I have a Xantrex XW-MPPT60-150 solar charge controller. The moment came where I need to replace the fuse that protects the charger. The problem is that I need to replace it with Littlefuse KLKD 1 (600V DC, 1A Fast-acting) or equivalent.

The closest I found is a BOSS ceramic fuse 500V, 2A... and I don't know if I can be sure that this fuse will protect the charge controller in case of over current.

Here's a picture of both fuses, the old one on the left and the wanna-be new one on the right:

Picture of both fuses

Can anyone help with this? It's a bit urgent because I'm off grid and I don't want to harm my system, nor face a short-out.

1 Answer 1


I'm pretty sure you don't want to substitute that fuse.

First off, the original fuse was rated for 1 A, while the new one is rated for 2 A. You'll have twice the current allowed in your system before the fuse goes. Second, the power (wattage) permitted to pass through the second fuse is 67% greater than the original fuse would allow.

Grainger has an equivalent fuse for about $12, if you've got a store around where you live or if you can wait for it to ship. Just make sure the physical dimensions match as well.

  • but this is the problem, i't will take a new fuse more then a week to get to me. so in the mean while i'm electricity-less, and it's a pain. i details above i already new, but the question is if somehow the fuse grade is enough, cause the overprotected the circuit. Commented Mar 22, 2011 at 3:30
  • 1
    @Asaf: True, there's usually some degree of safety factor, but I'd doubt it's 2x. Unless you really want to risk destroying your system, don't substitute that fuse. Have you looked at the specs for the solar charger controller? You may be able to find an actual max current rating somewhere in the documentation.
    – Doresoom
    Commented Mar 22, 2011 at 13:39
  • it doesn't say there... but you right, i probably shouldn't. Commented Mar 22, 2011 at 14:08

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