curry set up for a 4 mile round trip commute. That uses a 24volt pack with 2 12v/12ah batteries. Distancewise, this'll take me a good bit over 10 miles before starting to konk out on me, down hill one way and pedal assist back up the same and some on the flats against the wind. This one's a heck of a long hill.
 
Your personal experience kind of matches mine. A couple of years ago i put together a Yakima trailer with a hubmotor. They recommended 4 18 a/h batteries. (48 volt 500 watt motor) I thought that would be a bit heavy not to mention expensive, so I opted for 4 7 a/h batteries, and rigged up a little generator using a weed eater engine. Worked very well. I found that my rule of thumb is about 1 mile per amp hour.....and this was in below freezing weather. With the little generator of course the range was determined by how much fuel I had. A little added bonus was that on e bay I could get the batteries for about $10.00 a piece. This was all with SLA batteries. I don't have any personal experience with the newer technology batteries.
 
Less amp*hours will decrease your range. It's a rating of capacity: how many amperes can be delivered for an hour.
 
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Oh, okay then. So a 24v/8ah battery pack should do me just fine for my commute and a bit more if the need should arise. Also 36v/8ah should be plenty for my wife and daughter's 36v 500 watt hubs. Thanks guys! (^)

This online place is selling their hub kits for $238. Rim with hub motor, rack with controller, throttle and battery pack if desired. Comes with 3 12v/12ah batts. According to their order form, I can order the kit without the batt pack at an adjusted price. This way, I can order the lighter batts from another online store.

I'm opting for the hub kits as my wife and daughter like the "stealth". Only thing is we only have a 350 watt hub and it doesn't have enough power and speed for them. Takes forever to get up to all of maybe 15mph. They wanted something a little more peppy. (?) I'd go the Curry route, but the price I found for the hubs is hard to beat.
 
My experience is much worse than yours. On an 8hr set you should get 2/3 the range as the 12ah or so it would seem.
 
deacon said:
My experience is much worse than yours. On an 8hr set you should get 2/3 the range as the 12ah or so it would seem.
Click to expand...

2/3 the range is plenty for my commuting purposes. 4 miles isn't much and I only use the motor on the hills at the bridge and going to work. Usually against the wind. Coming home, I use the motor just to get up to speed and pedal the rest of the way till I hit those hills again. I usually get home, then take off again to do some shopping and pick up lunch. Another couple miles at least.

Those 8ah batts should work well and I can save the big batts for longer rides.....like down to the North Shore to check out the monster Winter surf.
 
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