Batboard

I'm in the process of converting my whole radio shack to a 12V system after I acquired two very large 12V 100 AH UPS batteries hooked in parellel.
My issue is that of how to keep a reasonable charge on them with a float charger that has as little ripple as possible. Anyone
have a decent source for this or any experience in what to avoid as to not re-invent the wheel.

Thanks
Mark

If you're interested in maximum life of your batteries in float service try looking at http://www.batterytender.com (in your backyard).

There are a number of extended threads in prior years on this subject.

My short answer: assuming that you will only be drawing DC from the batteries (i.e., no need to combine inverter and transfer functions), my strong (and only) recommendation would be TruCharge by Xantrex. For 2 G27-31 batteries (nominal 100AH per or 200AH for the bank), I'd get the 40A version.

In the application you describe (where the batteries are almost always on some form of charger and only rarely support load on their own), the big problem you run into is that very few chargers (including none of the ones that come as options on Motorola base stations) are capable of true float mode. Rather, they will always supply a minimum current into the batteries. This eventually raises voltage far too high, boils off electrolyte, and prematurely kills the batteries.

I have a number of installations that use the recommended chargers or their equivalent. Some have been in service for over 5 years (one for over 10 years), and they haven't killed a battery yet. Well worth the cost.

By the way, while I've never detected a ripple problem from the recommended equipment, it shouldn't really be an issue anyhow; the batteries are acting as huge filter capacitors.

Thanks guys...I'll take a look at the products/website you listed.

Mark

Mark,

I use the IOTA DLS 55 with the IQ charge option for the same purpose you are planning for. Its works well with the two 75Ah AGM batteries in parallel and a RIGrunner 4012 distribution panel. I have purchased the DLS line of supply/chargers pretty cost effectively from Ebay and if I need any other items from IOTA I have purchased from Master Tech and they have a very knowledgable staff to help out with any problems. I am not affilaited with them - just a very satisfied customer......dan n2aym

http://www.iotaengineering.com/

The IOTA Distributor I use is below

http://mastertech-inc.com/