One alternator, solar panels, and 2 banks

[OldManMirage]

Ok guys and gals, I am getting information overload. I have always had pretty standard and simple systems and never had to worry much about it. BUT, I'll be doing long term cruising instead of weekend stuff and I'm trying to set up for that.

I have an alternator, I have solar panels, and I have two banks. One is a group 24 starting battery and the other is the house bank, 3 group 31's. Both are and will be FLA's in order to simplify. The battery mounts are all there and solid so I don't really want to change this aspect.

Important to note most charging will come from solar. I have a very good regulator for the panels (3 - 100w panels). Engine is my backup for when needed. I will size consumption to my supply. I'm flexible.

I am going to rewire pretty much the whole boat and replace the old panel so I can change just about anything. I have a single selector switch but I can change to a 3 switch setup similar to what is on the Compass Marine website. In fact I'd like to.

So.....anyone got a good wiring diagram ? Lol. Any advice is appreciated.

[smac999]

Run the solar and alternator to house bank. Buy a xantrax echo charger to charge engine battery.

[OldManMirage]

That does seem to be the way. I had time on my hands this morning and I've been sitting here researching this for literally hours. I really can't find a simpler solution.

Done !

Thanks for all the help CF. Found a post that had links to so much info !

[a64pilot]

I know a simpler way, put your battery switch to ALL.
If your worried about your house bank going dead and taking the starter bank with it, then once charged switch back. The engine starter battery will be sitting there connected to nothing, how long til dead?
Then once a week or however long is your decision, but put it back to all for a day or when your motoring.

[OldManMirage]

Originally Posted by a64pilot

I know a simpler way, put your battery switch to ALL.
If your worried about your house bank going dead and taking the starter bank with it, then once charged switch back. The engine starter battery will be sitting there connected to nothing, how long til dead?
Then once a week or however long is your decision, but put it back to all for a day or when your motoring.

Switch back is of course the problem. Or rather, when you forget. And my experience has always been that you forget when you need it most.

I think its called Murphy's Law.

The other method just outlined eliminates that issue. And it's super simple to implement the change. And not super expensive.

[Mike OReilly]

Originally Posted by OldManMirage

Switch back is of course the problem. Or rather, when you forget. And my experience has always been that you forget when you need it most.

I think its called Murphy's Law.

The other method just outlined eliminates that issue. And it's super simple to implement the change. And not super expensive.

Not arguing for either solution. Just that I’ve done both, multiple times. On my previous boat it came with the standard 3-way switch, two banks. I rewired completely (as you are doing), and changed so charging was idiot-proof. Used an ACR to combine the banks. Worked great. Never had to think about it.

Current boat has standard 3-way switch, two banks; almost exactly the same as your current set up. Solar runs to house bank. I can combine both banks with the 3-way. Alternator runs through 3-way, so charges the selected bank, or both banks. Also works great.

It is now an automatic habit for me to check state of the selector switch before we start or stop the engine. I appreciate the discipline of having to think about it. Keeps me more engaged with the batteries and charging systems.

But not having to think about it is good too .

If I ever rewire completely I might install an automatic joiner (is an echo charger the same as an ACR?). But there are plenty of actions we discipline ourselves to do on a sailboat. Checking the charging state of the selector switch is just one of many.

[a64pilot]

I guess I obsess about my bank too much as I don’t see accidentally killing my bank anymore than accidentally running out of fuel.
I may one day run out of fuel, but it won’t be a surprise.

[OldManMirage]

Yeah that's a good point too. As someone who has a Private Pilot's license I never could understand how a pilot could run out of fuel. The checks were ingrained into me during training and I just never skipped them.

I guess there is a lot to be said for making a checklist and using it often enough that it becomes second nature.

The setup with an ACR still seems to me to be best. I want the security of having battery in reserve for starting the engine. As the saying goes, better to have and not need it than to need it and not have it.

Of course I'll need to make sure I check it often enough.....

[kas_1611]

If it helps I have 3 banks; Engine, House and Thrusters.

All are independent from each other (ie no 1/2/all/off switches).

The alternator charges all three through a Sterling ProSplitR 180.

The mains charger does the same although without the splitter.

My 2x32w flexible solar panels charge the House through a 10amp regulator although I hope to add a 3rd panel and upgrade the regulator to a 20amp double charge one (ie charge the House then Engine or Thruster once House is full).

I'd always advocate KISS - Keep It Simple Stoopid - as it makes it easier to troubleshoot and reduces chances of faults.

[Kita]

What is the advantage of using 3 100 watt panels over say one 300? Wouldn't it be more simple to go with a single 300? I'm about to do some upgrades & have 1 100 watt now with one 12 volt marine agm start battery & 2 6 volt trojan 105s as a house bank & am looking to upgrade to a 300 watt solar panel & add another house battery. .

[kas_1611]

Originally Posted by Kita

What is the advantage of using 3 100 watt panels over say one 300? Wouldn't it be more simple to go with a single 300? I'm about to do some upgrades & have 1 100 watt now with one 12 volt marine agm start battery & 2 6 volt trojan 105s as a house bank & am looking to upgrade to a 300 watt solar panel & add another house battery. .

None if you are only worried about total amps but a single panel will suffer from shading at some point. 3 panels minimise the shading so you can get a higher overall amp input on average.

I can move my flexi panels around on top of my bimini, for example, to minimise the shading from the back stays, boom or mast. With a 3rd panel I could have 2 running longitudinally either side and one laterally along the back to further minimise shading and maximise the amps in.

[stormalong]

Checkout the battery combiners from Yandina.

Combiner 160 Sheet

I have had one on my boat for about 20 years and it is still going strong. Easy to install and no voltage drop between batteries. Fully automatic.

[Bill O]

I had friends that had issues with an Echo charger not charging a secondary bank. I prefer the simpler 2 bank battery switch as more robust switch compared to electronic "switch" which is less prone to failure.

I'll agree with the comments that the solar should be directed to your house bank. Not knowing what solar controller you have, do you have an auxiliary output that could be hooked up to the start battery? This would then put a small charge on your start bat. to keep it fully charged while the main load goes to the house.

Cheers,
Bill O.

[OldManMirage]

Originally Posted by Bill O

I had friends that had issues with an Echo charger not charging a secondary bank. I prefer the simpler 2 bank battery switch as more robust switch compared to electronic "switch" which is less prone to failure.

I'll agree with the comments that the solar should be directed to your house bank. Not knowing what solar controller you have, do you have an auxiliary output that could be hooked up to the start battery? This would then put a small charge on your start bat. to keep it fully charged while the main load goes to the house.

Cheers,
Bill O.

Hey Bill,
No second output from the charger. But I think I have it sorted. Everything to the main bank, standby battery for starter on an ACR type charger. Keeps everything simple and still only need one battery switch. I like it !

[Bill O]

Originally Posted by OldManMirage

Hey Bill,
Everything to the main bank, standby battery for starter on an ACR type charger. Keeps everything simple and still only need one battery switch.

That would work. The bluesea ACRs are a little pricey but would simplify things and easy to set up.

Bill O.