Solar !

[christophert]

Evenin, all.

 

I'm looking for someone who's well informed regarding solar? Shortly, I'll be fitting 600 watt of solar on my boat and wondering if a 50 amp charge controller will be large enough? I was thinking of a Victron MPPT 100/50 - 50amp. Although there are cheaper on the market, I'd be happy to go with this.

 

The thing is, the bigger ampage you go with these, the more ridiculously priced they get. I'd like to go 80 amp but ....

 

 

[matty40s]

The Victron will not make the most of that solar array.

Bite the bullet and buy a MPPT controller with a high enough max voltage to take the panels in series, or series/parallel, with room for expansion. The Victron will not provide this.

[christophert]

The Victron will not make the most of that solar array.

Bite the bullet and buy a MPPT controller with a high enough max voltage to take the panels in series, or series/parallel, with room for expansion. The Victron will not provide this.

So would you suggest an 80 amp?

There's so many controllers out there, it's hard to know which is a good make and which is turd like?

Solar panels I've chosen. SolarWorld, a German panel. They're good leading brand and well built.

[Sea Dog]

I believe that most of the Victron controllers current limit to their ratings, but can accept a fair bit more without damage. This is set out on their site somewhere, bit iirc it's a bit of a dig to find it. 600 watts will give you 50a at 12V so that unit ought to be fine. Most of the time you won't be close to 50a. It does not allow for expansion but then you're starting at 600w.

 

Edited to add: Matty is right about it being better to wire in series should you need to get the absolute maximum out of the panels though. Depends on whether you think you'll have all the performance you need already. Pays yer money...

Edited October 20, 2016 by Sea Dog

[christophert]

I believe that most of the Victron controllers current limit to their ratings, but can accept a fair bit more without damage. This is set out on their site somewhere, bit iirc it's a bit of a dig to find it. 600 watts will give you 50a at 12V so that unit ought to be fine. Most of the time you won't be close to 50a. It does not allow for expansion but then you're starting at 600w.

Thanks, Sea Dog. I think it'd be plenty but will go have a read later. Part of me is saying go bigger to allow for expansion, but the price shoots through the roof at 80 amps

The other alternative would be to fit a second cc if I was to expand. There's plenty of 30 amps going at a good price. But I want to get this right. Go for a good make and pref an 80 amp. May have to dig deeper in pockets... Hope I don't have to sell myself down that dark alleyway again.

Edited October 20, 2016 by christophert

[Sea Dog]

Part of me is saying go bigger to allow for expansion, but the price shoots through the roof at 80 amps

 

 

Yeah, exactly, which was what drove my take on it - bang for buck rather than outright power. There's more than just that one way though.

[christophert]

Can anyone recommend a good MPPT Charge controller? There's plenty out there, but I don't wanna buy a banana skin :-(

[Top cat]

Ive been using one of the smaller Victrons for 3 years now and it has worked perfectly. It does have one small foible that may have been corrected in later versions. If we have been cruising enough to almost charge the batteries say 95%. Then it thinks they are charged and holds them at 13.8V ( float voltage)nd wont allow the panel to charge any more till the voltage has dropped to less than 13.2V for one minute. I fool it by running the hairdryer for about 45 secs which pulls the voltage down enough to restart the charge cycle. If I don't bother its no big deal as the batteries drop enough in about an hour.

I'm told that the latest version allows you to set the float voltage with a smart phone app so you could force it to finish offcharging with a software dodge. I expect other controllers may have the same limitation as the don't know what current the alternator has been putting in they just see volts.

 

Regarding size you can attatch more than the rated power to a Victron without damage as it will self limit. Also solar panels rarely if ever put out their max rated power, they need to be cold and at 90 degrees to the sun which has to he hight in the sky. Something that happens in Antarctica but not here.

 

Go for as many panels in series as your controller will take this cuts down the current so losses are less and you have a better chance ofreaching the battery voltage +5 v you need to start charging in poor weather.

 

If you decixe to expand you would be better off using a second controller because as yourpanels spread down the boat there is more chance of some of them being in the shade. One shaded panel will reduce the output of everything else attatched to that controller. Having multiple controllers gives a better chance of your panels operating at their optimum. Some domestic systems have an inverter controller for each panel.

I am assuming you are going for an MPPT controller they really give more power from a given panel especially in less than optimum conditions.

The victron web site has a downloadable calculator to help size your solar system, you can select panels , their configuration and controllers and it will tell you what works.

 

The Victron don't have fancy displays just leds to tell you whats going on.

Its important to mount the controller near the battery as charge voltages vary with temperature. I made the mistake of having the controller in the boat and batteries in the engine bay, odd things happened for a while.

 

Hope that helps

 

Top Cat

[christophert]

Ive been using one of the smaller Victrons for 3 years now and it has worked perfectly. It does have one small foible that may have been corrected in later versions. If we have been cruising enough to almost charge the batteries say 95%. Then it thinks they are charged and holds them at 13.8V ( float voltage)nd wont allow the panel to charge any more till the voltage has dropped to less than 13.2V for one minute. I fool it by running the hairdryer for about 45 secs which pulls the voltage down enough to restart the charge cycle. If I don't bother its no big deal as the batteries drop enough in about an hour.

I'm told that the latest version allows you to set the float voltage with a smart phone app so you could force it to finish offcharging with a software dodge. I expect other controllers may have the same limitation as the don't know what current the alternator has been putting in they just see volts.

 

Regarding size you can attatch more than the rated power to a Victron without damage as it will self limit. Also solar panels rarely if ever put out their max rated power, they need to be cold and at 90 degrees to the sun which has to he hight in the sky. Something that happens in Antarctica but not here.

 

Go for as many panels in series as your controller will take this cuts down the current so losses are less and you have a better chance ofreaching the battery voltage +5 v you need to start charging in poor weather.

 

If you decixe to expand you would be better off using a second controller because as yourpanels spread down the boat there is more chance of some of them being in the shade. One shaded panel will reduce the output of everything else attatched to that controller. Having multiple controllers gives a better chance of your panels operating at their optimum. Some domestic systems have an inverter controller for each panel.

I am assuming you are going for an MPPT controller they really give more power from a given panel especially in less than optimum conditions.

The victron web site has a downloadable calculator to help size your solar system, you can select panels , their configuration and controllers and it will tell you what works.

 

The Victron don't have fancy displays just leds to tell you whats going on.

Its important to mount the controller near the battery as charge voltages vary with temperature. I made the mistake of having the controller in the boat and batteries in the engine bay, odd things happened for a while.

 

Hope that helps

 

Top Cat

Top Cat, very helpful, thank you. I was going to mount the controller in the bedroom but I'll re consider that. I'll go take a look at Victrons calculator. I don't suppose you have the link by hand do you?

[Phil.]

Can anyone recommend a good MPPT Charge controller? There's plenty out there, but I don't wanna buy a banana skin :-(

If you want a good one go for the outback 60 or 80.

[Top cat]

Here it is scroll down quite a way

 

https://www.victronenergy.com/support-and-downloads/software

 

Its not straight forward to use , you have to input 1 in the voltage field for 12V operation 2 for 24V and the module and panel selection cont down the foelds in the table.

 

here is a page that explains how to interpret it

 

https://www.victronenergy.com/blog/2014/03/28/matching-victron-energy-solar-modules-to-the-new-mppt-charge-regulators/

 

Top Cat

[Murflynn]

can we assume that OP is using say 6 panels with a nominal voltage of 19v each, then the controller should be rated for say 120v ?

 

OP to confirm please.

[WotEver]

If you want a good one go for the outback 60 or 80.

+1

[MtB]

If you want a good one go for the outback 60 or 80.

 

 

In what way is an Outback 60 or 80 'good'?

[wullie]

Top Cat, I was going to mount my controller in engine bay, but on reading instruction it said to mount it in cool dry area, now my engine bay is cool and dry but when engine running would think it would get pretty hot, same advice for invertor, I would rather fitted them here but now confused, do I, or don't i your advice would be appreciated.

[WotEver]

 

In what way is an Outback 60 or 80 'good'?

Anecdotal evidence on here would appear to show that they're reliable and effective.

[Top cat]

Top Cat, I was going to mount my controller in engine bay, but on reading instruction it said to mount it in cool dry area, now my engine bay is cool and dry but when engine running would think it would get pretty hot, same advice for invertor, I would rather fitted them here but now confused, do I, or don't i your advice would be appreciated.

The Instructions that came with my controller said to mount near the batteries as the temperature sensor is inside the controller case. It is also rated with good environmental protection IP something or other. Other controllers may have a remote temperature sensor or may be less well protected in that case I would mount in the cabin. Best thing to do is read the manual taking note of the environmental specs.

 

The invertor isn't charging your batteries so any temperature difference is irrelevant and the cooler the better so my invertor is mounted in the cabin.

 

Top Cat

[MtB]

Anecdotal evidence on here would appear to show that they're reliable and effective.

 

 

A bit like a Tracer then (and a few others) but more expensive?

[Arthur Brown]

The inverter and charger need mounting close to the battery so that the thick high current cables don't have to be thick and expensive to avoid excess volts drop. An inverter will draw about 100A per KW drawn, so short fat wires are needed. the charger could well supply 50 to 80 amps so again short thick wires are needed.

 

Remember that some solar systems can be extended more easily than others, and that a MPPT controller will make about 20% more electricity from the same sun and panels. Also consider that some components can be repurposed later if you ever decide to extend the array. Also that a complete system can be joined to another system at the batteries so a 30a controller and panels can feed the same batteries as another 30A controller and panels.

 

If you end up with a small array contributing to your domestic needs, this can be repurposed later to feed the engine battery when you have a larger array for domestic use.

 

-Don't forget the starter battery's needs! Once the engine will not start you need to pay for help usually.

[WotEver]

 

A bit like a Tracer then (and a few others) but more expensive?

Yeah, just like that

[Phil.]

A bit like a Tracer then (and a few others) but more expensive?

No nothing like Tracer at all.

Edited October 21, 2016 by Phil.

[MtB]

No nothing like Tracer at all.

 

Your claim that the Outback is better is meaningless without giving reasons.

[tree monkey]

 

Your claim that the Outback is better is meaningless without giving reasons.

Outback and morningstar are 2 makes that have generally very good reviews I looked at a lot of sites when choosing my controller and these 2 always seemed well regarded.

Of course I would say this cause I've got a morningstar

[MtB]

Outback and morningstar are 2 makes that have generally very good reviews I looked at a lot of sites when choosing my controller and these 2 always seemed well regarded.

Of course I would say this cause I've got a morningstar

 

 

Yahbutnobut no-one seems to be able to come up with any reasons why those two get better reviews!

 

(I just bought a new Tracer... )

[Phil.]

Your claim that the Outback is better is meaningless without giving reasons.

Ok. I am a firm believer in you get what you pay for. Cheap Chinese stuff rarely meets my requirements, and where production of electricity, and the consequences of equipment failure could be quite severe, I prefer to use equipment from a more reputable source.