Trojan Boat Forum

Good morning all! Thinking of changing my batteries out this winter as I got a subtle indication the other evening that they are nearing the end of their life…lights dimmed almost out after a few minutes off the charger/alternators. I’ve had good operation from these the past year or so, but the previous owner never indicated when these batts were replaced. So, I’m suspicious of there age.
In any case, since I’m not on the boat and near my manual, what size (Group number) did Trojan outfit these boats with originally? I’m running the three batt setup…one for each engine and one dedicated to the genny.

Thanks in advance for any info.

Scott

I have an 89 mid cabin so specs are probably the same
for start batteries I have group 31
and for the genny I have a group 24 not sure if a group 27 would fit
hope that helps
rr

mrrudely wrote: ↑Thu Dec 01, 2022 12:26 pm I have an 89 mid cabin so specs are probably the same
for start batteries I have group 31
and for the genny I have a group 24 not sure if a group 27 would fit
hope that helps
rr

Thanks mrrudely! I agree, specs are probably the same. I have the opportunity to reconfigure the battery box/compartment while I’m there due to some rotten wood below that’s supports it. So, I may change things up a bit, but 31 and 24 respectively, would be plenty of size to fill.

Starting Batteries should be group 27 and generator is 24. The box was molded for two 27s and one 24 As a general rule 27s have more power than the 24. I am not sure if the 31 would fit. Mrrudley did you have to modify the box for 31s?

prowlersfish wrote: ↑Fri Dec 02, 2022 9:10 am Starting Batteries should be group 27 and generator is 24. The box was molded for two 27s and one 24 As a general rule 27s have more power than the 24. I am not sure if the 31 would fit. Mrrudley did you have to modify the box for 31s?

Prowlersfish,
Does that battery box criteria also apply to a mid cabin? Because the pic shows a non-mid, perhaps an express?

my battery box looks like the photo
the 31's are about 1" longer than the 27's and about 1/2" higher
I had no problem getting the 31's to fit but I just realized the 24 is probably not being held down properly

rr

Scott67 wrote: ↑Fri Dec 02, 2022 11:12 am

prowlersfish wrote: ↑Fri Dec 02, 2022 9:10 am Starting Batteries should be group 27 and generator is 24. The box was molded for two 27s and one 24 As a general rule 27s have more power than the 24. I am not sure if the 31 would fit. Mrrudley did you have to modify the box for 31s?

Prowlersfish,
Does that battery box criteria also apply to a mid cabin? Because the pic shows a non-mid, perhaps an express?

Yes I checked on the mid cabin and It's supposed to be the same box as a mid cabin. I will double check. Not an express for sure

Scott67 wrote: ↑Fri Dec 02, 2022 11:12 am

Prowlersfish,
Does that battery box criteria also apply to a mid cabin? Because the pic shows a non-mid, perhaps an express?

The photo is indeed from a mid-cabin. FWIW The express is a liner boat and you can tell that's not.
When you get to your boat post some pics.

I reconfigured mine. My start batteries are both 31's and I have two 6v (27) house batteries in between them facing side to side. Those connect to my other 6v batts which are located in a new box behind the factory one. I'm pretty sure the 31's will fit w/o making any changes. I had to modify the cover on my to accommodate the add'l height of the 6v batts.

While you're in there, I would recommend replacing every single wire/cable connector including the ground busbar. That's behind the battery box and really hard to access unless you remove it. This will take many hours but you will nip a lot of future problems in the bud. The battery solenoids have bunch of wires as well. I did the same for the battery cables at the same time.

Bob

BobCT
The original wiring has the start batteries doubling as house batteries
I left mine that way ( experimenting with dual purpose 31's) and added a deep cycle house battery to run my inverter only
I have an ACR to charge the house battery
Eventually I would like to change the house battery to a lithium and change the ACR to a DC/DC charger
Also I plan to add a dedicated generator battery
I'm curious as to how yours is wired and your thoughts
Sorry to sidestep Scott67
rr

Here's what I wound up doing. I don't have a generator (and don't have a real need for one) so I added a 3k inverter running off four 6v golf cart batteries. Two are inside the factory battery box along with the two group 31 start/house batteries (I shouldn't have called them start only). Those I upgraded to dual purpose 31's and those work well. The only heavy draw on these batts is my cabin fridge so I installed a switch when I re-made the AC/DC panel. That way, I can switch it from one battery to the other and share the load for an overnight.

The "real" house/inverter bank powers my wetbar fridge, stereo/amp, add'l 4,000 GPH bilge pump, underwater lights, microwave and a dedicated AC inverter outlet in the cabin. There I can plug in on demand - coffee pot, toaster oven, tea kettle, hair dryer, etc.

All my TV's are hardwired 12v so the only things I can't use on the hook are my AC and stovetop (which I don't even use in the slip).

I'm good for up to two days depending on usage. I've never gotten the inverter bank down to even 50% which includes a lot of heavy usage like toaster oven for 20 mins, hair dryer, etc. It's an amazing setup for my use.

Bob

Bob
Thanks for that, makes me feel like I'm on the right track.
Question, why the dedicated 110 outlet? My inverter is wired to all the outlets.

rr

I thought about an inverter/charger which would cover the entire boat. But, when I really thought about what we would be using the inverter for, it was all stuff in the galley so a home run to a dedicated outlet from the inverter was easy. Separately, I tied in the microwave at the panel so I can switch it from shore to inverter.

mrrudely wrote: ↑Mon Dec 05, 2022 12:15 pm BobCT

Sorry to sidestep Scott67
rr

No worries Bob, I'm learning a lot from this. As I mentioned, I'm reconfiguring my battery compartment too. Although I do have my generator, I feel the space down there can be better utilized and also allow for a step to get into the ER without crushing the battery box top.

Scott

On the "crushing" comment. I added plywood strips running front to back (epoxied and screwed to the factory cover). I positioned them so they squarely line up on the tops of the batteries and avoid crushing the cables.