Mppt solar controller

[Deleted member 1063]

Here we go again, I'm after a mppt 30amp controller but which ones are people buying and where from. Can't really afford a victron so was looking at the epever but seen some horror stories of copys.
Willing to pay upto £100 but who do you trust on the internet ? All advice will be much appreciated.
Thanks in advance Rob

 

[Molly 3]

Look on u tube many cheap mppt controllers are fake ,they are named and shamed . epever from photonic universe should be good

 

[Beemer]

This is what I have installed, in conjunction with a small control box, like the ones below.

12V solar panels charging kits for caravans, motorhomes, boats, yachts, marine

12V solar panel solar charging kits for motorhome caravan boat campervan yacht marine off-grid

www.photonicuniverse.com

EPEVER MT50 LCD Display Remote Meter, Remote Meter Suitable for Tracer-A/An/BN Series 10-100A MPPT Solar Charge Controller: Amazon.co.uk: Garden & Outdoors

EPEVER MT50 LCD Display Remote Meter, Remote Meter Suitable for Tracer-A/An/BN Series 10-100A MPPT Solar Charge Controller: Amazon.co.uk: Garden & Outdoors

www.amazon.co.uk

Works really well on my system.

 

[St3v3]

Bimble solar are also good

 

[wildebus]

I think people assume Victron kit is out of their budget, but as an example, the controller from Photonicuniverse above is only around £5 less then you can pay for a slightly more powerful Victron MPPT Controller that comes with a 5 year warranty.
And the Model with the Bluetooth Feature so you can setup and monitor the Solar via your phone is available at an extra cost which is less than the MT-50 Remote Meter Display.

Put those two together and you could get a Victron Unit for the same kind of cost and a better warranty ....

 

[wildebus]

Here we go again, I'm after a mppt 30amp controller but which ones are people buying and where from. Can't really afford a victron so was looking at the epever but seen some horror stories of copys.
Willing to pay upto £100 but who do you trust on the internet ? All advice will be much appreciated.
Thanks in advance Rob

You say you want a 30A controller. What size PV Array are you installing? it is easy to oversize (and so overspend) when it is not neccessary.

I am fitting a 220W array next week and I specified the Victron 75/15 Controller for it. The Customer decided to upspec slightly to the 100/20 Controller as he wanted some slack. The 100/20 (inc Bluetooth) can work with upto 290W and can be had for £150. (I would have no hesitation at using the 100/20 at upto 340W either if say £150 was the top budget as the amount of time the extra wattage that gets chopped is achieved is negligable).

 

[Deleted member 1063]

You say you want a 30A controller. What size PV Array are you installing? it is easy to oversize (and so overspend) when it is not neccessary.

I am fitting a 220W array next week and I specified the Victron 75/15 Controller for it. The Customer decided to upspec slightly to the 100/20 Controller as he wanted some slack. The 100/20 (inc Bluetooth) can work with upto 290W and can be had for £150. (I would have no hesitation at using the 100/20 at upto 340W either if say £150 was the top budget as the amount of time the extra wattage that gets chopped is achieved is negligable).

Just been reading another post about running two or more controllers together and the fact they interfere with each other. So am now thinking I need 40amp if I run them all together as I've running about 500watts

 

[wildebus]

Just been reading another post about running two or more controllers together and the fact they interfere with each other. So am now thinking I need 40amp if I run them all together as I've running about 500watts

yup, I would agree with that.
500W is a nice little array I am contemplating increasing mine from 400W to 600W and would need to change my Victron 100/30 to a 100/50 unit (I'm commited to Victron units as I have a full Victron monitoring system). I would have not minded just getting a smaller 75/15 for the extra 200W but as you say, two controllers rarely play well together unless you get the High Capacity ones from the Top Manufacturers.
(as an example, Solar has been pants for last two days so I plugged in my van to EHU this evening as I need a full bank to go away with tomorrow. As soon as the mains charger came on, the Solar Controller went into Float mode as it saw the higher voltage at the battery).

 

[Deleted member 1063]

Ye, I think I know where I'm going now ( spend more money)

 

[SquirrellCook]

You say you want a 30A controller. What size PV Array are you installing? it is easy to oversize (and so overspend) when it is not neccessary.

I am fitting a 220W array next week and I specified the Victron 75/15 Controller for it. The Customer decided to upspec slightly to the 100/20 Controller as he wanted some slack. The 100/20 (inc Bluetooth) can work with upto 290W and can be had for £150. (I would have no hesitation at using the 100/20 at upto 340W either if say £150 was the top budget as the amount of time the extra wattage that gets chopped is achieved is negligable).

Just a thought. If your PV array was capable of lets say 1000Watts and you fitted a 100/20 Victron unit. All that would mean is that the charge current would never exceed 20amps? I know that your potential solar capacity would be wasted, but that 1kw array would be able to produce 100watts more often that 1kw. Or am I misunderstanding how it works?

 

[Okta]

Just a thought. If your PV array was capable of lets say 1000Watts and you fitted a 100/20 Victron unit. All that would mean is that the charge current would never exceed 20amps? I know that your potential solar capacity would be wasted, but that 1kw array would be able to produce 100watts more often that 1kw. Or am I misunderstanding how it works?

That might not be the case. My Votronic MPPT manual clearly specifies Watts and Amps as solar input limits not as charging output limits. For example the 250 model has a solar input limit of 250W and 15A. An overloaded unit might blow a fuse but it might possibly burn out the electronics as well. In my opinion very much not worth the risk.

 

[wildebus]

Just a thought. If your PV array was capable of lets say 1000Watts and you fitted a 100/20 Victron unit. All that would mean is that the charge current would never exceed 20amps? I know that your potential solar capacity would be wasted, but that 1kw array would be able to produce 100watts more often that 1kw. Or am I misunderstanding how it works?

What would happen [with the Victron Controller] is any power generated that would exceed the limit of the controller gets discarded. I did a rough chart to illustrate this, posted below, with Amps on the vertical axis.
So if the controller was a 20A unit, as the potential output current rises above 20A, anything above that is lost and the charge current goes flatline.


Does this matter? Well, you are potentially wasting charging capabilty but some things to consider.
1) The Solar Array only peaks for a very short time in the day; plus even that peak will only happen for a few months of the year.
You may have a large array installed just so you get better harvesting outside the peak times but don't actually have a need to achieve 100% of the arrays capabilty.
2) Depending on your battery type, capacity and level of charge, even if you had a 30A controller and your array COULD produce 30A, the battery may only be able to accept 20A or even less, so you may get the benefit of a the higher capacity controller for a very small time.

Whether it is worth undersizing depends of how much you want to achieve (remember it is rarely good to charge a Lead Acid battery at over 20-25% of its capacity, so a 100Ah battery would not want more than 25A anyway); Plus the cost could be a factor - jumping up a level could potentially be quite pricey and if you are only just under the arrays maximum limit it may not be worth it (taking factors above into play)?

That might not be the case. My Votronic MPPT manual clearly specifies Watts and Amps as solar input limits not as charging output limits. For example the 250 model has a solar input limit of 250W and 15A. An overloaded unit might blow a fuse but it might possibly burn out the electronics as well. In my opinion very much not worth the risk.

I don't know about the Votronic controller, but the Victron Controllers are designed to work as I describe above and there is no issue having a 'oversized' array connected to it.

 

[Okta]

I don't know about the Votronic controller, but the Victron Controllers are designed to work as I describe above and there is no issue having a 'oversized' array connected to it.

Interesting. I notice that the Victron refers to over current protection whereas the Votronic only talks about overcharge protection (to protect the battery), a subtle difference in the wording. I don't know about the Victron controller but would be interested to know where it loses the excess current. I can see a couple of amps being lost fairly easily but in the unlikely example given with a 1000W array and a 100W controller it would need to dump/divert/resist over 50A and I would have thought this would be more problematical.

 

[wildebus]

Interesting. I notice that the Victron refers to over current protection whereas the Votronic only talks about overcharge protection (to protect the battery), a subtle difference in the wording. I don't know about the Victron controller but would be interested to know where it loses the excess current. I can see a couple of amps being lost fairly easily but in the unlikely example given with a 1000W array and a 100W controller it would need to dump/divert/resist over 50A and I would have thought this would be more problematical.

I would think it just doesn't bring in the excess in the first place so doesn't need to dump it.
It would be no different to a 1000W array with a 100A Solar Controller getting full sun at high noon, but the battery is already full and so only taking in 2-3A instead of the theoretical ~80A.

 

[wildebus]

Thought I could illustrate this using the info from the controller I have (a 100/30 - so 100V max and 30A max)....

My batteries are full as plugged into EHU today until around 1:30pm, so got very little call for Solar.
The top graphic is the input from the panels; the bottom graphic is the output to the batteries; the MPPT controller in the middle is converting the higher voltage into higher current.

If you compare the two orange (current) lines, you can see the shape is pretty well identical, showing that what is being allowed into the controller in overall power terms is determined and limited by what is being demanded by the battery system on the other side (with a couple of percent extra to compensate for controller losses of course)

 

[Okta]

I guess I am underestimating the cleverness of modern electronics.

 

[wfdTamar]

The one I got has a couple of great features (not sure if others have them). Votronic Duo Digital.

Can charge the leisure battery and the starter battery. Can tell an AES (automatic) fridge to run from 12 volt when there is excess solar (both batteries fully charged). This makes it a great option for winter storage as it might keep both batteries charged.

 

[SquirrellCook]

It's a funny thing electrical charge. It's easier to think of a chemical change in a battery as it gains or losses charge. But what about those sneaky photons entering your solar panel? If it's left in sunlight and out of circuit do they just quietly leave via the wires? The more resistive load you place on the panel the more volts drop and the current rises to the panels capabilities. Whilst in sunlight the panels get hot. Do they get cooler as you harvest the energy? That's enough silliness for one morning.

 

[RAW]

Here we go again, I'm after a mppt 30amp controller but which ones are people buying and where from. Can't really afford a victron so was looking at the epever but seen some horror stories of copys.
Willing to pay upto £100 but who do you trust on the internet ? All advice will be much appreciated.
Thanks in advance Rob

I got a Victron MPPT 100/30 for £150 I think it is the best you can buy to be frank.
I would just up your budget a bit or save up until you can get one.
If you are up North then seek advice from Ian Emberton at Xerogrid which is where I got most of my set-up from, cables, panel and controller.

Cheers
Robert

 

[Deleted member 1063]

Thanks to all for the advice. I've now ordered the Epever 40amp and MT-50 from photonic universe. Got a bit of rewiring and another panel to fit before next trip. ? so much for a budget.