Change Battery Configuration (separate house from start battery bank)

[Andrew]

My 2004 34PC has a battery config the same as discussed in many threads:
1) port start and windlass/thruster (2 start batts)
2) stbd start and house (2 deep cycle batts)
3) gen start (1 smaller start batt)
- switch to combine 1) and 2)

... and as mentioned in several threads, I also don't love the idea of engine start and house being combined in the same bank.

I haven't found a thread of anyone changing it - swapping out batts switches, changing the configuration, etc - anyone done this?

Here's my desired end state:
1) port start (starting batt)
2) stbd start (starting batt)
3) house and maybe gen start (deep cycle or Li Ion in the future, but that's another thread)
Add ACRs, preserve the ability to combine when needed...

Thoughts?
Andrew

 

[GSENT]

You can configure the batteries any way you want depending on your needs. You should have a 3 bank charger and possibly a separate charger for the generator. I like the idea of a separate house system but still have the parallel capability in case of issues.

 

[AllDodge]

Don't charge Li Ion with a ACR or off any motor charger, they need special charger. The good thing is that last a long time on one charge

Should be able to charge it from Gen powering the special charger, check specs

 

[TurboJoe]

My 34pc is setup as follows:

Port: 2 x Group 31 deep cycle house, windlass, thruster, port start
Starboard: 2x Group 27 agm start batteries
Gen: 1 x Group 24 start battery

I just replaced the two Group 31's and had the same thoughts as you. I used odyssey AGM group 31 deep cycle batteries. While it is true that a deep cycle is not ideal as a start battery, two group 31's should have no issues starting a 496 with gear reduction starter.
So I thought about changing it all, but then left as is. I did change the battery charger to a promariner and moved the remote display to the cabin where the old galvanic isolator display was.

If my house runs dead, the starboard group 27's can start the starboard engine, then parallel over for a port start very easily. I always want the generator battery by itself so (provided the gen is in working order) I can start that and charge both banks as needed in a jam.

 

[MRR]

Mine is diesel with 3 port (start + house), 2 starboard start, and 1 generator. Considered separating the house battery from the port and adding a second house battery - but there really isn't a good place to put 7 batteries. While I have managed on several occasions to drain the port battery enough that the engine won't start either a) starting the starboard and paralleling, or b) firing up the generator and waiting for the battery to charge has always worked out fine. Ended up seeming like more hassle than it was worth to change it.

 

[GandDFreehold]

My 34 PC is set up similar to MRR. I have an ACR that separates port start from house. 3 Bank Charger, starboard, port/house and generator. Also tie switch between port and starboard.

 

[V1rowT8]

Lifepo4 batteries don’t do well living in, or being charged in a hot space. It shortens their lifespan noteably. That’s one of the reasons I passed with our design boat. You’d also need to upgrade alternators/wiring, and preferably go to external regulators for Lifepo4 technology batteries. Otherwise, I’d wager that you’d kill your OEM alternators over a short timeframe as the Lifepo4 batteries are eager to draw/accept higher charging current. In fact, their life span is further reduced if not charged aggressively.

As an alternative, Firefly batteries could be an excellent option for a higher capacity house battery bank….provided that the remaining batteries are compatible with your existing charging source.

 

[gustaf]

Interesting - my '04 34PC is setup the same way as TurboJoe's. I wonder if someone modified yours at some point @Andrew.
I would not suggest putting house and generator in the same bank because if you run that all down, you will not be able to fire up the generator and run the charger.
I had thought of reconfiguring my batteries as well but have not gotten around to it and honestly not sure if I will. My thought was that 2 batteries to start one motor is a bit overkill so dedicate one of the starboard batteries to the starboard motor and one to the port motor and have the ability to parallel them, keep the generator battery for the generator and then have a bank completely dedicated to house and possibly add a 3rd battery to that. But after using the boat for a few years which included staying on mooring for about a week every summer, we've been able to use it just as it is which includes refrigeration running the whole time. I run the generator a couple of times a day to charge the batteries and whatever other needs we might have at the time (hot water, galley, etc).

 

[Andrew]

Interesting - it does seem like there's lots of variety in the way the boats are configured...

The issue I have with stbd start and house being the same bank is that (similar to others) you can run down that set of batts then need to rely on the port start and tie-switch to get the stbd going - basically, the backup plan (tie-switch) is now the actual plan... or put another way, I'm just 1 problem away from being stuck...

We'll see how ambitious I feel over the winter - I think I need new batts for next spring, so I feel now is the time. Will post any / all progress and failures.

My first challenge is going to be finding new battery switches - I currently have 3 on/off switches (port on/off, stbd on/off, tie on/off). I'd like to convert that to 3 on/off/combine switches (one for each batt bank) and of course fit them in the same location...

 

[V1rowT8]

My 07 34 came OEM with two group 31s on the port side, that serve as house and port starting. Two M7 group 24s for stbd starting, and one M6 group 24 for genset starting. OEMs were Deka. Currently running Lifelines of the same size…

 

[undercover]

While I don't have a 34 and wasn't looking to do exactly what you're doing, I did totally reconfigure the batteries on our boat. I made a bunch of cables and used some terminal posts to simplify the layout but didn't mess with the switches or add any ACR's. I learnt in the past not to rely on automatic transfers and the such because they will let you down ievitably at the wrong time. Just manual switches for me.

Anyway, stock on the 31, you have a grp 27 for stb starting and a grp 31 for port starting/house. I added a gen and inverter and added a motorcycle lifepo4 battery to start the gen and another grp 27 for the inverter (that's all that would fit). The trouble with that setup was the inverter battery would only charge on shorepower or gen, and the gen battery had a manual charger (brick plugged in in the aft cabin).

I ended up taking a grp 27 and made it do double duty as stb start & gen start - that's it. Then I used 2 grp 31's in parallel for port start/house/inverter. These are now all charged by running the engines or shore/gen (from the onboard charger). The key piece to know before doing a similar setup is you have to disable the alternator/magneto on the genset if you're going to use the house charger to charge its battery. Otherwise, each charger/regulator sees the voltage from the other and thinks the battery is charged, and they sort of ping off each other without charging the battery much (while using the genset to power the onboard battery charger).

Point is you can get creative, and do pay attention to having 2 chargers simultaneously charging the gen battery (it's own alternator and the boat's onboard charger) as I've seen many setups like this with poor charging. And, like other's have mentioned, keep your gen starting battery separate from house loads. If you don't have room like me, it's better to combine that role with an engine start battery as those theoretically should never get drained.

 

[Rogeo]

Good afternoon,

I am about to start a renovation of a 1989 29PC.

It has twin penta 31 engines with DP290 outdrives.

The original spec was with 41 engines but a previous owner replaced them for fuel economy.

I will be replacing all of the batteries, as the boat has sat for 12 years.

I don’t have a generator.

So my plan was to separate the batteries, one for each engine, and a seperate bank for house power.

I do like the idea of having engine batteries completely seperate, and each engine being able to provide a charge source.

I’m just not sure what the best way of doing this is?

For example, if I have them completely seperate, is there a way of connecting the house batteries to one of the engines once it is running?

I am still investigating this boat, I believe that one engine has its own battery and the house connected to it.

Would anyone have any advice?

I am planning on adding a simarine system to mount into the cabin, as I can have waste tank, fuel and water tank levels at a glance.

Many thanks

 

[AllDodge]

For example, if I have them completely seperate, is there a way of connecting the house batteries to one of the engines once it is running?

Can be done with a Automatic Charge Relay (ACR) or with a isolator

 

[Andrew]

For example, if I have them completely seperate, is there a way of connecting the house batteries to one of the engines once it is running?

There's a couple options here:
- an isolator works. It's basically a diode, is simple but causes a ~0.7V drop in the charge voltage...
- better is an ACR. This is a 'smart' relay that connects the two battery banks when it detects charging voltage levels. No voltage drop here... and there are some options that might be useful (can also activate to charge start battery if house is being charged by shore power charger for ex...)
- DC-DC charger is likely where I'll end up - basically similar to an ACR, but can provide the battery being charged whatever voltage profile it needs - in my case, I could use it to charge lead-acid house batteries, but if I change to LiIon house in the future, I just change the DC-DC profile and I'm good...

Of note - none of these solutions work well for paralleling batteries for emergency start - still need a switch for that ...

Cheers, andrew

 

[ArcadiaPC27]

While I don't have a 34 and wasn't looking to do exactly what you're doing, I did totally reconfigure the batteries on our boat. I made a bunch of cables and used some terminal posts to simplify the layout but didn't mess with the switches or add any ACR's. I learnt in the past not to rely on automatic transfers and the such because they will let you down ievitably at the wrong time. Just manual switches for me.

Anyway, stock on the 31, you have a grp 27 for stb starting and a grp 31 for port starting/house. I added a gen and inverter and added a motorcycle lifepo4 battery to start the gen and another grp 27 for the inverter (that's all that would fit). The trouble with that setup was the inverter battery would only charge on shorepower or gen, and the gen battery had a manual charger (brick plugged in in the aft cabin).

I ended up taking a grp 27 and made it do double duty as stb start & gen start - that's it. Then I used 2 grp 31's in parallel for port start/house/inverter. These are now all charged by running the engines or shore/gen (from the onboard charger). The key piece to know before doing a similar setup is you have to disable the alternator/magneto on the genset if you're going to use the house charger to charge its battery. Otherwise, each charger/regulator sees the voltage from the other and thinks the battery is charged, and they sort of ping off each other without charging the battery much (while using the genset to power the onboard battery charger).

Point is you can get creative, and do pay attention to having 2 chargers simultaneously charging the gen battery (it's own alternator and the boat's onboard charger) as I've seen many setups like this with poor charging. And, like other's have mentioned, keep your gen starting battery separate from house loads. If you don't have room like me, it's better to combine that role with an engine start battery as those theoretically should never get drained.

I have a 27 PC with a similar battery configuration - one group 24 stbd start and one group 31 port start/house/windlass. Just bought the boat, doesn’t have a generator. Thinking of adding a second group 31 in parallel and maybe carry a rechargeable jump start battery for peace of mind.

 

[Andrew]

An update to my original post. I decided over the winter to tackle an upgrade to the battery layout in my 34PC to separate House from the Start batts. I'll start a new thread for that topic.

Here's how my boat was actually wired and some pics 'behind the panel' - in short, it was wired as I first posted EXCEPT that the port start batts are physically located to stbd and vice-versa (stbd start batts physically located to port). This explains my original confusion.

Current layout:
1) stbd start and windlass/thruster (2 start batts)
2) port start and house (2 deep cycle batts)
3) gen start (1 smaller start batt)
-switch to combine 1) and 2)

Here's the panel that likely everyone shares:

... and the back of it: Formula quality as expected - all connections were tight, cables marked, and dissimilar metal plastic washer between stainless bolts and aluminum panel. A couple of cable were pretty tight / short so had to be removed to get this pic.



A diagram of how everything is connected (including charger connection):


... which matches the Formula wiring diagram: