Surefire CN400 DC blowing fuses

[candlepowernoob]

Greetings all,
Long time lurker, first time poster. I have a Surefire L7 with the CN400 charger. Recently, the CN400 has been blowing fuses in the DC mode, and I cannot figure out why. Replacement fuses have been 2 amp buss, 250v. The DC charger stays plugged in to the cigarette lighter receptacle 24/7, and there is always a battery in the charger. The power cord has no kinks, frays, or other defects that I can see. After I replace the fuse, I put a battery in the charger, the red charging light comes on for about 30 seconds or so, then the fuse blows again. The charger and batteries are about one year old. When I plug the charger in to an AC source, everything works fine. I called SF customer service, however, they were no help. I am hoping there is a simple fix. Please help!

 

[SilverFox]

Hello Candlepowernoob,

Welcome to CPF.

There isn't much to go wrong with that charger, and if it works OK on AC that would suggest something is wrong with the DC cord or your fuses.

Another possibility is that the battery pack is shorting out.

A higher current fuse may allow things to heat up to the point where you can determine where the problem is. If a 5 amp fuse blows the same way, there is something shorting out.

Tom

 

[candlepowernoob]

Thanks for the quick response. Are you suggesting that there could be a problem with one of the batteries?

 

[SilverFox]

Hello Candlepowernoob,

Since the charger is working on AC, I think we can rule that out.

Tom

 

[Mr Happy]

A silly and obvious question, but is a 2 A fuse rated high enough? What are the input power requirements specified for the battery cradle?

(The fuse in a 12 V DC car plug is typically rated 10 A or greater. Electronic devices will draw less than that, but the fuse is mainly there to prevent fires in the event of a short circuit.)

 

[Illum]

+1 I was wondering about that as well, most automotive auxiliary sockets are 10A fused..:thinking:

 

[SilverFox]

Hello Mr Happy,

I believe the charger charges at 1.2 - 1.5 amps. A 2 amp fuse may be cutting it too close.

Tom

 

[candlepowernoob]

A 2 amp fuse is what was in line when it was new. I called SF customer service to verify, and they told me 2 amp as well.