How to connect an additional, portable solar panel

[Ralph Hardwick]

I'm hoping that someone on here can point me in the right direction with a little solar conundrum.

We are a few weeks away from getting our first motorhome. At the moment we are thinking of a new Swift Champagne (Escape) 622 from Brownhills.

It comes with a 100W solar panel connected into the Sergent controller and an 80 Ahr habitation battery.

We are planning to do a fair bit of 'off-grid' camping and so I plan to add at least one more battery into the system. Exactly what battery, I'm not sure until I actually get the van. I would prefer around 200 Ahr (i.e. 2 x 100Ahr) but don't really want to throw away a perfectly good one. Saying that, I have heard some uncomfortable stories about the AGM batteries fitted as standard, so a complete change might be worthwhile. Anyway, I digress.

When I increase the Ahr capacity I also want to increase the solar charging. I already have a 60W folding (portable) panel which I used to use with my Land Rover.

What I would like to do is add this to the charging system and leave it portable so that I can 'track' the sun and maximise the charging. It will also allow me to put the panel away from the van if I end up parked under shade.

Can anyone give some ideas of how and where to connect this into the existing charge circuit? Ideally, I would have a bulkhead mounted socket wired into the correct terminals of the existing controller. I could then just plug in the panel when I wanted.

Being a bit of a nerd I would quite like it if the Swift/Sergent control panel would report the total charge current from both panels.

Any advice, tips or guidance (especially from anyone who's done something similar or who's familiar with the Swift Escape systems) would be greatly appreciated.

 

[andy63]

I'd be inclined to forget about adding capacity to the inbuilt system and go straight to the batteries through a seperate controller...
Save issues like the portable panels usually having an inbuilt controller already...and what's the max wattage the swift set up can handle ??

Easiest way to aggegrate the state of charge and battery capacity is to fit a battery monitor device that uses a shunt and make sure all connections to the battery pass through the shunt..
The points you make about the portable pannel are valid enough but in practice they become a pain ..not to mention the security issue of having to be around while its in use..
Andy

 

[Ralph Hardwick]

Thanks Andy. I understand that the Swift controller can handle 10 Amps. So in theory no more than 120W. However, that doesn't allow for inefficiencies, clouds, angle of the sun, dirt, etc. etc.
I understand the 'Shunt' and how it works as I used to have a charge meter fitted on my Land Rover. However I was hoping that someone would be able to come up with a way of using the existing monitoring system. Saying that Ithink you are probably right that I will need to create a 'parallel' charge circuit.
As for security, I would only add the extra panel while we were around.

 

[tonyidle]

Does your portable panel have it's own controller? How was it connected to the Landrover? Simplest way is to make it totally independant with it's own controller mounted on the panel. It can then be plugged into a habitation area 12v socket to charge the hab battery(s), cab 12v socket if you want to boost the starter battery, or a pair of croc clips to charge any other battery. It will not affect your existing solar set-up (or any other charging source).

 

[tonka]

On my Autotrail I had 2x 110 amp batteries and 120w solar running through the Sargent unit EC500. Worked ok for me.
The issue will be if you add another panel and separate controller it will confuse the Sargent ( I already asked them that question).
So. You would be best by taking solar out of the Sargent and having a separate regulator, maybe one that gives you the data Info you want to see.

If you have the EC500 another option is leave existing panel and configure it for engine battery only. Then use the new panels and regulator just for leisure. This was a Sargent suggestion.

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[Lenny HB]

Better too get a decent MPPT regulator and ignore the Sargent one. It is just a ceap PWM one bungend in the back of the unit.

 

[Ralph Hardwick]

Does your portable panel have it's own controller? How was it connected to the Landrover? Simplest way is to make it totally independant with it's own controller mounted on the panel. It can then be plugged into a habitation area 12v socket to charge the hab battery(s), cab 12v socket if you want to boost the starter battery, or a pair of croc clips to charge any other battery. It will not affect your existing solar set-up (or any other charging source).

I had a fixed 100W panel charging the leisure battery and starter via a CTEK BSB controller. I used to connect the portable panel directly to the starter battery via a 12v socket. The CTEK detects the raised starter battery voltage and then 'siphons off the extra charge back to the leisure battery. It basically assumed that the extra current was coming from the alternator as if the engine was running.

I'm not sure if the sargent does the same.

The folding panel does have its own controller and I did wonder about simply plugging it into an existing hab socket I just wasn't sure that this would work the way I expected.

So expanding this a bit; if I connect the portable panel to the habitation battery (via a specific external socket) thus putting the existing and portable charge circuits in parallel with each other this should increase the total charge rate without causing any problems to the existing system.?

On my Autotrail I had 2x 110 amp batteries and 120w solar running through the Sargent unit EC500. Worked ok for me.
The issue will be if you add another panel and separate controller it will confuse the Sargent ( I already asked them that question).
So. You would be best by taking solar out of the Sargent and having a separate regulator, maybe one that gives you the data Info you want to see.

If you have the EC500 another option is leave existing panel and configure it for engine battery only. Then use the new panels and regulator just for leisure. This was a Sargent suggestion.

So that seems to answer my question above. Running a parallel charge system will b*gger up the sergent. Unless I connect it to the starter battery thereby fooling the sergent into thinking it was alternator current.

Better too get a decent MPPT regulator and ignore the Sargent one. It is just a ceap PWM one bungend in the back of the unit.

I have heard this before, but as the van will be brand new and under warranty, I wanted to keep it as close to spec as possible for the first few years. Plus I had hoped to maintain the Swift Command monitoring system as this links with the mobile app.

As the introduction of another controller would seem to, either confuse the sergent controller or prevent the Swift monitoring I wonder if I can simply splice into the fixed panel feed before the controller, add a socket and plug my extra panel into that. This would put the existing and extra panel in parallel with each other and feed into the sergent controller thereby 'fooling' the controller into thinking I have a larger panel.

If I do this should I bypass the portable panel controller and just connect the straight feeds?

 

[andy63]

So that seems to answer my question above. Running a parallel charge system will b*gger up the sergent. Unless I connect it to the starter battery thereby fooling the sergent into thinking it was alternator current.

I can't see how having two separate charging systems could damage the sergant... if it has some sort of battery monitoring capacity then it may cause an issue as it wouldn't see the benefit of the other charging source in terms of its input , but I think that's unlikely..
it could be one charging source will be more active unless there is demand for the second one, ie batteries are low or you are running a healthy load, but that shouldn't damage anything..

If I do this should I bypass the portable panel controller and just connect the straight feeds?

yes, if the present system can take the combined wattage you would just connect the panel less its controller as the in built controller will cope..

Andy

 

[tonyidle]

I can't see how having two separate charging systems could damage the sergant... if it has some sort of battery monitoring capacity then it may cause an issue as it wouldn't see the benefit of the other charging source in terms of its input , but I think that's unlikely..
it could be one charging source will be more active unless there is demand for the second one, ie batteries are low or you are running a healthy load, but that shouldn't damage anything..


yes, if the present system can take the combined wattage you would just connect the panel less its controller as the in built controller will cope..

Andy

Or if you connect your portable direct to the battery it will have no effect on any other charging connection. You will run the risk, however slight, of over-charging the battery to which you connect it.

 

[Late Starting]

I took up this query with SARGENT a couple of years ago the answer was that the Solar controller might manage it if not in full Sun and not giving off the full possible Voltage BUT THAT THE SARGENT MAIN PANEL WOULD NOT COPE WITH IT causing it to shut down. or BURNOUT.
There is no way to use the monitoring system already fitted as you would
have to go through SARGENT main panel to do that.
That information was got direct from SARGENT technical at a show.
Late Starting ( Cliff )..

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[DBK]

If you can fit 200W on the roof it will generate about the same power when the sun is low, say 30°, as a single 100W pointed directly at the sun. Plus of course it will generate much more when the sun is higher - which is when solar works best anyway. If you want to go to France and use some of their free aires then you will find at times you can't put the panel outside because of local rules or there isn't room to put it out because of MHs parked beside you. Roof mounted panels are widely used for good reasons.

 

[Ralph Hardwick]

Or if you connect your portable direct to the battery it will have no effect on any other charging connection. You will run the risk, however slight, of over-charging the battery to which you connect it.

A fair point, this is why I am keen to maintain the monitoring facility.

I took up this query with SARGENT a couple of years ago the answer was that the Solar controller might manage it if not in full Sun and not giving off the full possible Voltage BUT THAT THE SARGENT MAIN PANEL WOULD NOT COPE WITH IT causing it to shut down. or BURNOUT.
There is no way to use the monitoring system already fitted as you would
have to go through SARGENT main panel to do that.
That information was got direct from SARGENT technical at a show.
Late Starting ( Cliff )..

My understanding (from the manual for the Motorhome) is that the Sargent controller is rated to 10 Amps max. This is the limiting factor. The main panel should be matched and rated to cope with the maximum that the controller can deal with.

The fixed panel is 100W which would give 8.33 A at its maximum efficiency.

My portable panel is 50W (not 60 as I originally posted) so it's maximum output would be 4.17A.

This gives a combined maximum amperage of 12.5A. So a 25% overload possibility. This could cause the situation you mention above.

However, this is only likely/possible if both panels are connected and producing at full efficiency which is highly unlikely as I will explain below.

If you can fit 200W on the roof it will generate about the same power when the sun is low, say 30°, as a single 100W pointed directly at the sun. Plus of course it will generate much more when the sun is higher - which is when solar works best anyway. If you want to go to France and use some of their free aires then you will find at times you can't put the panel outside because of local rules or there isn't room to put it out because of MHs parked beside you. Roof mounted panels are widely used for good reasons.

In an ideal world, I would love to fit a larger panel on the roof and I realise that this would be the optimum fit and forget system. My reasons for not going down that route are almost totally mercenary.

It would mean replacing the existing 100W panel which would then be redundant (although I might be able to recoup some cost by selling it).
I already have the portable 50W panel which would then be redundant.
Increasing the fixed panel capacity over 120W (by replacing or adding additional panels) would require another charge controller because of the low spec of the sargent unit and would then preclude me from monitoring the system via the integrated system (onboard and App).

In reality, I see the portable panel only being used early or late in the year if we plan on staying somewhere for more than a couple of days.

In the summer months, we will use less power and get more exposure for the fixed panel, so I'm hoping that the fixed 100W will be enough.

When using Aires etc. we are likely to be moving on within 1 or 2 days and so the engine will help top up the fixed panel. I fully appreciate the Aire/wild camping rules of nothing outside the van and so I hope the fixed panel will cope.

Earlier and later in the year, there tends to be less 'oomph' in the sun and it is around for less time. In addition, our power usage is likely to increase because of the longer nights/evenings.
If we park up (most likely on a site) for more than a few days then I can foresee that the fixed system might not cope. This is when I would 'deploy' the extra panel. The 10 Amps is the limiting factor with the existing system so my aim will be to monitor the charge rate to ensure that I keep it as high as I can whilst staying within this limit.

Hopefully, that explains my reasoning (however flawed it may be )

 

[andy63]

The fixed panel is 100W which would give 8.33 A at its maximum efficiency.

Where are you getting those output figures from for a 100w panel
I would have thought more like 5/6 amps max..I'm sure that's all my 100w panel could output and i dont think I ever saw that..
Andy

 

[Richard n Ann]

Where are you getting those output figures from for a 100w panel
I would have thought more like 5/6 amps max..I'm sure that's all my 100w panel could output and i dont think I ever saw that..
Andy

It's 100/12v but the panel will be 19v ish. So with a pwm controller 5.26 amps. Or a really efficient mppt controller with no losses 8.33 amps. But he did say they were ideal maximum figures

PS oh bugger, I've got involved in another solar thread I was going to keep out of this one

 

[andy63]

It's 100/12v but the panel will be 19v ish. So with a pwm controller 5.26 amps. Or a really efficient mppt controller with no losses 8.33 amps. But he did say they were ideal maximum figures

PS oh bugger, I've got involved in another solar thread I was going to keep out of this one

Well make sure you get a photo of that and I'll believe you.. the voltage has to be high enough to enable charging and i doubt you will ever see 8 amps ..whatever controller you use... unless its magic
Andy

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[Richard n Ann]

Well make sure you get a photo of that and I'll believe you.. the voltage has to be high enough to enable charging and i doubt you will ever see 8 amps ..whatever controller you use... unless its magic
Andy

No it won't happen will it. Nothing has no losses

 

[Ralph Hardwick]

Sorry Guys

I was quoting the pure mathematical maximums. I do realise that you won't get near to those figures and that was part of my reckoning that the 10A Sargent controller would be able to cope with the 100W + 50W combination I had planned.

My 100W panel fitted to my Land Rover used to reach 6.5A via a CTEK MPPT controller when the sun was full overhead, the sky was clear and the panel was clean.

That wasn't very often

 

[Richard n Ann]

I've seen 9.2 amps from our 150w panel with Votronic duo 250 running the show. I was watching with excitement and took a picture to frame and cherish

 

[Ralph Hardwick]

That's superb as that pretty much guarantees that my 100 + 50 combination will be okay. Thanks

 

[Camping Gaza]

I've seen 9.2 amps from our 150w panel with Votronic duo 250 running the show. I was watching with excitement and took a picture to frame and cherish
View attachment 304766

I am curious.... I know this is a reply to an old post but......

Your monitor shows 100 percent charge, and you batt voltage 13.9 (float voltage I assume) Why is your solar feeding 9.2 amps into your fully charged and floating battery? I would of thought the reading would be in milliamps at this stage. Were you drawing a lot of current at the time of the picture? If you were I would expect your voltage to be reading a lot less

I don't get it (bear in mind I'm no expert)

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[Richard n Ann]

Dunno, I leave it to it. I think that was September with the solar panel propped at 40° South, the sun was partly behind an olive tree until just before the photo was taken, so it had been charging slowly for a while, then when the sun cleared the tree - boom, maximum power! ??

Also the Votronic controller might not have been considering the battery was 100%

 

[Camping Gaza]

Make sure you are not cooking your battery!

 

[Richard n Ann]

Make sure you are not cooking your battery!

Yeah, that was about 11am iirc. It always drops to 0.4 amps mid afternoon ?

 

[Camping Gaza]

sounds about right!

 

[hilldweller]

Are you sure you're not being led down a blind alley just because you have this small panel going spare ? It's a lot of messing about for 50W.

Better to throw the biggest panel you can fit alongside the other one or even instead of the other one and feed to the battery direct via a better controller than the sargent one.

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[Ralph Hardwick]

Are you sure you're not being led down a blind alley just because you have this small panel going spare ? It's a lot of messing about for 50W.

Better to throw the biggest panel you can fit alongside the other one or even instead of the other one and feed to the battery direct via a better controller than the sargent one.

Things may have changed since I started this thread. We may now end up buying a Motorhome without a fitted panel. If so then I will probably go for a 150W or 200W roof mount and not bother with the portable.

If we do get one with a 100W fitted I don't see it as being too hassle to plug it in when needed, The only fiddle will be adding the socket in the first place which is a lot less hassle than swapping or adding another panel on the roof.

It also gives a little bit of flexibility if we end up parked in shade as we can move the portable around.