I've spent a lot of time thinking about this as well and believe that it can't be done any cheaper than buying large format Li Ion batteries. But, I do think someone smarter than me can make another option work. I see the following options for these old conversions (other than a new lead acid pack which I can assure you makes no sense at all). I hope someone with EE skills can sort it out and say what really is best.
1) Try to find a wrecked EV with undamaged pack and get the pack out of it. I have seen "rolled" unsalvagable leafs for $7500. Get the car, lots of work though. Get the pack out of it. Try to get any other good Leaf parts and sell them to make as much of your money back as possible. Reconfigure that pack for your car. Some of the off brand EVs actually use batteries very much like your conversion. For example, the Wheego LiFE uses a 30 kwh 108V pack. If you could find a rolled Wheego cheap, you could get a set of batteries. 2) The large format Li Ion batts aren't off the table. A decent sized pack can be bought for around $5k. But someone needs to find a cheap way to make a reliable (even if dumb) BMS. The charger cutoff is relatively simple, but if you aren't a EE, anything electrical like this turns into a project that you need lots of help for. It's above my head even to make the charger cutoff switch more or less a BMS, unless someone gives me an exact parts list and schematic. 3) I still like the idea of a dual pack. The 10-12 small Hawkers with very small Li Ion pack in parallel. I think that can make sense if you don't need too much range. Also, the Lead serves as a very poor man's BMS. Not a good BMS, but better than nothing. I like the same idea of 10 Hawkers paired with 4 strings of NiMH D cells. That could work very well for my needs if I could find a way to keep the strings of cells from backfeeding each other (and burning up). I have some EE skills, but this type of power electronics is unfamiliar to me. I assume you would have to build some kind of control circuit for each string with components much like a motor controller and have them switch on and off based on some criteria. I wish I knew more and could do this. I've been doing this EV stuff for over 15 years, and there are no good answers. I have 2 conversions, one very much like your Aspire. 144V system, Curtis 1231C, 9" motor, very good high quality build. Right now, it has a pack of dead lead (just sitting virtually abandoned in the driveway) and I don't know what to do with it. Lead is $2k for 12 Trojan T1275's and that gives only 25 mile range and lasts maybe 10k miles. The math says it makes no sense. My other car is even worse. It runs on 10 Interstate Group 29 Marine batteries. The car is so junky I can't even justify replacing a handful of batteries to keep it on the road. I do drive it but I do a lot of stopping and charging. So, just like you, I am stuck. Looking for a good answer. I'll probably end up selling both my conversions and buying a second production car. I already have a 2011 Leaf. But, 2 drivers need 2 cars. If I can sell both cars, I'd probably take a good look at the Wheego because it uses off the shelf parts just like a conversion and I know I can keep it on the road (fix it myself if necessary) just like my old conversions. The Leaf is more difficult to maintain and requires the Nissan dealer and their much more expensive parts and labor. It's simply more complicated whereas the Wheego is just a high end conversion. As for the spot welding, I am a trained expert in resistance welding battery packs for consumer electronics. It can be done, but you are looking at a solid week of work and no idea the electronics required. I'd rent a machine or find a local battery pack manufacturer to borrow the equipment from. I used to do this day in and day out and can weld about 1500 welds per hour assuming all material is sitting there ready to go. There are many people out there who can weld even faster than me. -- View this message in context: http://electric-vehicle-discussion-list.413529.n4.nabble.com/18650-battery-for-EV-use-Recommendations-tp4664996p4665002.html Sent from the Electric Vehicle Discussion List mailing list archive at Nabble.com. _______________________________________________ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA)
