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Old 05-02-2004, 05:54 AM   #1
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Default Linear/ Pulse charging

Can anyone tell me the difference, and why it is that you are meant to use linear for NiHM?? What damage does Pulse do to NiHM??

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Old 05-02-2004, 06:54 AM   #2
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I would like to know that too; I have a pack of unmathced Sanyo 3000 HV, which is down to 2000-2100 mAh in discharged capasity at 20 A discharge rate.

They have been charged on a pulse charger with trickle charge. They have also been equalized down to 0,6 volt pr. cell on a Orion EQ. Charge rate was always 6,5 amps.

Personally, I believe it was the pulse and/or the trickle charge which lowered the capasity, but I would like to hear from someone with knowledge in this.
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Old 05-02-2004, 07:59 AM   #3
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linear is one constant charge at one amperage

pulse is like it charge for a few seconds or so at a time then stops and begins again from my understanding...i dont know if the short stops result in a small discharge or not though

i think the pulse charge was meant to help older cells come back a little if they are tired or havent been used in awhile...kinda like a tiny zap...sorry i cant help more...maybe someday can clear it up for you
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Old 05-02-2004, 09:18 AM   #4
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Never pulse your NiMH, always only use Linear charging.
Your charger must be capable of peak-detecting a NiMH.

Pulse charging is only for nicads.
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Old 05-02-2004, 09:45 AM   #5
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Default what is. . .

Flex Charing in the LRP Pulsar Competition?
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Old 05-02-2004, 10:15 AM   #6
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I believe flex charging is just anouther name for pulse charging.
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Old 05-02-2004, 10:37 AM   #7
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Integy tech support told me that no matters if the pulse charger DOESN't make a BZZZZZZZZZZZZZZZZ noise during charging....

if the charger makes this noise then it won't safe to NIMH cells...
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Old 05-03-2004, 07:16 AM   #8
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Seems like we all knows the rules, but nobody know WHY it is this way?
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Old 05-03-2004, 07:31 AM   #9
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I'm not exactly sure why....its just one of those unwritten rules.
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Old 05-03-2004, 08:00 AM   #10
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Like Anonymous says. Linear keeps charge current constant. Pulse turns charging on and off constantly and the charge current you've chosen will be the average current.
Pulse should give you slightly higher voltage, depending on cells. You're charging at higher amperage but giving the cells time to rest between pulses so they don't heat up as much. The first NiMH cells were very sensitive to charging current.

It is flex charging you don't want on your NiMHs, flex charging reverses the charging current momentarily to condition the cells. (I've heard that GP cells like flex charging and all the stuff we used to our NiCds but couldn't do to Sanyo and Panasonic NiMH because of their fragile construction)

Cole, cells lose capacity over time, they dry out and change their characteristics when the plates get "anodized" and crystals form in the insulation. You could try to slowly discharge the cells to zero and then charge them at 1C to 2C (C=Capacity. 3000 mAHr cells = 3amp charge current = 1C) with pulse charge and flexing until they're very hot, it will probably increase their capacity somewhat. But it could kill them permanently .
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Old 05-04-2004, 03:09 AM   #11
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Thanks, andsetinn.

But it's confusing that most of the mathcers (if not all) says use linear charge for NiMh, not pulse. And now you say the opposite?

I'm familiar with the differences between pulse and flex and linear.

About my older packs, I tend to begin charging them at 7 amps, to get the most punch out of them.... I'm racing stock Then they may last as long as they can

About loosing capasity, my NiMh have lost a lot, while my NiCd 1700 and 2400 almost havent lost anything And the NiCd's are older AND more abused
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