Solar panel controllers limit of power. (1 Viewer)

[GWAYGWAY]

I have fitted a panel to the roof of my Hymer and it has the same controller as the vehicle charger system, it just clipped on and plugged in. However as the panel is 120 watt I could do with a bit more so I would contemplate fitting another further along the roof but the controller is limited to the wattage it can control. to 140 watts maximum.
Question is can I fit another panel and another controller and use them to feed the same battery bank (3X90amphour) by just fitting the output from the second controller straight to a fused connection and the batteries, Is a diode needed or would the battery bank voltage act on both controllers equally, allowing them to limit the total inputs from the related panel???

 

[andy63]

if im understanding your intentions, fitting two separate solar systems to the same battery bank doesn't sound ideal.. there may well be conflict and you wont get the maximum benefit..
far better to upgrade the controller and put both panels through that.. if the vans power supply unit isn't capable of handling the wattage you intend ( thats if the existing panel is wired directly through the vans management panel ) then wire it independently.. there should be no problem but it would pay to check it wont cause a conflict with the vans system..
Andy

 

[tonyidle]

Simple answer is yes. The batteries will charge from whichever charging option is outputting the highest voltage be it alternator, EHU charge, solar 1, or solar 2. Charging sources outputting a lower voltage will be ignored. There is no need for any action on your part other than to fit your next panel exactly as you suggest.

Edit: just seen Andy63 post: so I'll just emphasise that there will be no conflict with anything. No matter how many different charging sources are added to the same battery.

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[Lenny HB]

If you have a LRM1218 they can take 275 Watts so you can just fit another panel and use MC4 2 way connectors on the roof so no wiring as such.

 

[andy63]

Simple answer is yes. The batteries will charge from whichever charging option is outputting the highest voltage be it alternator, EHU charge, solar 1, or solar 2. Charging sources outputting a lower voltage will be ignored. There is no need for any action on your part other than to fit your next panel exactly as you suggest.

Edit: just seen Andy63 post: so I'll just emphasise that there will be no conflict with anything. No matter how many different charging sources are added to the same battery.

the way I see it is one of the solar systems will most probably take priority,as you indicate... that may well prevent the second system from providing an effective charge as it sees a healthy voltage on the batteries and depending on type just shut down..
ive not come across it but do remember reading something about some vans power management panels incorporating a battery state indication... if panels were wired in independently it was causing problems with the battery charging as no account was taken of the charging done by the solar ...
Andy

 

[GWAYGWAY]

If you have a LRM1218 they can take 275 Watts so you can just fit another panel and use MC4 2 way connectors on the roof so no wiring as such.

I was hoping you were quoting the one I have fitted but it isn't the same it is a Schaudt, but not that one it is smaller and couples direct to the third connector on the box and iit came prewired with the multiconnector already on to clip in.
The ideal would be to be able to Y junction the second panel on the outside but I need to find out more.
T have just been out and it is an LR1218 as against the LRM 1218 They look different but does the rating come from the title 12V 18 amps?????

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[Boringfrog]

I was hoping you were quoting the one I have fitted but it isn't the same it is a Schaudt, but not that one it is smaller and couples direct to the third connector on the box and iit came prewired with the multiconnector already on to clip in.
The ideal would be to be able to Y junction the second panel on the outside but I need to find out more.
T have just been out and it is an LR1218 as against the LRM 1218 They look different but does the rating come from the title 12V 18 amps?????

https://www.motorhomefun.co.uk/foru...lar-to-electroblok-on-hymer-of-similar.89018/

 

[hilldweller]

the way I see it is one of the solar systems will most probably take priority,as you indicate... that may well prevent the second system from providing an effective charge ...
Andy

Solar controller 1 is set for 13.65V
Solar controller 2 is set for 13.7V ( manufacturing tolerance )

Battery is down to 12.1V - both controllers will dump all they can into the battery.

But at 13.65 things get interesting - controller 1 stops charging. Controller 2 goes that extra 0.05V.

What the hell, the battery is charged.

 

[two]

Having two separate systems will provide greater resilience. If anything happened to a component in one system (such as stone damage or shading to one panel), the other one would still be able to continue.

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[Lenny HB]

I was hoping you were quoting the one I have fitted but it isn't the same it is a Schaudt, but not that one it is smaller and couples direct to the third connector on the box and iit came prewired with the multiconnector already on to clip in.
The ideal would be to be able to Y junction the second panel on the outside but I need to find out more.
T have just been out and it is an LR1218 as against the LRM 1218 They look different but does the rating come from the title 12V 18 amps?????

Yes LR1218 is 18 amp and can take 275 watts of panels.
If you have Gel batteries the LR1218 is fine but I wouldn't use it with AGM batteries, once the batteries are charged and have reached 14.2v the regulator maintains that voltage continuously, Gels can handle it but it's a good way of shortening the life of other types of batteries.

 

[tonyidle]

the way I see it is one of the solar systems will most probably take priority,as you indicate... that may well prevent the second system from providing an effective charge as it sees a healthy voltage on the batteries and depending on type just shut down..
ive not come across it but do remember reading something about some vans power management panels incorporating a battery state indication... if panels were wired in independently it was causing problems with the battery charging as no account was taken of the charging done by the solar ...
Andy

It is true that an independant solar input will bypass any clever capacity metering but only in a good way .

 

[GWAYGWAY]

The other question I would like to know about the panels themselves. We see panels of various sizes and shapes but they are all different outputs.. HOW do you tell the output by just looking so that I can check the same output to match it with, as I always understood they need to be the same capacities/ output when coupled together. Is it the number of cells multiplied by the nominal output per cell, is so what is that output?

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