NiMH battery packs

[MrMobodies]

I received two battery packs an notice they are both under 1.2v upon measuring them.

I was told many years that if they are below 1.2v near about the 1v range for a long period of time they might not fully charge up again during charge and discharge cycling.

One pack shows 7.27v
7.27v /7 cells =1.03v

The other pack 7.93
7.93V /7 cells =1.13v

Is this not good or am I being paranoid?

[wraper]

I was told many years that if they are below 1.2v near about the 1v range for a long period of time they might not fully charge up again during charge and discharge cycling.

That's some BS.

[tom66]

Prolonged storage at very low voltages might damage the cells but you've little to lose just trying to charge the pack up.  NiMH cells are very safe and thermal runaway is essentially impossible, especially for small cells like these.

A bigger problem is if one cell in the pack is weak, during usage that cell can be reverse-biased, which does permanently damage it. 

[wraper]

Prolonged storage at very low voltages might damage the cells but you've little to lose just trying to charge the pack up.

1V per cell is not a very low voltage though.

[tom66]

Prolonged storage at very low voltages might damage the cells but you've little to lose just trying to charge the pack up.

1V per cell is not a very low voltage though.

Agreed, if it's uniformly distributed across the pack.

But if it's 6 cells at 1.2V and 1 cell at 0.7V then it can be an issue.

[MrMobodies]

But if it's 6 cells at 1.2V and 1 cell at 0.7V then it can be an issue.

Yes that's what I am worried about.

I'll let the seller know and charge discharge them see how they perform.

[wraper]

Prolonged storage at very low voltages might damage the cells but you've little to lose just trying to charge the pack up.

1V per cell is not a very low voltage though.

Agreed, if it's uniformly distributed across the pack.

But if it's 6 cells at 1.2V and 1 cell at 0.7V then it can be an issue.

That would be unlikely and would require a huge charge level imbalance. These cells likely just self discharged to about 1V.

[tom66]

That would be unlikely and would require a huge charge level imbalance. These cells likely just self discharged to about 1V.

Well, the trouble is we have no idea how the pack was stored beforehand, and whether it has been underdischarged.  Hence my disclaimer.  Yes, it may well be normal self discharge but it could also be an abused/returned pack that has been sold on.

[wraper]

It those are not LSD cells, they'll self discharge to from full to empty within a few months.