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"I don't live in the past. I'm always excited by what I'm doing in the present." Sir Clive Sinclair


Author Topic: Looking after your batteries  (Read 1006 times)

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Karl

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Looking after your batteries
« on: 26, June, 2009 - 10:19:49 »
Browsing through the BVS site, I came across this info ;

Battery cycle life is very dependent on depth of discharge. For an extreme example, take the Prius. It limits battery charge discharge to only the middle 30% of the battery capacity, it never fully charges the batteries and never discharges them below about 50%. The result is that the cycle life is well in excess of 20,000 cycles, probably closer to 30,000 cycles, although the individual cells are probably rated at around 1000 to 2000 cycles when fully charged/discharged.

The other point is to do with the accuracy of battery specifications. Stated cycle life may well be under conditions far removed from those in normal EV use, so some sort of correction might be required to get a sensible estimate of battery life.

Finally, there's the issue of cycle life versus calendar life. For lithium batteries it may well be that calendar life dominates, as age-related loss of capacity might be greater than cycle-related loss of capacity.

Overall, charging "little and often" and not discharging the batteries deeply, will give a better cycle life, with the possible exception of some cell types that like the occasional deep discharge/charge.

Bear in mind that some battery types require careful cell monitoring and control to get the best life from them. Lithium cells, in particular, are very fussy about being charged and discharged within very closely controlled limits. Looked after, they have a long service life, allowed to get out of balance and their life can be very short indeed, which will play havoc with your running cost



Then there is also this advice;

That said, with lead acid batteries at least, it is a good idea to discharge them to much lower levels once a week or so - otherwise you'll find your overall range will reduce.


I must admit all I do is charge them up at the end of a run, and give them another top up charge before the next run.

 

Offline Umpa

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Re: Looking after your batteries
« Reply #1 on: 26, June, 2009 - 16:22:03 »
My very expensive calcium battery is dead after just 5 months. I used it with a Halfords Advanced Charger and alway charged it right after a run usually with only one green light out, and never ran it past the Sinclair battery protection. I'm now on my 85AH Fullers leasure battery.  I hope to get a replacement.

I'm looking forward to the Sinclair battery I'm getting tomorow ;)