Battery charger and switch advice

[mattman]

Hi folks,

The Promariner ProSport8 battery charger in my '84 sailboat recently stopped powering on, so I started looking into a replacement. It's my first boat and has a relatively "complicated" electrical setup, so I've taken the last few days to really investigate if it's the most appropriate setup for my needs.

My 12V batteries are 1xCranking, 2xHouse (126 AH each)

My shore load is basically just the fridge, which is rated at 48W (4A)

The electrical setup as far as I can tell seems to be exactly what is shown in the third schematic of the following page under "Can Isolate a failed battery":

https://www.bluesea.com/resources/17...l_Applications

In total there are 3 ON/OFF switches and 1 ACR. The master switch powers the house, and I realized will not charge my batteries if I turn it OFF when I leave the boat, so it's left on 24/7. I also have a Starter switch that powers the starter, also always ON. Lastly it has a "Emergency Parallel" switch that combines the batteries if I need extra start juice, this is left OFF.

The ACR is connected directly to the positive and negative bus, so I believe this deviates from the schematic slightly?

The charger configuration is only using one of its available output banks, and was wired directly to the positive/negative bus, not to each individual battery bank. I assume this means I'm not getting the most efficient charger possible since the batteries aren't given individual attention?

So given that, I'm hoping to get advice on:

What type of charger should I get? I'm told the ProSport wasn't a great charger for my needs. Perhaps the ProNautic 30A? Or a single-bank like the NOCA Genius 10A? Is it worthwhile to utilize the dual-output on the chargers or are my needs simple enough that just using the ACR to combine a single charger output is good enough?


And just out of curiosity, would it be worthwhile to replace the 3 separate switches with the BlueSea "Dual Circuit Plus" battery switch? It would simplify the wiring a bit, but hey it ain't broke, so maybe just leave it alone

[john61ct]

Sterling Power ProCharge Ultra and ProMariner Pronautic P series both let you optimize setpoints for different chemistries in future.

ACR is fine if not separate outputs.

Only rewire switches if you want to improve functionality.

[mattman]

Originally Posted by john61ct

Sterling Power ProCharge Ultra and ProMariner Pronautic P series both let you optimize setpoints for different chemistries in future.

ACR is fine if not separate outputs.

Only rewire switches if you want to improve functionality.

Is 20A good for my setup or should I spring for the 30A? And sorry to beat a dead horse, but even though these chargers have 3 outputs, it's totally acceptable to just use a single output to charge all 3 batteries?

[john61ct]

House bank vs Starter chemistry type?

If possible voltage setpoint recommendations from mfg?

[mattman]

Originally Posted by john61ct

House bank vs Starter chemistry type?

If possible voltage setpoint recommendations from mfg?

All 3 are wet-cell.

House batteries are Interstate Batteries SRM-29
Interstate Batteries Results Page - Marine R/V - 12 Months Free Replacement - 675 CCA

Starter is Interstate 24M-XHD
Interstate Batteries Results Page - Marine R/V - Int Marine/RV 12M Free - 800 CCA

[smac999]

Wire 2 of the outputs to 2 banks
You defiantly should not need the switches on for charging... wire direct to battery. With fuses

The acr connects to each battery. Before switches.

I would go 30a.

[Zil]

My promariner 40 amp has 3 positive connections. The book says I only need to connect one for my single bank.

[ranger58sb]

Originally Posted by matthidinger

My 12V batteries are 1xCranking, 2xHouse (126 AH each)

My shore load is basically just the fridge, which is rated at 48W (4A)

The charger configuration is only using one of its available output banks, and was wired directly to the positive/negative bus, not to each individual battery bank.

What type of charger should I get? I'm told the ProSport wasn't a great charger for my needs. Perhaps the ProNautic 30A? Or a single-bank like the NOCA Genius 10A? Is it worthwhile to utilize the dual-output on the chargers or are my needs simple enough that just using the ACR to combine a single charger output is good enough?

Originally Posted by matthidinger

Is 20A good for my setup or should I spring for the 30A? And sorry to beat a dead horse, but even though these chargers have 3 outputs, it's totally acceptable to just use a single output to charge all 3 batteries?

I can't speak to your switches and ACRs, etc. but I'd say if you have any electronics load while underway (plotter? depth? radio? etc.) and depending on how they're wired, then you might be using more battery capacity than just the fridge...

And if so, probably faster charging capability (30A vs. 20A) could well be useful in the long run.

I suspect I'd maybe go even larger (e.g., 40A), in case you sometime decide to go to batteries that will accept charge faster.

Originally Posted by smac999

Wire 2 of the outputs to 2 banks

Originally Posted by Zil

My promariner 40 amp has 3 positive connections. The book says I only need to connect one for my single bank.

It would be common to use two of the charger outputs, one to each bank... and the third charger output may need a short jumper to one of the other two. (Ours is like that.) The ProMariner manual will advise, if you go that route. (You can download their manuals in advance.)

I suspect ProMariner may also say that ideally each bank should be approximately similar in size (capacity) although they may have gotten over that by now, with products newer than our original 40A charger.

-Chris

[john61ct]

30A minimum, 40 would be better.

Separate outputs better than ACR, but latter OK.

When the House bank dies, get proper deep cycling replacements.

[roland stockham]

Yes you should be using a twin output charger wired directly to the batteries. Also VHF and pumps should be directly connected (I use a small bus bar for this). Everything else should connect after the isolation switches. This is so you can isolate power in the event of a fire as well as turning things off if you leave the boat. The only issue with the ARC is if it combines the batteries while the chargers are running then they both get the same charge, effectively you have a single bank. If the house bank is deep cycle and the starter is, well a starter batt it will get significantly overcharged each time the house bank is charged because the charger should be in a longer absorption phase the start batt needs. Your system sounds OK if you will spend most of your time at a dock with shore power and go out for 1-2 day trips. For cruising of life at anchor you will probably find that the whole system needs upgrading (normal when converting a boat for cruising or sailing remote areas away from docks)

[Ironman162]

Would you consider an inverter with a 50A inbuilt charging facility?
I know this is a bit lateral but it simplifies the circuit considerably. It would allow everything to remain as is and it switches over automatically when on shore or generator power.
I've got one on my boat and can only speak highly of it although I deliberately disabled the generator to start automatically on low voltage. It was the point where things got a bit too automatic to my liking. Just a personal preferance.

I hope you can find a way forwards that works for you! There are quite a few options available but as always, the fewer devices one have, the more reliable the system.

[john61ct]

Originally Posted by roland stockham

The only issue with the ARC is if it combines the batteries while the chargers are running then they both get the same charge, effectively you have a single bank. If the house bank is deep cycle and the starter is, well a starter batt it will get significantly overcharged each time the house bank is charged because the charger should be in a longer absorption phase the start batt needs.

Not actually a big issue in practice, but yes if easily avoided that's better.

[mitiempo]

Originally Posted by john61ct

30A minimum, 40 would be better.

Separate outputs better than ACR, but latter OK.

When the House bank dies, get proper deep cycling replacements.

There is nothing wrong with utilizing the ACR for charging the start battery - from any source. As long as the batteries are the same type - Fla as in this case - the start battery will not be overcharged. At a given voltage the battery determines the current it accepts not the charge source.

When plugging into shore power the house bank voltage will slowly rise. At about 13.6 the ACR will close combining the banks.

This is what ACR's are for and they do their job very well. The house bank is always the bank most in need of current so it is the priority.

I would keep the 3 separate switches. It is preferable to the Dual Circuit switch as in a dead start battery situation you never want to combine the dead one with one that is charged. The 3 switches allow you to use either bank alone for house loads or starting.

I would go with the Pronautic of either 30 or 40 amps. Excellent chargers.

[john61ct]

I have said from the beginning the ACR approach is fine.

If a multiple output charger eliminates the need for an ACR I think it's better.

In some designs, like my "Main vs Reserve" there may well be an expensive bank in the "starter position".

Yes no overcharging is possible from a current POV, but personally I don't want continual Absorb voltage pushing on my expensive Reserve bank when it is always at 100% full.

So also from that POV an intelligent charger approach is better than a dumb combiner.

I generally prefer B2B DC-DC best of all.

But I concede the "better" is not worth the expense for most, the ACR approach, or even $50 solenoid is generally just fine, after all, most don't even spend much on their Starter anyway.

[mitiempo]

Originally Posted by john61ct

So also from that POV an intelligent charger approach is better than a dumb combiner.

While the Pronautic is an intelligent charger it only sees one bank. It has diode protected outputs and is a single charger which, like most chargers does not adjust for multiple banks. The battery determine the current accepted. As long as the most depleted bank - the house bank - is in bulk the starter battery will see the same voltage.