Getting Rid of the House Bank

[scottinsydney]

I've killed yet another set of port side lead acid batteries through leaving lights on. Another time a float switch malfunctioned and the batteries never recovered. And Covid lockdown absence killed another set. Aghhhhh.

There has to be a modern day way to disconnect the house DC load from the port battery bank???

Our big lithium battery system has worked great the past 2.5 years. Our idea would be to have it now also power the house DC load. If there was a leak, the bilge pumps would run for a much longer time on the lithium batteries anyway.

The port lead acids would then be dedicated to engine starting only.

Before I bring in the marine electrician, what would be the technical issues? Where to disconnect house load? How / where to do the grounding? Yes, we'd need to convert 48v to 32v, but Analytic Systems say they can do this for me.

Ideas?

 

[Dan Mapes]

Why not install battery protection inbetween the house and batteries? Leave the starting circuits out of the loop?

 

[Captain Ralph]

Why not install battery protection inbetween the house and batteries? Leave the starting circuits out of the loop?

I think your typing about a lil gizmo that turns a load off at a set voltage so the batteries don't get to low or flat.
I have always been a fan of this.
Sadly, I don't think it is available available for 32V systems.

 

[Captain Ralph]

Why are the battery chargers off?

Can you install a mini 32v battery bank for the house? A bank of deep cycle golf cart batteries would shine and not eat up to much room.

 

[scottinsydney]

Thank you.

I've looked at and used voltage sensitive house switches before. They would also disconnect the bilge pumps.

I do wish to use the capacity of the lithium batteries which will turn off automatically without damage and/or charge quickly with the solar panels. I don't ever want another set of lead acids.

How to achieve goals in my original post?

 

[carolinacoast]

I have had similar challenges with dead batteries, but was able to bring the golf cart batts back up with a trickle charge. Can't offer advice directly to your proposed solution. A monitoring system for shore power, bilge pumps that sends a text when things change has worked so far. I have other battery banks always charged and ready if I had a dead bank.

 

[cww]

The only time leaving a light on would ruin a battery is if they were low on water anyway. How often are you checking the water levels?

 

[Pascal]

You keep the boat on a mooring, don’t you?

I m not a big fan of using step down converters as it is one more thing to fail. You re also going to need a pretty big one to serve the entire house system.

In theory all you should have to do is run adequately sized wires from the converter output to the existing house battery switch

Or why not keep the existing house bank, but replace the on off battery switch with a switch what work let you select either the house bank or the converter output. This way when on the boat, you can run the lights, heads etc off the house bank and you switch to the lithium bank when off the boat.

 

[Dan Mapes]

Thank you.

I've looked at and used voltage sensitive house switches before. They would also disconnect the bilge pumps.

I do wish to use the capacity of the lithium batteries which will turn off automatically without damage and/or charge quickly with the solar panels. I don't ever want another set of lead acids.

How to achieve goals in my original post?

I was afraid that would be the case.

 

[scottinsydney]

We have worked out in theory how to bypass the house bank with the lithium battery.

We went looking fore answers and as it turned out there was some corrosion buildup on the 0000 battery post near the batteries. Batteries are now working as they should which is a relief.