New Solar Panel odd behaviour

[ralphporter]

Hi,

I just installed a new solar panel (renogy 175w) I had two small ones but they were not producing hardly any output (.1 amp).

I've used the existing CMG 10amp controller.

I've noticed some different behaviour now and it may just be because the new panel is actually outputting some juice

I have a three way switch for the 12v Car Battery, Off and Aux battery. It was always the case that when I switched to the OFF position the CMG controller went dead as did the lights etc. Now when I switch to off sometimes the CMG stays live, so do the lights and the voltage suggests 20v, then a while later it may switch off OR sometimes it just goes out straight away particularly if I switch from Car Battery to OFF.

I'd appreciate some insight into this if anyone has one, the only thing I changed beyond the panel itself was to remove an isolating switch sitting between the panel and the CMG controller, not sure why it was put in but I guess to remove the solar charger from the equation whilst on hook up since it will continually blink away trying to charge a full battery.

Many thanks,

Ralph.

 

[stevec]

It is normal to disconnect the solar panels from the charger before disconnecting the charger from the batteries. When connecting up again battery connected first then the panels. The isolator switch you mention may have been for this very purpose. To isolate the panels before taking the batteries out of circuit. Having the panels permanently connected and switching the battery on and off may have had a detrimental effect. Other, more experienced Funsters will have further insight.

Edit,
I see you are new on here and from Norwich so welcome from another Norfolk boy.

 

[Dramfineday]

. I'm sure the experts in this stuff will be along to help you shortly. Meantime welcome and good luck.

 

[jollyrodger]

You could well be /have been damaging your regulator by isolating the batteries first.
As already mentioned the isolater you removed was there for the purpose of disconnecting panel first then the batteries.

Oh &

 

[ralphporter]

Many thanks for the welcome, the isolation switch I never used to be honest it was always left on and it was clearly a DIY bodge.... hence why I removed it, from what I've read and the wiring diagrams it's not needed or in fact not even a desirable addition since it just adds more connections and resistance.

I am puzzled though why I'm seeing the behaviour I described when switching the original 12v selector, as far as I can tell the only difference is the fact that I have a good working panel now but I'm also not sure how to ascertain the rest of the system is working correctly.

Many thanks,

Ralph.

^{_{Subscribers  do not see these advertisements}}

 

[ralphporter]

. I'm sure the experts in this stuff will be along to help you shortly. Meantime welcome and good luck.

Thank you very much

 

[denisejoe]

I would change the controller to one that has auto switching from leisure battery to engine you could do away with the switch

 

[GeoffnDee]

You could try disconnecting both the solar and battery at the controller then reconnecting the battery to the controller before reconnecting the solar in case the controller needs a reset to work ,with the new panel , at the correct 12v output as is required.

 

[ralphporter]

Well the selector switch between the 3 modes is the original with the van, I wouldn't want to mess with that to be honest, the isolation switch already gone.

The crux of what I'm getting at is why the controller and the 12v system is still alive sometimes fir a little while now when I switch the 12v off whereas before it just clicked off. Is it because it's getting plenty of power from the panel or is there another problem, I don't know what's between the solar controller and the battery but I guess another bit of kit original to the van...

 

[Jake Royd]

Well the selector switch between the 3 modes is the original with the van, I wouldn't want to mess with that to be honest, the isolation switch already gone.

The crux of what I'm getting at is why the controller and the 12v system is still alive sometimes fir a little while now when I switch the 12v off whereas before it just clicked off. Is it because it's getting plenty of power from the panel or is there another problem, I don't know what's between the solar controller and the battery but I guess another bit of kit original to the van...

Just a thought. Maybe you have a capacitor somewhere acting as a momentary reserve of energy. Some in the charger maybe that are seeing some energy going up from the panel rather than down from the charger?

^{_{Subscribers  do not see these advertisements}}

 

[ralphporter]

Thanks Jake, I mean absolutely possible but I'd have no idea to be honest, I'm clearly no expert , maybe I'll try and trace the wires from the solar controller to the battery and see what they pass through on route.

I wonder why the voltage would read 20v when it's exhibiting this behaviour, is that like a combination of the van and leisure batteries or something?

 

[GeoffnDee]

If the 3 x way switch is standard fitting on the van, was the solar system ? as each time you switched from off to a battery there would be a connection made between the solar panel , controller , and battery in the wrong order which will effect controller output.
This would also account for the 20v you are now seeing sometimes, if the controller is confused , and also why the isolation switch was fitted. (to switch off the solar input until a battery was selected first as this would be needed for the controller seeing 12v when connected to enable it to know what voltage to work to, , it can put out 20v if the correct voltage is not sensed)
It would be better to wire the controller (if not already damaged) output to the leisure battery and fit a Vanbitz battery master between it and the starter battery (if you want both batteries solar charged) or ,as has been suggested, fit a duel output controller that will charge both batteries, either way would not involve the 3 x way switch which could be the problem.
I would disconnect the solar until this is sorted out as 20 v will ruin your batteries and possibly other electrical items.

 

[pappajohn]

and the voltage suggests 20v,

Your controller has failed.
Controller input from the solar panel is around 21v, the output to the battery should be around 14v.

 

[stevec]

As several people have said you really need to be able to isolate the panels from the controller (I used a removable fuse for this… serves two purposes). Then disconnect battery, leave for a minute then reconnect. Maybe a reset is all that’s needed. I agree that the 20v you are seeing is probably parasitic from the panels.

 

[ralphporter]

If the 3 x way switch is standard fitting on the van, was the solar system ? as each time you switched from off to a battery there would be a connection made between the solar panel , controller , and battery in the wrong order which will effect controller output.
This would also account for the 20v you are now seeing sometimes, if the controller is confused , and also why the isolation switch was fitted. (to switch off the solar input until a battery was selected first as this would be needed for the controller seeing 12v when connected to enable it to know what voltage to work to, , it can put out 20v if the correct voltage is not sensed)
It would be better to wire the controller (if not already damaged) output to the leisure battery and fit a Vanbitz battery master between it and the starter battery (if you want both batteries solar charged) or ,as has been suggested, fit a duel output controller that will charge both batteries, either way would not involve the 3 x way switch which could be the problem.
I would disconnect the solar until this is sorted out as 20 v will ruin your batteries and possibly other electrical items.

So essentially run direct from the controller to the leisure battery (I'm not worried about the van battery to be honest)

How does that interact with the hookup side of charging then, two things attempting to charge the same battery?

^{_{Subscribers  do not see these advertisements}}

 

[ralphporter]

And no the solar panel installation isn't original I'm sure of that....

 

[ralphporter]

Your controller has failed.
Controller input from the solar panel is around 21v, the output to the battery should be around 14v.

It seems to be fine when I'm switched to the batteries though, for example I switch to the leisure battery and the controller blinks wildly at around 14v and the input amps blink between 0 and X this apparently normal when the battery is already fully charged. Switch to the van battery and it shows 14v steady and 3 to 4 amps steady, so I assume it's charging as the van battery is likely low. Then turn to the off position and I get the 20v thing perhaps...

 

[GeoffnDee]

The solar connection from the controller to the leisure battery is normal (best with a fuse fitted) and is not a problem when on hook-up as the solar controller and mains charger will both stop allowing further charging when the battery is fully charged by either method. The solar connection to the controller must be made after the battery is connected to it as the controller needs to know what voltage to allow through (12v) from the 20v that the solar is putting into it.
Your controller may be damaged so you need to check the battery voltage when you connect up, if it is over about 14,5v up to 20v when the solar is working / charging the controller will be faulty and need replacing

 

[ralphporter]

So looking at the wiring, the positive and negative to the battery disappear into spaghetti junction, certainly not straight through, looks as though the negative gets split to the battery and fuse box, the positive I can't trace properly but it's on a journey for sure.

When I switch to leisure battery the CMG controller activates and the voltage rises up to 14.9 before it cuts out and starts blinking away.

Today when I switch to off, the controller momentarily shows 20v then clicks off.

I think I'm getting more confused , the installation of the controller output to battery must have been done professionally I think, it's too neat and intricate for a bodge job.

I'll disconnect the panel as suggested by several people and switch to leisure battery then reconnect the panel but then I'd need to leave it on leisure battery permanently or refit the isolation switch I guess.

 

[jollyrodger]

This may help you

Wiring a Marine Solar System

How to wire a marine solar panel system on your boat

www.custommarineproducts.com

Midsummer Energy

TSMC thin-film solar panels using CIGS rather than silicon

midsummerenergy.co.uk

^{_{Subscribers  do not see these advertisements}}

 

[ralphporter]

So looking at the wiring, the positive and negative to the battery disappear into spaghetti junction, certainly not straight through, looks as though the negative gets split to the battery and fuse box, the positive I can't trace properly but it's on a journey for sure.

When I switch to leisure battery the CMG controller activates and the voltage rises up to 14.9 before it cuts out and starts blinking away.

Today when I switch to off, the controller momentarily shows 20v then clicks off.

I think I'm getting more confused , the installation of the controller output to battery must have been done professionally I think, it's too neat and intricate for a bodge job.

I'll disconnect the panel as suggested by several people and switch to leisure battery then reconnect the panel but then I'd need to leave it on leisure battery permanently or refit the isolation switch I guess.

So tried this, it behaves identically in either sequence as far as I can tell, I assume it's functioning ok when switched to leisure battery since it cuts off charge at 14.9 volts inline with the manual.

 

[pappajohn]

So tried this, it behaves identically in either sequence as far as I can tell, I assume it's functioning ok when switched to leisure battery since it cuts off charge at 14.9 volts inline with the manual.

Unusual, the controller should reduce to a maintenance/float charge....not switch off altogether.

 

[ralphporter]

Sorry I didn't mean cut off as in go dead but it starts cycling around from 14v up to 14.9v and the numbers blink on and off, again it dies say in the manual thus is indicative of a fully charged battery.

 

[autorouter]

In the manual it is very clear about the order of connection during installation. Connect the battery first, then the solar panels. It also says the controller auto-selects between a 12V system and a 24V system. That is the reason for connecting the battery first, before the panels.

If you disconnect the battery and leave the panels connected, the controller will be in an unpredictable state. You have noticed that sometimes it can output 20V, which is really only possible if it is (mistakenly) thinking there's a 24V battery connected to it.

Even if that changeover switch was originally wired like that when the van was new, it's still a bodge. To change battery feeds, you should isolate the panels, switch over the battery, then reconnect the panels. You shouldn't ever have the panels connected with no battery connected.

 

[ralphporter]

Well the original change over switch isn't really anything to do with the solar installation, it just lets you select the 12v source for the van utilities i.e. Van Battery, Leisure Battery or No Battery.

The solar controller has (beyond my real understanding) somehow been integrated with the results of that switch, in that I guess it's intended to provide charge to either battery when that input is selected, it only shows the 20v when it's isolated from both i.e. I've selected no battery and therefore effectively disconnected all my utilities.

Oddly though it seems to have been working for years, I'd never used the isolator switch because essentially I didn't understand why it was there. So every time I switched on my 12v system to leisure battery the CMG had apparently been activating and charging and when I turn off the 12v the CMG naturally shuts off since it's not attached to the battery anymore.

It behaves the exact same way whether I connect the battery first or the solar panel first as far as I can tell but it only wakes up when the battery is connected, I assume the circuitry in the CMG only takes power for its own use from the battery input not the solar panels.... So maybe since all connections are already physically made when the battery is "made live" via the van switch it's not a first come first serve situation, is that plausible?

I see the solutions as given are to put the isolator switch back and actually use it or to try and reconfigure the wiring direct to the leisure battery from the CMG so that the controller remains in all the time.

Many thanks

^{_{Subscribers  do not see these advertisements}}

 

[pappajohn]

Forget all the messing with switch's and isolators, just connect the controller directly to the leisure battery with a 15a fuse at the battery end.
You're overcomplicating a simple operation.

 

[AgeingAndrew]

Well the original change over switch isn't really anything to do with the solar installation, it just lets you select the 12v source for the van utilities i.e. Van Battery, Leisure Battery or No Battery.

The solar controller has (beyond my real understanding) somehow been integrated with the results of that switch, in that I guess it's intended to provide charge to either battery when that input is selected, it only shows the 20v when it's isolated from both i.e. I've selected no battery and therefore effectively disconnected all my utilities.

It's a PWM controller, it will have an open circuit ouptut voltage of around 20V, or whatever the panel provides. It's voltage is pulled down by the battery to around 12Volts.

 

[GeoffnDee]

Forget all the messing with switch's and isolators, just connect the controller directly to the leisure battery with a 15a fuse at the battery end.
You're overcomplicating a simple operation.

If you go down this simple route make sure you remember to isolate the existing battery wire you remove from the controller as it will be live when your 3 x way switch is in use (except off position) or perhaps you can disconnect the wire elsewhere and use it.

 

[ralphporter]

Yes thanks this was what I was pondering, the existing cabling disappears into the mess of wires around the fuse box and other components, I don't think I could reuse them and don't really want to touch them since they look original to me, so I'd need to run some new cable and as you say isolate the controller ends of the existing ones.

I've not really convinced myself that it's not working as is to be honest, but obviously I accept that it's not a conventional installation from what everyone has said, for which I'm very grateful.

The problem is I like the idea of being able to turn off the controller because when the van is layed up for a period I leave it on hookup timed to come on for a few hours a night to keep the batteries topped up. With the solar on all day they'd be constantly drip fed and I've read that's not good.

So reintroducing the isolator switch and using the existing wiring gives me ultimate flexibility but I need to remember to use it when switching on the 12v.

However the concensus seems to be the simple solution direct to battery so I think that's probably what I'll do but maybe add the isolator for the panels so I can disengage them during winter months etc

I'm really bad at making decisions

 

[GeoffnDee]

ralphporter The solar does not drip feed it only tops up the battery when it needs it to keep it fully charged (when fully charged it stops charging until the battery needs topping up with charging again). My solar is connected and in operation every day Winter/Summer so the battery is always fully charged and if I was to switch the charger on it would only mean the battery would become fully charged a bit faster at which point both charger and solar would shutdown until needed again to top up the normal battery power loss that happens.
Most new Motorhomes now have Solar fitted as standard and they are not switched off and on but are left connected full time.
I have fitted an isolation switch in the solar panel to controller lead but that is only to make disconnection easy if I needed to remove the battery at some time for any reason in the future without needing to remove solar wires from the controller first.

^{_{Subscribers  do not see these advertisements}}