Which MPPT Controller to buy?

[The Nomad]

Advice please on which MPPT solar panel controller to buy........
We presently have an 80 watt solar panel on the roof of our motorhome, which feeds the batteries through a basic (ie not an MPPT) solar panel controller located inside the vehicle.
The leisure batteries it feeds are a matched pair of Varta "Silver" 110Ah sealed-for-life "wet" batteries, plus a 90Ah cranking battery for the engine.
I'm intending to add a further 80 or 100 watt solar panel in the coming weeks, to increase our wild-camping independence options.
Question please:
I understand that an MMPT controller is "better" than an ordinary type. Is it really a lot "better"?
Can anyone with a good knowledge of the different brands of such MPPT charge controllers recommend which to buy, and size/capacity I'd need in order to handle two solar panels totalling 160 watts capacity?
Links to any suitable ones on eBay or Amazon, or other online suppliers would be greatly appreciated.
Many thanks!

 

[Richard n Ann]

We went for the Votronic Duo 250 mppt controller as it also charges the engine battery and it means we can use the van radio

 

[tacr2man]

How much space do you have on roof , as this is a good VFM
https://www.bimblesolar.com/offgrid/12v/260W-budget-kit-mppt-mounting-used

You could leave existing panel for starter battery and use new system for hab batts.

 

[Minxy]

I've just bought a Votornic Duo 250 for our camper from here:

Amazon product ASIN

 

[The Nomad]

How much space do you have on roof , as this is a good VFM
https://www.bimblesolar.com/offgrid/12v/260W-budget-kit-mppt-mounting-used

You could leave existing panel for starter battery and use new system for hab batts.

.


Unfortunately not much space left - I can add a 100 watt one on as maximum.

So the controller would need to handle a maximum of notionally 180 watts.
A it happens there is an original panel up there (as well as the second one I've already added) which was put on as original equipment by Benimar, and which works through the Benimar control panel.
But it's an antiquated control panel and I didn't want to bugger about with it, so when we added the first additional 80 watt solar panel we routed it independently through it's own controller to leisure batteries. It's this separate, newer independent system that I would like to augment with another 80 or 100 watt panel.

It may be in due course that I can route the original small Benimar panel to just charge the engine battery.

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[Allanm]

We have a Victron 75/15 that works well. I think it will handle 220watts.
You can get a Bluetooth dongle that will enable you to monitor the controller and update software when necessary.
I can recommend it

 

[Lenny HB]

Another vote for the Votronic I have just fitted an MPP 350 (I have 300 w of solar) works very well when the sun is at a low angle.

 

[Driventemple]

What is the Open Circuit voltage of your existing panel? MPPT controllers work better with panels that produce higher voltages - 24v upwards. You may increase the available voltage by wiring the old and new panels in series ie two 18v panels can give an output of up to 36v, but if one is in shade then they both be affected. I fitted a 140W panel to my last van and an Epever controler. The outputs can be seen here:

You can see the MPPT controller took the 24v at 2.7A output and increased available current to 4.4A to the battery.

 

[Driventemple]

Forgot to mention:



This was the one I fitted - and will use again on the 'new' van.

 

[Hettie's Crew]

Votronic fan here, just fitted one in place of the Photonic Uniiverse PWM 10amp controller that was fitted. Batteries used to show 12.7 going down to 12.5 after an evenings light use. Now show 13 and haven’t gone down.
I’m convinced they were never fully charged before.

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[The Nomad]

Another vote for the Votronic I have just fitted an MPP 350 (I have 300 w of solar) works very well when the sun is at a low angle.

They look very good.

We are almost always wildcamping/on Aires but don't use mains hookup, usually when parked up for a few days before moving on our fridge runs on gas.

But I particularly like the idea that with enough wattage of panels on the roof, if there's enough surplus power coming in then once the habitation and engine batteries are both full, the charge controller can tell the Dometic AES fridge to change to 12 volt power (from the Habitation batteries), to stop that energy being wasted.... and thus save on gas usage on sunny days.

Have you wired up that "AES" linkage from your charge controller to your fridge? Does it work ?

Does anyone else use that "AES" fridge linkage from their Votronic 250 or 350 charge controller?

 

[funflair]

Does anyone else use that "AES" fridge linkage from their Votronic 250 or 350 charge controller?

We have had Votronic controller for a few years now and its great, teamed up with their solar computer which is just a simple cat5 type plug,

Yes I have the fridge wired on the AES output but for it to work you need a fridge with S+ connection of you may have to do a fiddle to make an older D+ only fridge work, my fiddle was a diode on the end of the alternator wire stopping the AES signal going down through the alternator windings. Some people have it wired to modern S+ fridge but find that the AES from the Votronic takes priority over 240v hook up and they don't get a good freeze that way as the 12 element is lower wattage than the 240v element, ours work in the right sequence

Martin

 

[Lenny HB]

They look very good.

We are almost always wildcamping/on Aires but don't use mains hookup, usually when parked up for a few days before moving on our fridge runs on gas.

But I particularly like the idea that with enough wattage of panels on the roof, if there's enough surplus power coming in then once the habitation and engine batteries are both full, the charge controller can tell the Dometic AES fridge to change to 12 volt power (from the Habitation batteries), to stop that energy being wasted.... and thus save on gas usage on sunny days.

Have you wired up that "AES" linkage from your charge controller to your fridge? Does it work ?

Does anyone else use that "AES" fridge linkage from their Votronic 250 or 350 charge controller?

Wired the AES output on my MPP 350 to the S+ terminal on the fridge. Last few weeks the fridge has been running on 12v for at least 2 hours a day so looking at around 10% saving on gas.

Only problem is the stupid Domectic fridge has 12v solar as the priority energy source. So when you are on EHU and the batteries are charged the Votronic AES output turns on and the fridge switches to 12v, not ideal as the 12v element is 50w lower than the 240v one.

I have fitted a switch inline with the AES output on the Votronic, I may fit a mains power relay but not that important as like you hardly ever use mains.

 

[The Nomad]

Wired the AES output on my MPP 350 to the S+ terminal on the fridge. Last few weeks the fridge has been running on 12v for at least 2 hours a day so looking at around 10% saving on gas.

Only problem is the stupid Domectic fridge has 12v solar as the priority energy source. So when you are on EHU and the batteries are charged the Votronic AES output turns on and the fridge switches to 12v, not ideal as the 12v element is 50w lower than the 240v one.

I have fitted a switch inline with the AES output on the Votronic, I may fit a mains power relay but not that important as like you hardly ever use mains.

Many thanks for that.

So if I understood you, you've wired the aes wire from the solar charge controller to the D+ terminal on the fridge, but have also installed an on/off switch into that wire.

If on EHU you keep that switch off, so fridge uses mains electric; but at all other times you turn switch on, so fridge will take 12volt supply whenever solar controller tells it there's surplus power from the solar panels that it can use.

I assume when sun goes down the controller just breaks off contact with the fridge and fridge then switches to gas. . ..

Is that how it works?

 

[Lenny HB]

Many thanks for that.

So if I understood you, you've wired the aes wire from the solar charge controller to the D+ terminal on the fridge, but have also installed an on/off switch into that wire.

No, I wired it to the S+ terminal on the fridge.

If on EHU you keep that switch off, so fridge uses mains electric; but at all other times you turn switch on, so fridge will take 12volt supply whenever solar controller tells it there's surplus power from the solar panels that it can use.

Yes

I assume when sun goes down the controller just breaks off contact with the fridge and fridge then switches to gas. . ..

Is that how it works?

In theory yes but in practice only runs for a couple of hours a day, I find at this time of year on a bright sunny morning it switches to 12v for about an hour then back to gas and couple of hours later when the batteries are charged it will switch back to 12v for an hour or so. It does this so your batteries always remain in a good state of charge.

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