We keep blowing fuses...

M

MuleHawk

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Nov 22, 2015
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87
Location
Colorado
we have 100w Zamp on the roof and 120w portable Zamp and we have now blown 3 fuses at the battery, today we blew the fuse, I replaced it and within 2 mins it blew out again. Am I bringing in too much power from my panels? This is one of the first sunny days we have had in weeks. I'm virtually clueless when it comes to electrical so any help would be appreciated.

Attached is the location of the fuse and how my batteries were wired up by the previous owner, maybe they have it wired incorrectly? Would higher amp fuses fix the problem? It is a10a fuse. Thanks!

ImageUploadedByWander The West1468776831.595912.jpg


www.mulehawk.com
 
I did a test since I have spare fuses with both panels connected and when they are pulling in more than 13 amps the fuse blows every time. My charge controller is the 15amp Zamp from the FWC factory, PaulT mentioned FWC only puts in the 30amp controller in new campers, could this be the problem?


www.mulehawk.com
 
A 10 amp fuse won't handle a 13mps for long. You would need to up the fuse size to 15 amps. I assume this is when both panels are making power for a combined 13 amps. If something is wrong in the controller/panels, it could be drawing 13 amps to blow the fuse. Cover one or both of the panels and verify the current drops below 13amps to ensure there is no problem. Probably want to measure your battery voltage also, with and without the fuse installed.

220W/15VDC = 14.5A
120W/15VDC = 8A.

The 10A fuse is a good choice for only the roof top panel. Adding a 2nd panel you need to upsize the fuse to 15 or even 20A.
 
Figured as much but wanted to be sure, I'll buy a few and see if that fixes the problem. Should I upgrade all the fuses behind the charge controller too? They haven't blown but I don't want to have to keep driving 50+ miles to parts stores from our campsite in the boonies.


www.mulehawk.com
 
I do not know what other fuses you have and what purpose they serve. The single wire going to the battery is the combined output of panels through the charge controller so that needs to be 15A at least.

The panels themselves probably use 10A each which should be fine. If you have schematics you can take a picture of them and post them, that would be easier to assist.
 
MuleHawk. You should also call Zamp and FWC. You need to make sure the controller is large enough to handle both panels.

I have 2 batteries, Zamp 100W panel on the roof, and a portable 80W Zamp to plug in. The roof panel and rear solar plug are both wired to the Zamp controller, so Zamp recommended the portable without the controller. You may need a larger controller
In either event a couple of phone calls should get you the right answer.

Sent from my SM-G900V using Wander The West mobile app
 
x2 on what longhorn1 just said.

The amp fuse that ZAMP put in was likely intended to be that size. The controller may not be able to handle both panels.
 
Mulehawk a question,probably doesn't have anything to do with your problem.I noticed
in your photo you have two batteries,one I can see is an AGM ,are they both AGM?
Also what is the wattage input amount on your controller? You may not have a big enough controller
to handle the output of the solar panels.
Frank
 
Both are AGM. I called Zamp when the first fuse blew out and they weren't familiar with how FWC wires up their system which I found strange but they didn't say anything about my 15a controller. My portable panel has its own controller which I didn't realize isn't recommended by FWC until after I purchased it.

I bought a few 15a and 20a fuses, I'm going to test them out before bugging FWC. Naturally the sun has decided to hide behind afternoon clouds now that I have better fuses haha.


www.mulehawk.com
 
The 15 amp Zamp in my 2014 Hawk also had a 10 amp fuse on the output of the Zamp located on the battery. As K7MDL says, a 30 amp is Zamp's recommendation. Mine blew after I added my second panel and it saw the bright Utah sun on its first full exposure. After replacing with a 30 amp fuse, all has been fine since.

The fuse is to protect the wiring, not to control current from the controller. That's the charge controller's job.
Paul
 
Hmm I wonder why FWC throws 10amp fuses in there if it's against Zamp recommendations? I'll give these 20amp fuses a try since I have them but I'll buy a pack of 30a just in case.


www.mulehawk.com
 
I replaced my fuses prior to having them blow. I was curious why such a low amp fuse was used, contrary to the controller manual recommendation.

I guess a 100W panel alone wouldn't blow a 10A, but once you start using the controller closer to its capacity via additional panel(s) then you want to change the fuse size to accomodate.
 
We have a 2014 Grandby, front dinette. Where would I find these fuses? We have 2 batteries and the Zamp Controller. We have 100W Zamp on the roof and I purchased an 80W Zamp portable in 2015 (without controller). Wondering whether there is another fuse on the wiring from the rear plug to the controller.

We have used the portable on numerous occasions and haven't had any problems.

I would like to know what I'm looking for and where. jd
 
DesertDave said:
I replaced my fuses prior to having them blow. I was curious why such a low amp fuse was used, contrary to the controller manual recommendation.

I guess a 100W panel alone wouldn't blow a 10A, but once you start using the controller closer to its capacity via additional panel(s) then you want to change the fuse size to accomodate.
Click to expand...
This.

It is always better to over protect if it does not affect the function. Missing is the communication/awareness that a smaller than recommended fuse was installed (but still ample to function and protect) and needs to be changed when you increase power later. Most likely an assumption is made that a professional is installing the equipment and it should be a normal matter for them to check each fuse to match the install requirements.
 
longhorn1 said:
We have a 2014 Grandby, front dinette. Where would I find these fuses? We have 2 batteries and the Zamp Controller. We have 100W Zamp on the roof and I purchased an 80W Zamp portable in 2015 (without controller). Wondering whether there is another fuse on the wiring from the rear plug to the controller.

We have used the portable on numerous occasions and haven't had any problems.

I would like to know what I'm looking for and where. jd
Click to expand...
Mine has 3. Two behind the controller and one at the batteries as in the photo I posted. Not sure if I should upgrade the fuses behind the controller but they haven't been a problem for me. Just the one at the batteries.


www.mulehawk.com
 
longhorn1 said:
We have a 2014 Grandby, front dinette. Where would I find these fuses? We have 2 batteries and the Zamp Controller. We have 100W Zamp on the roof and I purchased an 80W Zamp portable in 2015 (without controller). Wondering whether there is another fuse on the wiring from the rear plug to the controller.

We have used the portable on numerous occasions and haven't had any problems.

I would like to know what I'm looking for and where. jd
Click to expand...
Output fuse on the battery in black module in center fuse holder. May be underneath other wires.

full




Input fuse module on each solar panel yellow lead behind Zamp in upper right corner. Red tape indicates for which panel.
full



Paul
 
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