Paralleling one 'A' battery to another 'A' battery 3

[marks1080]

Hi folks, looking for some insight from everyone...

I'm replacing all of the DC station service equipment at a large 230/115/27.6 station. I'm pondering different outage scenarios related to different design options available to me. Let's assume that the old DC stn srvc (the one to be replaced) is fully in service, and my new DC stn srvc is installed (ATS stacks, batteries, Dist. panels, etc...) but not feeding any load. Does anyone see a problem for briefly paralleling the old 250VDC 'A' battery with the new 250VDC 'A' battery for brief periods of time? This would really help reduce outage times. I know you would never want to parallel and 'A' battery to a 'B' battery, but I've never been in a situation where I technically had two separate 'A' or 'B' batteries available.

Both the old and new 'A' batteries are 250VDC floating.

Personally, I can't see any reason why I wouldn't be able to do this, but when I talk about it, it makes some of the 'higher-ups' nervous. The specific benefit for my job would be drastically reduced outages at this station, which is quite large and feeds the better part of a large city.

Any insight would be appreciated. Thanks!

 

[marks1080]

DanEE: once again, great advice. Thanks!

 

[ScottyUK]

Ours get a periodic full discharge test down to 1.0V/cell and recharged. We don't see much memory effect, if any, and the service life is very long without any significant intervention (for the recombination types) other than keeping them clean. The oldest (vented, non-recombination) cells on tripping & control duty were retired just before their 40th birthday, with capacity slightly below nominal and the wooden carriers looking a little tired. Not a bad innings.