3 Battery banks and 1 MPPT charge controller?

[MBLittle]

We're in the process of our refit and are adding 600W solar with a 40a MPPT Tracer to our 675ah Trojan T105 house bank. I would also like to charge the stater and windlass batteries...

So how can I configure charging the 3 banks from 1 MPPT controller?

I have searched here and google and come up blank...

[sailorboy1]

To start I don't think a 40a controller is enough for 600W.

But to charge you could dod switches, relays, isolators

[MBLittle]

Originally Posted by sailorboy1

To start I don't think a 40a controller is enough for 600W.

Well, yea, technically 600W is 50amps, but that would be at PEAK output if the panels we're facing the sun completely. These are the Renogy flex panels and are being mounted horizontally on the bimini, with boom shading most likely.

[MBLittle]

Originally Posted by sailorboy1

But to charge you could dod switches, relays, isolators

I'm also looking for easy...

A stretch, I know...

[Dsanduril]

An ACR is made to do exactly that (if you charger controller doesn't have multiple outputs). Joins together the batteries when the voltage on the charging side is higher than some pre-set value. Something along these lines:

https://www.bluesea.com/products/cat...harging_Relays

One caveat, they can be a little tricky with solar, when there isn't a lot of current available closing the relay and connecting a deeply discharged battery can lower the output voltage at the MPPT controller to the point that the relay opens. Then voltage goes up, relay closes, voltage drops, relay opens.... Another issue, if you are using more power than the solar is generating while the ACR is closed you'll be drawing from all three banks (because they are essentially connected through the ACR).

You can also put a big diode (and heat sink) in the connection to each battery, but you will lose about 0.5 volt and have to adjust all the settings on the MPPT unless it has a separate sensing line. A little wasteful of a precious resource.

Or you can look at an "echo charger" (specify a "solar echo charger" when searching), there are lots of those made for this same purpose, some with a little better control around the connection/disconnection than an ACR. Many of them charge a primary battery until "full" (can sometimes be defined, sometimes not) then switch to the secondary(ies). Others charge both at the same time like an ACR.

Lots of options, I've used the ACR route as my system is simple, hopefully others will chime in with other options.

[Ex-Calif]

What about something like this to charge the start or house?


Amazon.com : MinnKota MK-1-DC Single Bank DC Alternator Charger : Trolling Motors : Sports & Outdoors

[twinboat]

I am using 2 Victron, Cyrix -i 100, in my system.

My 675 watt solar goes to my 800AH house bank, along with my 100 amp alternator and 75 amp, charger outputs.

I use 1 Cyrix to combine my house to thruster batteries. I then use the second Cyrix to combine the thruster to the engine battery.

The Cyrix has voltage and time delays to control it from kicking in and out.

My priority is to charge my house bank first, then my thruster batt.
Since I lightly use the thruster the Cyrix combines the start batt. pretty fast, but neither, before the house is up to 13 volts for 10 minutes.

Once the solar drops below 12.8, the combiners cut out, so no thruster or engine battery power is used.

I have been using this setup for 3 years now, almost full time cruising, and it had been trouble free and I am happy with it.

Just my setup

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[zboss]

Echocharger. Cheap, works great, Gets the Mainesail seal of approval, and is easy to install.

Battery Chargers | Auxiliary Battery Charger | Xantrex

[btrayfors]

Yes, the Xantrex EchoCharge is the way to go.

You'll need two of them: one for the start battery and one for the windlass battery.

I've installed a bunch of them, and have had one on my own boat for 11 years. Absolutely automatic and trouble-free.

Connect the MPPT controller output to the house battery bank.

Bill

[twinboat]

Looks like the echo charger cuts in at the same volts, just only handles 15 amps.
You didn`t address his need to charge "2" other batteries.

I set mine up to combine in stages, to prevent my alternator from overheating.

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[btrayfors]

Originally Posted by twinboat

Looks like the echo charger cuts in at the same volts, just only handles 15 amps.
You didn`t address his need to charge "2" other batteries.

I set mine up to combine in stages, to prevent my alternator from overheating.

Sent from my VS840 4G using Cruisers Sailing Forum mobile app

????? Not sure I understand your comment.

I did specify TWO EchoCharges...one for the start battery and one for the windlass batteries.

15A is more than enough to keep these batteries topped up.

His original question was how to charge three banks (house, start, windlass) with one MPPT controller. The EchoCharges will do that. And, they'll do that -- automatically -- with ANY charging source....solar, alternator, battery charger, wind, etc.

No need to switch anything.

Bill

[zboss]

Originally Posted by btrayfors

????? Not sure I understand your comment.

I did specify TWO EchoCharges...one for the start battery and one for the windlass batteries.

15A is more than enough to keep these batteries topped up.

His original question was how to charge three banks (house, start, windlass) with one MPPT controller. The EchoCharges will do that. And, they'll do that -- automatically -- with ANY charging source....solar, alternator, battery charger, wind, etc.

No need to switch anything.

Bill

I don't think people realize how simple the echo charger is. Its one step above screwing in a lightbulb.

[twinboat]

I understand the echo charger. I just had the cyrix combiners, that also connect with 3 wires.

Two posts crossed paths, and my post about " "2" other batteries" was in response to the post from zboss.




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[SailorGerry]

I've used the Echo Charger but I prefer (and now use exclusively) the less expensive and more versatile Magnum Energy Smart Battery Combiner (ME-SBC). For about $110, you get 25 amps of charge power and the ability to adjust your set points… Smart Battery Combiner (ME-SBC) - Magnum Energy, Inc.

[Frugal]

You may need to take into account that your 40 amp MPPT may suffice on nameplate 50 amps of panels. But on occasions I have had all panels producing maximum output and have nearby cumulus clouds adding reflected radiation. The output has exceeded the nameplate wattage. Suggest you break up your panels into two or three series with MPPT's on each. Safer redundancy and you could direct the outputs to either battery bank or all with heavy duty rotary switches.