Adding another solar panel

[Benhudson]

Hi we have a Autotrail Frontier Navajo 2010.
Because of the use of medical equipment at night I have woken to very low leisure battery capacity.
Usually we are off grid and I don't really want to get a generator.
So my question is has anyone added a solar panel yo a existing solar panel system?
If yes ant advice please.

 

[Bessy765]

Ideally match the new one to the same output as existing, what amps can your regulator handle. If not a mppt one I would suggest you fit one as they are more efficient in harvesting solar gain.

 

[oldiesontour]

So long as your existing controller and cables can handle the extra as said match the new panel output to the existing panel...if any of the above is not doable,a new panel with it's own controller and wiring is another alternative

 

[Scully]

Explanation of mixing panels. Can be done but as others have said simpler to try and match panels and make sure your controller can handle resultant volts and amps.


Depending on the time you are going to spend off grid, installing a second battery in parallel rather than extra solar might be a simpler solution.

Or do both.

 

[MisterB]

I know it's not what you asked but what battery do you have ?
Benhudson

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[fishplug]

The other thing worth having (if you don't already) is a B2B charger so you're not completely reliant on solar for topping off the batteries.

It's a juggling act between having enough battery to power what you need comfortably and finding a way of putting that power back into the system.

I've got spare AGM and Lithium batteries which I need to get round to advertising so if you are considering expanding the battery capacity then it might be a cheaper way than buying new. The 200Ah AGM was one of a pair - the other of which was sold on here so you can confirm with them that it was as described, the lithiums are 3 x 100A LiTime Minis which I replaced on a bit of a whim at the black Friday sale with a single Fogstar drift purely because it's a tiny bit smaller but also because it will talk to my 'smart van' which I'm (stupidly) integrating into my conversion....

 

[Benhudson]

2 x 110ah normal lead acid leisure batteries

I know it's not what you asked but what battery do you have ?
Benhudson

 

[oldiesontour]

Have you considered a folding panel,or is that too much hassle ?

 

[Benhudson]

I might go that way.

 

[oldiesontour]

I might go that way.

Can be the easiest...panel with controller on the back either a plug socket (Anderson) or simple crock clips to batteries...and much better yield than roof.I got a nice 200w folding for just under £100.simple PWM controller under £10 and plenty good enough for folding

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[MisterB]

2 x 110ah normal lead acid leisure batteries

Perhaps, funds allowing, an investment in a lithium battery might be the answer. If you intend using the motorhome regularly, it might be a worthwhile investment, especially as it's healthy related.
Additional solar will only help if there is 'sun' available, a B2B might be a better investment if you move around a lot?

 

[raysalaugh]

The Sargent solar regulator can only handle a maximum of 120w, better to fit as big a panel or panels the roof can take and run through a separate mppt regulator direct to the batteries.

 

[Benhudson]

The Sargent solar regulator can only handle a maximum of 120w, better to fit as big a panel or panels the roof can take and run through a separate mppt regulator direct to the batteries.

I read that yesterday, so thanks for confirming.

 

[Jimbohorlicks]

2 x 110ah normal lead acid leisure batteries

I would consider changing those for lithium. For the weight of those you could increase your power to 400ah.or thereabouts and are relatively cheap.
You could just start off with 2 x100ah.
Really depends on the space you have.
For your solar you can increase that as said plus you may need to change your controller.
Another case may be to just add 2 x 100( or 1 larger lithium) as a seperate battery bank and power these from a seperate solar and controller. Then use these for your medical equipment.

 

[DandJ]

Yes, it's a bigger expense but, I'd think swapping the 2 x 110ah lead batteries for just 1 x 280ah LiFePo would be the way to go. You'd end up with over twice the usable power.

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[BouncyBoatFolk]

2 x 110ah normal lead acid leisure batteries

Where are those battery's currently located?
Mike.

 

[Benhudson]

I would consider changing those for lithium. For the weight of those you could increase your power to 400ah.or thereabouts and are relatively cheap.
You could just start off with 2 x100ah.
Really depends on the space you have.
For your solar you can increase that as said plus you may need to change your controller.
Another case may be to just add 2 x 100( or 1 larger lithium) as a seperate battery bank and power these from a seperate solar and controller. Then use these for your medical equipment.

Would I have to change the charging circuit, or will the existing charge the lithium?

 

[Benhudson]

Where are those battery's currently located?
Mike.

In a cupboard under the floor of the motorhome, accessible from outside, very low down, I have to sit on the floor to get them in and out.

 

[DandJ]

Would I have to change the charging circuit, or will the existing charge the lithium?

I believe it will depend on what you currently have.
I am an absolute beginner on this subject...we have 1 x 140w panel and 2 x 85ah lead acid batteries (one is dead)...those nice chaps at offgridsolutions are replacing the two batteries with 1 x 280ah LiFePo and adding an extra c140w solar panel. It is a lot more expensive than simply replacing the dead lead battery...but will make the van far more usable.

 

[BouncyBoatFolk]

In a cupboard under the floor of the motorhome, accessible from outside, very low down, I have to sit on the floor to get them in and out.

Do you know what,if anything is under the drivers seat?
Mike.

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[Jimbohorlicks]

Would I have to change the charging circuit, or will the existing charge the lithium?

No I would have a second circuit just for your med stuff. And add a lithium charger for when on ehu etc.£20 off e bay.charge them independently. A seperate solar should charge them up ok and as said a portable solar could also be used and swapped between the 2 circuits as required.
We have 2 lithium circuits. Just because they are different manufacturers. Fed from 2 x banks of solar and a seperate portable panel that we hang from the awning rail and connect to either of the circuits but normally just on the main hab one. Our other circuit (2 x 100ah lithium) does the tv, deisel heater and her hair dryer etc.the main circuit ( 3x 100ah) runs the van , inverter that we have the airfryer on, kettle , microwave etc ( but not all together)
You could also build it up to suit your budget..
Don't forget a lithium uses 100% of its power unlike a lead acid at best 50%.
Food for though anyway.

 

[Benhudson]

Do you know what,if anything is under the drivers seat?
Mike.

Theres a smal space about 150mm high, i put jump leads a hi viz and tow strap in there.

 

[Miggs]

I also have an Autotrail, I fitted an extra 200 watt panel with it's own mppt controller wired direct to the leisure batteries (2 x 90 amp). I then set the Sergent controller to only charge the vehicle battery with the original 100 watt panel when parked for extended periods.
This arrangement has worked perfectly for us.

 

[Kannon Fodda]

Add second solar on roof with it's own controller and wiring direct to the batteries. Existing wiring would be too small for the current of two panels (wiring in Autotrail is always minimal), so that and the existing controller would have to be changed, so keeping separate is simplest. Also by keeping separate overcomes any issues of dissimilar panel sizes or one in part shade.

But consider if added solar is enough to solve the problem. What happens on a cloudy day or two with little solar input? Even at this tine of year the flat panel will have limited good charging overhead sun time. Are your two lead acids still holding a good charge or are they aging. Even new 2x110Ah is only 110Ah useable, and as they age it will be less than that. Are you arriving on site with a full charge and how long does that need to last - what current does your kit draw per day?

If you are using more than you can store then battery upgrade would be my first look, and then look at how to recharge. Regrettably Autotrail Sargent charging systems are often very limited. I suspect the engine recharge max current is low and you need to drive many many hours to get your current batteries recharged. With need for critical medical kit, it probably is time to delve into the wallet for a lithium with B2B charger upgrade.

 

[BouncyBoatFolk]

Theres a smal space about 150mm high, i put jump leads a hi viz and tow strap in there.

If it's just a bit a bit taller, one of these on it's side might work, https://www.fogstar.co.uk/collectio...fWYYZivWb69RJgHYCO0C-ssTLF45ZMxkaAvB6EALw_wcB .Attach it''s own dedicated panel, and an inverter.You then have a stand alone system. Or in your case, perhaps just buy one of those battery in a box systems, no work involved other than a bit more solar, but dearer.
Mike.

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[Benhudson]

I also have an Autotrail, I fitted an extra 200 watt panel with it's own mppt controller wired direct to the leisure batteries (2 x 90 amp). I then set the Sergent controller to only charge the vehicle battery with the original 100 watt panel when parked for extended periods.
This arrangement has worked perfectly for us.

Hi, were having the same problem? That's a great idea, I will look into it, one problem is our storage is undercover.

 

[fishplug]

The three ones I have spare are the LiTime Mini 100Ah.

I originally bought them in part for the compact form factor.

Don't know if they may be of interest but happy to discuss if they are.

I'd agree that a separate solar panel and MPPT controller for them would be my chosen route for medical equipment. Keeps it separate and independent from your 'normal' consumption. Also means that if one system fails for whatever reason, you've still got a second one as a backup.

I keep looking at folding panels. I really like the idea, especially as it means you can park in the shade on a sunny day and run a cable out to the panel in the sun.