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Old 01-21-2003, 10:03 PM   #16
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I have sourced my batteries especially from a local supplier and they are definately NiMH and definately 2400mAh and definately High Voltage.
I will try and find some Info on my charger. It is not a well known manufacturer but seems to be quite good quality. It cost me $265.00Australian Dollars... The charger seems to Auto Detect whether it is NiMH or Nicad< I have no manual control over the setting.

If you charge by temp then do you have a recommended temp reading??
I am going to try charging by the voltage drop method and see how it goes. I am also going to ensure the packs are cool before charging them. Would putting them in the fridge before charging to cool them help any??
Thanks for all your help

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Old 01-21-2003, 10:13 PM   #17
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Steevo,
Again ...keep in mind this info applies to 3000nmh.
for sanyo/6 amp charge/.04-.05 peak detect/ 120 degrees F
for panasonic/4-5 amps/ .02-.03 pd/ 108-115 degrees F

Just curious...who is manufacturer of your batteries?? Checked Sanyo site and they do offer a 2400 NMH. I suppose it's all a matter of marketing.
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Old 01-21-2003, 10:57 PM   #18
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My 2400s are by powertech. They are available from a local supplier. My 3000s are SMC Sanyo NiMH Cells.

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Old 01-21-2003, 11:05 PM   #19
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Steevo;

If the Treshold is NON adjustable on your charger, then look for a drop of around .03 volts (and the pack is warm) then just take it off the charger. As for the over charging, I'm going to bet it is an auto detect problem. A good pack might see 50-100 mah over the rating, but 200+ seems like too much (overcharged).
As for your Hissing and spitting pack, circular file (Trash can) it.
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Old 01-21-2003, 11:49 PM   #20
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Thanks Pops and every one else who gave their input,
I'll Put all suggestions into use and see what comes up trumps.
I might take the charger to where I bought it and ask them what they think as well.

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Old 01-22-2003, 03:51 AM   #21
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someones already said it, but I'll say it again...

mmmmmm............ fried batteries..................aaaaarrrrhhhh!!!!

Firstly, I would consider not buying the 2400 NiMHs again ( I don't know if you have other packs of the 2400s besides the fried ones). Since they are not something which is common in RC, they may not be too tolerant of high charge/discharge rates, ie it might not be the charger. I have seen RC packs take alot more than their nominal capacity and survive.... it's not good for them but I suspect 300mah extra wouldn't usually make an RC cell explode (well at least not when re-peaking) Take note that 2400 may only be their NOMINAL capacity

They may have high voltage or be a lot cheaper than the matched packs, but there are other cells out there which are cheap and very similar to the racing cells. Ideally, stick to what most racers use if you can.

Secondly, it seems extremely odd that a $265 dollar charger does not have a peak detect function with auto cutoff, but does have a digital voltage readout. The fact that you said your charger has "peak detect autocut circuit with mosfet" written on it should mean that it will switch the charge off itself, eliminating the need for you to switch it off. I suspect that unless the circuitry is dodgy, this is actually what's happening when it beeps, but in the case of the 2400's it's just not beeping early enough to stop the cells from overcharging.

On some chargers, the NIMH mode is for transmitter packs. If you are having probs with your sanyo 3000's, and they are HV's, I would be tempted to try the NiCD mode, as these cells can handle punishment. Whatever you do, make sure you try it first on a charge at home so you can monitor the pack constantly and use the advice above like monitoring the temp and if possible the voltage dropback. Generally, you will then be able to pick up signals before a pack fries....like it getting really really HOT: flaming:

Once you have it sussed at home, then try it at the track.

The best piece of advice here comes from your own last post,

ie: ask where you bought it from. If that fails, ask someone at your local track.
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Old 01-22-2003, 04:05 AM   #22
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Sleek,
What the charger does is not actually switch the charge off but takes it from "Fast Charge" to Slow Charge mode where it continues to charge but at a much slower rate. What I have been doing is waiting for the charger to beep which indicates that it has reached its peak and then disconnecting it so it does not try putting any more charge in. But by this stage there is usually about 2600 milli Amps in the battery instead of around 2400 mAh. It is funny though because my 3000mAh Sanyo Packs seem to charge OK. I fear that it is just the batteries not being mainstream batteries used for RC Cars.
The other thing is that my charger does not have a switch for switching between Nicad and NiMH. It has some sort of MOSFET and Fuzzy Logic which seems to do all the thinking.
I think I will just stick to the SMC batteries and be done with it.

Thanks for your advice
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Old 01-22-2003, 01:21 PM   #23
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On my charger you choose the charging profile by pressing the start button a set number of times! ie. once for mimh, twice for nicad and so on. The charger beeps the same number of times and has a mode led that flashes at intervals to show which charge mode is selected. I think perhaps this maybe the problem here. I have never heard of a charger that auto selects between the battery types.

good luck
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Old 01-22-2003, 01:36 PM   #24
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On my charger you choose the charging profile by pressing the start button a set number of times! ie. once for mimh, twice for nicad and so on. The charger beeps the same number of times and has a mode led that flashes at intervals to show which charge mode is selected. I think perhaps this maybe the problem here. I have never heard of a charger that auto selects between the battery types.

good luck
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Old 01-22-2003, 03:44 PM   #25
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Food for thought...

I have 4 cell GP3300's from World Class Batts which consistently take 3700+ in on a charge....

Don't worry about sitting and staring at your DVM waiting to see a 0.02 or 0.03 drop - feel the batteries.... are they warm?? then they are charged... Sanyos can take some serious heat - 120 degrees F - Oscar Jansen from Orion is talking about taking the GP3300's to 50 degrees C... HOT!! This shouldn't fry the packs... think about how hot your packs get just in discharging running a low wind mod in TC!!!

I have watched people charge brand new NiMH cells on a timer charger... JUST MAKE SURE THEY DON'T GET TOO HOT AND YOU WILL NOT FRY YOUR PACKS!!

OUT - Wilde
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