Solar Panel Isolation

[PeteH]

Word of caution, I read that currently, there is a move away from AGM?. The reasoning is a bit unclear , but The Germans, who where fitting them to Cars, have I believe stopped using them?. Any one clarify?.

I was always taught, Source, Fuse, (Switch), Battery/Appliance. I don`t think that has changed?

 

[poppycamper]

Autorouter... thnx Yes I can now see what you are saying about "the graphs"... No wonder I could not get my head around them as charging profiles... Just goes to show how a small bit of disinformation can cause major headaches.

 

[autorouter]

I was always taught, Source, Fuse, (Switch), Battery/Appliance. I don`t think that has changed?

No it's not changed. But it's all based on the idea of 'prospective fault current' What is the likely maximum current in the event of a short-circuit or ground fault? Most electrical supplies will send huge currents that will heat up normal-sized wires and cause fires. Mains, lead-acid batteries, lithium batteries, all these need fuses for protection.

Solar panels have the short-circuit current clearly written on the label. It's little more than the normal (maximum power point) current. So there's no danger of huge currents heating up wires, even for a dead short. A fuse is not required.

As others have said, a fuse can be used as a convenient isolator for maintenance etc. But it isn't necessary and will never blow due to overcurrent.

 

[Lenny HB]

Word of caution, I read that currently, there is a move away from AGM?. The reasoning is a bit unclear ,

Because they are totally useless piles of unreliable junk. Well that's my opinion having had a van with AGM's.

 

[MR. FUSION]

Interesting that domestic & industrial PV panel fires are now thought significant enough the govt to start an investigation. First report says it thinks there may be a significant under reporting of linked fires for various reasons.

https://www.gov.uk/government/publications/fire-incidents-involving-solar-panels

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[Lenny HB]

Interesting that domestic & industrial PV panel fires are now thought significant enough the govt to start an investigation. First report says it thinks there may be a significant under reporting of linked fires for various reasons.

https://www.gov.uk/government/publications/fire-incidents-involving-solar-panels

A bit different they run loads of panels in series producing high voltages I don't think it can be compared to a Motorhome intallation.

 

[BOWHOUSE52]

Word of caution, I read that currently, there is a move away from AGM?. The reasoning is a bit unclear , but The Germans, who where fitting them to Cars, have I believe stopped using them?. Any one clarify?.

I was always taught, Source, Fuse, (Switch), Battery/Appliance. I don`t think that has changed?

Thats true I was about 3 new AGM batteries then yesterday read an independent report yesterday and it was saying two main things 1 was the type of on-board chargers that are built into a big majority of Motorhome are not powerful enough to keep AGM batteries fully charged also most Alternaters are not powerful enough ether and was suggesting this may have been the reason for our Motorhome Alternaters burning out because it was flat out all the time trying to fully charge our AGM batteries The other reason that AGMs have a problem if you lucky enough like us to go for long periods to spain these batteries don't like the high temperatures that you get there
So not sure what kind of battery to buy As anyone got eny comments

 

[Richard n Ann]

Interesting that domestic & industrial PV panel fires are now thought significant enough the govt to start an investigation. First report says it thinks there may be a significant under reporting of linked fires for various reasons.

https://www.gov.uk/government/publications/fire-incidents-involving-solar-panels

Our solar installs are neither "domestic" or "industrial" just small mobile systems, with no grid tie inverters or mains involved at all.

 

[Lenny HB]

Thats true I was about 3 new AGM batteries then yesterday read an independent report yesterday and it was saying two main things 1 was the type of on-board chargers that are built into a big majority of Motorhome are not powerful enough to keep AGM batteries fully charged also most Alternaters are not powerful enough ether and was suggesting this may have been the reason for our Motorhome Alternaters burning out because it was flat out all the time trying to fully charge our AGM batteries The other reason that AGMs have a problem if you lucky enough like us to go for long periods to spain these batteries don't like the high temperatures that you get there
So not sure what kind of battery to buy As anyone got eny comments

My last Hymer had AGM's they laster 18 months, I replaced them with Sonnenschein 78a/h Gels. When I bought the current van the Gels in the last van were only just over a year old so I got the dealer to swap them for the AGM I wasn't having those again. Then I added a 3rd Gel. All going well original 2 are 4 years old and the newer one will be 3 years old in March.

Gels take longer to charge but can be discharged to 80% DOD, although dearer than Flooded Cells the very long life and greater power available makes them very cost effective over the long term.

 

[poppycamper]

Bowhouse52.. Now would be a good time for you bite bullet and embrace the lithium uprising.

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[MR. FUSION]

Our solar installs are neither "domestic" or "industrial" just small mobile systems, with no grid tie inverters or mains involved at all.

Yes, I posted that out of interest. When I was doing my installation, There was a repair specialist in wales I think, who I think stated on his site that a fire was caused by non fusing of the solar panel on a moho.

 

[BOWHOUSE52]

Yes, I posted that out of interest. When I was doing my installation, There was a repair specialist in wales I think, who I think stated on his site that a fire was caused by non fusing of the solar panel on a moho.

As anyone tried the new EFB range of batteries

 

[autorouter]

Yes, I posted that out of interest. When I was doing my installation, There was a repair specialist in wales I think, who I think stated on his site that a fire was caused by non fusing of the solar panel on a moho.

The reports don't say that non fusing is a problem. The causes seem to be that the normal power from the solar panels is passing through faulty components that then heat up or arc to cause a fire. Many of them are water getting in due to poor installation details. Such fires are more likely on a 4000 watt house roof array than a 100 watt mobile setup.

 

[Don Quixote]

As anyone tried the new EFB range of batteries

Also known as AFB (Advanced Flooded Battery) and ECM (Enhanced-Cycling-Mat) I have been looking for a while now as current batteries are 5 years old and will be replaced this year whilst back in the UK.
They were developed to meet the demands of Start-Stop systems, but some are already using them. Good read:

Battery Technology Advances mean big savings and better batteries for Caravans/Motorhomes

The best Leisure Battery is also one of the cheapest - Powerframe Varta LFD90 and Bosch L5. A Deep cycling and Starter battery in one.

www.aandncaravanservices.co.uk

 

[Minxy]

On previous campers I just put a fuse holder in the positive wire for each of my solar panels between the panel and the solar regulator, that way I could just pull the fuse when I wanted to isolate them from the system. Do NOT put one between the solar regulator and the vehicle's battery or electroblock (or equivalent) as it could cause serious damage to the solar regulator if there is nowhere for the 'input' power to go to.

You lost me there Mel.. That's exactly where you do put a fuse on the solar system and the ones ive done the instructions tell you to fuse the output side of the controller..
The input or panel side is protected anyway and instructions don't generally ask for a fuse there... But as you have said it can be a handy way of isolating the panels?
Andy

Oops. I have switches between mine and the batteries so I can isolate them to prevent them from draining the battery when not in sunlight or if I’m disconnecting the batteries etc. Not that I ever really turn them off but thought when fitting it may be useful. Never thought about what would happen if the input power had no where to go. Best make sure I leave either the cab or the habitation switched on just in case. I also have fuses on the panel wiring I could pull as well if needed. Might be safer. Lol

I believe in putting a fuse inline on the + output from a solar panel as there supposedly have been fires caused by runaway panels and the regulator has not tripped them out. So an extra fuse is a good idea, as is treating a solar panel like a live battery, so in my book it requires a fuse before going into anything else.

Just to clarify my earlier comments, when I said not to put one in the lead from the solar reg to the battery I meant as the ONLY fuse in the system.

When I installed the solar panels in our Globecar this is what I did for each solar panel:

• the positive cable went into the solar regulator (SR) positive input connector with an inline fuse (to be able to isolate if required and also blow if there was a major issue with overcharging (no matter how rare)
• the negative cable went straight to the SR negative input connector
• the output positive and negative cables from the SR went into the input connections on the electroblock (EBK) as appropriate

Whilst the EBK has fuses in it if they are removed or blow for some reason, or the EBK failed, the SR would then be receiving the full charge from the panels with nowhere for it to go which could damage the SR - I used a Votronic SR and I'm sure it specifically said never to have an input going into it without anywhere for it to go - I'd rather replace a fuse than a solar regulator!

Hopefully that makes sense but I'm on a very poor internet connection here so apologies if it is still confusing.

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[andy63]

and also blow if there was a major issue with overcharging (no matter how rare)

and thats the point I was making...
if you had left it at installed for isolation purposes thats fine but you have gone on to say its for safety purposes... what rate of fuse would you use. ???? ...lower than the short circuit current means if the panels are producing at full capacity you could be blowing a fuse...and the current can't exceed the short circuit current... so a fuse for protection is not required..the short circuit ocurrent of a panel is known and can't be exceeded... the wiring that should be used won't be damaged by said currents, and the regulators have their own protection built in...

Whilst the EBK has fuses in it if they are removed or blow for some reason, or the EBK failed, the SR would then be receiving the full charge from the panels with nowhere for it to go which could damage the SR

that just doesn't happen... the logic of that is they have designed a regulator that could fail if a fuse goes and it goes open circuit..
if it goes open circuit then there is power going nowhere.. it won't damage anything...

thats the way I see it ...hope thats clear..
Andy

 

[Lenny HB]

Also known as AFB (Advanced Flooded Battery) and ECM (Enhanced-Cycling-Mat) I have been looking for a while now as current batteries are 5 years old and will be replaced this year whilst back in the UK.
They were developed to meet the demands of Start-Stop systems, but some are already using them. Good read:

Battery Technology Advances mean big savings and better batteries for Caravans/Motorhomes

The best Leisure Battery is also one of the cheapest - Powerframe Varta LFD90 and Bosch L5. A Deep cycling and Starter battery in one.

www.aandncaravanservices.co.uk

Nice to see you posting on a battery thread again John.