Controller to van battery fuse blowing (1 Viewer)

[Bs28]

The solar panel was fitted when I bought the van a couple of years ago and it's worked great. The beginning of this year I noticed the 10amp fuse blowed between the controller and van battery. I have changed the fuse a number of times and it keeps blowing just on this battery. I have narrowed it down to it blows when the engine starts or sometimes when it stops but not otherwise. I have just changed the controller as it was relatively cheap and true to form it worked ok until I started the van, then blew. It is not a large panel so the fuse rating looks correct for that and wire. The wire to the leisure battery has same size fuse and not blowing. I have tried adjusting the charging priority - same result. The voltage is good on both batteries in the 12.4 - 12.7 dependant on temperature, so I happy the panel/alternator is charging correctly.
Any suggestions?

 

[pappajohn]

Sounds very much like the two batteries are linked at the controller and starting the engine is drawing starting amps (350 or more) from BOTH batteries simultaneously and blowing the fuse.
Is it a twin outlet controller....two battery neg/two battery pos terminals.

 

[Bs28]

It's a duo battery controller i.e. Battery 1 and 2 I am 100% the connections are correct, the old one was ok and the new one I connected I was careful to make sure + and - was correct.

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[Bs28]

I have been out fiddling now it's dark so the panel is not giving a charge this is what I found.
1. The controller to leisure battery still does not blow.
2. The controller to van battery blows every time I replace the fuse, now even if the engine is not started.
3. If I disconnect the solar panel from controller I can replace the fuse, it does not blow and I can stop and start the van engine and it still does not blow. If I then reconnect the solar panel it does not blow until I start the engine and it blows again. I am then back to 2 above.

I put it all down to the controller, but as I replaced it I am at a loss. All the connections are correct.

 

[tonyidle]

Did you disconnect the panel from the controller at any time and especially before replacing any fuses?

 

[pappajohn]

There's a conflict somewhere between solar charge and alternator charge.
Certainly sounds like a short in the solar to engine battery wiring.
Think I would bin the engine battery to controller circuit before something serious happens and fit a B2B charger instead.

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[Bs28]

'tonyidle' prior to replacing the fuse first time I did not disconnect the panel but on replacing the controller I did disconnect the solar panel. But then reconnected as per instructions batteries first then solar.

'pappyjohn' I did have a feeling it's a short as well but the wiring looks very well fitted. If it was a short between the controller and battery it would go all the time and disconnecting the panel would make no difference? If there is a fault between the controller and panel would not the fuse go on leisure battery to controller as well?

Am I missing something?

Sorry for being dim what is a b2b charger?

 

[pappajohn]

A device which links the engine battery to leisure battery but when the engines running it fools the alternator into thinking the battery is low and needs full charge current....normally its just a few amps.
As the alternator is banging out max amps it takes very little time to charge your leisure battery.

 

[powerplus1]

A device which links the engine battery to leisure battery but when the engines running it fools the alternator into thinking the battery is low and needs full charge current....normally its just a few amps.
As the alternator is banging out max amps it takes very little time to charge your leisure battery.

hi all

i would suggest that you put a ammeter inline with the fuse lead to see what power is drawn when starting

also i would put a volt meter across the starter battery to see what voltage the battery drops to when the starter is turning

let us know

barry

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