Willie, To try and interpret your answer on David's question: It looks like you are not running your golf carts with golf cart batteries (flooded lead acid) which would give you what you are asking for: occasional charging and easily a year (when used little) between watering. This is also likely the lowest cost and lowest complexity (no BMS, no sophisticated charger). I find that my daily driver EV (1989 Ford Ranger conversion with 20 GC batteries as pack) needs to be watered every half year with sparingly charging (about once a week I will charge them fully, meaning that they will be kept near 2.5V per cell for 2-3 hours at the end of the charge cycle, for the rest I typically charge to between 70-90% depending on how far I need to go next. I might be able to stretch watering periods to a year without exposing plates, but I rather be on the safe side and water every half year give or take a couple months.
Cor van de Water Chief Scientist Proxim Wireless office +1 408 383 7626 Skype: cor_van_de_water XoIP +31 87 784 1130 private: cvandewater.info www.proxim.com This email message (including any attachments) contains confidential and proprietary information of Proxim Wireless Corporation. If you received this message in error, please delete it and notify the sender. Any unauthorized use, disclosure, distribution, or copying of any part of this message is prohibited. -----Original Message----- From: EV [mailto:ev-boun...@lists.evdl.org] On Behalf Of Willie2 via EV Sent: Wednesday, June 17, 2015 1:15 PM To: Electric Vehicle Discussion List Subject: Re: [EVDL] Bicycle battery On 06/17/2015 01:55 PM, EVDL Administrator via EV wrote: > Can you be a little more specific here? What makes them so expensive? The miniBMS modules suffer from exposure to the elements and they are not well protected in golf carts or the Zap. Or my Ranger. Rodents have chewed a lot of the signal wires, which have been too light a gauge. I've been told that the cells self discharge at quite different rates so that, when left sitting, the battery gets badly out of balance or some cells go to zero and self destruct. Also, I seem to have some vampire loads that lead to discharge in a few months or less of non-use. The real problem is that I'm not willing to jump on a problem as soon as it develops; I tend to let it sit for months. By that time, I'm likely to have lost some cells. I may use only one or two of these farm EV conversions at a time but I've been trying to keep about five ready to use at any one time. Right now, I have two golf carts, the Zap, and the Ranger all dead and I am able to use only a golf cart and the imiev. The imiev is WONDERFUL, completely trouble free. So far. I believe the imiev is going to be considerably cheaper than the Zap. Or even a golf cart. My experience is that the big cells with miniBMS have a mean time to failure of about two months. Maybe less. I'm looking for a year or more with no more maintenance other than charging every couple of months. > > Golf cars are pretty economical and reliable with lead golf car batteries. I can not agree. In my experience, lead in golf carts is FAR more demanding in terms of maintenance. Monthly watering, bad battery connections, corrosion, rusted out battery boxes, general nastiness, ever declining capacity. _______________________________________________ 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) _______________________________________________ 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)
