What water type is best for topping up ni-cad cells?

[hallmg]

Hi,

Was wondering what types of water is best for topping up UPS nickel-cadmium cells?

We have steam condensate water and treated water available, treated water has been through reverse osmosis.

Any suggestions would be much appreciated.

 

[ScottyUK]

How pure is your condensate? Most boilers are dosed with oxygen scavenger, inhibitors, and so on. RO water should be OK, but again check your purity.