new batteries, what type and size

[jbinbi]

I have an e33, not posting in that thread as this is sort of generic...

Boat is 2 years old and came with 2 group 31 115AH batteries.

One of the cells is dead on one of the batteries, checked with hygrometer after chartplotter kept turning off and resetting when starting the engine on battery 1.

Local battery guy here I thought is very good, here is what he said.

1. replace both batteries. Otherwise the old one will suck up more charge and they won't charge evenly. I am pretty sure this is true.

2. He thought going AGM would be more efficient. I have stock yanmar 29hp with 60A alternator, I am not sure how much more AH I can add to this setup without getting a larger alternator. My boat is kept at a mooring, many times for daysailing I will use it for maybe 15 min out and 15 min back in, so I want to have the most efficient battery for receiving charge.

Any thoughts on this? thanks.

 

[Chief RA]

Read what Maine Sail (moderator) recommends for batteries. I am pretty sure he says wet cells. Since your battery is only 2 yrs old I might only buy one. To me, that would greatly depend on the condition of that used battery. Maine Sail will probably advise on that also. Chief

 

[nola2172]

If you don't have solar charging, then I am not sure wet cells would be the way to go unless you are on the boat pretty much all the time. They need a much more frequent input charge or they start to go bad. AGM batteries are designed to be able to take longer times between each charge. Also, not to plug anyone specific, but Sams Club has a relatively inexpensive Group Size 31 AGM for sale if you or someone you know can get into Sams. We just bought one a couple of weeks ago, so while I can't say how long it will last, the first couple weeks have been pretty good.

 

[jbinbi]

Thanks for the quick reply. Is there a sticky from him on batteries? I can't find any new threads on batteries...

Because both batteries charge together, if one battery is much less efficient at accepting charge (don't know if a 2 year old battery is in that category) meaning it will take most of the charge being put out, the newer battery is getting less of the charge? I don't know how smart my battery charger is. It is stock on a 2012 e33.

Also, the battery dealer mentioned that batteries from hunter are very generic and not of great quality, he won't sell this brand even though he says it is only like $30 less than the other brands he carries. I guess $30 x all the batteries hunter sells a year probably does add up, but to me, if i had my choice of paying 130 for this or 160 for a better battery, it is a no brainer.

 

[Chief RA]

Scroll down Forum listings to Featured Contributors and click Musings with Maine Sail. You need to know what he thinks about your 2 yr old battery as it is on the threshold between new and old. As I all ready mentioned: you need to test that battery for its condition.
Be careful with dealer recommendations as they will sell you what makes the most money if they can. AGM: ask Maine Sail. I would not pay much attention to anyone else as he does this professionally.
Chief

 

[Hello Below]

Check the make and model of your e33 charger, but mine came with a Protech 1230i an advanced fully automatic electronic 4 stage but far from smart charger. It holds its own, but just, in servicing my 4 x US Battery 2200 XC (232Ah) house batteries in addition to a single 12v deep cycle starter battery (110Ah).

 

[jbinbi]

Thanks. Was just on the boat today looking at this. Same charger, but I only have 2 batteries, Group 31 wet cells. In fact, today I noticed that the charger was set for sealed, not wet cell/agm1.

Also, with 4 batteries, do you have 6V set up as 2 pairs, or do you have 4 12V. Each of my group 31 has 115AH, so I have the same total as you.

 

[Hello Below]

Yes 2 pairs of 6v for a total of 464Ah or 232Ah usable.

 

[jbinbi]

Interesting. Where are your batteries located. Mine are under the starboard settee, right under the where the breaker panel is. The seat cushion comes out, the batteries are there, I don't have a separate start. The charger and inverter are in the forward section of the that settee (the table is in the middle).

 

[Hello Below]

Interesting. Where are your batteries located. Mine are under the starboard settee, right under the where the breaker panel is. The seat cushion comes out, the batteries are there, I don't have a separate start. The charger and inverter are in the forward section of the that settee (the table is in the middle).

Three under the aft stbd settee (2 x 6v plus 1 x 12v starter battery very tight fit), 2 under the fwd stbd settee (2 x 6v). I had the charger moved to behind the fwd stbd settee back. I don't have an inverter.