Overpanelling up to 700 watts fine for tracer bn 4215? Also explainer on what makes it worthwhile

[Gueyog8a7]

If I am understanding right so far overpanelling is just taking advantage of the fact that the panels will never achieve maximum rated output so we are using more to eek out what we can of those lower solar days. Also once summer comes round and they would be achieving the highest output they could, if it goes over the rated maximum, they will just shed off the excess wattage as heat dissipation? Is that right or did I miss anything?

So I looked on the forum beforehand and saw people have greatly overpanelled tracer bns even beyond my stated intended wattage. I think I saw someone post over 1100w. I looked in the manual and it said 520w max and 780 pv array max. So I am fine? I am thinking 4 or maybe even 5 if I can squeeze one more, totalling 3, on the side.

For reference these are the panels I want to use. Either 4 or 5 adding to my existing two.

Hmm I just saw there are 200w flexibles. Could I mix and match with the existing 2 of the first ones I linked above or no?

Would be 12v volt and in series btw.

 

[Gueyog8a7]

Please help. I want to buy some more asap as I am living in -8c conditions and my battery is close to 0%!! Hovering at 13.0 and 12 volts lifepo4.

So overpanelling up to what wattage ok and also can I mix and match panel types so then I could maybe get higher wattage on the same surface area.

 

[littleharbor2]

Please help. I want to buy some more asap as I am living in -8c conditions and my battery is close to 0%!! Hovering at 13.0 and 12 volts lifepo4.

So overpanelling up to what wattage ok and also can I mix and match panel types so then I could maybe get higher wattage on the same surface area.

This is an older chart from the maker of your CC. It gives you a good idea if possible overpaneling limits.

 

[mikefitz]

some more asap as I am living in -8c conditions

More panels won't do much to add to your input at this time of year in your location, fixed to a van parked in the shade. Options are shore power, AC charger, DC to DC charger from vehicle alternator, LPG or petrol generator.

Adding panels In series must be the same current rating, adding in parallel the same voltage rating.
You could use two 200 watt panels in series, then connected in parallel with the two existing series 100 watt

 

[Gueyog8a7]

This is an older chart from the maker of your CC. It gives you a good idea if possible overpaneling limits.

Thanks. That is interesting. Is there any point overpanelling over a certain point? I know in the more recent manual I read it says it is wasteful but if money were no object then it would be worth still for the same reasons as initially right, to get more from less than stellar weather/environmental factors? Not that I want to go to max just to help me understand.

 

[littleharbor2]

Thanks. That is interesting. Is there any point overpanelling over a certain point? I know in the more recent manual I read it says it is wasteful but if money were no object then it would be worth still for the same reasons as initially right, to get more from less than stellar weather/environmental factors? Not that I want to go to max just to help me understand.

I would over panel in the case of being in a particularly hazy, cloudy area or bad orientation of the array. If your panels are relatively flat you tend to get much better production in summer but poor production in the winter so expect lots of clipping in the summer. One thing you can do to mitigate excess clipping is to take a string of panels out of service then, provided you have multiple PV strings.

 

[Gueyog8a7]

I would over panel in the case of being in a particularly hazy, cloudy area or bad orientation of the array. If your panels are relatively flat you tend to get much better production in summer but poor production in the winter so expect lots of clipping in the summer. One thing you can do to mitigate excess clipping is to take a string of panels out of service then, provided you have multiple PV strings.

By clipping you mean losing potential? Doesn't matter in summer though does it because that is the highest yield season. I will be way over my requirements then as I am just wanting to be able to get enough in winter to cover (diesel) heating electricals mainly.

Someone else just mentioned that 90 degrees is the way for winter so that is great because I planned to do that for 3 panels, on the side, just because that is where there is room. To see that will actually yield better results for the winter is a nice bonus.

 

[littleharbor2]

Your SCC will cut off charging amps at its rated output any excess potential is unused.

Get the "Solar Tilt" app for your phone. It'll give you the correct tilt for anywhere, at any time of the year.

 

[Gueyog8a7]

Could people also comment on discussion based on this thread. user 12voltinstalls is saying that I cannot use the max pv stated in the manual but do not understand why. Please open discussion on my recent question there in that thread. Namely what is the max in series I could go with those panels.

Oh and as an update my panels have been performing much better lately, even behind the house. I notice I can get even better performance behind the house on semi cloudy days sometimes than clear direct sunlight. I have been up to 2.2 amps for quite some time which is very high for me. Probably nothing for some people. So performance is definitely up so maybe I do not have to overpanel much if at all now since things will keep going up as spring here pretty much here with the snowdrops out. Still want to know answers to OP though if I choose to come this winter.

I still have no idea if 200/300w will be enough even in summer as I still have tested average loads. Heating will be not required but still diesel stove for and hour or so a day and tablet charging. Still must wait and see how things work out. So might still want more panels even in peak as I read an article that stated even in summer they will not work at near peak, maybe I read like 50% max average, though whether they will be enough is yet to be seen.

Any ideas what to expect for uk summer?

 

[Gueyog8a7]

Someone please respond. Still no idea on the capabilities given what the other user said in above linked post throwing salt on the idea of overpanelling.

 

[Gueyog8a7]

I just got a reply from epever support which seems to say the same as manual:

Ok, we give you a reference:
For Tracer415BN series controller with 24V battery, the Voc of solar panels can not exceed 138V, the Isc can not exceed 40A, the rated power recommend don't exceed 780W. The old manual is changed now, we only recommend connect 780W solar panels.



If the weather in your country is not well, we recommend the power do not exceed 900W, and please let Voc as soon as possible.

So they are saying even higher than the 780 still? Can someone clarify the other figures? I don't understand the voc or lsc stuff? Just tell me how many panels of those 100w ones I could put max in series for 12v or other config if no good .

Ok they reply again saying lower for 12v:

Oh, if it is 12V, the rated power can not exceed 520W. Voc and Isc limit is same.



You can purchase 6 pcs 100W solar panels and connect them 6 parallel or 2 series 3 parallel.

I have seen people one here go to 1100w though so are these only guideline references? I could not go above 700w anyway on the van due to space but wondering if 700w would still be ok given others have gone much higher?

Why do they say 520 when the max limit on the next table states 780w? All rather confusing to me.

 

[Gueyog8a7]

Why no one can answer this for me please help.

 

[sunshine_eggo]

RTFM:

https://www.epever.com/upload/cert/file/1811/Tracer-BN-SMS-EL-V1.2.pdf

You can put up to 1560W on a Tracer 4215BN on a 12V battery.

This array must NEVER EXCEED 150Voc in any conditions.

@littleharbor2 provided this in post #3.

I don't see that you've asked a meaningful question that's not answered by the above.

If you have additional questions, please post them succinctly and number them for reference.

 

[Gueyog8a7]

RTFM:

https://www.epever.com/upload/cert/file/1811/Tracer-BN-SMS-EL-V1.2.pdf

View attachment 192569

You can put up to 1560W on a Tracer 4215BN on a 12V battery.

This array must NEVER EXCEED 150Voc in any conditions.

@littleharbor2 provided this in post #3.

I don't see that you've asked a meaningful question that's not answered by the above.

If you have additional questions, please post them succinctly and number them for reference.

Thanks, yes I have read my current manual, which states lower max I think only 780 for even 4215, which would still be fine for my purposes, as well as the above many times but did not understand totally. can you explain what voc means in terms of how it pertains to max allowable panelling?

Also the user in this reply is saying probably not possible which led me to question it. Are they wrong? As I didn't understand why I was not able to say which is what has led to confusion given that previously most are saying, like you and post 3 you can indeed massively over panel but the voc stuff threw me off. They are saying voc takes precedence so which is right? limited by voc or not and therefor can go by the max pv array power figure of 1560? If the open circuit voltage takes precedence why would they even put the max pv array figures at all?

EDIT: Oh I see you are also saying what the other user I linked is saying as well that they should not exceed the voc.

I simply want to know how many total of the 100w renogy panels I could use in series max.

 

[sunshine_eggo]

Thanks, yes I have read my current manual, which states lower max I think only 780 for even 4215, which would still be fine for my purposes, as well as the above many times but did not understand totally. can you explain what voc means in terms of how it pertains to max allowable panelling?

That's the current manual from the manufacturer. If you can confirm you have that unit, it applies.

Voc is a value printed on the back of solar panels and printed in their datasheets. It's the open circuit voltage, i.e., when no current is flowing, the cells are 25°C and there is 1000W/m^2 of power hitting the panel, the a voltmeter will read the Voc value.

When you place panels in series, their Voc adds. When you place them in parallel, Voc does not add.

If you had 4X 100W panels with a Voc of 22V in series, the array would be 88Voc.

Also the user in this reply is saying probably not possible which led me to question it. Are they wrong? As I didn't understand why I was not able to say which is what has led to confusion given that previously most are saying, like you and post 3 you can indeed massively over panel but the voc stuff threw me off.

I won't comment on that post without reading the entire thread for context. I'm not investing that much. Your questions and issues are very basic, so I'm not participating in unnecessary complication.

Regardless of the 780W or 1560W limitation, you've confirmed other limitations render that difference moot, so further discussion seems like a waste of everybody's time.

Do you have any additional questions?

 

[Crowz]

I had posted earlier that I had over 1100watts on one of my 4215bn's for years. I had over 2kw on it at one point

As mentioned the voltage is the absolute limit. DO NOT exceed the max voltage the charge controller can handle EVER.

Watts only comes into play with the safety feature that protects against you hooking it up backwards.

 

[Gueyog8a7]

That's the current manual from the manufacturer. If you can confirm you have that unit, it applies.

Voc is a value printed on the back of solar panels and printed in their datasheets. It's the open circuit voltage, i.e., when no current is flowing, the cells are 25°C and there is 1000W/m^2 of power hitting the panel, the a voltmeter will read the Voc value.

When you place panels in series, their Voc adds. When you place them in parallel, Voc does not add.

If you had 4X 100W panels with a Voc of 22V in series, the array would be 88Voc.



I won't comment on that post without reading the entire thread for context. I'm not investing that much. Your questions and issues are very basic, so I'm not participating in unnecessary complication.

Regardless of the 780W or 1560W limitation, you've confirmed other limitations render that difference moot, so further discussion seems like a waste of everybody's time.

Do you have any additional questions?

Ty for your patience.

So, just to check the panels which have Open-Circuit Voltage (Voc): 23.5V taken from the site, I would be able to use maximum of 6 panels in series giving 141, however what about summer time which will likely be over 25c? Does this mean they would break the scc and thus I should lower to 5 panels max?

 

[Gueyog8a7]

I had posted earlier that I had over 1100watts on one of my 4215bn's for years. I had over 2kw on it at one point

As mentioned the voltage is the absolute limit. DO NOT exceed the max voltage the charge controller can handle EVER.

Watts only comes into play with the safety feature that protects against you hooking it up backwards.

How were you able to get that much and not exceed the voc? Open-Circuit Voltage (Voc): 23.5V per panel for my current panels so I can only do 5 since 25c will be exceeded in summer and I don't want to take them down in summer to put them up at other seasons?

 

[sunshine_eggo]

Ty for your patience.

So, just to check the panels which have Open-Circuit Voltage (Voc): 23.5V taken from the site, I would be able to use maximum of 6 panels in series giving 141, however what about summer time which will likely be over 25c? Does this mean they would break the scc and thus I should lower to 5 panels max?

It's backwards. Colder temperatures cause higher voltages. Using estimated values, 6S of those panels would exceed 150V at 10°C. I would limit them to 5S.

How were you able to get that much and not exceed the voc? Open-Circuit Voltage (Voc): 23.5V per panel for my current panels so I can only do 5 since 25c will be exceeded in summer and I don't want to take them down in summer to put them up at other seasons?

Per above, when you parallel them, the voltage does not add.

When building an array, it's important that all strings in parallel have the same Vmp, so you can't put a string of 3 in parallel with a string of 4.

 

[Crowz]

You go in series till just under the max voltage and then do that over and over with the remaining panels in parallel.

Example.
100w+100w+100watt+100watt > 100w+100w+100watt+100watt > 100w+100w+100watt+100watt etc.
So your making a 400watt panel out of 4 of them and then you hook that 4 panel "pack" to the next 4 panel "pack".