Charging Batteries that need negative delta V??

[viperx07]

I just got the ICE charger and I have been looking at some batteries online and for example, some of the Trinity ones say that you need a charger that can do zero delta V or negative delta V. What does it mean by negative delta V? Can the ICE do that? If not, I should just charge it at zero delta V or can I charge it at 5mV for example?

[SS Pede]

I don't know why they call it "negative" delta V. Must be a technical term. Any decent peak charger will work. Your ICE will be great. Assuming these are modern NiMH cells 5mV per cell would be fine (that's 30mV for a 6 cell pack). Might get away with a bit less. But there's no way to set a peak theshold of zero or negative.

[viperx07]

the ice can have zero.

[SS Pede]

Oh...well I'm not sure what that would do. Don't use that feature, stick with 5mV or so. :)

[guver]

0 is surprizingly accurate and all peak chargers and batteries use "negative" whether it is specified or not. It is because it is a DROP. Less than <<

I wish it went from 0-20 and didn't skip 1 and 2 mv.

[Duster_360]

Ice has an option for setting a "ZEROpk" or zero volt delta peak for nimh. This means the charger will try and find the "exact" voltage peak. The manual says only batts in good condition and you have to use currents and voltages that are clean and stable for that setting to function.

Maybe the requirement for clean and stable power is why Ice skips 1 and 2mv for possible settings. I had prob at office I used to work in and watched IT guys set up and measure voltage and freq coming out of the wall, the amount of fluctuation was startling, voltage and freq was all over, 108-124v, 52-63cps. Using an AC based charger, I had trouble in my house with false peaks until I put the charger on an isolated circuit.

[viperx07]

But with an INTEGY SHE power supply and ICE charger it should be good right?

[SS Pede]

Hmm, learn something new every day. I guess I was thrown off by the fact that "most" batteries will false peak on most chargers if you try to set the peak threshold really low. I guess zero would be a really accurate charge!

That power supply will work but I seem to remember people recommending a 15A power supply for the ICE. Unless there's a 15A version of the Integy PS that I'm missing.

[viperx07]

why would u need a 15 amp if im only charging at 5 amps?

[Duster_360]

It depends on how "clean" the DC output is.

Thats a relatively expensive power supply, tech on Tower mentions voltage is filtered - expect that means its clean. Realize the Ice manual also says the batts have to be in good condition. I'd expect it to work with good batts using zeropk.

The Ice manual calls for a 15amp supply so the charger will be "fully enabled".
Higher amps are needed to charge a batt and run a lathe or breakin a motor at the same time. If you're only charging, you won't need as much. I'm only using a 10amp PS and mine has never had a prob charging.

[viperx07]

does that mean I can use 2 ICEs on one SHE power supply if im going to charge at around 5 amps each?

Another thing: I just built a brand new IB4200 matched pack and when I did zero delta V, it only went to about 4000 mah and discharged 3700 of it. Tthen I did 0 dV and did repeak, so it went 3973, 4241, and 4474. That discharged 3962. Later on I did normal charge with 5 dV, and it went to 4263 and discharged to 3963. Weird huh? Any explanations?

[guver]

The power requirement for the input is directly related to the output (add a small bit for heat/inefficiency) Multiply the voltage by the current. Any number of chargers can be used on a power supply. The currents cannot be compared, neither the voltages unless the other one is identical.

Ok that's maybe confusing.

output voltage of 6 cell pack multiplied by current equals power requirement. (9 volts x 5 amps = 45 watts) Doing the calculation backwards tells you which power supply is required (45 watts / 12 volts = 3.75 amps) If you are using two ice chargers then you will need 7.5 amps (use 8 amps+) for the power supply.

[Duster_360]

....Another thing: I just built a brand new IB4200 matched pack and when I did zero delta V, it only went to about 4000 mah and discharged 3700 of it. Tthen I did 0 dV and did repeak, so it went 3973, 4241, and 4474. That discharged 3962. Later on I did normal charge with 5 dV, and it went to 4263 and discharged to 3963. Weird huh? Any explanations?

New batts can take several charges before they settle down. Try again after several more charges. Since these are matched to start with, doesn't sound like zeropk is that hot of an option.