Pulse vs. linear charger for nimh?

Pulse vs. linear charger for nimh?
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Pulse vs. linear charger for nimh? - 3/10/2006 4:36:38 AM

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I will need to charge 3500-3800 nimh car packs.
Did I read some where that nimh batterys don't like pulse charging?
Tossup between Piranha Dig. Peak (linear, but no discharge) and Intellapeak (discharge capable, but pulse charge)

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RE: Pulse vs. linear charger for nimh? - 3/10/2006 12:15:34 PM

gerwen

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Results from the real studies done on it show that pulse (if it's the same as reflex, burp, etc.) gives no benefit to a battery. I haven't heard anything that says it harms them either.

For more info, http://www.rcbatteryclinic.com/ there's a link on the left side of the page.

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RE: Pulse vs. linear charger for nimh? - 3/10/2006 1:51:00 PM

richrd

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This ounds like fun post no to people agree on this

So IMHO it's a gimick.
On the other side it's designed to shake the plates to help clean off the oxides. Said to help old batteries with memory problems.
But very hard to prove anything so we people can say anything.

I tryed it once on me but I don't remember the out come

Rich

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RE: Pulse vs. linear charger for nimh? - 3/10/2006 2:53:34 PM

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In my thirst for knowledge, I read somewhere in RCU that NiMh's don't like the "Pulse", "Burp", charge.
Being a newbe, I guess I was overly concerned.
The DuraTrax Intellipeak, which I was prepared to order, is a pulse charger.
I'll be charging IB3800's from "Boat Guy".

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RE: Pulse vs. linear charger for nimh? - 3/10/2006 5:32:57 PM

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I'll chime in here on pulse chargeing. It is correct that some will disagree and most will recommend against "pulse" chargeing. Many chargers for nimh batts are a pulse charge, I question whether the intellipulse chargers are pulse chargers at all. Even so they are ok to use on nimh batts regardless. I'll try to post a few graphs of what I consider a pulse charge and a linear.

On the 2 specific chargers you mention the digital piranha is the more featur packed and far more adjustable yet it has a 3 amp max on ac and a 5 amp max on dc. The intellipulses have a 6 amp max, yet the recommendation is not to go over 3 amps for nimh. My thought is that the digital piranha is closer to a pulse than the pulse is. Really depends on how one wants to define "pulse"

The digital stops every minute for 5 seconds, the pulse just keeps a constant charge rate. (It may pulse so fast I cannot measure faster than 1 second intervals.)

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RE: Pulse vs. linear charger for nimh? - 3/10/2006 6:01:11 PM

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Thanx for your help.
I may be "Over-thinking" this this car thing, but as you may have heard, pattern guys tend to be some what anal..
As the "old retired guy" of the group, I have been charged (no pun) with assembling info to steer us (again, no pun) in the right direction.
A couple guys will use lipo's as they are familiar with them, and the wiring mods required.
I have always used Nicads, so I have a lot to learn about NiMh.
The Intellipeak has a discharge function, which I will need in "forming". Or so I've heard.
Thanx again, and keep the info coming..croz

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RE: Pulse vs. linear charger for nimh? - 3/10/2006 6:07:29 PM

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Here is the digital piranha at 5 amps

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RE: Pulse vs. linear charger for nimh? - 3/10/2006 6:11:35 PM

guver

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Here's one of the intellipulse chargers at 6.5 amps

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RE: Pulse vs. linear charger for nimh? - 3/10/2006 6:14:44 PM

guver

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Here's what I consider a "pulse" charger, a reverse pulse I would consider one that actually applies a discharge every once in a while. I have no real data, but really do not think it makes much of a difference. I do think that on a forming ot balance charge it is good to have a nice constant linear rate.

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RE: Pulse vs. linear charger for nimh? - 3/10/2006 6:22:09 PM

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Good stuff.
I expect to apply the forming charge with my Hobbico Multi charger at 250Mah for 16 hours or so. (3800 packs)
They will then be discharged on the Intellipeak.
Cycle will be repeated 3 times befor charging with the Intellipeak at 3Am.
Does that sound feasible?

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RE: Pulse vs. linear charger for nimh? - 3/10/2006 6:57:43 PM

guver

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I think 24 hrs would be in order for a rate of 250 ma on a 3800 pack. If you do not charge all the way up the balance may never occur.

3800/250 = 15.2 hrs then x 1.6 =24.32 total hrs.

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RE: Pulse vs. linear charger for nimh? - 3/10/2006 7:08:48 PM

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Well taken.
The next choice on the multi charger is 500 Mah.
Would that be too high of rate for about 8 hours?

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RE: Pulse vs. linear charger for nimh? - 3/10/2006 7:30:23 PM

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A multiplier of 1.4 should be used. maybe like 3800/500 = 7.6 hrs x 1.4 = 10.64 hrs

the other one probably should have been 1.7 x 15.2 hrs = 25.84 hrs.

The multiplier keeps going up as the rate goes down. How about a 250 cycle then a 500 cycle? Will the charger stay on constant or does it have a time out feature? Appliance timers work great too.

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RE: Pulse vs. linear charger for nimh? - 3/10/2006 8:02:19 PM

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It's a constant rate, much like a wall charger, except charge rates may be selected at 25-50-100-250-500 Mah.
I thought I read that NiMh packs don't like to be on a charger longer than 24 hours.
There again, perhaps I'm "over-thinking".

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RE: Pulse vs. linear charger for nimh? - 3/10/2006 9:16:56 PM

guver

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Hmm, I have heard about no pulse chargeing, but never heard the 24 hour one.

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