E34-2 Battery replacement/upgrade

[Phr3d]

There are 2 group 24 batteries under the bunk (and a dedicated start battery in the lazarette). They used to be good for several days - now 1/2 a day at best. The NewMar 20/35 charges them...some, charging with the alternator is the same result...some.

I'm trying to repair them with a NOCO genius charger.


The space is almost 14" wide. Will group 31 fit under the lid?

 

[Frank Langer]

When considering purchase of new batteries some research is usually well worthwhile. Most battery sites give the dimensions, length, width and height, so you can determine if they will fit. Group 31 were too large for our boat, but your battery locker may be different. Group 27 may also be an option for you.
It's also important to determine what kind of battery is most suitable-- flooded wet cell (cheapest, but takes longer to charge and gives off gasses when charging, so not approved near sleeping quarters), AGM (more expensive, can be drawn down lower, recharge faster and don't give off gasses) or even lithium, though that gets alot more complicated. Adding a solar panel with appropriate controller can help solve some charging issues. The kind of charger (multi stage, amperage, etc) is also important.
Lots to think about....
Frank

 

[HerbertFriedman]

My 87 e34 has two group 27 wet cell batteries in the compartment just under the mattress in the rear berth and I put one group 24 starting battery near them in the space one would normally go to service the packing nut or dripless seal.

 

[JSM]

I have 2 group 31 in the battery compartment on our 34-2 (1987).

 

[Christian Williams]

Are the batteries old? Probably just need new ones--with a modern charger.

I'm a fan of AGMs, eight years and counting, originals still good. I never enjoyed digging into the battery compartment to check fluid levels.

"Group" is just the physical size, and yeah, they have to fit. I have made that mistake.

 

[phildogginit]

I’m considering upgrading/expanding batteries on my 34-2 and thinking about locations for the start battery.
-lazarette for start? @Phr3d how did that go?
- next to shaft ? Herbert ?
- I’ve heard of house batts being moved to under settee in front of galley as well

wondering how your experiences are

 

[HerbertFriedman]

I am going to my boat tomorrow and will take photos, but next to the standard E34 battery compartment (in the aft berth under the mattress) where I have two lead acid group 27, ~100 amp hrs each, wired in parallel, is a another access hatch. This access panel is normally meant to service the dripless or flax shaft coupling. I was able to fit a lead acid group 24 (Interstate from Costco or Walmrt) into that space and still have access to the dripless coupling. I bought a plastic battery box to contain the battery and laid down some epoxy so that the battery box would not move around. Getting the battery box in required some contorted movement but not much. I wired the house bank (two grp 27's) to the 12V instrument panel and the single grp 24 to the starter motor. My Victron charger has provision for to charge three banks so I only used two plus I have a Balmar ACR (automatic charging relay) to charge both house bank and starting battery with the alternator output going directly to the house bank.

 

[N.A.]

I have a 34-2, and cannot imagine how to get a start battery (unless it's a very, very small one) into that access area for the packing gland.

I actually just got a start battery added to the boat (along with a new Victron charger -- thanks to recommendations from folks here : ) , and it is under the galley sink, over to port on the way to being under the refrigerator compartment. It's not a full-size battery like the house bank ones, but it is decent sized. The location seems fine to me.

At least my 34-2 has a refrigerator compressor under the settee in front of the galley sink, but it would have to be a small start battery to fit there. It was suggested to me I pull out the compressor -- it is true I never use it -- but, well, I figure maybe someday I'll want it.

My house batteries are 'Lifeline' brand AGMs; AGM's just seem a lot easier to deal with. I agree with @Frank Langer -- some research goes a long way; not all batteries are created equal, and diesel 'deep cycle' ones are not always actually that good, despite the name. My batteries are very heavy because... they have a lot more lead than many others (heavy as lead, literally.) And so should last longer... so far so good anyway. Interestingly, the other main users of these batteries are the RV folks. There seems to be a decent bit of overlap in some things between the RV and boat communities in terms of equipment /maintenance needs.
PS: AGMs have different charging requirements -- worth setting up your charger parameters right for them when you get them.

 

[Captain Pete]

FWIW, Prior owner of my 32-3 installed a separate start battery in front of the water heater to starboard of the stuffing box. There is a separate switch mounted just under the inboard lip of the lazarrette locker. Pics are from when I first got the boat. Battery needed replacement, which I somehow did (with $ in the cuss jar) from the quarter birth where the two house batteries are located. I don't know what kind of access you may have on a 34 but the 35-3 I owned for a while did not have the easy access through the quarter birth the 32-3 has. Getting in the larger starboard locker on the 35 was easier though.

I have had pretty good luck with autozone marine wet cell batteries of 24, 27, and 31 sizes as they are economical, have a decent warranty, seem to last fine, and are readily available. I have 3 autozone 31's on my trawler (2 for thruster and one for generator - the house batteries are 130lb 8Ds), 3 autozone 24's (or maybe it's 1 24 start and 2 27 house) on my 32-3, and I just installed 2 31 start batteries on my latest project, which also has 3 tired AGM house batteriess that I will likely wind up replacing with the autozones. The autozones work fine for my purposes and allow more boat bucks for other things.

 

[bsangs]

Two DieHard Heavy Duty Group 31s in our 35-3. They're lead acid. Replaced them in 2024, after the previous owner had used them for about five years, and us for two. They work perfectly for our needs. DieHard 31HDS30

 

[Christian Williams]

It is remarkable to me that my three AGM Group 31 batteries were installed seven years ago, have made two trips to Hawaii and typical local use, and still show 100 percent on the meter. They're kept at float by shore power.

I'm sure there's some loss, and haven't had them load tested. Still, quite an achievement for all the use they're had, and still performing.

Added later:

Loren, I don't know the brand. Records were lost.

Note: I was previously satisfied with lead acid, but the electrician recommended AGM, which are sealed. "Why do you want to have to check fluid levels?" I came to appreciate his point, since checking my bank requires emptying the Qberth. AGM, if nothing else, removes a nagging maintenance concern for owners whose boat doesn't provide easy battery access.

 

[Loren Beach]

It is remarkable to me that my three AGM Group 31 batteries were installed seven years ago, have made two trips to Hawaii and typical local use, and still show 100 percent on the meter. They're kept at float by shore power.

What make and model are they? ("Just asking for a friend.")

 

[Phr3d]

I’m considering upgrading/expanding batteries on my 34-2 and thinking about locations for the start battery.
-lazarette for start? @Phr3d how did that go?
- next to shaft ? Herbert ?
- I’ve heard of house batts being moved to under settee in front of galley as well

wondering how your experiences are

I don’t know why my previous response didn’t make it through the internet - so, sorry for much delayed response.

My boat originally was sold with either a 35 amp alternator or 55 amp for a “heavy duty“ option.

That wiring probably wasn’t ever considered sufficient for MFDs, radar, underwater lights, inverters, and so on.

Now there is 140AH X 2 LITHIUM group 31 batteries. Wiring had to be changed to support the 120 amp alternator. Make yourself comfortable with ABYC for your application - especially 10% vs 3% voltage drop charts. Running start battery wires through engine compartment heat to get to cockpit locker will increase resistance and wire thickness.

Start battery is in cockpit locker - but takes up space the 10.5’ dinghy wants.

Solar is 200x2 watt panels. We charge the dinghy battery, run the microwave and the hair dryer.

 

[HerbertFriedman]

Sorry for the delay in getting photos of my starting battery installation in my 87 E34 but here they are. I have two group 27 lead acid, ~100 amp hr batteries wired in parallel for the house bank and one group 24 lead acid battery for the starting battery. The start battery is located adjacent to the access for the house bank, in the aft berth. In the photo, that hatch is the smaller one adjacent to larger access for the house bank. With the access covers removed, you can see the starting battery and next to it is the prop shaft with the black rubber bellows of the dripless seal. I put the starting battery in a battery box as per safety requirements and used some thickened epoxy to make a ridge in the hull floor to keep the battery box from moving. Recently, I had the dripless seal replaced and the tech had to do a fair amount of grinding to free up the clamp, which was changed to a split type, so there is plenty of room to work.

 

[phildogginit]

Sorry for the delay in getting photos of my starting battery installation in my 87 E34 but here they are. I have two group 27 lead acid, ~100 amp hr batteries wired in parallel for the house bank and one group 24 lead acid battery for the starting battery. The start battery is located adjacent to the access for the house bank, in the aft berth. In the photo, that hatch is the smaller one adjacent to larger access for the house bank. With the access covers removed, you can see the starting battery and next to it is the prop shaft with the black rubber bellows of the dripless seal. I put the starting battery in a battery box as per safety requirements and used some thickened epoxy to make a ridge in the hull floor to keep the battery box from moving. Recently, I had the dripless seal replaced and the tech had to do a fair amount of grinding to free up the clamp, which was changed to a split type, so there is plenty of room to work.

Is that just in front of fuel tank ?

 

[HerbertFriedman]

yes, the hatch in the plywood to access the fuel tank is just behind the two hatches shown in the photo.

 

[cawinter]

There are 2 group 24 batteries under the bunk (and a dedicated start battery in the lazarette). They used to be good for several days - now 1/2 a day at best. The NewMar 20/35 charges them...some, charging with the alternator is the same result...some.

I'm trying to repair them with a NOCO genius charger.


The space is almost 14" wide. Will group 31 fit under the lid?

Yes. #267 (1988).

 

[Phr3d]

Yup, I went to lithium and 2 group 31s fit nicely. The Victron solar controller seems to manage it all by itself.