Separating House Batteries from Starting and Separating Gen Battery

[Robf]

Everyone
I have read hundreds of threads looking for someone that has done what I am wanting to do, to no avail.
I have a 2004 390 MY which is set up with two series 31 batteries on the port and starboard side to serve as house and starting batteries for both engines and generator. There is no isolation of the house from the starting batteries.

I would like, at a minimum, to isolate my starting batteries from being drawn down from the house. I would also like to add a separate battery to start the generator.

I have done this before in a Silverton with Manual battery switches, but the electronic switches on the Sea Ray have me baffled in adding the relays as have done before.

Has anyone attempted this project, or something similar, and if so, can you share your experience?

Thank you,
Rob

 

[ttmott]

So from two banks to four right?
You have three alternators and probably a three bank charger (converter) with one bank unused; maybe a two bank charger....
Assume then two batteries for one motor, two batteries for the other motor, one battery for the genset, and, what, three batteries for the house?
That is a total load of (if all Group 31's) of around 900 Ah. Here is how I would do it:
I would install Automatic Charge Relays between each of the four banks. Up-size the engine alternators to 100 amp minimum then you would need to add another charger/converter and the AC power wiring and breaker needed for it. Normally, in Sea Rays the Port bank manages the helm and all nav. systems and the starboard band the house. Both the port and starboard have safety systems (bilge pumps, fire systems, blowers, etc) mixed in with them and that would need to be sorted out. Then a battery switch needs to be added with a primary breaker and connecting to the wiring to the house side.

 

[Robf]

currently, the port side and starboard side split house duties with two batteries in parallel on both sides to handle the house loads and starting engines and generator. Last weekend I was at the city levee for 4 or 5 hours while me and my family toured some sites and came back and the port side was dead, which coincidentally starts the generator! Fortunately I could fire the starboard engine and emergency start the port side. I have installed automatic charging relays before, but this was with manual battery switches that I switched out from the on-off type to the multiple battery side on each side, however, my question is really how to incorporate this with the Sea Ray's electronic battery switches? Do I pull all the wiring from these switches and rewire to the manual switches or is there some way I can put the ACR setup in place before the electronic switches? (I don't want to disable the ability to switch off the batteries from the saloon in the main panel) I assume the lead from the starter would have to be pulled from this switch and moved to the manual switch at a minimum, but not sure. My final setup as I imagine would be two series 31 on each side split with the ACRs on each side, so would only need two banks from the charger, one for each side. The third bank would just be the starting battery for the generator, which I would envision being a 27. Additional thoughts?

 

[ttmott]

I see. So, first I would then get the generator on it's own battery and a manual battery switch for it; make sure the generator's alternator will be dedicated to that battery. Second, add a third battery to each of the port and starboard banks and leave all of the boat's wiring and switching alone. Third, put ACR's between each of the three banks. Fourth, upsize the engine's alternators to at least 100 amp probably best at 120 amp. And, last get a good three bank charter/converter like a pro-marine 2050.
This configuration will be just about bullet proof, tolerate any single point failure, and have fast charge recovery. So when the engines or a engine is running all of the batteries are being charged. When the generator is running all of the batteries are being charged both through the generator's alternator and the charger. If every thing is running a charging capacity of around 300 amps is possible...
Just some thoughts.

 

[Robf]

ttmott, thanks for the well laid out plan. Let me do some digesting of this proposed set up and put some pencil to paper. I believe I understand what you are saying, but let me think about this and see what I currently have on the boat in the way of alternators and the stock charger. I really appreciate the help!
Rob

I see. So, first I would then get the generator on it's own battery and a manual battery switch for it; make sure the generator's alternator will be dedicated to that battery. Second, add a third battery to each of the port and starboard banks and leave all of the boat's wiring and switching alone. Third, put ACR's between each of the three banks. Fourth, upsize the engine's alternators to at least 100 amp probably best at 120 amp. And, last get a good three bank charter/converter like a pro-marine 2050.
This configuration will be just about bullet proof, tolerate any single point failure, and have fast charge recovery. So when the engines or a engine is running all of the batteries are being charged. When the generator is running all of the batteries are being charged both through the generator's alternator and the charger. If every thing is running a charging capacity of around 300 amps is possible...
Just some thoughts.

 

[Robf]

ttmott, After some thought and review I did have a couple observations/questions. To separate the generator, I would need to pull (reroute) the wiring from the generator battery relay to the port battery relay and reroute this wiring to the dedicated battery to separate it from the port battery bank. Then on the main battery banks, I am a little fuzzy on how the current setup would support the ACRs between the batteries. The current system has the alternator and starter from each engine with a single wire to the battery switches, whereby the ACR setup normally has the charge side going to one side of the bank (the house) and the starter wire going to the other side of the bank thereby isolating the starting battery to the starter. If you put the battery banks on the outside of the current switches, as wired, and the ACRs separate the batteries due to discharge, the starting battery will be isolated from the starter. Am I missing something?
Rob

 

[ttmott]

I'm a bit confused going through that. Confused on "generator battery relay" and "port battery relay"; are the generator and port engine on the same bank only separated by the remotely operated switches? Relays?

If so they yes that works even better; add a dedicated battery to the generator battery relay and be done with that.

Typically the battery switches (relays) do not completely isolate the batteries from all loads. For example the charger and the boat's critical circuits (bilge pumps) are on the battery side of the switch (unswitched). Alternatively, the switched loads are the engine and it's alternator, and all other non critical loads like house, helm, audio, etc. So, an ACR will be installed on the unswitched side of the batteries (same as the charger and critical loads) or better stated directly on the batteries. An ACR between the batteries simply monitors for differential voltage. An ACR senses when the voltage of either of the batteries rises to a level indicating that a charge source is active (13.0V for 2 minutes). The ACR′s contacts then connect and the ACR applies the charge to both batteries. If the voltage on both of the batteries subsequently drops to 12.75V for 30 seconds, the ACR will disconnect, isolating the batteries (from Blue Seas literature). In this arrangement it doesn't matter if the battery isolation switches are open of closed. For example, one engine running; it's alternator is charging, That charging alternator will charge at just over 14 volts to it's battery bank. Since an ACR connects that bank to another and a differential voltage is established to trigger the ACR that running alternator will also charge the connected battery bank wither that other bank's switch is open or closed.
https://www.bluesea.com/resources/1366

 

[CliffA]

I am always one of the first people to applaud someone undertaking projects on our boats to either make them perform better or to customize them to our personnel taste.....

but on the surface this seems like a pretty daunting project (and potentially dangerous if you do not have a thourogh understanding of how to do it) .....if I may ask a question would it not be much easier to just increase the size of your battery banks and charger to lessen power drain instead of undertaking this massive rewiring project?....

or maybe just carry a battery jumper pack on board at all time for piece of mind.....

cliff

 

[ttmott]

I am always one of the first people to applaud someone undertaking projects on our boats to either make them perform better or to customize them to our personnel taste.....

but on the surface this seems like a pretty daunting project (and potentially dangerous if you do not have a thourogh understanding of how to do it) .....if I may ask a question would it not be much easier to just increase the size of your battery banks and charger to lessen power drain instead of undertaking this massive rewiring project?....

or maybe just carry a battery jumper pack on board at all time for piece of mind.....

cliff

I think that is essentially what he is doing and getting his generator on a unique battery. Only other real change is to add ACR's between the battery banks and maybe if required a 3 bank charger.

 

[CliffA]

I think that is essentially what he is doing and getting his generator on a unique battery. Only other real change is to add ACR's between the battery banks and maybe if required a 3 bank charger.

OK, thanks.....I certainty am in no position to judge anyone on the projects they have done or will do to their boat....I have done plenty of things to my boats I am sure would raise questions by others.....electrical mods are not my strong suite.....so when I was reading the thread it just seemed like an enormous amount of work was going to be needed and that is OK if that is what the OP wants.....I have an enormous respect for electricity and when I read the questions the OP had asked and the scope of work he wants to do i must admit I got a couple hairs on my neck to stand up.....just one wrong connection during the project could have devastating results.....I know it is none of my business but just could not help but ask questions...

there are plenty of people out there like me that genuinely care about the well being of others even if it means getting a little 'nosey' sometimes...

good luck on the project.....

cliff

 

[Robf]

ttmott and cliff, thanks for the comments and concerns. I have done this very thing on a 1998 Silverton. Replaced the single battery switches with dual, upgraded the battery charger, put a separate battery on the generator, installed ACRs and installed multiple banks of AGM batteries with monitors. This system was, as ttmott said earlier, "bullet proof". To clarify my prior post, both the charging side (alternators) and starter side of the engines run to the stock electronic battery switches with the batteries on the other side. The generator battery switch currently connects to the port side battery switch and both to the port side battery bank. So, I believe I will, at a minimum, need to remove the wiring bridge between the port battery switch and generator battery switch in order to isolate the generator from the port side bank and it from the generator battery. My further concern is that the since the starters and alternators both connect through the factory switches, if this is not changed, and in a discharge situation where the ACRs separate the battery banks, the non discharged batteries will be on the wrong side of the switch and separated from the starter circuit. (Assuming the house circuits are still coming through the factory switches.) I believe I need to get down in the engine room and open up the circuit breaker box and identify the circuits to get a better feel. I am going by the wiring schematic right now. The minimum I want to do is separate the generator on its own circuit and change out the batteries to new AGMs. I do appreciate the feedback and suggestions! I will keep all posted.
rob

 

[Jack Wesolowicz]

Understanding this is an old thread I'd still like to ask about the the next step in the process of adding an ACR and separating house battery from starting battery... REWIRING THE LOAD. Everything I read deals with wiring the ACR to the batteries. But no one gives info/suggestions what needs to be done to actually separate/rewire the load from existing wiring once the ACR is added. I don't have a load center on my 1989 220CC Cuddy Cabin. When the batteries are turned on then the helm switches get power. So I guess you can say my helm is my load center. After some research looking at similar boat schematics it seems the helm gets power from the ignition switch FUSE.

Do I have to run a separate wire from the now isolated house battery to the helm wire, which I disconnect from the ignition switch fuse? I'm pretty sure the answer is yes but maybe there are other suggestions. Can anyone give examples where they actually separated the load on their boat, and how they routed the wiring?