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New guy needs help with charger

New guy needs help with charger

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Old 02-02-2009, 05:21 AM
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Angry New guy needs help with charger

MRC Super Brain 989
Hi guys I need some help with this charger. I have been trying to set it up for a 4500 NiMh battery and the darn thing wonít charge completely. I think that I donít have the correct settings I have tried four different batteries and I get same result with all of them. Below I have the link for the USERíS MANUAL and what settings I have for Charging and Discharging. I would really appreciate any and all help that I could get from anyone and thanks in advance for your help.

http://www.modelrectifier.com/resour...989_manual.pdf

Note: A cycle includes both a discharge and a charge.
Note: 1,000 mAhís equals 1 Amp. Example: 3300mAh is 3.3 amps and 640mAhís is 0.6 amps.

You can use this formula to determine (approximate) charge/discharge
times for a battery pack in good condition
Capacity ų Amperage = Time
Example: 3000 mAh ų 1500 (Amps) = 2 hours.
If the capacity is lower than the amperage then multiply the result by 60 and that will give you time in minutes. Example: 3000 mAh ų 6000
(Amps) = 0.5 x 60 = 30 minutes.

Charging

Type: NiMh
Cell: 6
mAh: 4500
Amp: 4.50
Cut off Peak: 5mV
Temp cut off: 140F
Trickle Amp: 0.10

Discharging

Type: NiMh
Cell: 6
mAh: 4500
Amp: 2.00
Cut off: 0.90
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Old 02-02-2009, 05:31 AM
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How many mah does it put in?? What is the temp when it is done? How far down do you run it before charging? Discharge it to 5.4v (6-cell)and go from there.Also I charge my nimh packs at more than 1C. I charge my 4200mah at 5.5 amps.
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Old 02-02-2009, 06:20 AM
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how do you know its not charging all the way??

turn it on to a charge only mode, instead of a cycle mode
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Old 02-02-2009, 08:21 AM
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Originally Posted by whitrzac View Post
how do you know its not charging all the way??
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Old 02-02-2009, 09:23 AM
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Racer1812

It put in about 2700mah at the end of the charge. Temp was 110, basically with my discharge settings that I have I start the charger and let it do its thing and once it is done I start charging. Now you mentioned to discharge it at 5.4v (6-cell) can you explain that in more detail please also on the more than 1C what do you mean by that I know that all of this questions may sound dumb for someone that knows what theyíre doing but for a rookie itís hard. Thanks for your help I do appreciate it.
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Old 02-02-2009, 09:31 AM
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Whitrzac

I know itís not charging all the way by what I get from the charger display and the numbers that I get at the end of the charge. As for the mode I have tried both and I get the same result.
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Old 02-02-2009, 09:49 AM
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It doesn't sound wrong that it's 110 degrees when the delta peak cuts it off. It's an either-or (temp or delta peak), whichever peaks first. Up the delta to 6 and you might get closer to 140 degrees. I think 120 is hot enough.

Superbrains are notorious for false peaking when on AC power with high output. If you use the DC inputs from a battery or power source you'll have more reliable results. If you're using the AC cord, you'll need to turn down the amps you're charging at - try 3.5.

It's also possible that your 4500 mah packs are sub-par, especially if they're old or has been sitting idle for a couple months or more. Packs after storage typically need several cycles to come up to full capacity.
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Old 02-02-2009, 02:06 PM
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are they tenergy??
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Old 02-02-2009, 02:16 PM
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I'm sure someone can explain this better than me but basically 1C is equal to mah divded by 1000 equals 1C charge rate in amps.

example 4500mah/1000 = 4.5 amps, 4200 = 4.2amps, 3300 = 3.3 amps

The exact charge rate is much important with lipo packs than nimh
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Old 02-02-2009, 03:56 PM
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Originally Posted by tiko View Post
Now you mentioned to discharge it at 5.4v (6-cell) can you explain that in more detail please
You've already got it covered actually. The last line of charger settings in your first post: Cut off: 0.90 This is per cell, the discharge stops when the battery voltage reaches 0.9 volts per cell. Or 5.4V for a typical 6 cell pack.

0.9 volts per is probably the most common cut off voltage, but the amp draw is typically higher for cycling.

Suggestion: Check each cell's temperature at end of charge (and discharge). Is there a hot one compared to the others? Might indicate a weak cell.
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Old 02-02-2009, 05:02 PM
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Originally Posted by tiko View Post
Racer1812

It put in about 2700mah at the end of the charge. Temp was 110, basically with my discharge settings that I have I start the charger and let it do its thing and once it is done I start charging. Now you mentioned to discharge it at 5.4v (6-cell) can you explain that in more detail please also on the more than 1C what do you mean by that I know that all of this questions may sound dumb for someone that knows what theyíre doing but for a rookie itís hard. Thanks for your help I do appreciate it.
just because you have a 4500mah pack does not mean you're going to be able to get 4500 into them. unless you start out with a totally dead/fully discharged pack (which you aren't, and shouldn't be) the 2700mah reading is all your charger is allowing to be put into them before peaking -- kinda like on a real car when you have a half-empty 20 gallon tank, you're only going to be able to put 10 gallons or so into it.

does that make sense?
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Old 02-02-2009, 05:15 PM
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i have quality 4200 packs that when discharged to .9v/cell they will take up to 4200-4300 mah to reach full charge. On a side note the lower the charge rate the more mah you will put in before the battery peaks but it also lowers the packs out-put voltage slightly... Racers are more worried about this.
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Old 02-02-2009, 07:21 PM
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Originally Posted by whitrzac View Post
are they tenergy??
yes they are
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Old 02-02-2009, 07:25 PM
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Suggestion: Check each cell's temperature at end of charge (and discharge). Is there a hot one compared to the others? Might indicate a weak cell.[/QUOTE]

Ok Dave I'll try that
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Old 02-02-2009, 07:31 PM
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Originally Posted by RobbieT View Post
just because you have a 4500mah pack does not mean you're going to be able to get 4500 into them. unless you start out with a totally dead/fully discharged pack (which you aren't, and shouldn't be) the 2700mah reading is all your charger is allowing to be put into them before peaking -- kinda like on a real car when you have a half-empty 20 gallon tank, you're only going to be able to put 10 gallons or so into it.

does that make sense?
Yes it does, but even if I drain the battery and try charging it afterward it still wonít charge fully
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