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Imax B6 problem/question?

Imax B6 problem/question?

Old 07-17-2016, 05:52 PM
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Default Imax B6 problem/question?

Hi guys!
I'm new on this forum. Also, my english is a little rust (sorry).

So, I have an original Imax B6 and I did a pack battery with 8 Nimh batteries. Each cell has 1,2v. The total of the 8 cells is 9,6v (it's for my old rc car. The original battery broke).
The batteries brand is Turnigy 2550mah (LSD - low self discharge). Before use the pack, I decided to fully charge each cell. However, the Imax didn't stop charging at 2550mah. When I took a look, it was at almost 3000mah (didn't stop). It happened in every cell. The Imax doesn't stop charging each cell.
I use manual mode in Nimh charge. Fist I use 0.1amp. Then 0.2 amp. Then 0.3amp. But it's the same.
Also, the cells doesn't warm up.
What's happening?

I tried to discharge all of them to 0,1v. But in some cells, the Imax stoped at 1v or 0,9v. Only on 2 cells it stoped on 0,25v
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Old 07-17-2016, 11:47 PM
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At such low charging current the delta peak (stop) detection will not work. And because the low current the overcharge is disipated in a low -not to feel- heat due the low current.

If it is an AA battery pack then charge them with 1.2 to 1.8A
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Old 07-18-2016, 12:16 AM
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Discharging a nimh to 0.1V would destroy the cell permanently. Where did you come up with that idea? 0.9V per cell is the lowest you should go. And just as the above post states - delta peak does not work with very low currents.
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Old 07-18-2016, 01:30 AM
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What is the delta peak? I mean, the delta peak is the same in every Imax?.
I put, now, 0,5 amp and the cell started warming up
However, the Imax show 1,57v (charging) and didn't stop yet. Is it normal?

First, I put low current to not damage the cell (low current is better than high current).
I decided to discharge them fully to charge them fully, to know the exactly capacity...
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Old 07-18-2016, 02:43 AM
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To be honest, one simple google search about delta with batteries peak will give you a lot of information.....

While charging the voltage of the pack will raise up. When it reaches the peak it is almost full. Beyond the peak the voltage will drop again, after some (5 to 10) mV per cell voltage drop the delta peak is detected and the charger stops.
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Old 07-18-2016, 06:22 AM
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With 0,5amp, now the capacity is almost 2000mah and the voltage is 1,57v. However, the cell charged last night to 2550mah (I stopped, because the current was 0,3amp). So, the cell, now, must have 4550mah. It should stopped... The capacity of the cell is 2550mah.
Something is wrong with the "delta peak"...
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Old 07-18-2016, 06:52 AM
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Originally Posted by Roelof View Post
To be honest, one simple google search about delta with batteries peak will give you a lot of information.....

While charging the voltage of the pack will raise up. When it reaches the peak it is almost full. Beyond the peak the voltage will drop again, after some (5 to 10) mV per cell voltage drop the delta peak is detected and the charger stops.
I did a research, but I didn't understood very well the "delta peak". How can I know the delta peak for my AA Turnigy 2550mah LSD?
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Old 07-18-2016, 09:04 AM
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As long the charger is in NiMh mode the delta peak by default is right. The only thing is that it needs a higer charging current to create that delta peak effect where the charger acts on. The overcharge will not damage the battery, many cheap charging systems do work in this way.

Again: with such slow charging currents the delta peak is not detected and the overcharge is transferred into heat what you will hardly notice. It is not that you push 4500mAh into the battery.

Your battery is for sure full. Use it and when empty use a higher charging current as sugested or buy a simple wall outlet charger or a multi charger like the famous Robbe 5 charger and stay charging with those low currents.
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Old 07-18-2016, 10:55 AM
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Thank you very much, guys!!

My 8 cells are spot welded in serie (9,6v).
So, I can charge them in serie in Imax with high current (it will detect the delta peak, right?)

Or I can charge them in serie with Imax with low current (to preserve them), but with a limit of 2550mah (capacity limit on settings on Imax), right?
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Old 07-20-2016, 06:13 PM
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Default Delta Peak Imax B6

Hi everybody!

How can I know the right delta peak to use on Imax B6?
I'm charging some 2550mah 1,2v AA turnigy (LSD - low self discharge) cells with low current (0,2amp). However, the Imax doesn't stop at 2550mah (even 3000mah, etc).
The cells don't heat (only a little little little warm)
I'm using the Auto mode (better for low impedance. Same as LSD? :s )

Thanks!
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Old 07-20-2016, 08:29 PM
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As previously mentioned with low charge rates the delta peak detection will not work, at least not reliably. Go by time/capacity with low charge rates. The extra capacity is going into heat, but it is slow enough they don't get excessively hot. Still don't leave it on for extended periods, will cause damage over time.

Or use a higher charge rate (amps), then the delta peak should work. I've had good luck with 0.5A on those cells (different chargers), others have reported needing around 1A or maybe even more for the delta peak to work reliably. Depends some on how well the individual cells within the pack are matched.

I can't remember the delta peak I've used with nimh offhand, will try to check and update.
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Old 07-20-2016, 08:38 PM
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Some info that may be useful.

Simple Guidelines for Charging Nickel-based Batteries

The charge efficiency of nickel-based is close to 100 percent up to 70 percent charge. The pack remains cool but it begins to warm up with decreased efficiency towards full charge.
Nickel-based batteries must cool down on trickle charge. If warm, trickle charge is too high.
Consumer chargers do not always terminate the charge correctly. Remove the batteries when warm to the touch. Discontinue using a charger that “cooks” batteries.
Charge at room temperature. Do not charge when hot or at freezing temperatures. (See BU-410: Charging at High and Low Temperatures)
Nickel-based batteries are best fast charged; a lingering slow charge causes “memory.”
Nickel- and lithium-based batteries require different charge algorithms. A NiMH charger can also charge NiCd; a NiCd charger would overcharge NiMH.
Do not leave a nickel-based battery in the charger for more than a few days. If possible, remove the packs and apply a brief charge before use.

Charging Nickel-metal-hydride
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