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PostPosted: Tue Feb 20, 2007 9:56 am 
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Joined: Wed May 31, 2006 10:34 am
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Location: J'ville, Wellington
Kelvin got me a charger that discharges, and charges at various amps for a good price. I would highly recommend it. Night and day between this and the timed charger I was using prior to that. Even just for bashing around the back garden.


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PostPosted: Tue Feb 20, 2007 12:19 pm 
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Shane,

If your not racing seriously a discharger isnt a necessity. Its is nice to have though. Just remember to put some charge back into your cells if you have flatten them right off. if theres still a reaonable amount of power in them then just leave them like that.

BTW did I send you that info the other day? I should have some charges in the next couple of days. I finally tracked them down.


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PostPosted: Tue Feb 20, 2007 7:25 pm 
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idle wrote:
dischargers come in handy. I discharge cells/packs, or rather cycle them, if I haven't run them in a while.

Shane, depends on what you call cheap, but the one thing I can say is don't get a cheap charger. Especially those nasty ones with a timer dial. Minimum order would be an e-station from J&Ns. They're about $150. Otherwise I'd recommend a MuchMore charger or something like an Apex Sigma (or whatever evolution Apex is up to today).

Get one that can do charge/discharge cycles, with adjustable voltages, and if it's real flash it'll be able to charge at variable ampages. The variable voltage jobbies are good because they help prolong cell life by slowing down the charge when the cells get too hot. At 5 amps, those cells are going to get mighty hot after 50 minutes. Too much heat for too long will (eventually) cook the batteries. If you give them a full charge and chuck them straight in a car without waiting for them to cool down, you're speeding up their death.

Some variable chargers detect heat and slow down the charge rate, while some are totally programmable, so you can set them to 5.5 amps for the first 1000mah, then down to 1.5 amps until they get to 2000mah, then 5.5 amps again for the final charge.


I have an Orion advantage charger which also does "step" charging. Worked fine on 3300's and after a bit of research, apparently isn't really required with 4200 NiMh. Linear charge at 5 amps(mod) and 6 amps(stock) seems to be the go. Unfortunately the cell temp at peak voltage was in farenheit and I couldn't find a conversion thing to work it out :wink:

Heat isn't the killer of these cells, as it was with the older "first generation" of NiMh though(3000 sanyo/powers from waaaaay back). Excessive heat of course is a bad sign, as is venting of material :shock:

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PostPosted: Tue Feb 20, 2007 10:15 pm 
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Joined: Tue Oct 18, 2005 11:14 pm
Posts: 743
Location: wellington
very interesting.. amazing how much battery technology actually changes without appearing too different to the average joe...

a google search gave me this as the first hit:

http://www.wbuf.noaa.gov/tempfc.htm

bookmark that puppy.


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 Post subject: Hitec Peak Charger
PostPosted: Wed Mar 07, 2007 9:27 pm 
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Joined: Sat Jan 28, 2006 3:08 pm
Posts: 49
Location: Waikanae
Can a 7.2V battery pack be charged correctly with my Hitec Peak Charger through a car battery charger? The Peak charger runs at 2Amps, and the Car battery charger 2.5Amps.

It would be easier for my son to charge it this way, rather than relying on our car battery.

Would this work? Would it still detect the peak charge?


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PostPosted: Wed Mar 07, 2007 9:40 pm 
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Joined: Tue Aug 08, 2006 8:50 pm
Posts: 67
Location: kapity coast
yes surprisingly it works i tryed it because i coulnt get hold of a car battry half the time

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