Solar panel fuse

[Shamu341]

Hi, I'm in the process of installing a new solar pane as the previous one give up the ghost.
The charge controller I'm using is a Solar SR135TL, the in-line fuse is missing but I think it was 7.5amp although not sure.

Would a 7.5 fuse be ok for this controller the rating of which is 8 amp?. The panel is a Wattstunde 65w

 

[rogerthebodger]

Are you talking about a fuse between the panel and controller or between the controller and the battery/

The fues between the controller and the battery is requird close to the battery less so between the panel and the controller

 

[Shamu341]

The fuse holder is between the controller and the battery.
Close to the battery.

 

[KompetentKrew]

I can't see how you could blow a 7.5A fuse on the 12V side of the controller with a 65W panel.

I'd expect to get about 4.5A - 5.5A at 12V - 14V to get your 65W.

But I know nothing about solar, so no doubt someone will be along shortly to tell me that I'm wrong because I haven't accounted for…

 

[Pete7]

The SR135TL is quite a good PWM solar controller, but I don't remember a fuse so if its a separate in line wasn't part of the original controller. Could be the wiring from the controller to the battery is too small. I would put a 10A fuse in line with new wiring and carry on.

 

[PaulRainbow]

Hi, I'm in the process of installing a new solar pane as the previous one give up the ghost.
The charge controller I'm using is a Solar SR135TL, the in-line fuse is missing but I think it was 7.5amp although not sure.

Would a 7.5 fuse be ok for this controller the rating of which is 8 amp?. The panel is a Wattstunde 65w

The controller rating is the max permissible current, the 65w panel will be less. A 5a fuse will be adequate.

 

[Shamu341]

The wiring to the battery is fairly chunky.
The controller rating is the max permissible current, the 65w panel will be less. A 5a fuse will be adequate.
So nor harm then if I use a 7.5a?

 

[VicS]

I can't see how you could blow a 7.5A fuse on the 12V side of the controller with a 65W panel.

I'd expect to get about 4.5A - 5.5A at 12V - 14V to get your 65W.

But I know nothing about solar, so no doubt someone will be along shortly to tell me that I'm wrong because I haven't accounted for…

Any connection to the battery should be fused to protect the wiring from the high current the battery could deliver in the event of a short circuit, The installation instructions recommend 20 amps ( to protect 4mm² wiring)

The SR135TL is quite a good PWM solar controller, but I don't remember a fuse so if its a separate in line wasn't part of the original controller. Could be the wiring from the controller to the battery is too small. I would put a 10A fuse in line with new wiring and carry on.

I would go along with your suggestion of a 10 amp fuse for the installation in question

The wiring to the battery is fairly chunky.
The controller rating is the max permissible current, the 65w panel will be less. A 5a fuse will be adequate.
So nor harm then if I use a 7.5a?

I'd expect 7.5 amps to be OK

 

[thinwater]

In the UK you will probably never see more than 50-65% of the rated wattage, due to low sun angle and partially charged batteries. 65 W is theoretically impossible away from the tropics; even if you adjust to a 90 degree sun angle, there is still increase atmospheric absorption. This is why you UV index is typically a paltry 7-8 vs. 9-11 in Florida. So more like 3 amps max. on the best day, and 2-2.5 most of the time.

 

[Shamu341]

Excellent, I think I'll use a 7.5a
Many thanks for all your replies

 

[PabloPicasso]

Excellent, I think I'll use a 7.5a
Many thanks for all your replies

How'd you get on with rhat 7.5amp fuse, all good??

 

[Shamu341]

Yes thanks, all good so far