Solar charge controller choice?

[MINESAPINT2]

Hi,

I have just ordered an 80w Mono panel and did not realise how complex choosing a controller could be.

Firstly MPPT or PWM.

I have 2 battery banks one 110a and one of 220a (3 batteries in total, all cranking).

I am planning to connect the 220a bank to the solar panel but could buy a dual controller and connect both banks?.

I think I have understood (more or less) that MPPT controllers can accept high voltage and have the ability to convert the excess voltage into charge (amps). However the PWM chargers have to waste any excess voltage over and above the battery voltage which I find is usually about 13.? volts.

To take full advantage of am MPPT controller I understand you need to be producing excess voltage regularly but with a single 80w panel this seems unlikely. I therefore understand the argument for me to fit a MPPT controller is borderline.

Added to this I have read several times lots of PWM controllers are advertised and labelled as MPPT.

What prompted me to post here for your advice is I have looked at a few controllers which require a remote programmer in order to use them. I noticed one said the default setting is for flooded lead acid batteries, if you need to change this to sealed, gel or a?? you will need the remote programmer. This was an extra £80.

I think this outlines my situation and look forward to your wisdom/recommendations.

Thanks

Mike

 

[Stemar]

Cheap and cheerful (£33):

EP Solar Duo-Battery Solar Charge Controller 12/24v 10A. £33.30

Worked great for me for 8 years. Still going strong when I sold the boat. I set it up to charge the starter battery first, then the domestic, on the basis that I could live with dim lights, but I really, really wanted the engine to start. In reality, it never took long to top up the starter, so the lights only got a bit dim once.

Or MPPT (£88)

20A Dual Battery 12v/24v MPPT charge Controller - EPever DuoRacer DR2210N-DDS - 100VOC PV - LCD Meter

Which is what I've got for the twin 50w panels to go on the new boat. Don't know if it's any good, as fitting is a project for this winter.

It used to be pretty simple. Low budget, get PWM, more money and/or lots of panels, get MPPT, but prices for MPPT have dropped recently.

 

[Kelpie]

Nothing wrong with a simple, basic, cheap PWM controller. A 10A one to suit your panel would be about a tenner, slightly more for a dual-bank version.
MPPT has a lot of advantages but the cheapest that you will get a genuine one is just under £100. They tend to work much more efficiently, and can work with higher voltages (e.g. big 32v panels, or series arrays). Unlike PWM, they won't be damaged by too much current so you can add more panels without necessarily having to upgrade the controller. And they tend to have more features like Bluetooth or support for different battery types.

 

[Boathook]

I fitted this Victron Energy MPPT 75|15 Charging Controllers earlier this year. Programme it via bluetooth and an app on the mobile phone. Not cheap but I got fed up with the cheap ones not seeming to get the battery voltage up. In theory I have 80W from 2 panels but might fit a third next year as all the electronics use quite a bit (all lights are LED).

 

[Koeketiene]

Hi,

I have just ordered an 80w Mono panel and did not realise how complex choosing a controller could be.

Firstly MPPT or PWM.

I have 2 battery banks one 110a and one of 220a (3 batteries in total, all cranking).

I am planning to connect the 220a bank to the solar panel but could buy a dual controller and connect both banks?.

I think I have understood (more or less) that MPPT controllers can accept high voltage and have the ability to convert the excess voltage into charge (amps). However the PWM chargers have to waste any excess voltage over and above the battery voltage which I find is usually about 13.? volts.

To take full advantage of am MPPT controller I understand you need to be producing excess voltage regularly but with a single 80w panel this seems unlikely. I therefore understand the argument for me to fit a MPPT controller is borderline.

Added to this I have read several times lots of PWM controllers are advertised and labelled as MPPT.

What prompted me to post here for your advice is I have looked at a few controllers which require a remote programmer in order to use them. I noticed one said the default setting is for flooded lead acid batteries, if you need to change this to sealed, gel or a?? you will need the remote programmer. This was an extra £80.

I think this outlines my situation and look forward to your wisdom/recommendations.

Thanks

Mike

My setup is similar to yours: 1 x 90aH starter battery and 2 x 165ah in one domestic bank.
I have a 90W and a 40W solar panel.

I opted for one of these: https://www.batterymegastore.co.uk/product/victron-energy-smartsolar-mppt-75-15-scc075015060r/

After one year I have been very impressed with my setup and it suits my needs (boat on a swinging mooring). My batteries are always fully topped up - even at this time of year.
There are cheaper options available, but this product does IMHO provide value for money.

 

[lustyd]

Will Prowse on YouTube is probably one of the better sources of info here and he shows you his testing too. He tests all kinds of kit at all budget levels with no apparent agenda.

 

[AngusMcDoon]

Added to this I have read several times lots of PWM controllers are advertised and labelled as MPPT.

Yes, there are lots of fake MPPT controllers which are PWM inside, usually supplied by Chinese sellers on ebay. There are youtube videos aplenty where they rip apart the fakes. If there's no big inductor inside, it's not MPPT. A budget brand of genuine MPPT controllers is Epever. The 10A Tracer is about £50. Anything less labelled as MPPT is likely to be fake.

 

[Wing Mark]

Yes, there are lots of fake MPPT controllers which are PWM inside, usually supplied by Chinese sellers on ebay. There are youtube videos aplenty where they rip apart the fakes. If there's no big inductor inside, it's not MPPT. A budget brand of genuine MPPT controllers is Epever. The 10A Tracer is about £50. Anything less labelled as MPPT is likely to be fake.

Some of those people on youtube are complete pillocks who know nothing, couldn't find an inductor in the RS catalogue.

MPPT is not about having an inductor.
The world is full of PWM (and other modes of regulation) DC-Dc converters. These generally have an inductor in.
But the inductor can be a small thing, sometimes even just a printed trace on a PCB
I've got a really old PWM converting solar regulator. It puts more A into the battery than it gets out of the panel. It seems to regulate the panel volts to about 18V.
Genuine MPPT is 'maximum power point tracking' this means regulating the panel volts/current to whatever value extract most power, dynamically.

There are a lot of solar regulators which are not even PWM really, they just switch the panel to the battery and switch off which the battery volts rise above a certain level.

If you've got panels where the Pmax voltage is about 18V, the extra current you can get by converting it to 14.4V would be 25%, if the conversion was 100% efficient. Modern convertors can be well up in the 90s, so you're possibly getting up to around 20% extra current into the batteries at some points in the charging cycle. But if that matters much, you probably need more panels to be sure of properly charging the batteries?

The big issue should be the quality of the algorithm which controls the charging.

Also power conversion allows panel voltages to be higher, like 36V panels, so you can have lower wiring losses, at the expense of less resistance to shading.
I've worked on products which have multiple MMPT controllers, each of which is just a little $4 IC.

There is a hue market of solar powered kit out there, most of it not optimised for the way people use solar on boats.

 

[PaulRainbow]

Hi,

I have just ordered an 80w Mono panel and did not realise how complex choosing a controller could be.

Firstly MPPT or PWM.

I have 2 battery banks one 110a and one of 220a (3 batteries in total, all cranking).

I am planning to connect the 220a bank to the solar panel but could buy a dual controller and connect both banks?.

I think I have understood (more or less) that MPPT controllers can accept high voltage and have the ability to convert the excess voltage into charge (amps). However the PWM chargers have to waste any excess voltage over and above the battery voltage which I find is usually about 13.? volts.

To take full advantage of am MPPT controller I understand you need to be producing excess voltage regularly but with a single 80w panel this seems unlikely. I therefore understand the argument for me to fit a MPPT controller is borderline.

Added to this I have read several times lots of PWM controllers are advertised and labelled as MPPT.

What prompted me to post here for your advice is I have looked at a few controllers which require a remote programmer in order to use them. I noticed one said the default setting is for flooded lead acid batteries, if you need to change this to sealed, gel or a?? you will need the remote programmer. This was an extra £80.

I think this outlines my situation and look forward to your wisdom/recommendations.

Thanks

Mike

As a few others have suggested, i'd go for the Victron MPPT 75/15, with Bluetooth. You can set the charging regime to whatever you want and monitor it all from a smartphone or tablet. Good quality kit that will be perfectly OK if you decide to fit a second panel.

 

[Manosk]

I also have 2 100w solar panels connected to a victron 75/15 controller Excellent piece of kit and at 15A can accept up to 220w of solars

 

[pessimist]

Another vote for the Epever range we've had them on two consecutive boats and one in the office. Found them to be reliable and good value for money. They also provide a standard modbus interface.

 

[noelex]

The overall gain of MPPT vs (so called) PWM controllers is not enormous (assuming the input voltage is suitable for both technologies). The gain is still valuable, especially if the physical space for solar panels is limited, as it is on most boats.

While the manufacturers of MPPT controllers claim “up to a 30% gain” around 5 -15% is a more realistic average. This type of gain will still be seen with a single 80w panel. However, this gain will only be seen with a good quality MPPT controller. Many of the cheap MPPT controllers have poor tracking and have low overall performance, which can be worse than the much simpler PWM controller in some circumstances.

The better MPPT controllers also tend to have better and more user adjustable battery regulation (although these features are available in a small number of PWM controllers if you search). This can be more important than the voltage conversion technology built into the MPPT controllers.

The small Victron MPPT controllers are hard to beat for the price.

 

[Laminar Flow]

Another vote for the Epever range we've had them on two consecutive boats and one in the office. Found them to be reliable and good value for money. They also provide a standard modbus interface.

Agree, we have had one for years. It charges well, can be dialed in for any type battery and has a display to let you know how well it is doing. Never any problems whatsoever.

We got one a couple of sizes larger than we would have needed for or 300W array to give us the opportunity of upgrading in the future should we need it. To date that has not been necessary. The price difference was minimal. They used to be available on various German solar sites at a very reasonable cost, especially at the annual winter sale.

In Northern climes a MPPT is more efficient. We would never go back from solar and I have tried pretty much all the other charging variants.

 

[Jamie Dundee]

I’ve had these on my last two boats, excellent. 12V solar panels charging kits for caravans, motorhomes, boats, yachts, marine

 

[Laminar Flow]

I’ve had these on my last two boats, excellent. 12V solar panels charging kits for caravans, motorhomes, boats, yachts, marine

Yep, that's it. Comes in various sizes.

 

[Jamie Dundee]

Yep, that's it. Comes in various sizes.

I also fitted the remote meter as the controller is hidden away, the controller can be programmed directly from the remote. For less than £30 why not?

 

[Laminar Flow]

I also fitted the remote meter as the controller is hidden away, the controller can be programmed directly from the remote. For less than £30 why not?

View attachment 126256

Yes, I thought about that too, but our charger is in the wheelhouse next to the helm and hence made an extra display obsolete.
Initially I would obsessively check on how well the charging was going, but it has bee so successful that I no longer bother.

 

[stuartwineberg]

Cheap and cheerful (£33):

EP Solar Duo-Battery Solar Charge Controller 12/24v 10A. £33.30

Worked great for me for 8 years. Still going strong when I sold the boat. I set it up to charge the starter battery first, then the domestic, on the basis that I could live with dim lights, but I really, really wanted the engine to start. In reality, it never took long to top up the starter, so the lights only got a bit dim once.

Or MPPT (£88)

20A Dual Battery 12v/24v MPPT charge Controller - EPever DuoRacer DR2210N-DDS - 100VOC PV - LCD Meter

Which is what I've got for the twin 50w panels to go on the new boat. Don't know if it's any good, as fitting is a project for this winter.

It used to be pretty simple. Low budget, get PWM, more money and/or lots of panels, get MPPT, but prices for MPPT have dropped recently.

+1 for Epever controller, inexpensive and effective and photonic universe folding panels

 

[Buck Turgidson]

Another vote for Victron.

 

[gregcope]

+1 to all the victron suggestions. And its blue. To be serious however it is MPPT and the bluetooth app is great for config.