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Old Oct 08, 2011, 05:09 AM
Registered User
Cardiff, S. Wales, UK
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LiPo charging problems, anyone else experienced this?

Hi all,

I've been having a few charging issues with my LiPo's recently. Basically what it boils down to is that my Ripmax Sigma EQ charger repeatedly reports massively inbalanced cells and refuses to charge. Sometimes it reports balanced cells then stops half way through a charge stating "cell voltage too high"...

Now I know for a fact that, having checked with a volt meter, the cells are all within 0.2v of each other. So why is it that sometimes the charger reports differences of up to 2v?...

The answer I thought was to buy a new charger, which turned up this morning - a Turnigy Accucell 6. Well, what can I say, the exact same problem only this time the charger reports some cells at 5.5v and FLAT REFUSES to charge. The Ripmax charger would at least bite eventually and read the cells correctly but the Turnigy...no chance...

Has anyone else had similar problems? It's beginning to become a bit of a nause having to restart the charge over and over again!

One thing to note, both chargers, regardless of what battery I try - 2S or 3S, report cell #2 to be the problem cell.

Cheers,

Jon.
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Old Oct 08, 2011, 05:36 AM
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Staffs, UK
Joined Nov 2003
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Are you plugging the balance leads in direct to the charger(s) ? Or through a connector board of some sort....which may have a problem with some of the connectors ?

Several different packs and two different chargers with exactly the same problem and apparently nothing in common seems a bit unlikely .

Steve
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Old Oct 08, 2011, 05:55 AM
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Cardiff, S. Wales, UK
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Quote:
Originally Posted by slipstick View Post
Are you plugging the balance leads in direct to the charger(s) ? Or through a connector board of some sort....which may have a problem with some of the connectors ?

Several different packs and two different chargers with exactly the same problem and apparently nothing in common seems a bit unlikely .

Steve
I know it seems unlikely Steve, very strange. yes I'm plugging directly into the charger, just can't figure it out!
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Old Oct 08, 2011, 06:54 AM
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Florida
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Not absolute but most probably a bad connection or two somewhere in the malfunctioning unit. Can you open it up enough to check all connection? Most often this is in the balance connectors paths.
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Old Oct 08, 2011, 12:50 PM
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Quote:
Originally Posted by Rodney View Post
Not absolute but most probably a bad connection or two somewhere in the malfunctioning unit. Can you open it up enough to check all connection? Most often this is in the balance connectors paths.
But exactly the same problem in two completely different "malfunctioning units" ? It's not impossible but it's VERY unlikely.

Jon, how many different Lipos have you tried which show these identical symptoms ?

One other thing, grasping at straws here, but from what you're saying the only thing common is whatever you're running the chargers from. Battery or power supply ? Can you check the voltage ? If it's a power supply I wonder if the output smoothing has collapsed and you have an almost unregulated supply. That could do some strange things to the charger but I've never seen your specific problem, particularly not presenting identically in two different chargers.

Steve
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Old Oct 08, 2011, 01:07 PM
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So. Cal.
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IMO, there's likely nothing wrong with either charger. It's far more probable that your problem is with your pack connections.

Could be a broken tap wire under the shrink sleeving near the wire exit. Are you absolutely certain that all balance wires and connectors on your lipolys are intact? Is this happening with multiple packs?

I've seen some cell checkers that had larger pins than standard JST-XH. When checking a lipoly, these larger pins deform the contacts within the lipoly balance plugs. The balance plugs subsequently make poor or intermittent contact when attempting to charge. You might check this.

Mark
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Old Oct 08, 2011, 01:50 PM
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USA, AZ, Gilbert
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Mark is correct, broken tap wire OR a worn out pin. More likely to be the tap wire.
Carefully isolate one wire at a time and give a gently pull on each one. If one feels like a stiff rubberband you found the intermittent disconnect. If it pull out, well, no explaination needed

Rick
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Old Oct 08, 2011, 08:42 PM
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Ontario, Canada
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Quote:
Originally Posted by rampman View Post
Mark is correct, broken tap wire OR a worn out pin. More likely to be the tap wire.
I had a similar problem with my Hyperion EOS606i charger. Turned out it was bad balance connections. The intermittent connection was causing my charger to terminate the charge early (over/under voltage alarms) or refusing to charge at all.

On inexpensive lipo's the balance wires don't take stress very well and easily brake at the solder joints on the pack terminals. A bit of cutting and careful soldering have fixed the few I had.

Sidenote: I've been buying Gen Ace packs lately. They use nice fine stranded wire for the balance connectors (it's far more flexible) and the wire is routed separately out of the pack. I've never had one fail on me yet.

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Old Oct 09, 2011, 04:45 AM
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Hey guys,

thanks for all the advice. I know I said my old charger did the same thing but not all the time and as it happens has been behaving fine the last 2 days...

I've tried 4 lipo packs, all fail on the new charger but charge on the old one, two of the packs are near new so I don't think it's a loose connection...

I'm going to try a different voltage supply as slipstick suggested. The charger came with a 3rd party 15v 5A supply that looks like a laptop charger...and a cheap one at that. Going to try it from my car battery to see how it goes...

[EDIT] - Tried the car battery - same result. Uploading a video to Vimeo now to show exactly what's happening so I can put it to the vendor if he doubts my claims.
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Last edited by Jonno271; Oct 09, 2011 at 05:37 AM.
Old Oct 09, 2011, 08:44 AM
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Cardiff, S. Wales, UK
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Well they say a picture paints a thousand words so a video must be better right?...

Here's what's happening -

Charger (2 min 8 sec)


Watching this makes me think the new charger's duff! What do you guys think? As you can see the Ripmax charger shows even cell voltages of around 4v whereas the turnigy shows over 5v on cell #2.
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Last edited by Jonno271; Oct 09, 2011 at 09:12 AM.
Old Oct 09, 2011, 11:30 AM
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New charger is duff.
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Old Oct 16, 2011, 10:58 AM
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Cardiff, S. Wales, UK
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You were right Rampman, got a replacement that works fine
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