Which MPPT 10A solar controller?

[Chewbacka]

If you are losing half a volt then instead of having a charging voltage of say 14.4v the battery will only be getting 13.9v which will reduce the charging current so will charge a bit slower, but it is not as bad as it sounds, as the batteries charge up they will take less current which will reduce the volt drop, so the final few percent that takes a long time (and lowish  current) will be at close to the correct voltage.

 

That said I would put it on the list of jobs to be done.

[peterboat]

On 19/06/2018 at 15:24, WotEver said:

This sentence doesn’t make sense. If it can output a max of 15A then that’s what it does. As long as the input voltage isn’t exceeded you can put 1kW of panels on it and it’ll still deliver 15A maximum. 

Are you sure I have two controllers one a midnight very expensive warns about over wattage, and a cheap ebay mppt one which does the same. John my mate destroyed his tracer by having to high a wattage into it so I believe what it says on the tin knowdays

[reg]

3 hours ago, peterboat said:

Are you sure I have two controllers one a midnight very expensive warns about over wattage, and a cheap ebay mppt one which does the same. John my mate destroyed his tracer by having to high a wattage into it so I believe what it says on the tin knowdays

Was it too high a wattage or too high  a voltage? 

My tracer BNs have over current protection the 20a one cutting  out the controller at 20a with no ill effects but if the input should go over 150v then Epsolar warn it may destroy  controller. 

Apparently it will flash all the leds to warn of the over voltage but if no action is taken then apparently it will fail. 

 

I know the over current protection works because the 2 panels going through my controller  are capable of producing over 20a.

 

Never tried the over voltage and don't Intend to. 

 

So what WotEver said holds true for my controller. 

 

Note the above applies to the Tracer BN 10a and 20a controllers, may differ for other models and tracer series 

 

Edited June 23, 2018 by reg

[reg]

On 19/06/2018 at 15:24, WotEver said:

This sentence doesn’t make sense. If it can output a max of 15A then that’s what it does. As long as the input voltage isn’t exceeded you can put 1kW of panels on it and it’ll still deliver 15A maximum. 

What WotEver said ^^^^

Edited June 23, 2018 by reg

[peterboat]

59 minutes ago, reg said:

Was it too high a wattage or too high  a voltage? 

My tracer BNs have over current protection the 20a one cutting  out the controller at 20a with no ill effects but if the input should go over 150v then Epsolar warn it may destroy  controller. 

Apparently it will flash all the leds to warn of the over voltage but if no action is taken then apparently it will fail. 

 

I know the over current protection works because the 2 panels going through my controller  are capable of producing over 20a.

 

Never tried the over voltage and don't Intend to. 

 

So what WotEver said holds true for my controller. 

 

Note the above applies to the Tracer BN 10a and 20a controllers, may differ for other models and tracer series 

 

No his voltage was ok even allowing for the cold and facing the sun, it was over wattage that was wrong, both my expensive midnite controller and cheap MPPT warn against it. Go on the midnite website they have a workout chart which dictates which controller you need very good and if wattage didnt matter they woulnt put it there would they?

[reg]

37 minutes ago, peterboat said:

No his voltage was ok even allowing for the cold and facing the sun, it was over wattage that was wrong, both my expensive midnite controller and cheap MPPT warn against it. Go on the midnite website they have a workout chart which dictates which controller you need very good and if wattage didnt matter they woulnt put it there would they?

I was referring to Johnny your mate with his Tracer where I can't find any documentation on over wattage on epsolar site. 

I know I run my tracer with over wattage as it gives me a reserve for winter. 

I have no knowledge of the midnite mppt so not in a position to question it. Interesting site though may have a plough through it, thanks for the pointer 

Edited June 23, 2018 by reg

[Chewbacka]

38 minutes ago, peterboat said:

No his voltage was ok even allowing for the cold and facing the sun, it was over wattage that was wrong, both my expensive midnite controller and cheap MPPT warn against it. Go on the midnite website they have a workout chart which dictates which controller you need very good and if wattage didnt matter they woulnt put it there would they?

Wattage is important because if you buy panels capable of say 1000w why would you buy a controller that can only pass say 200w to the batteries?  Save your money and buy 200w of panels, is the logic.

[Markinaboat]

Anyone have the Mastervolt MPPT?

 

https://www.mastervolt.com/products/solar-charge-controllers/scm25-mppt/

 

 

[reg]

45 minutes ago, Chewbacka said:

Wattage is important because if you buy panels capable of say 1000w why would you buy a controller that can only pass say 200w to the batteries?  Save your money and buy 200w of panels, is the logic.

The reason is simple I want spare capacity for winter. I already had the 20a controller plus another 2 x 10a controllers (the reason why is historical) 

The 2 x 10a controllers have individual  120watt panels going into them 

The 20a controller has a total of 350watts of panels connected which combined are well below the 150v max allowed but are capable of producing on a very sunny day enough power to provide for over 20a output. Thus overcapacity only occurs on very sunny days for a short period if time so I am happy for it to self restrict at 20a because by then the batteries are pretty much charged and, importantly, I have the other 2 panels still charging. 

 

I could off gone to the expense of buying a newer higher capacity controller but that would of been a waste of money as I am getting sufficient output with my current setup. 

 

The biggest advantage of having a larger array comes in winter where I am able to get more input to the controller than I would have if I had sized my panels for optimum summer conditions. 

 

Basically I get more than enough in summer but need to squeeze as much output as I can during winter. 

 

Essentially the solar array is sized for winter, summer is not an issue. 

 

Hope that makes sense. 

 

Edited June 23, 2018 by reg

[Richard10002]

1 hour ago, reg said:

 

Essentially the solar array is sized for winter, summer is not an issue. 

 

I fitted 490w of solar and a 40A Tracer BN MPPT.... 1 panel is flat, the second is angled a bit at the sun. Until Mid March, I had to run the genny to charge every day, getting more or less nothing worth having from the solar.

 

Are you saying that, with 590W of solar, and 40A of MPPT, you get some meaningful power in the winter - what could I do better?

[Robbo]

9 hours ago, Chewbacka said:

Wattage is important because if you buy panels capable of say 1000w why would you buy a controller that can only pass say 200w to the batteries?  Save your money and buy 200w of panels, is the logic.

Because the majority of the times the panels only produce 200watt or less and when they can produce more there’s enough daylight hours to cover your needs for charging your batteries.   Why buy a big controller when you don’t require one?  Save your money and buy a smaller one is the logically choice.

Edited June 24, 2018 by Robbo

[WotEver]

16 hours ago, peterboat said:

Are you sure

Yes

[WotEver]

23 hours ago, peterboat said:

John my mate destroyed his tracer by having to high a wattage into it

That’s simply not possible. Too high a voltage, certainly, but the controller couldn’t care less what capacity the panels have. 

 

Think of a mains charger. If it’s fed from a 13A supply then it has in excess of 3kW ‘feeding it’. If it’s a 20A charger it doesn’t die because too much power was ‘pushed into it’ it simply outputs 20A (if the batteries demand that much).  Now feed that same charger from two phases, giving it 400V instead of 230V. You’ll let out all of the magic smoke. Apart from some tracking of the input voltage by varying the load on the panel (the mpp bit) there’s no difference between a solar charge controller and a mains charger. 

[reg]

20 hours ago, peterboat said:

No his voltage was ok even allowing for the cold and facing the sun, it was over wattage that was wrong, both my expensive midnite controller and cheap MPPT warn against it. Go on the midnite website they have a workout chart which dictates which controller you  need very good and if wattage didnt matter they woulnt put it there would they?

OK I have been intrigued enough by the midnite controller to have a look around. My understanding is that the controller will display wattage and a wattage factor if it displays 1.2 this means you have exceeded the wattage by 0.2 so you are wasting 0.2 of the input power. Again my understanding is that this in itself doesn't matter it just means that at that point in time your mppt is under specified to utilise the total power available.

Their solution to this appears to be buy another controller or an additional controller, I believe you can string the some of the midnite controllers together, if you want to utilise all of the power. However they don't, as far as I can find out, say if your not bothered about the 0.2 and are happy to accept the waste during optimum periods then stick to just the controller you have. 

However it is important to take into account, by sticking to the controller showing 1.2, that your max voltage is not being exceeded. 

 

My Tracer does not have the advanced display feature for over wattage and that doesn't concern me in the least (one less thing to worry about) I'm happy that if I keep my  max solar voltage and max current within the controllers parameters then I can utilise it as I have previously stated. 

The only minor concern I have is that I am relying on the over current circuits to protect my system but c'est la vie

Edited June 24, 2018 by reg

[reg]

After all of my badly worded waffle about over sizing solar arrays to provide capacity for winter charging I have found this clearer explanation from Victron

See Q4

https://www.victronenergy.com/live/drafts:mppt_faq

Which basically confirms that exceeding max voltage or max current input parameters could potentially damage a controller but not over wattage. 

Which again is basically what WotEver was saying. 

Hope this answers your question. 

Edited June 24, 2018 by reg