Battery Bank / Bilge Wiring

[hinzee623]

My next project is to re-wiring my bilge pumps, install battery trays and just perform a little house keeping on my battery bank. It would appear that it has been DIY'ed a few times. My question to the community, especially if its similar to mine; how does you're battery bank look? Wired? currently my system is 3-Deep Cycle batteries (27, 24, 4 group). I have solar as well, not sure where it goes, i.e. which battery is being charge. I can't trace back to what battery is being used as a starter/crank. I think two batteries are wired in series. So I would like to make it nice and neat and more manageable. Thoughts?

As for my bilge pump, existing, there is NO float switches for my three engine compartment bilges. The bilges switch are manual, and located under the salon floor. So, my project is to installed three NEW bilge switch (S1, S2, S3,) some where in the salon. Install three new float switches, and I want it to be wired to one common buss that runs all the bilges. See my one line diagram. I believe its a solid layout/design. If anyone has thoughts or lessens learned, would like to know your opinions.

[Petemait]

As far as the starter battery it would be just whichever one you choose on the battery switch.
With the solar, if you leave the switch on "All," the solar panel would charge all the batteries assuming they all go through the switch. I have a small panel which i have charging one of the batteries and i turn the switch to off when i leave the boat. I usually start the boat with the other battery that way i know i have a fresh battery if i need it. I do not run the fridge all the time just if we are on a trip.
Good luck hinzee

[bud37]

So you asked, in a perfect world your start batteries should be start batteries not deep cycle, deep cycle for house only. Now that said, the only cables on the batteries should be the main cables, any connections should go to buss bars with all the wiring/cables the correct color.

As for the bilge pumps, they really need float switches, now are you sure they are not the types that have float switches in the pump itself....make sure the pump manual on switches are at the helm station so they can be controlled while underway.

KM had a 3607 I think, maybe he could speak to the way the boat was wired.

[Viper]

Ideally the solar charging should be charging the house bank (deep cycle). You don't mention start batteries which is what you should be using to start your engines. Unless you're using 6 volt batteries or have a 24 volt system, I trust you meant batteries are hooked up in parallel and not series; positive to positive and negative to negative. I suspect it's not how you're wired but the best setup is each engine has its own start battery, and the house loads are connected to a separate deep cycle house bank, all being charged while isolating one bank from another.

Usually from factory, you have two banks; one for starting and one for house loads with a selector switch to manage which bank you draw power from. This is not an ideal setup for a few reasons.

I can't be sure from the pics but it looks like the 4D battery might be paralleled with the smaller battery which is not good. All the batteries in the same bank should be of the same spec. You should also clean the terminals, and you needs to cover the terminals with protectors, at least the positive ones. As mentioned, you should minimized the wires on the batteries to just the battery cables, the other auxiliary wiring should be connected to a buss bar.

I don't see any circuit protection in your diagram, each circuit/pump should be fused. I am also not a fan of an "OFF" option on bilge pump switches at the helm, too easy to bump the switch and inadvertently shut them off completely. An LED for each circuit also helps as a visual to let you know the pump is running, and alerts you in case you accidently switched it to the manual position.

[Phrancus]

I'm a bit surprised by the location of the batteries, isn't that very low in the engine bay and will that not get flooded in case of need for the bilge pumps?

If you're going to re-work the whole business you might want to consider a battery watch (vetus bm3 link to manual with schematics) I have that bw 3 but surely there are many others.

The battery banks are connected to/through a central unit. This directs charging current to the banks that need it and disconnects the house bank if it's gets depleted so the starter bank remains at charge. Docked it also directs the charging current from a charger to the right banks. And all that is controllable/visible on a little display that can be mounted elsewhere. On that panel I can also disconnect the house bank.
Wiring is schematically simple, but when you start adding main switches, fuses and perhaps some indicators here or there you have quite a job ahead of you. Especially the thick battery wires are a job to prepare: for the cost and their importance you don't want to put in too long or short cables and crimp less than perfectly.

It's worth it though, found quite some problems due to wiring that took a lot of time to find due to non-labeling, strange routing, bad connectors along the way. Go all the way and you can fix anything that will happen quickly and adequately beause you know where to look and what to leave untouched.

[hinzee623]

Source of the post I'm a bit surprised by the location of the batteries, isn't that very low in the engine bay and will that not get flooded in case of need for the bilge pumps?

If you're going to re-work the whole business you might want to consider a battery watch (vetus bm3 link to manual with schematics) I have that bw 3 but surely there are many others.

The battery banks are connected to/through a central unit. This directs charging current to the banks that need it and disconnects the house bank if it's gets depleted so the starter bank remains at charge. Docked it also directs the charging current from a charger to the right banks. And all that is controllable/visible on a little display that can be mounted elsewhere. On that panel I can also disconnect the house bank.
Wiring is schematically simple, but when you start adding main switches, fuses and perhaps some indicators here or there you have quite a job ahead of you. Especially the thick battery wires are a job to prepare: for the cost and their importance you don't want to put in too long or short cables and crimp less than perfectly.

It's worth it though, found quite some problems due to wiring that took a lot of time to find due to non-labeling, strange routing, bad connectors along the way. Go all the way and you can fix anything that will happen quickly and adequately beause you know where to look and what to leave untouched.

One of the bilge pumps is located in this compartment. The batteries currently sit on a platform, but are not secured. That is why one of my to-do's, is install a battery tray/box and secure it. It's definitely not a great or easily accessible location. There is a wood plank that covers that actually (makes it easy to traverse the engine compartment. That is why in my original post, I was interested in seeing other peoples layout. The boat is a 1986, I am a little curious how it looked when it rolled out of the factory.

To the other commenters, appreciate you input! I am aware of the in line fuses, just forgot to draw them! I agree, that the starter batteries should be "starter" batteries! Unfortunately these are the cards I was dealt, hence this 'fun' little project to sort out this battery bank. I am really OCD about this stuff, so it really irks me that its a rats nest of wirings and improper layout/distribution. I also want to be careful, because right now, I have a perfectly function boat, no issues thus far, so I want to make sure whatever I do ain't going create a problem for me! At least during the summer, don't want to lose any time out on the water.

[bud37]

Something I forgot to mention......one of the problems with batteries sitting low in the bilge can be that they can/may be sitting in water at times. If you have ever tested across the top of a dirty battery you will find that there can be a voltage bleed from the terminals to the case to the surrounding bilge water. This can lead to corrosion of metal parts......just something to be aware of for a nice instal......good luck with your project.

[km1125]

You need to trace a few of those wires out and diagram those connections to see what's really going on. I agree with Viper, it looks like that 4D is in parallel with the battery on the left, which is NOT a good idea. If that's the case, then you have two battery banks. The single battery on the right and the two batteries in parallel on the left. You can disconnect one set at a time and then put the battery switch on position "1" or "2" and see if anything works to determine which bank is actually "1" and which is "2".

The location of the battery is stock on a 3607, but there were only two group 27 or group 29's in there. Since either could function as a HOUSE, they were both deep cycle or dual purpose. Mine had two battery boxes towards the rear of that compartment and were wired into the battery switch (which is located up underneath the lower step). I ended up adding two 6V in series for a dedicated house bank and maintained the two 12v as starting batteries. While they do seem low in the bilge, you'd have to get about a FOOT of water in there for water to really be a problem. There is a 3/4" platform that lays across the stringers that covers the batteries and provides a place to stand while you are working in the compartment.

I had planned on modifying the configuration to the below model, but I ended up selling it before I got there. That plan would have allowed either engine to charge the house bank but isolated the house from the engines and provided a dedicated start battery for each engine. If there were any problems, you could tie any or all of the batteries together by switching the various switches to "2", which was a common buss. What I really like about this config is that each engine charging circuit is separate but if one fails then the other will actually keep the failed battery from dying via a path through BOTH VSRs. However, you would see a voltage drop difference if you were checking voltage at the helm, giving you a clue to a problem.

Boat_battery_wiring_diagram.jpg

In the interim, I had the configuration below, which worked VERY well. It separated the house bank but allowed any running engine to charge the house (via the VSR) Everything to the right is the original stock config with the switch, engines and batteries. I added the house switch, house battery, VSR and cables back to the engine switch. With this configuration, you could always manually connect the house to the engine batteries if necessary to jumpstart the engine or to bypass a non-functional VSR.

Boat_battery_wiring_diagram_one_engine_switch.jpg

[km1125]

To address the bilge pump discussions:

There were originally just two bilge pumps, a forward and aft. The forward was just ahead of the main bulkhead underneath the stairs down to the galley. The pump was just aft of that same bulkhead in the engine compartment. (that's the lowest spot in the engine bilge when the boat is stationary). There was no pump in the aft stateroom, as that area drains into the engine room bilge. Both pumps had switches at both helms, which were only two position switches - AUTO and MAN, so you could manually activate either switch. There are two separate breakers in the main panel that feeds the bilge circuits for each pump. The "Auto" breakers are fed directly from a battery on the input side of the main battery switch and the "MAN" breakers are fed from the main breaker panel which is on the output of the battery switch. There was no indicator or alarm at either helm and I had caught myself leaving one or both switches in "manual" every once in a while and then hearing the pump(s) still running after I got back to the dock. The lowest part of the forward bilge is up near the shower sump so any collected water will stay there until you get up on plane, where it rushes back to where the fwd bilge pump is, but it may not be enough to trigger the float switch so when I got on plane I would frequently kick that pump to manual for a minute or so in case some water needed to be removed.

I always thought it would be a good idea to block that opening from the engine room bilge to the aft stateroom bilge and add a dedicated pump back there, but I never did that. I did add a very small (500 GPH) automatic bilge pump right next to the engine room that would suck any water out down to about 1/4" and would take care of any of that "nuisance" water such as the water that drips from the shafts. That left the big pump just for emergencies or unusual conditions.

[hinzee623]

Source of the post You need to trace a few of those wires out and diagram those connections to see what's really going on. I agree with Viper, it looks like that 4D is in parallel with the battery on the left, which is NOT a good idea. If that's the case, then you have two battery banks. The single battery on the right and the two batteries in parallel on the left. You can disconnect one set at a time and then put the battery switch on position "1" or "2" and see if anything works to determine which bank is actually "1" and which is "2".

The location of the battery is stock on a 3607, but there were only two group 27 or group 29's in there. Since either could function as a HOUSE, they were both deep cycle or dual purpose. Mine had two battery boxes towards the rear of that compartment and were wired into the battery switch (which is located up underneath the lower step). I ended up adding two 6V in series for a dedicated house bank and maintained the two 12v as starting batteries. While they do seem low in the bilge, you'd have to get about a FOOT of water in there for water to really be a problem. There is a 3/4" platform that lays across the stringers that covers the batteries and provides a place to stand while you are working in the compartment.

I had planned on modifying the configuration to the below model, but I ended up selling it before I got there. That plan would have allowed either engine to charge the house bank but isolated the house from the engines and provided a dedicated start battery for each engine. If there were any problems, you could tie any or all of the batteries together by switching the various switches to "2", which was a common buss. What I really like about this config is that each engine charging circuit is separate but if one fails then the other will actually keep the failed battery from dying via a path through BOTH VSRs. However, you would see a voltage drop difference if you were checking voltage at the helm, giving you a clue to a problem.

Boat_battery_wiring_diagram.jpg

In the interim, I had the configuration below, which worked VERY well. It separated the house bank but allowed any running engine to charge the house (via the VSR) Everything to the right is the original stock config with the switch, engines and batteries. I added the house switch, house battery, VSR and cables back to the engine switch. With this configuration, you could always manually connect the house to the engine batteries if necessary to jumpstart the engine or to bypass a non-functional VSR.

Boat_battery_wiring_diagram_one_engine_switch.jpg

km1125, as always, very good information! Definitely shedding light as to what is factory vs DIY on my boat. Appreciate those one-diagrams too. Follow up question, do you have a battery charger? I have Professional Mariner 35 amp battery charger, its located in the stateroom closet. I would have to assume, since my battery bank, as is, its wired differently than the factory, so must assume the battery charger is probably wired differently as well.