lead acid / agm conversion

[dakno]

I have a house bank of 3 gp24 deep cycle lead acid batts installed in mid 09. They are now 5 yrs old. They live under the quarter berth, which is poorly ventilated and makes access difficult for servicing. It is nerve racking to stick your head in this space, slide batts around , pop off the tops and add water with a baster and hope nothing sparks...

Wm agm's go on sale next week, something I have never seen. My batts now are charged with a full time 20a multi bank charger, with all 3 outputs looped together sending all output to house bank. I also have 1 maint free lead acid starting batt that only gets charged by alt or occasional car batt charger. I now I will have to change the setting on my multi bank charger. Also, sometimes when running engine for long periods I will set batt selector to "both" thinking this is sending alt charge to both the start and house batt's.

Questions 1. with batt switch on "all", does this send charging current to both banks. 2. Do AGM's require much less service than the lead acid batts 3. what am I overlooking?

[a64pilot]

ALL or Both on a battery selector should gang all or both banks together into essentially one big bank, so yes that should send any charging to all batteries.
The caveat I guess is unless yours is wired somehow different than any I have ever seen anyway.

AGM batteries should require no servicing other than an occasional cleaning of the posts, but really shouldn't require that either.

Even if on sale, I bet West Marine is still an expensive place to buy batteries.

[colemj]

Also, your sealed LA starting battery will do just fine on your AGM charging regimes, so you won't have a problem with it in the mix.

I agree with pilot that even on sale, you may find a better deal on AGM's than West Marine. But who knows?

Mark

[Ex-Calif]

Sounds like you have a good workable plan and understand the need for a different charge regime.

I would consider adding an ACR and not worrying about the start bank charging at all. From a practical standpoint on a diesel the size of a Hunter you can likely stay in "house" mode at all times and use the house to start the engine. Your start batt just becomes a "backup" for when the house is "too low" to start the engine.

I am going with the BlueSea 7611 for about $80 on amazon.

<edit - I am a bit confused as to what a "maint free" LA start batt is. is this an AGM? GEL? or other? Either way I don't think it matters)