Jon "Sheer" Pullen asked: > > Remember, the manual states the max temperature for discharging > > (driving) as 60C (140F), but the limit for charging is specified as > > just 35C (95F), so quite a bit of heating can occur while driving > > before it becomes a discharge problem, but it doesn't take much to > > cause a charge problem. (Even in Vancouver summertime temperatures > > can get warm enough that a pack of Evercels could exceed 95F at the > > end of a drive.) > > [looks up with some suprise] Um, can you send me a copy of > the spec sheet where you found this number?
It is found at the bottom of page 2 of the Evecel .pdf manual 'Operating Instructions for Sealed NiZn', Rev. 1.5 (09/25/2000), in the 3-bullet section 'Special Notes (Standard 7-cell Module)'. It is repeated again at the top of Section 4.0 'Maximum Charge Rate and Temperature' (where it also states that the maximum allowed charge rate is C/1.5). Section 4.3 does provide a table of temperature compensation values for 6C windows about each of 0C, 20C, and 40C, however, the warning about not charging above 35C or discharging above 60C appears in enough places that I think they really did mean it ;^> ... at least at that time. I'll gladly send you a copy of my [obsolete?] manual offline, and would greatly appreciate receiving copies of more up to date data from you offline (it might do wonders for reducing the number of silly questions ;^), although it might be reasonably argued that spec revisions issued recently might be applicable to recent Chinese production batteries but not to 'old' production units such as yours. > I'm just telling you what I've observed. The batteries cool > off quickly (they're at ambient in less than 2h) when the > load is removed. > Well, obviously, one of the goals of the BMS (which as you'll > recall I included in the price tag earlier) would be to turn > on the charger when the batteries had cooled off below a > certain threshhold. Yes, well, still not terribly convenient if you stop somewhere for 2-3hrs, plug in immediately for a desperately needed opportunity charge and return in 2 hours to find the charger just starting, or only having run for 1/2 of the available time. Temperature management would eliminate this concern. > One of the problems is that I don't know if 'half-cycles' > count. Just by looking at my milage, you can tell I haven't > gotten 50 full cycles in.. I've done a lot of little cycles.. Sorry, if you stated your mileage, I missed it. > Based on the kwh counter on my inverter, I surmise I'm > getting about 98 AH out of my evercels right now. Cool! Cheers, Roger.
