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glancyguy

Peak Charging For Idiots

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Hello,

I purchased a peak charger for Christmas, replacing my Tower Hobbies 15 minute wind-up cheapo. I thought using a peak charger would take the science out of determining whether a battery is getting the right charge. It is science and I am clueless. The charger asks me 4 things:

1) Battery type "NiCd or NiMh" - Easy one

2) mAh- Another easy one

3) AMPs - The intensity of the charge - 3 AMP max for AC current

4) Peak Detection - mV/C - ABSOLUTELY CLUELESS

The instruction manual recommends that I should set this to 3mV/C for NiCd and 6mV/C for NiMh. The manual then went on to say that if I set it too low, it may cut off before the charge completes. If I set it too high, it may overcharge and damage the battery. I set the mV/C to 6 (as the manual suggested) and charged my 4600 maH NiMh battery. When it was done, the battery was borderline hot. My goodness. I was under the impression that a peak charger figured this all out for me. B)

Here are my batteries:

Tower Hobbies NiCd - 1500 and 1900

Duratrax NiMh - 3800 and 4600

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you have a good question there. i dunno. my peak charger does all of that automatically. all i have to do is set the amp rate. what kind of charge is that one?

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OK.. You seem to have the first 2 sorted, so that just leaves the charging current, and the delta peak settings...

Battery / cell manufacturers generally recommend "Fast Charging" at a rate no greater than 1C, (or 1 x the capacity of the battery)...

For me personally, I would set the charge current to the chargers maximum of 3A and leave it at that for all of your batteries...

For the Delta Peak Voltage setting, its probably easier if I give you a basic explaination of what it is.. When a NiCd or NiMh battery reaches full charge, the voltage hits a maximum (PEAK) value, and then "changes" (DELTA meaning change) and the voltage starts to drop or reduce as the battery starts to go into overcharge.. So this setting referrs to the point at which the Batteries Voltage reaches its PEAK, and then Changes (DELTA) and starts to drop...

What a "Delta Peak" charger does is monitor the batteries voltage, and when it senses the Change in Peak voltage, the charger turns off with the battery being fully charged.. With your charger, you can adjust the point at which the charger registers the change, so as to remove the possibility of having a pack false peak, and also ensure that the pack is fully charged.. The greater value you set the Delta Peak setting at, the more your charger will overcharge your battery..

Most NiMh packs dont like to be overcharged at all, so I generally use a setting of between 3 - 6mV per cell (8mV/cell maxumum for my older packs)..

For NiCd, I generally use a setting of between 8 - 12mV per cell (but sometimes upto 15mV/cell for my very old packs)..

You will have to experiment with the Delta peak setting, but I recommend starting with a low setting, and gradually increasing it if need be.. If you find that the charger is turning off, but the batteries are not warm, then they have probably "falsed peaked", and you will need to restart the charger.. (When NiCd and NiMh batteries are fully charged, they should be slightly warm (not hot) to the touch..)

I hope this helps..

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You will have to experiment with the Delta peak setting, but I recommend starting with a low setting, and gradually increasing it if need be.. If you find that the charger is turning off, but the batteries are not warm, then they have probably "falsed peaked", and you will need to restart the charger.. (When NiCd and NiMh batteries are fully charged, they should be slightly warm (not hot) to the touch..)

I hope this helps..

Great post and it helps a lot. I set the peak at 3 for my 3800 and it was warm. When I set it to 6 for my 4600, it was hot. So, is it safe to say that I should set the 4600 permanently to either 3, 4, or 5?

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ok. heres a question for you. if the batterys should be warm not hot, does that mean that my peak charger is over doing it since they are border line hot?

also, is false peak detection/elimination that same thing as delta peak?

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ok. heres a question for you. if the batterys should be warm not hot, does that mean that my peak charger is over doing it since they are border line hot?

also, is false peak detection/elimination that same thing as delta peak?

im new to this but i bought a n ansmann powerjack 6 delta pro it was cheap and works just fine its not a fast charger ,takes about 3 hours but its has a red light when its charging an a green light when its done simple but effective.

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ok. heres a question for you. if the batterys should be warm not hot, does that mean that my peak charger is over doing it since they are border line hot?

also, is false peak detection/elimination that same thing as delta peak?

Look, charging is not an exact science... There are just too many possible charger / battery combinations to know how each setup will perform..

As a NiCd or NiMh battery reaches its peak (full charge), and then starts to go into overcharge, it will start to warm up, as the battery starts to burn off the additional energy that is supplied by the charger as heat... Obviously, if the charger didnt stop charging at this time (say if you were using a timer charger or charging leads), then the battery would continue to heat up, and ultimately result in the pack failing...

I am not at all familiar with the term "false peak detection/elimination"... A "false peak" is probably best described as an "ERROR" in the charging process, where for some reason, the batteries voltage has dropped below the chargers set or preset delta peak voltage value, and the charger has turned off without the battery being fully charged.. That said, yes, increasing the dalta peak voltage value will reduce the risk of a false peak, but at the risk of overcharging your pack.. False peaks are inconvenient, but they will not damage your battery and this is why I suggested selecting as low of a delta peak setting as possible, and then increasing it as required...

If you feel that your charger is "overcharging" your NiMh packs, then you may want to check that your charger is designed to charge NiMh battery packs.. Often the main difference between a NiCd charger and a NiMh /NiCd charger is the preset "delta Peak" setting... IMO, if you have a charger that does both NiMh and NiCd, and there is no way of altering he delta peak setting or setting it to NiMh or NiCd mode, then obviously the manufacturer has had to compromise on the delta peak setting, and use a delta peak value that is high enough to stop a NiCd pack from false peaking, but yet low enough so as to not overcharge a NiMh.. (again, only a theory)...

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you have a good question there. i dunno. my peak charger does all of that automatically. all i have to do is set the amp rate. what kind of charge is that one?

What type of charger do you have? I need something that will do all that for me automatically :)

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It seems really odd to me that that this charger would ask you what type of pack you have (nicad/nimh) and then still ask you for the delta value. On an inexpensive charger, these settings SHOULD be one and the same. I can tell you that if your pack is too hot for your liking after charging is complete, simply lower the delta peak value. This will cause the charger to shut off sooner.

Nicad should have a GREATER mv/cell than Nimh, because Nimh is much more sensitive to overcharging. I wonder if they have a typo in the manual (and a bad one at that)... :(

Chargers that feature False Peak elimnation typically referes to a feature that locks-out the voltage monitor for the first few minutes of charging. Thats because most Nimh cells have a tendancy to experience voltage drop as the cell chemistry warms during the beginning of the charge. The current through the cells generates heat which lowers the internal resistnace of the cells and therefore causes the voltage to go down (this is a good thing). Unfortunately this early voltage drop can cause a peak-detection charger to shut off prematurely.

If the pack isn't warm when the charger shuts off, the battery has false peaked... :lol:

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