Solar Power to charge two batteries

dolabriform

dolabriform

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Hi All

I have two identical batteries on the boat, with a switch to select either or both. When running the engine I select both, so they both get charged by the alternator.

I want to add a 50w solar panel to keep them topped up, with a Victron controller:
https://store.meadotech.com/#!/Vict...Solar-Charge-Controller-12-24V-10A/p/50109522

Can I connect the output of the solar controller directly to the same input on the switch?

Thanks

David
 
dolabriform said:
Hi All

I have two identical batteries on the boat, with a switch to select either or both. When running the engine I select both, so they both get charged by the alternator.

I want to add a 50w solar panel to keep them topped up, with a Victron controller:
https://store.meadotech.com/#!/Vict...Solar-Charge-Controller-12-24V-10A/p/50109522

Can I connect the output of the solar controller directly to the same input on the switch?

Thanks

David
Click to expand...

Yes but the down side is that you will have to leave the switch in an "on" position to charge either or both batteries when you might normally switch everything off.

The BlueSolar PWM-DUO Charge Controller has two outputs which could be wired directly to the two batteries allowing both to be charged with the main isolator/ selector switch "off"

https://www.victronenergy.com/upload/documents/Datasheet-BlueSolar-PWM-DUO-Charge-Controller-EN.pdf
 
VicS said:
Yes but the down side is that you will have to leave the switch in an "on" position to charge either or both batteries when you might normally switch everything off.

The BlueSolar PWM-DUO Charge Controller has two outputs which could be wired directly to the two batteries allowing both to be charged with the main isolator/ selector switch "off"

https://www.victronenergy.com/upload/documents/Datasheet-BlueSolar-PWM-DUO-Charge-Controller-EN.pdf
Click to expand...

Brilliant, thanks Vic.
 
It would be desirable to be able to leave the boat with batteries off not paralleled. However if you are happy to do so then leave switch on both position. An alternative arrangement would be to fit 2x diodes from the solar panel positive (anodes opposite the band or arrow tail together on solar +ve, cathodes with band each diode going to 2 different controllers and so to batteries. This will need another controller. olewill
 
Stemar said:
I have one of these http://www.sunstore.co.uk/product/ep-solar-duo-battery-solar-charge-controller-12-24v-10a/

It's set up to charge my starter battery until it burps, then turns its attention to the domestic one. It isn't the cleverest type of controller, but my 40w of panels keep the batteries fully charged and doesn't require them to be linked.
Click to expand...

I have the same controller but with a single 40W panel and I used to have one channel directly connected to 600Ah of house battery (3 batteries in parallel) and the other channel directly connected to 200Ah of engine start battery (2 batteries in parallel). It kept all the batteries fully charged during the 6 months when the boat is not used.

This winter it has been relegated (regulated :)) to engine start battery duty only.

Richard
 
Going through a very similar thought process to Dolabriform, though I intend to go up to as much as 200W eventually.

The problem with the Victron unit shown is that it's not an MPPT charger, though for a 50W panel that may not be an issue. There is an MPPT dual battery charger from Votronic, but it doesn't have the nice Bluetooth features of the Victron MPPT chargers (which only have one output).
At the moment I'm leaning towards the cheap Sunstore one Stemar and RichardS mention, with the intention of replacing it when Victron pull their finger out.
Anyone know of a good MPPT dual-battery solution with good remote viewing capability?
 
lampshuk said:
Going through a very similar thought process to Dolabriform, though I intend to go up to as much as 200W eventually.

The problem with the Victron unit shown is that it's not an MPPT charger, though for a 50W panel that may not be an issue. There is an MPPT dual battery charger from Votronic, but it doesn't have the nice Bluetooth features of the Victron MPPT chargers (which only have one output).
At the moment I'm leaning towards the cheap Sunstore one Stemar and RichardS mention, with the intention of replacing it when Victron pull their finger out.
Anyone know of a good MPPT dual-battery solution with good remote viewing capability?
Click to expand...

I would fit the Victron controller. Then either, leave the engine battery to fend for itself (which will be fine unless you leave the boat for long periods unattended), fit a 2nd, smaller, panel to look after the engine battery, or fit a split charge system. The split charge system would be a good solution, as it could make sure all batteries get charged without having to fiddle with a 1-2-B switch, or leave it on both.

A reminder about leaving 1-2-B switches on the "both" setting.... whilst the switch is on "both" the batteries are in parallel, effectively a single bank, should a battery fail in such a way to drain the other batteries you are left with no way of starting the engine, should you forget to take it off of "both", the same thing could happen as your domestic circuits deplete the batteries. "Both" is for emergency use only.
 
Yep. Got it.

I've re-written this next post about 6 times and each rambling draft has led me to re-think my battery strategy, so let me restrict it to this:

What do you think of the Cyrix-CT? Would it provide both battery selection and charge-changeover functionality?
 
Stemar said:
I have one of these http://www.sunstore.co.uk/product/ep-solar-duo-battery-solar-charge-controller-12-24v-10a/

It's set up to charge my starter battery until it burps, then turns its attention to the domestic one. It isn't the cleverest type of controller, but my 40w of panels keep the batteries fully charged and doesn't require them to be linked.
Click to expand...
I have the 20A version but have the domestic batteries being charged first then turns its attention to the starter battery. Works well for me with 100W of panel.

Donald
 
lampshuk said:
Yep. Got it.

I've re-written this next post about 6 times and each rambling draft has led me to re-think my battery strategy, so let me restrict it to this:

What do you think of the Cyrix-CT? Would it provide both battery selection and charge-changeover functionality?
Click to expand...

If you fit the Victron controller and connect it to the domestic bank, then add the Cyrix, both batteries will get charged by the solar panels and also by the alternator.

You may then want to consider your switching arrangement, what do you currently have ? What batteries do you have ?
 
PaulRainbow said:
leave the engine battery to fend for itself (which will be fine unless you leave the boat for long periods unattended),
Click to expand...

My solar doesn't charge the engine battery and it's fine for a couple of months, most likely longer with no loads. When away, I disconnect my car battery and that's fine for 6 or more months, starts first turn when reconnected.
 
RichardS said:
I have the same controller but with a single 40W panel and I used to have one channel directly connected to 600Ah of house battery (3 batteries in parallel) and the other channel directly connected to 200Ah of engine start battery (2 batteries in parallel). It kept all the batteries fully charged during the 6 months when the boat is not used.

This winter it has been relegated (regulated :)) to engine start battery duty only.



Richard
Click to expand...

what sort of engine has a 200Ah start battery? (genuine question!)
 
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