Bad battery?

 
Old 01-28-2009, 08:39 AM
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Default Bad battery?

I know this isn't a Max Amps battery but it replacement will be so I thought you might help me.

The first Lipo I bought was a Venum 5000 2S2P in September 08, my daughter has been running it in a stock truck and complaining that it hit the cutoff, it's a xceleron system set at 3.4V.
.

Last night I ran it myself and after a five minuets sure enough it hit the cutoff.

My question is this, with it being 2P How would you ever really know if one cell was weak? Or balanced for that matter? with only three wires in the balance plug I would think they were balancing the pairs and not each cell.

I just found out about storing Lipo's at 60%, and this battery was always stored full, could that be the culperate?
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Old 01-28-2009, 08:58 AM
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Originally Posted by balistic
I know this isn't a Max Amps battery but it replacement will be so I thought you might help me.

The first Lipo I bought was a Venum 5000 2S2P in September 08, my daughter has been running it in a stock truck and complaining that it hit the cutoff, it's a xceleron system set at 3.4V.
.

Last night I ran it myself and after a five minuets sure enough it hit the cutoff.

My question is this, with it being 2P How would you ever really know if one cell was weak? Or balanced for that matter? with only three wires in the balance plug I would think they were balancing the pairs and not each cell.

I just found out about storing Lipo's at 60%, and this battery was always stored full, could that be the culperate?

That is one down fall of a 2S2P pack you could have a cell fail in one group. Good quality cells helps. And yes if you have been storing the pack foe 3 weeks or more fully charged that can also cause issues. I would check the pack with a volt meter once right at the point when the LVC trips on you to make sure it's the pack and not the esc. Make sure to check the voltage right away as the pack will start to recover but if it close to the LVC point then it's the pack.

Jason
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Old 01-29-2009, 12:35 AM
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I cycled it on the Hyperion I just got and the capacity is good, it balanced fine and seems good.
I guess I am going to look at the Xceleron again and see what is going on? I may have the cutoff too high? 3.7V
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Old 01-29-2009, 06:22 AM
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set your cut off for 3.2 per cell. It's possible that pack isn't holding the voltage under load and dipping below 3.7 per cell when your running. I would still check it with a volt meter if possible.

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Old 01-29-2009, 10:43 AM
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If only I had a 1/10th chassis dyno.

I have the Losi program on my lap top at work so tonight I am going to check what I put the cutoff to. I could probably use the low voltage alarm I just got for the slash since the light will tell me what the voltage drops to while I run it?
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Old 01-29-2009, 10:46 AM
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Just by a 25 dollar volt meter and check the pack when it does it it's the best way. An LVA will not give you a close enough reading. Messing around with electrics you really should have one anyways.

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Old 01-29-2009, 11:21 AM
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I have a volt meter, what I am having a hard time thinking with is how to run it under load and read it? The alarm you guys sell had the LED that will blink of change color and blink at 3.4-3.3 volts, thats why I was thinking of using it.
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Old 01-29-2009, 11:43 AM
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All you really need to check is the volatge at the point it cuts at if you want to do an underload check simply hook the volt meter up and run the truck at full then touch the tires to say carpet real quick. That would be a burst shot and should give you a reading.

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Old 01-29-2009, 09:55 PM
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I checked the settings in the Xcelerin and found it set to 6.8 2s.

I tested the battery I had trip durring the race and could only get it down to 7.1 before it cut off. /this battery had just come off the store function on the Duo.

I changed it to 6.4 and retested and couldn't get it to cutoff on the bench or running it for a few minuets afterwards.

What I am wondering now is if the Xcelerin might be a little off, too sesitive by a tenth or two?
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Old 01-30-2009, 09:41 AM
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It could be off a bit. I would go down to 6.2 volts and you should be good.

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Old 01-30-2009, 09:31 PM
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thanks for your help.
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Old 02-06-2009, 09:46 PM
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I ran this truck again though I forgot to change the cutoff from 6.4 to 6.2. I ran practic and one heat with no more issues.
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