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View Full Version : What happens when discharge cutt-off is to low?


LED
2011.09.04, 01:30 PM
Hey

I was wondering, what happens to batteries if the discharge cut-off voltage is to low.
I have been using a PN discharge tray for a couple of months now, and I checked to what voltage they discharge. Like I read on the forum here other people also state that its much lower then 0.7V. Mine are all between 0.45 and 0.52 V after 2 hours in the tray.

So again, whats the ffect on the batteries?

Thank you

RC.DNA
2011.09.04, 01:48 PM
Take a look at the Over-discharge section. Over-discharge will cause polarity reversal.
http://en.wikipedia.org/wiki/Nickel-metal_hydride_battery

benmlee
2011.09.04, 07:53 PM
Take a look at the Over-discharge section. Over-discharge will cause polarity reversal.
http://en.wikipedia.org/wiki/Nickel-metal_hydride_battery

Discharging batter on the PN battery tray will NOT cause voltage reversal. Wikipedia said: "further discharge may cause permanent damage in the case of multi-cell packs, due to polarity reversal"

Only happens in multi-cell pack. Voltage reversal only happens in the car where cells are connected together. Never when cells are separate like in many discharger like the PN one.

LED
2011.09.05, 02:02 AM
I tought as much to,but it doenst realy provide an answer to my question.
I would like to know if the cells get damaged because they are discharged to 0.5V instead of 0.7.

tastetickles
2011.09.12, 07:24 AM
My experience with NiMh cells and packs is they never really die straight out even when they do not accept charge anymore when over-discharged. Over discharging is undoubtedly bad for the cells but you can always revive cells that refuse to charge by using non-trickle chargers that charge at 200mA, bring the voltage up and the regular charging can be done. They don't hold charge as long any more though but they are really cheap, lipos on the other hand are like over-fertile women no matter how much precautions you take.