Originally Posted by
morph999
The Dewalt batteries are actually A123 cells which are the best on the market for lithium. They aren't cheap at all by any means. They are actually the most expensive batteries you can buy. Lithium is measured by the Watt-hour or WH. Those dewalt 36v packs are 36v 2.5AH packs so you get about 36 x 2.5 = 90 wh which will give you about 3 or 4 miles range before it cuts out. So if you bought two of them, and you say they are about $150, that's $300 for about 6 - 8 mile range. That's horrible. If you can find new dewalt packs on ebay for $50, that'd be a pretty good buy. Whenever you look at lithium, measure how many watt-hours it has in the battery and that will tell you whether it's a good buy. My 36v20AH thundersky was $360 + $30 shipping so $390. I got 36 x 20 = 720 wh so 390/720 = about 55 cents per watt - hour.
I don't recommend SLA unless you think you just want to enjoy the e-bike for the summer and then it's not too bad. I think you should keep looking for a couple more weeks until your motor comes. Get a 2nd opinion on the pingbatteries. I personally don't think they are all that great but you are welcome to ask around and see what people think. Try endless-sphere.com forum . Someone just posted a ping problem today actually.
http://endless-sphere.com/forums/vie...hp?f=3&t=19682
Thanks for the link. Similar, but not exactly the same problem as mine. For one thing, mine was only tested with one controller (the first one never worked). Mine worked for about a week or so. I peddle and only have a short distance each way to and from work (total of 10 miles). The way back in mostly uphill, so it really pushes the 250W motor, so I made sure to help it as much as I could. Then, similar to what was described in that post, I lost the power half way there. Turned the controller off and switched off the battery. It came back after a few minutes, but died again not long after. As I repeated this, it took longer and longer to come back on, and eventually I had to wait at least several hours to get it back. Last night, following a suggestion, I tried to drain it completely at home with no load, and with a gentle throttle to draw small amount of current. Died the same way. Left on over night, and in the morning wasn't coming back on as before. Waited until the afternoon - charged it back, it had gone from just over 43V to just under 40V. It came back on, but the same as before.
If there is any chance that I can use it; I will keep it. I can always use it when I want a longer range. Not sure if you can put them on series, being two different batteries, and different voltages; but if it is possible then it would be great.
I am selling it dirt cheap to someone on Thursday - he seems to know more about batteries and power. Is there any way I can check it (without opening up the package) to see if I should hold on to it?