SMT3000I2U battery voltage offset

[Anonymous user]

Hi everyone, new to this forum ... hope someone can help me out

My SMT 3000 appears to show an incorrect battery voltage. Now for example it shows 55,6 V where the batteries are only 49,2 V measured with my fluke .....

I have tried a couple of things like "brain dead"and "cold start" and even faking a battery replacement, but nothing will help.

Consequently, the unit thinks that the batteries are full and does not charge. (or rather, it applies 49,2 V and thinks it is drop charging)

Anyone any clue as where to look at ?

Many thanks ahead, Michael

[BillP]

I had this and never found out why, in the end I replaced it.

[BillP]

Hi Michael - 

When you are checking the voltage with your fluke, are the batteries installed in the UPS or disconnected?

Liam

[Anonymous user · Accepted solution]

Hi Liam, thanks for reacting.

I did both, that is I measured both situations. Batteries in series but isolated from the unit, and connected. When connecting, the voltage does not change. The unit does discover the batteries and states a voltage that is around 6 Volts too high and says that the batteries are charged to 100%

What can be the case here? how does the unit measure the voltage of the batteries (and charger) 

Thanks ahead, Michael