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View Full Version : Precious battery treatment?


VONDUTCH
17-01-2007, 11:16 AM
Well you guys seem to be such a treasure trove of info and advice thought I'd give it another go.
What's the deal with the charging and discharging of Ni-Mh batteries? I've not yet met anyone or read anywhere the reasons behind their precious treatment. Are modified motors so wild that they cannot last 5-6 mins offroad-in my limited experience this is not true.We get 4000mah batteries and use perhaps half that and then discharge the rest only to recharge them again-I thought Ni-Mh had no memory and that was one of their advantages?
I realize I'm only a beginner but I use my 3300mah for at least 2 if not 3 heats (bargain;) ) Now I will admit that's in a stock motored,low geared 2wd buggy but it still seems to fly in the face of what I see most other people doing???
I'm unemployed and on a tight budget but I'm sure I'm not the only one so what's the best factually correct advice on the treatment of batteries.Surely it can't just be about a case full of cells,specialised discharge trays,pc link ups and extreme priced chargers.
Hope this isn't too much to ask:( Thanks guys ahead of any help:)

mark christopher
17-01-2007, 11:37 AM
Glyn ward and battery manufactures are saying there is no need to discharge and re charge and topping up is ok

Hog
17-01-2007, 12:41 PM
From my experience, by far the best thing you can do with NiMH cells is to equalise them regularly.

I've never noticed any real change in performance if I'm running off a fresh charge, a top-up, or a partial dump and charge.

The drop in performance for me comes from when the cells are not regularly equalised - especially if your cells are not brand new or "matched" to begin with.

My 3700's get used once a week (until we come to the regionals :) ). They get charged on a Tuesday night or Wednesday afternoon (owing to time constraints), given a top up just before using them Wednesday night, then after the race I leave them as they come out of the car. I know they don't like to be left flat, and as the self-discharge rate is higher than that of a NiCad, it seems logical to leave them with more than their residual voltage in. The following Tuesday or Wednesday I will discharge them at 20A on my Eagle CDC to a 5.4V cutoff, then equalised on my LRP board (a good use of £15!).

They are just starting to lose their punch (more noticeable as I race 27T) but considering they were bought early 2005, are used weekly, and have done 2 seasons of S E Regionals, I don't think that's too bad.

Going to invest in some 4200's or 4300's before the 2007 season though. The 3700's will be relegated to 4 cell oval duty!