discharging batterys

Old 10-09-2003, 10:19 AM
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Default discharging batterys

i just made a auto cut off discharger and i just wanted to know if i should discharge it to 4.9 volts when it is connected to the light globes or when its has be disconnected
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Old 10-09-2003, 04:10 PM
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when its connected to the discharger
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Old 10-09-2003, 05:39 PM
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Originally posted by 414m2
when its connected to the discharger



you're a funny guy.


I remember many years ago, a DSE Nicad discharge kit instructions mentioned discharging only to 1.1v per cell (6.6volts for the whole pack) so that there is minimal risk that the cells might reverse polarity.
I dunno how relevant this is anymore with advancement in battery technology.
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Old 10-09-2003, 06:26 PM
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The current theory is that you should take them to 0.9v per cell or thereabouts. Some chargers like the eagle/trinity/whatever CDC take them to 0.8v per cell - this doesn't matter. Somewhere about that voltage is good.

4.9v for a 6 cell pack is fine - the CDC takes them to 4.8v. 4.9v for a 4 cell pack is kinda useless

-Scott
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Old 10-09-2003, 07:40 PM
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Discharge till its 4.8v and you cant go wrong....just dont leave it discharged for too long....like months or your cells will reverse...more likely in nicad.
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Old 10-09-2003, 07:48 PM
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i throught it was better to leave batterys discharged over long amount of time
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Old 10-09-2003, 07:53 PM
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Originally posted by sloany
i throught it was better to leave batterys discharged over long amount of time
only one or 2 weeks, after that it will damage if you don't put in just a bit of power.
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Old 10-09-2003, 08:06 PM
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Firstly, 414m2 is talking about NiMH cells when he says "dont store them discharged". If you're running nicads, discharge them to 5.4v or 4.8v or whatever and store them.

Discharge till its 4.8v and you cant go wrong....just dont leave it discharged for too long....like months or your cells will reverse...more likely in nicad.
Not sure what the hell he's on about here, but...

With NiMH cells there's a hundred different ways of treating your cells. Pick one and stick to it. Most guys either discharge to 5.4v and store it till next run (same as a nicad) or discharge to 5.4 and put 20% charge or so back into the packs then store it.

Some guys like SMC (http://www.smc-racing.com) recommend completely flattening your packs then dead shorting them - which goes against everything anyone's ever believed about r/c NiMH cells - but this DOES give you better voltage, at the cost of runtime! (ie runtime will decrease). This is generally used for stock racing. This will decrease the lifespan of your pack most likely though. Really only recommended if you know what youre doing.
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Old 10-09-2003, 08:16 PM
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after i ve finished discharging my batterys and disconnected it, it is around 7-7.1 volts is this alright or should i discharge them more
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Old 10-09-2003, 11:00 PM
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what dose the novak millenium pro discharge at
and what chargers do yous recomend.
im looking for one that dose everything needed for looking after
3300gp s
thanks
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Old 10-10-2003, 12:04 AM
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I use and recommend the Eagle CDC 6.0
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Old 10-10-2003, 12:10 AM
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Sloany, the 5.4v (or 4.8v or whatever) cutoff is the amount it cuts out at under load - not when it's just sitting there. Try putting a multimeter across the battery when it's discharging and see what the readout is just before it cuts off.

As for chargers, CDC 6.0 is the go. Probably the best bang for buck out there. Well, best that I know of anyhow.

-Scott
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Old 10-10-2003, 01:40 AM
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the voltage just before cut out is 4.9volts to 5.2volts(using different batterys) is this alright or should the cut off be higher or lower
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Old 10-10-2003, 06:23 PM
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Get a cdc v6....


if you leave nicad cells discharged for too long then they can reverse...lots of mine have for that same reason.
Nimh cells don't reverse so easily.

IF you want to store your nicad for a long time then put SOME charge in it or it will get damaged/reverse.

Sloany thats a good cut-off. Just leave it like that...
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Old 10-10-2003, 08:23 PM
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414m2 - I have never heard this before in my life. However I do see a fall in performance in my cells if I leave them dumped for two weeks instead of my usual one week. If you just discharge to 5.4v and then store them they don't loose charge quickly. I store mine with low drain dischargers attached so within a week they will be fully dumped and equalized. I would never leave my nicd's charged when storing, I only ever store them discharged.

414m2 - I doubt your cells reversed, they probably needed a few cycles to come back to life, I see this with my nicd's if I don't use them for a few weeks.
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