2 Bank Battery Chargers, and a Combiner

[rssailor]

Battery charging

Dan,
Combiner works well to charge two battery banks of similar size. With this said, what are your battery banks on board the boat? What kind of charger do you have? These are all factors in designing or up dating your system; size of the battery bank(s), current use patterns, battery chemistry (i.e. flooded, gel cell, agm). If you are using a one two all and off battery switch, a combiner would work fine on similar sized battery banks. One thing to keep in mind, if you have true deep cycle batteries, then they will have more internal resistance and take more time to charge than a lower resistance starting battery. I am saying that a deep cycle and a true starting battery put together with a combiner and the starting battery may get overcharged as it usually comes up to full charge first. Just an FYI for the rest, I am a marine electrician by trade and have been in the business for eight years now. Ryan Moonglow E-25+

 

[Dan Hayes]

I have a two bank system, both 85 AH flooded cell storage batteries. I've been thinking about replacing the starting battery with a combined starting/storage battery of the same size, but haven't yet. Thje batteries are only a year and a half old, and they appear to still be in good shape.

I recently bought a so called "smart" charger, that senses the voltage and changes the charging power according to how charged it is. That's what prompted my original questions, what would happen if I tried to charge both batteries?

This thing also has a "conditioning" mode, that more or less boiled electrolyte all over the place when I used it. I won't be using that feature again any time soon !

So, I've been disconnecting the batteries from everything when charging them, and actually not using the combiner, but the battery switch instead.

Wow, what a great thread - we've gone from batteries to combiners to isolaters to electrolysis - maybe we should toss in some stuff on pressure cookers again!

 

[cawinter]

xantrex

Just in case you missed it... XANTREX finally put out their XC-series chargers for basically the same price as the old TRUECHARGE line. Practical Sailor had a writeup on it. Looks like my waiting paid off.

(Just to confirm, I have no commercial or other interests in the company)

 

[Tom Metzger]

I think I am a little too conservative for the XC series right now. I am not sure I see $90 of advantage over the Trucharge 20+ (Defender prices). It does all sorts of wonderful things, but are they necessary?

I would have no problem with a shore power charger that did nothing but put out a constant float voltage. I can charge my discharged batteries with my alternator or wait for the float charger to bring them back up if the ac is lost at the dock for a long time.

BTW, the guy who wrote the Practical Sailor article on chargers was mostly clueless. I wrote to them with comments which weren't published, but they did publish a letter from Newmar which I had instigated.

 

[rssailor]

Combiner

Dan,
What kind of combiner is it? Does it have some kind of overide to shut it off. This would get your un-named new charger working great and you would not have to turn the battery switch at all. Just a reminder make sure you have some kind of circuit protection on the output of the charger within seventy two inches of the battery positive. Good luck. Ryan
By the way, the XC series works well, will be installing my third one in a week or so.