Backup battery charging

[Mike Mesford]

I have two 6 volt golf cart batteries that I’m using instead of a generator for occasional power outages (not uncommon in my corner of the world). I use small inverters to run our cable modem, router, phone and laptop chargers as well as controls for our gas powered water heater and gas stove. It’s not a very sophisticated system but it works fine. I’ve been charging the batteries with a cheap, old car battery charger. I’d like to invest in a more sophisticated charger with a float mode that I could leave connected at all times. Do I need to size the charger to the battery Ah rating? I’m thinking a small charger connected to a large battery would just take longer for an initial charge since the current is constant. After that the float mode would take over. Any thoughts on this or any other part of my scheme?

 

[Bluejets]

Sounds ok.
What sort of range difference were you referring to though.
E.g. What size are your 6v batteries and what max output of the charger?
You need to size you output on this and the actual load as well.
There are some really nice "smart" units around these days.

 

[Mike Mesford]

The batteries are rated at 208 Ah each and they’ll be wired in series. This is the charger I’ve been considering. Im open to suggestions!

 

[kellys_eye]

If you don't expect to get outages more often than every 2 days - or intend to run the batteries to their point of total emptiness - then that charger will do (it would take 40 hours to recharge them from flat).

 

[Mike Mesford]

Thanks folks, for confirming my theory. I’ll order that charger today. Appropriately enough the wind just came up out of nowhere and a gust blew our patio table/umbrella over. I’ll take it as a sign!