Guest Battery Charger

marvin4239 · Posted: Fri Feb 22, 2008 9:49 pm Post subject: Guest Battery Charger

I've had a problem with my start battery going dead lately if the boat set up for very long. My system has one start battery and two house batteries. The house batteries are wired in parallel. I've never really taken a close look at the way they were wired until today when I was trying to find out why my start battery wasn't charing from shore power. It charges fine from the engine. Well here's what I found. A fuse was missing from one of the charger outputs so I put one in and then noticed that instead of the outputs from the charger being tied to the batteries they were all tied together on a stud on the load side of the 1,2,all, off switch. Somehow this just doesn't seem right. Wired this way in order to charge from shore power you must have the switch on. Is there something I'm missing here? I'm thinking that the charging sequence wouldn't work properly with all three outputs tied together. The charger is the standard Guest 5/5/10 charger the factory puts in. Any thoughts?

Rob & Karen · Posted: Fri Feb 22, 2008 10:07 pm Post subject:

I have the same charger, but it is not wired that way. Mine is wired directly to the batteries. The batteries will charge regardless of the battery switch position. The 10amp output goes to the start and both 5amps go to the house battery (I have only one house battery).

If you look in the Guest owners manual, you will find that it is ok to combine the two 5amp outputs, but the 5amp outputs should not be combined with the 10amp output. I think you need to wire it straight to the batteries - 10 amp to the start and 5amp to each house battery, since the house batteries are in parallel.

Out of curiousity, where are your batteries stored? Are they all in the lazarettes? I am thinking of adding a second house battery.

Rob

thataway · Posted: Fri Feb 22, 2008 10:14 pm Post subject:

The correct way to wire the battery charger is directly to the batteries. You want a fuse in line within 7" of the batteries. (There should be a breaker on the battery charger). On twin engine boats, the Battery charger should be 5 amps each engine start battery and the 10 amps to the house battery.

marvin4239 · Posted: Fri Feb 22, 2008 10:17 pm Post subject:

Thanks for the info. I've been looking at the Guest info and I think I will redo mine as yours is.

My start battery is in the starboard lazarette and the two house batteries are in the port lazarette. I'm considering moving the house batteries to below the stove. I'd have to change to AGM batteries because of the fumes. With the two batteries in the port lazarette it puts to much weight on the port side. Especially if you are carrying a full port fuel and water tank.

marvin4239 · Posted: Fri Feb 22, 2008 10:25 pm Post subject:

Thanks Bob thats what I thought just thought there was something I was overlooking. I have the fuses the wires just don't terminate at the batteries. I'll be redoing it tommorrow.

hardee · Posted: Fri Feb 22, 2008 10:58 pm Post subject: Guest ???

I have a Guest 5/5 charger, twin 40 Yamahas and 2 batteries, set up one in each lazarette. I would like to find a manual for the charger. It did not come with the other papers on the boat and I would like to know more about how it works.

Anyone have a source for Guest Charger manuals?

Thanks,
Harvey
SleepyC Moon

marvin4239 · Posted: Fri Feb 22, 2008 11:07 pm Post subject:

Go to www.guestco.com/ www.guestco.com/ ·and the manual is downloadable.

Sea Wolf · Posted: Fri Feb 22, 2008 11:11 pm Post subject:

Harvey-

HERE's the Guest website page on a 10 amp (5+5) battery charger. The manual is at the bottom of the page (PDF file)

If this isn't the right model, you can find it on their site.

Many manufacturer's are including their owners manuals on line for their owner's convenience that lose theirs.

Joe. Teeth