# Battery bank and standby generator



## [email protected] (Feb 10, 2020)

We got gifted an onan 30.0DDA - 15R standby generator. It's a 30 kw 3 phase 60 hz standby generator. 

Anyone have suggestionson how to charge a 12v battery bank from the 3 phase power


----------



## exmar (Jun 29, 2015)

Sell it and buy something appropriate to your needs.


----------



## Melson (Dec 8, 2019)

Obviously can't be done directly. 
But any 120 vac input / 12 vdc output 'charger' would work (each phase is 120 vac to neutral). Or even a 240 vac charger between any two phases. 

Preferably you would use a regulated 12 volt float charger with a boost or charge mode. The output current of said dc charger isn't critical as long as it is regulated for proper output DC voltage - in this case could be 13.2 to 13.8 vdc.(varies depending upon the chemistry of the cells).
Anything from a couple amps DC and up would work, lower amp capacity would only mean a long charge phase.
A 'boost' mode is used for quick charging, after which it drops back to float mode for long term maintenance.

Hope I am properly understanding your Q...


----------



## iowagold (Jan 22, 2020)

[email protected] said:


> We got gifted an onan 30.0DDA - 15R standby generator. It's a 30 kw 3 phase 60 hz standby generator.
> 
> Anyone have suggestionson how to charge a 12v battery bank from the 3 phase power


ok first things first.
how many and what series of battery's?
what is your final battery array voltage?

what are your power needs for the rest of your power system?


----------



## Melson (Dec 8, 2019)

@iowagold, we may have misunderstood the question: I wonder if the OP is asking how to use the 3ph genset to power a single ph., 12v float chgr (presumably for the start battery)?
When I first tried to understand the Q I was thinking he wanted to connect ac to dc. Silly me. If I consider what I suggest above it makes way more sense.


----------



## exmar (Jun 29, 2015)

I like my original comment. Fuel cost and maintenance to run a 30KW, 3 phase machine to charge some batteries? And, if it's a military surplus, "purpose built" device, may be the reason it was "gifted." Waiting for the rest of the story.


----------



## Melson (Dec 8, 2019)

@exmar, I'm not sure that is what the OP is asking.

I, too, waiting for a clarification reply.
Very disappointing when a question is posted, people make an effort to help and then the OP ghosts.


----------



## iowagold (Jan 22, 2020)

I even tried a direct response..
nothing from the poster...


----------

