Blowing Fuses on the Grid Charger

[Artric]

My wiring has been checked. Everything is set. It's not moving when this happens, so I don't see why wiring would be an issue if it blows after a number of hours.

I blew another fuse last night. I didn't even plug in until it was getting dark, so in this case, heat wasn't an issue. I also was plugging into a surge protector. FYI, I'm only charging after 7PM until 8AM nowadays, so heat shouldn't be an issue (especially with both fans running at full speed).

Jim, the difference between our supplies is that my fuse is also protecting an RS-25-12 that is powering the case supply fan at a full 12v and also a 120mm case fan with four LEDs on the charger itself.

Now that I think of it, I didn't blow any of the 1A slow-blow fuses before I added in the RS-25-12 (I was using a similar wall wart, but didn't like the mess). I like the idea of the 10A fast-blow, so I think I'll go with that.

That will be fine for the inrush current, yes?

[Artric]

Allright, I picked up some 10A fast-blow fuses. Let's see how this goes! Will install/charge tonight.

[Mike Dabrowski 2000]

Art,
What is the total AC current draw when the charger with all supplies is on. Your Killawatt should tell you.
The large inrush current is only during a few of the 60HZ cycles in duration, which a slow blow fuse will easily handle. Jims approach of depending on the circuit breaker for AC side protection is fine, and many surge supressor plug strips also have built in fuses, both of which depend on the AC wiring to the power supplies being capable of carrying the 15A(breaker) current long enough .

The fact that it is blowing after it is on would point to your fuse being too close to the actual current flow, or an intermittent shorting of one of the supplies. We cannot rule out the possibility of one of the supplies having something wrong with it.
If you put a separate fuse on each supply input, and the same one always blows, that would be some strong proof of a defective supply.

[JimIsbell]

Originally Posted by Artric

Jim, the difference between our supplies is that my fuse is also protecting an RS-25-12 that is powering the case supply fan at a full 12v and also a 120mm case fan with four LEDs on the charger itself.

Now that I think of it, I didn't blow any of the 1A slow-blow fuses before I added in the RS-25-12 (I was using a similar wall wart, but didn't like the mess). I like the idea of the 10A fast-blow, so I think I'll go with that.

That will be fine for the inrush current, yes?

Not knowing what the inrush current on your setup is, I cant answer your question. BUT...I have NO protection on my input side because the 15 amp breaker in the house is my "protection" It is designed to handle instantaneous "inrush" currents without tripping (it has to handle things like refrigerators which can have huge "inrush" currents), but will trip if the current remains above 15 amps for more than a few milliseconds. That is all the protection I need.

I doubt that your inrush is much different than mine. The "wall wart" is a transformer across the line so probably has a high inrush.

Worry about fusing the OUTPUT if you must, but dont get too uptight about the INPUT.

[Artric]

Mike - I'll have to check with the Kill-A-Watt today.

Jim - So then, if I were to build a grid charger for someone else, it wouldn't be irresponsible of me to not include a fuse on the AC (input) side?

Was there a fuse on the input side of the units that were previously being sold by a user on this site?

[JimIsbell]

Originally Posted by Artric

Jim - So then, if I were to build a grid charger for someone else, it wouldn't be irresponsible of me to not include a fuse on the AC (input) side?

In todays litigiousness society, I refuse to answer that question. I, personally, would not build ANYTHING for anyone anymore.

There is nothing you can do or not do that some lawyer will not find a way to go after you. One mans irresponsibility is another mans open mindedness.

I have a Blog, <thefreerepublic.myblogsite.com> where I comment on the news from a conservative viewpoint. In this country, the US, I am protected by free speech unless, I yell fire in a theater, threaten the President, or incite to riot. Beyond that I feel fairly safe. Not totaly, but fairly. In the world of producing a product, its another world. Lawyers will come after you if, through her ineptitude, a customer spills hot coffee in her lap.

You will note that when I answer questions on this site I usually say, "This is the way I did it, not necessarily the way you should do it."

[Artric]

Just an update, I did switch to the 10A fast blow fuse and have had no problems. I didn't measure the inrush current though. I keep meaning to and forgetting - sorry!