95 330da battery arrangment

capt steve

Member
May 23, 2017
144
north nj
Boat Info
95 330 da no genny
Engines
7.4 merc v-drive
I found out the hard way my batteries are at the end of their serviceable lives. at this point im going to start making a plan for next season to upgrade the battery setup. I don't think I will need to go the route of an inverter , since I really don't use any AC functions while at anchor. my boat has the typical 2 battery bank for port / single starter for stbd. my genny is removed so I have the space under the seat with the gen battery leads in place. can I install a 2 or 3 battery deep cycle bank to the genny starter leads and will that feed right to the 12v side of the panel due to the fact that it should have been part of the charging system? I have the stock 30a promariner with isolator.
 
The port/house bank should be in the cockpit under the seat I think. The starboard engine and generator would be in the bilge? At least that was my setup. But I don't have a generator.

In any event I replaced my battery in the bilge with two 6v golf cart batteries wired in series to make a large capacity 12v dep cycle bank. I put two group 27 cranking batteries under the seat.

Then I rewired the house power feed from the starboard battery switch to the port switch. That shifted my house bank to the port side (and using the golf cart bank).
 
I have two in series in the bilge port side , I assume they are on the port switch (I really have to get in there and trace these out) as im posting from memory. under the seat , I have a single , and the two empty leads which I assume were for the gen that is now removed. I would love to utilize that for a separate house bank since in theory it should feed back into the panel right? I could then just shut the starting batt switches and ride off the house bank
 
I guess the battery set up is different with a genset than mine without. Once you sort out what is the house bank, just put the high reserve capacity batteries on that bank. If the batteries are 12v, you DONT want to wire them in series (you will create 24v and fry things), you want them paralleled. If you don't know the difference, google it to be sure.
 
Port bank is port motor and house. Under the seat is starboard motor. Empty leads would obviously be for the generator. Can't really change the port being house without a major rewire, or maybe swap at the switches under the seat? The generator leads wouldn't be big enough for a main engine. You could put a large house bank where the generator would have been and run new leads to the switch.

Generator battery was only hooked up to the generator and battery charger, not part of the "main" system.
 
Port bank is port motor and house. Under the seat is starboard motor. Empty leads would obviously be for the generator. Can't really change the port being house without a major rewire, or maybe swap at the switches under the seat? The generator leads wouldn't be big enough for a main engine. You could put a large house bank where the generator would have been and run new leads to the switch.

Generator battery was only hooked up to the generator and battery charger, not part of the "main" system.

On mine swapping the house feed was simple. It was an extra red feed wire at the back of the starboard switch. Just moved it over to same spot on the port switch.
 
thanks gents. this gives me a more clear picture of my possibilities. under the seat with the gen battery gone , I have room to put at least 3 group 27 house batts , so I want to take advantage
 
sorry , one more question. how does the house bank feed into the panel? I have the isolator that came with the boat. is that in line with the charger or the alternators? im looking at different batteries and chargers. not sure if the original promariner 30 is contributing to the battery life span.

also , concerning batteries, I saw the duracel group 31 agm at sams club for a nice price. can I use these for all my batteries? does it really matter if I use deep cycles for starting?
 
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im at the point where I need some input for decisions. I have ordered 4 x 6v golf batts with a special 4 battery box that I will be installing where the gen used to be on the stbd side. I also have 2 x 12v starting batts coming as well. the boat still had the original promariner 30 and battery isolator setup. so...
what I would like to do that makes sense is have a starting battery for each motor on its own switch and the house bank on its own switch isolated from the starting system.
what is the best way to achieve this? the gen wiring to the panel is still there and the gen starting battery box / leads are still under the seat.
would a boat yard know how to rewire to get this done? I think I would need another switch for the house bank though

as of right now , the plan was to put the house bank on the port feed as a member suggested on here , but if I have the opportunity, now I would like to keep the house bank separate from the starting batts

re-reading one of the prior responses, I see a suggestion to put the house bank on the former gen starting batt leads, this would facilitate charging, however, now how could I swap the house feed to that and off the port eng start?
I cant remember if there are 2 or 3 batt switches under the seat!
 
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The isolator is typically wired in-line with the alternators to prevent a fully charged battery from back-feeding to the alternators.

You might consider upgrading that promariner 30 to a modern smart charger. Older charges are pretty dumb and can contribute to shortened battery life and constant loss of electrolyte. I changed mine to a ProNautic 1240P. It's smart enough to switch over to a float charge once the batteries reach full charge.

Note, if you increase the amperage to 40, you should upgrade your two Converter breakers at the same time.
 
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so do I sh-can the isolator and charge and just replace with the new smart charger? I saw a decent 30a promariner new generation.

by the way , what is under where the gen used to be? can that be drilled / screwed into?
 
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so do I sh-can the isolator and charge and just replace with the new smart charger? I saw a decent 30a promariner new generation.

by the way , what is under where the gen used to be? can that be drilled / screwed into?

No. The isolator should remain in place. You would just upgrade your charger. Which Promariner are you looking at?

I will never advise nor dis-advise whether or where to apply a drill bit. :)
 
so do I sh-can the isolator and charge and just replace with the new smart charger? I saw a decent 30a promariner new generation.

by the way , what is under where the gen used to be? can that be drilled / screwed into?

The pronautic 1230P is a perfect replacement.

Under that shelf is a foam filled compartment. If you drill into it, you need to seal the holes well. That is where I mounted my battery box for the 2 6v golf cart batteries I installed. I have those two as the port and house bank. They also feed into my Xantrex inverter which is installed above the battery box in the cockpit storage bin (not in the bilge). I have two "dual" starting/deep cycle under the seat as the starboard starting batteries. On my boat the cockpit seat batteries "were" the house bank. I rewired the house feed wire (behind the battery switches) from the starboard bank to the port bank switch so the house draws from the golf cart batteries. All isolators etc were left exactly where they are and as wired by Sea Ray.

I replaced my 30amp Promariner charger with a Pronautic 1240P. I wanted 40 amps so it would charge the golf cart batteries faster.
 
thanks gents, creekwood, that paints a clear picture as my setup is pretty much identical. until I decide to go for an inverter, I will just set up as is. yes the 1230P is what I was looking at.
just a little confused, the house bank as stock , is set up on the port switch correct? I don't get why your stbd under seat batteries were your house bank.... wired like that previously or are being sarcastic? so your starting duties are relegated to just the stbd switch at the moment and under the seat? I have 2 x 12v batts right now installed port side in front of the water heater , don't know if that was the stock original setup. as well , does your parallel switch on the dash still function as intended?
finally , the 1230p is a 3 bank unit, are you using all three?
 
You are right. I have a good memory, but its short! The two in the seat were the port engine and the house. I have them now switched so that is the starboard engine start only. The golf cart bank is now the port engine/house bank and it is in the bilge.

I am only using two of the banks on the 1240P.
 
You are right. I have a good memory, but its short! The two in the seat were the port engine and the house. I have them now switched so that is the starboard engine start only. The golf cart bank is now the port engine/house bank and it is in the bilge.

I am only using two of the banks on the 1240P.
roger that. I would ultimately like to have each engine on its own switch / bank , and the house on its own to take advantage of the three bank setup. until I figure out how to get that done and still retain the "emergency " parallel switch function ,. im going to do what you did and locate the "port / house bank" to stbd bilge while switching the feed and use the 2 x 12 starting in parallel under the seat for starting duties. in the future if I wire in an inverter , I can prob use the old gen wires that are still there and which I imagine feed the AC side of the panel.

would I be able to use the current isolator for three banks?

sorry for all the questions and if im getting redundant, but I just want to be fully ready. if I add another batterY switch and put the house lead to it and connect to the 6v house bank and chargeR, I will , in essence add what I need right? my question is how to factor in the batter isolator for that 3 way setup so I get charging from the engines when running
 
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wow
I have a totally different set up. 2 under the seat than three in front of my generator. nothing on port side except the water heater and vac flush
 
wow
I have a totally different set up. 2 under the seat than three in front of my generator. nothing on port side except the water heater and vac flush
yeah I think maybe a previous owner thing? my port side currently has 2 x 12v in parallel which I assume is house, I have one under the seat for stbd starting and an empty tray with leads that used to be for the gen. maybe they moved that port bank . anyhow I want to reconfigure to something that makes sense and also gets some weight on the stbd side
 
yeah I think maybe a previous owner thing? my port side currently has 2 x 12v in parallel which I assume is house, I have one under the seat for stbd starting and an empty tray with leads that used to be for the gen. maybe they moved that port bank . anyhow I want to reconfigure to something that makes sense and also gets some weight on the stbd side

It looks like you are going to have to trace things yourself since the wiring may not be consistent. Mine was OEM with no generator so my wiring is probably different. And then I rewired it to switch the house bank. My water heater is on the starboard side. Large space aft of the water heater was used to install the new battery box for a 6vX2 house/port engine bank. The twin 12v in the seat is starboard engine only.
 

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