RE: Which solar panel to run my Isotherm Classic GE-80 Fridge?

[Nickm72]

Hi all,

Currently I have a 130w flexible solar panel connected to a Renogy DC-DC On-Board Battery Charger with MPPT which is connected to two LiFePO4 12V 100Ah batteries (and my starter battery).

That runs my Isotherm Classic GE-80 Fridge, led lights and a few QC 3.0 usb sockets for Ipad and phone charging without issue but I hang the solar panel off the guard rails when anchored and lay it in the cockpit when it's on it's mooring.

I want to fit a panel permanently to the coach roof between the lines that run through the deck organisers approximately 900mm apart.

I’m thinking of getting a 120W panel that is 1120mm in length so a couple of the 10mm lines would be laying over the panel - this would definitely keep up with the fridge.

Alternatively, I could buy a 80w panel that’s 850mm in length, so would not be directly covered by lines but am concerned that it might not keep up with the fridge in summer.

Does it matter if the edges of the panel (approx 110mm in from each end) are permanently shaded by the two 10mm lines?

I've added an example image of where mine would be going and the lines that would cover it slightly.

Thanks,

Nick.

 

[vyv_cox]

I had 120 watts of panel on a stern arch in Greece. This would keep the fridge running 24/7 in June and July but not other months, when engine charging would be needed. Increasing battery bank from 2 x 110 Ah to 3 x 110 Ah made a considerable improvement. With two batteries voltage would be down to 12.0 in the morning but 12.4 with three.

 

[Nickm72]

I had 120 watts of panel on a stern arch in Greece. This would keep the fridge running 24/7 in June and July but not other months, when engine charging would be needed. Increasing battery bank from 2 x 110 Ah to 3 x 110 Ah made a considerable improvement. With two batteries voltage would be down to 12.0 in the morning but 12.4 with three.

Thanks for getting back to me. I ordered a 130w panel in the end and will make it fit so it's not overed by lines. I know this keeps up with the fridge as it's identical to the one i used to lay out over the side. Might consider another battery though.

 

[Stemar]

Do make sure your lines don't shade the panel. It doesn't take mush shading to reduce output dramatically.

 

[Nickm72]

Do make sure your lines don't shade the panel. It doesn't take mush shading to reduce output dramatically.

Thanks for getting back to me and yes, I've been reading that since i posted. The boom runs over the top of it but that won't cast a shadow for very long. I'm going to stack my deck organisers, and/or put another diverter of some sort so that I can keep the lines clear of the panel.

 

[Black Sheep]

Sounds like you've made your decision, but for others in a similar position, it might be worth considering a rigid panel raised a few inches above the deck, with the lines running under it. Not always possible or convenient, but enables a larger panel without being shaded by the lines. Also rigid panels tend to be cheaper, longer lasting and more efficient than semi flexible. But are visually more obtrusive, and you can't stand on them. So not for everybody. But an option.

 

[Nickm72]

Sounds like you've made your decision, but for others in a similar position, it might be worth considering a rigid panel raised a few inches above the deck, with the lines running under it. Not always possible or convenient, but enables a larger panel without being shaded by the lines. Also rigid panels tend to be cheaper, longer lasting and more efficient than semi flexible. But are visually more obtrusive, and you can't stand on them. So not for everybody. But an option.

Maybe another year I'll build one of those canopies(?) at the stern and have a couple of rigid ones on top of that but this will have to do for this year.

 

[Stemar]

Thanks for getting back to me and yes, I've been reading that since i posted. The boom runs over the top of it but that won't cast a shadow for very long. I'm going to stack my deck organisers, and/or put another diverter of some sort so that I can keep the lines clear of the panel.

If you hadn’t already ordered your panel, I'd have suggested having a pair of half-sized panels, wired in parallel, so if one is shaded by the boom, at least the other will be giving everything. I did this on our previous boat, and the current one, and it works well as an idea. When not actually sailing, it's a good idea to pull the boom over to the side away from the sun, too.

 

[Keith 66]

A few years ago i fitted a GE80 fridge to our Sabre, It is powered by a single 60w solar panel on a pole mount on the pushpit. All the lights & nav lights are led's & it just works.
The solar panel mount is on a swivel mount that can be tilted & pointed at the sun. It is amazing the difference this makes & if at anchor say in Stangate i can get up in the morning as the sun rises over the sea wall, if the panel is facing the wrong way i just swivel it round & tilt it sunwards & the charge rate instantly jumps. It isnt shadowed by anything & works extremely well. the fridge goes on before we leave our mooring & is switched on 24-7.