Battery Combiner/Echo Charger

[Mhorowitz]

I have a house bank of 4 Grp 31 AGM batteries. I have a genset with a dedicated start battery. I would like to rig it so that when the house bank is being charged by shore power, engine alternator or Solar Power, the genset start battery gets trickle charged. I am not clear whether a battery combiner could accomplish this and how it would be wired.

Thanks

Mark

[exMaggieDrum]

If it were my boat I would install an Echo-Charger from Xantrex. It is simple and has always been reliable in the boats that I have installed them in. They are a snap to install and only use small (10-12 AWG) wires.

I wouldn't recommend a battery isolator as there is too much loss from the diodes. You could use a combiner but you really don't need it for what you are doing and you would need to use much larger gauge cables.

I would recommend having a parallel switch so you could start the genset with the house batteries if the genset start battery goes dead but you should not leave it on unless you need to do that, and then turn it off. A combiner could also parallel the batteries if there is a manual override if a charging source is not available. The combiners only combine when there is charge to the banks. (Or - you could use jumpers in an emergency if they are close to each other). Some gensets will charge their own start batteries.

[djmarchand]

I generally agree with Maggie's approach. But if you want to learn about combiners, go to yandina.com. They will be about half the cost of an Echo Charger but will not limit the current to your starting battery.

David

[Mhorowitz]

So with the Xantrex Echo Charger, if the Solar Panels bring the voltage up above 13 volts, will charge go to the Generator Battery?

[smac999]

how is your starter / house battery currently sharing charge? I would probably use the same system with the gen battery to keep things consistant.

[Andina Marie]

A Combiner100 at half the price of an echo charger will share the available charge going to the starting battery with the genset battery. The echo charger is limited to about 10 to 15 amps whereas the Combiner100 can handle the output of a 100 amp rating alternator.

An advantage is the Combiner100 is bi-directional so if the genset battery needs very little charge, the alternator on the genset will help to charge the starting battery.

Unlike the echo charger, the Combiner100 draws no current when not transferring charge.