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Problems with Ansmann 7.2v 2000mah NiMH battery

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M

marcobrien

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Got this battery with my HPI roto start, charged it twice & now it's only lasting a few seconds. I've noticed that when I plug into charger, after a few minutes led turns to green indicating a full charge (and switching to trickle). I've even left it charging overnight, but still no luck. It's NiMH.

Need to know whether it's likely to be a battery or charger fault so I know which to replace..

Thanks :)
 
Have you used the charger for other batteries? Volt test the battery and let us know what it is. It may be a bad cell in the battery dropping the voltage to a point where the charger doesn't read it. Or it may just be too dead for the charger to read it, even tho the cells are good. The battery may just need a 20-30 second bump on a manual charger to get the volts up to where the charger sees it.
 
Metalhead Matt said:
Have you used the charger for other batteries? Volt test the battery and let us know what it is. It may be a bad cell in the battery dropping the voltage to a point where the charger doesn't read it. Or it may just be too dead for the charger to read it, even tho the cells are good. The battery may just need a 20-30 second bump on a manual charger to get the volts up to where the charger sees it.
Click to expand...

I don't have a way to volt test it or have a manual charger to bump it. Is there any way to "trick" the Ansmann charger into bumping up the volts?
 
A couple 2-3 second hits with a 12volt car battery charger has done the trick for me a few times. Especially with nicd tool batteries that lay around for months. Just be careful and make sure you don't short out anything. I don't like giving advice like this but if it gets you going...:)
 
Metalhead Matt said:
A couple 2-3 second hits with a 12volt car battery charger has done the trick for me a few times. Especially with nicd tool batteries that lay around for months. Just be careful and make sure you don't short out anything. I don't like giving advice like this but if it gets you going...:)
Click to expand...

Will a few bursts from the Ansmann charger (until the LED turns green) work too? (Battery is definitely warmer if I keep unplugging/plugging in to bypass switching to trickle charge. When on trickle, battery is cold).

Given it 5 or 6 short five minute bursts on charger but still nothing from the battery so far..
 
Last edited:
Hmm. Sure you don't have a bad connection? Those Tamyia plugs are prone to bad contact. Does the charger charge the rx battery?
 
Metalhead Matt said:
Have you used the charger for other batteries? Volt test the battery and let us know what it is. It may be a bad cell in the battery dropping the voltage to a point where the charger doesn't read it. Or it may just be too dead for the charger to read it, even tho the cells are good. The battery may just need a 20-30 second bump on a manual charger to get the volts up to where the charger sees it.
Click to expand...

Is something like this suitable to test battery/charger output?

da8ahyna.webp
 
Metalhead Matt said:
Have you used the charger for other batteries? Volt test the battery and let us know what it is. It may be a bad cell in the battery dropping the voltage to a point where the charger doesn't read it. Or it may just be too dead for the charger to read it, even tho the cells are good. The battery may just need a 20-30 second bump on a manual charger to get the volts up to where the charger sees it.
Click to expand...

I've got hold of a multimeter. The battery is showing 8.5v. Does this mean it's OK? When I try the charger, it's not registering anything (the power light doesn't come on as if the multimeter doesn't activate the circuit).

Is there any way to easily load test the battery to simulate use?

yzahehyj.webp
 
Last edited:
That should be fine to test voltages.

Sent from my SPH-D710 using Tapatalk
 
Using it in a roto start & the roto start won't turn. It worked for ages until first charge, then about 10 seconds after 2nd charge, then nothing now..
 
Sounds like a bad connection where the battery plugs into the starter. Those plugs are fragile. A little tweak to the pins may be all that's needed. Or a slight pinch to the female connectors in the battery plug. Or the roto start motor got burned up. When you say it spun for ages, this is a concern. There's no reason for the roto to spin for more than 4-5 seconds. If the engine takes excessive cranking to start, there's another problem.
 
Metalhead Matt said:
Sounds like a bad connection where the battery plugs into the starter. Those plugs are fragile. A little tweak to the pins may be all that's needed. Or a slight pinch to the female connectors in the battery plug. Or the roto start motor got burned up. When you say it spun for ages, this is a concern. There's no reason for the roto to spin for more than 4-5 seconds. If the engine takes excessive cranking to start, there's another problem.
Click to expand...

No, I meant the battery lasted for ages. When you say a little tweak, do you mean bending/realigning them?
 
They look fine. This one has me stumped. I'd still tweak em to where they push together tightly and try it. Close em just a smidgen.
 

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