Solar inline fuses keep blowing.

[Blue Moon]

The 2 x 20amp inline fuses from my PV Logic Solar controller randomly keep blowing. They can be fine for days and then when I check my app only one circuit is showing a status. Check the fuse and it's blown. I've read somewhere that smart alternators can cause this problem and an isolator switch needs to be fitted and turned off when running the engine. My chassis is a 22 reg series 7 Fiat Ducato, Would this be fitted with a smart alternator or does anyone have any other suggestions?

 

[andykim]

Did you find out about the alternator?? The smart alternator puts out a lower charging voltage and up to 17v when you take yr foot off the accelerator, similar to f1 cars with kers. You can check the idling voltage with a multimeter.

 

[Blue Moon]

Did you find out about the alternator?? The smart alternator puts out a lower charging voltage and up to 17v when you take yr foot off the accelerator, similar to f1 cars with kers. You can check the idling voltage with a multimeter.

No, I've not had chance. I'm away in the van this weekend so before I set off I'm going to take the fuse out on the link from my controller to vehicle battery. If the fuse to the leisure battery doesn't blow whilst I'm travelling I think that will confirm my suspicions.

 

[activecampers]

How is VB/alternator connecting to the leisure system? B2B or simple split charge? if the latter, I'd expect more issues as 17v is capable and that will kill many other things eventually.

But not heard issues of blowing fuses - fuses blow based on current and not voltage so you may be heading in the wrong direction.
(Although I suppose a high voltage could confuse the controller and cause weirdness, but even if so, the controller can/should only put out as much current as its capable of based on its spec and solar input - so if, say, 100W solar - then at 12v thats around 8A. So whats the solar spec and whats the fuse? If assuming as an example 100W and 15A fuse then there is no way the controller would be able to blow that fuse without a serious internal fault like shorting to earth. Could be a wiring issue/short too. I'd be surprised if the controller would be able to blow the fuse without a fault.

Certainly, my 300W solar with 20A controller and 25A fuse has never failed once and lives happily with B2B & mains charger with engine running. (though our solar is set not to charge over 13.7v (LiFePo4) as if voltage at battery is at or above that, its either full enough or getting a charge source from elsewhere, so the solar system has a nap.

My MY20 ducato is smart, I would expect yours to be certainly assuming its adblue Euro 6D etc?

 

[andykim]

How is VB/alternator connecting to the leisure system? B2B or simple split charge? if the latter, I'd expect more issues as 17v is capable and that will kill many other things eventually.

But not heard issues of blowing fuses - fuses blow based on current and not voltage so you may be heading in the wrong direction.
(Although I suppose a high voltage could confuse the controller and cause weirdness, but even if so, the controller can/should only put out as much current as its capable of based on its spec and solar input - so if, say, 100W solar - then at 12v thats around 8A. So whats the solar spec and whats the fuse? If assuming as an example 100W and 15A fuse then there is no way the controller would be able to blow that fuse without a serious internal fault like shorting to earth. Could be a wiring issue/short too. I'd be surprised if the controller would be able to blow the fuse without a fault.

Certainly, my 300W solar with 20A controller and 25A fuse has never failed once and lives happily with B2B & mains charger with engine running. (though our solar is set not to charge over 13.7v (LiFePo4) as if voltage at battery is at or above that, its either full enough or getting a charge source from elsewhere, so the solar system has a nap.

My MY20 ducato is smart, I would expect yours to be certainly assuming its adblue Euro 6D etc?

Mine must be a smart alternator as well, I wasn't sure but I'll have to get the multimeter out it a 21 adblue euro 6 ducato.