Solar charge controller choice?

Not sure I'd call them small, they're sized to the load and an appropriate wire size. Lots of people like to oversize wires, but that's not really Victron's fault!

edit: also the only people I've ever seen complain about this have been adding bootlace crimps which are not necessary.
 
lustyd said:
Not sure I'd call them small, they're sized to the load and an appropriate wire size. Lots of people like to oversize wires, but that's not really Victron's fault!

edit: also the only people I've ever seen complain about this have been adding bootlace crimps which are not necessary.
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Understood. It’s been a while but if I recall the cables on my photonic 120 kit were too heavy for the relevant Victron Terminals. Certainly not criticising the quality
 
gregcope said:
75/15 takes 6mm2 cables
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So it says but this from, the victron community forum, this and many other comments led me to go for the Epever but as previous post says most of these people are putting a ferrule on but even so I was discouraged by the comments on a tight fit even for bare ends
MPPT 75/15 wire terminal too small for 6mm²
I have a MPPT 75/15 and the specs say the terminal fits a 6mm² cable. I tried that cable size and it does not fit. Without a wire end ferrule it may go in but just and it is a hassle, some strands being bend and staying out (not good), with a crimped ferrule of the correct size (it tried two types) there is no way this fits.
I have some pre-crimped cable from the solar panel (this is a kit) and the ferrule there look like a size too small and it is a 10 gauge wire which is slightly smaller than 6mm² as well. And even that barely fits.
So what am I doing wrong? Do I need to switch to 4mm² cable? It is only the 1.2m length from MPPT to battery, but 6mm² cable is what I have....
Sep 25 2020 at 7:18 AM
I'm so glad I am not the only one with this problem. So, yes they are too small. You have my sympathies.
Even a 4mm with a wire end ferrule is super snug in there.
For my PV panels I must use a 6mm cable so I am going to try to tin the cable in a nice smooth shape. Wish me luck.
But yeah, this really has me exercising all the colourful language I can think of....
 
stuartwineberg said:
Certainly not criticising the quality
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Sorry wasn't suggesting you were, just explaining that the size they use is technically adequate. For the record I did fit 6mm with mine and also used bootlace crimps and while a tight fit it actually was fine.
If you're struggling, use a bootlace crimp tool without the crimp. That'll squish it to a compact square shape, but in my experience 6mm fits just fine while round in these.
 
As said, 6mm does fit and there is no need for bootlace ferrules with the Victron controllers.

Ref the comment about using "oversize wires", there are times when one needs to use cables bigger than 6mm, to combat voltage drop, this still isn't a problem though, as thinner tails can be crimped on close to the controller.
 
It seems to me that a MPPT controller (I love my Victron 10A) if fed with 2 x12v panels in series (ie 40v max no load) can then get the most out of the panels at low light situations like winter in UK. So a 12v panel gives about 20 volts no load if feeding a PWM controller must give more than about 13.5v under load to get any charge into a 12v battery. The panel will not be able to provide enough voltage at low light to put anything into the battery.
By contrast 2 panels in series ie 40v max are going to produce more than 13.5v in lower light conditions. So some charge in worse conditions. But to do justice to the panels in series you need an MPPT controller.
(NB as far as I know all MPPT controllers are in essence buck converters and not capable of Boost function so must have at least 15v in to get any charge)
So yes go Victron ol'will
 
Thanks for replies and sorry I have not responded sooner,

Well my Solar Panel arrived yesterday - smashed to pieces. Replacement panel on its way.

Given the space available on my tiny sailing boat I am maxed out with an 80 watt panel so no need to consider buying a larger controller just in case I fit an additional panel.

The more I read about charge controllers the more I realise how complex they are.

I read one of the Victron PWM controller manuals which states (IMPORTANT) the solar panel must have 36 cells to use this controller and in addition made clear the wire selected must be constructed using thousands of very fine copper wires with illustrations in the manual. I was thinking of using the commonly available tinned Oceanflex (on ebay) but this may not be of requisite construction (have not checked).

You may be surprised to learn I do not own a mobile phone so using Bluetooth (whatever it is) is not as straight forward for me as it is for normal people. This is one of the reasons I was hoping to find a controller that is capable of being programmed without any auxiliary equipment.

I am in no rush - not expecting the Sun to put in an appearance in the foreseeable!

Look forward to reading any more replies

Mike
 
In that case, I'd go for the simple dual battery PWM controller I mentioned above. IIRC, set-up consisted of telling it I had flooded batteries, telling it which one had priority and hooking everything up. It then just got on with keeping the batteries charged.
 
The controller in #14 is programmed on the controller. I run 150w of solar through it although higher capacity versions are available.
 
MINESAPINT2 said:
I read one of the Victron PWM controller manuals which states (IMPORTANT) the solar panel must have 36 cells to use this controller
Click to expand...

This is even more critical with MPPT controllers that the input voltage is well above the battery voltage, so with both types of controllers less than 36 cells is not ideal.

However, it is quite rare to find a 80w solar panel with anything other than 36 cells, so you should not have any problems. The number of cells should be listed in the specifications or you can just count the number of squares visible on the front surface.
If you select one of the Victron MPPT controllers with a single panel it is sensible to avoid selecting a panel with a low voltage.
 
The above is a photo of my battery banks. The thin blue and brown wires have been removed. I have just read DUO charge controllers are designed for charging 2 separate battery banks.

You will note the 3 negative terminals are all connected. Are these banks defined as being separate regarding the use of a DUO controller?

Thanks

Mike
 
Yes. On Jissel, both batteries were earthed to the engine and it worked fine.

One detail, both the outputs from the pair of batteries come from the right hand battery. It 's considered good practice to take the + from one end of the bank and the - from the other to ensure even use. It probably doesn't matter much when everything's new and shiny, but it may once things get a bit grubbier and connections develop a bit of resistance.
 
MINESAPINT2 said:
The above is a photo of my battery banks. The thin blue and brown wires have been removed. I have just read DUO charge controllers are designed for charging 2 separate battery banks.

You will note the 3 negative terminals are all connected. Are these banks defined as being separate regarding the use of a DUO controller?

Thanks

Mike
Click to expand...
That looks like a 'bank' of two batteries and a separate battery.
But they will cease to operate as two banks if there is anything out of picture connecting them together, like a VSR for instance.
 
I can manually connect all 3 batteries together in an emergency using a toggle switch (if engine fails to start). Cannot work out what I VSR is?

Mike
 
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