Brand new Fully Max FB900HP-3S not discharging balanced

[alee132]

I bought a brand new Fully Max FB900HP-3S from protovapor. I threw it on my RC balance charger and charged it. It charged up to 4.2 a cell perfectly. Whenever I get a new lipo I like to cycle them on the charger a few times before I use it because I can tell if there is an issue with the cell and it also gets them up to full capacity. Well I noticed immediately after the first charge/discharge that one cell only got down to 3.59, the other 2 cells were fine but went a little under 3 probably trying to get the other cell lower. So I tried cycling it again, but it did the same thing.  I sent them an message. But this isn't normal behavior that I have seen from my other lipo's before. Am I correct in thinking that there could be an issue with that cell or the wiring too it?  I am not going to open it up and check it out as I am hoping if it's bad infact that they will replace it for me as I never even got to use it or anything before I figured this out.  Which is why I do it this way to begin with but this is my first fullymax battery. I had a couple turnigy 950 mah nano techs that worked great but I thought I would give this battery a try and this happened lol, its just my luck.

[blueridgedog]

Sounds like a bad cell.  I would return it prior to the hassle of building a mod around it.

[alee132]

I agree, it sounds bad too me but I wanted to make sure I wasn't incorrect.  Well I am just waiting to hear back from protovapor about it, messaged them last night and it's still early but no response thus far. I would assume they would replace it as it's brand new. Of coarse I had to solder a connector to it in order to plug it in and charge it and check it out.

[John]

It sounds like you have one cell with a fair bit more capacity than the other two. How many watt-hours does it think the battery has left when two of the cells hit low voltage cutoff? 

This doesn't necessarily hurt anything if you're getting the full rated capacity of the pack.

You expect some differential falloff at the very end of charge, but .6 volts is excessive. .2 or .3 from low to high at the low voltage cutoff would be perfectly normal, though. 

Protovapor have good customer service, so if the pack is a problem I imagine they'll take good care of you. 

[alee132]

John said:

It sounds like you have one cell with a fair bit more capacity than the other two. How many watt-hours does it think the battery has left when two of the cells hit low voltage cutoff? 

This doesn't necessarily hurt anything if you're getting the full rated capacity of the pack.

You expect some differential falloff at the very end of charge, but .6 volts is excessive. .2 or .3 from low to high at the low voltage cutoff would be perfectly normal, though. 

Protovapor have good customer service, so if the pack is a problem I imagine they'll take good care of you. 

Ya its just not sitting well with me that its as far off as it is on that one cell.   I got a message from protovapor and they are sending me a replacement thankfully.