one fuse two depthfinders

[sacnho]

Installing a dedicated 18 amp hr battery for 2 depthfinders.  Would it be OK to use one fuse for both positive leads?

Thanks

[Way2slow]

NO!!

If each calls for a three amp fuse, having two connected to a three amp will greatly increase the chance of constantly blowing the fuse.

If you go to a larger fuse to keep this from happening then you loose protection of both units because then if one unit goes bad, instead of having 3 amp fuse protection, you have what ever the larger fuse size you used. Greatly increasing the possibility of causing additional damage or even a fire inside the unit.

I know you can argue that if they draw 1.5 amps and are factory fused with a 3 amp, if you go to a 4.5 amp you still have 3 amp protection because the other unit is drawing 1.5 amps.  What if the other unit happens to not be  on.

[Ann-Marie]

Yes you can put in a larger fuse to run both.

Fuses do NOT protect the instrument from failure if it draws too much current. If it draws too much current it has ALREADY failed. Fuses protect the wiring and/or the failed instrument from melting insulation and catching fire.

The downside is that if the fuse blows you lose both.

[Fishing Rhino]

Is either or both of these units under warranty?

You better check with the manufacturer if running the two units with a five amp fuse voids the warranty.

[Way2slow]

Sorry, but for somebody that's "Supose" to know their electronics, that's about the dumbest statement I've ever heard.

No one said it was to protect the units from failure, I said they protect from additional damage upon failure.  After almost 30 years of electronics I've seen more than enough equipment destroyed beyound repair by over fusing.  It's a lot less expensive to replace a shorted diod that blew the proper size fuse than one that was over fused and melted runs, burnt holes in the circuit board, took out a lot of other components to the point the whole circuit board is total junk.

However, as I've always said, no one is going to tell me how to operate my equipment and I'm not going to try and tell someone else how to operate theirs.  If he wants to a 100 amp fuse in them, go for it, but no way in (open for interputation) would I do it with mine.

[Long Mike]

Adding an additional 3 Amp fuse for the additional head unit is such a simple matter that the subject is not really worth discussing.  Do it.

[Fishing Rhino]

Simple solution. Put a three amp fusible link in each line. It's what I had to do, since I had used up all the buss bar fused connections.

I posted about it before, but could not find the photo of it on the web. I don't like the glass tube fuses, but I found a nice mini spade fusible link that has a water tight cap which makes the fuse compartment watertight.

It only cost a few bucks, and it can be wired directly to a buss bar screw without causing a problem.

I got mine at an Ace hardware store, in the fuse section. They had two types of fusible links with the the mini spade type fuse. One had an open plug, and the other can be capped.

Wired beneath a console, out of the weather, the open type might be fine, since all the other fuses are exposed. I like the extra bit of security the capped version provides.

I found it.

[fishfordollars]

Such an easy solution. I always run a dedicated line and fuse for each unit.

[choupique]

Why would you not spend a couple of extra bucks on a fuse for each unit to protect them and all the money you have invested in them.  Seems like cheep insurance to me.

[Wayne P.]

Excellent advice Rino. The fuze holder and fuse is available at Radio Shack. In the marine environmnet the capped style (as pictured) is the best.

The holders for the round glass fuses have a tendency to break from temp changes, ozone, and the spring inside will get weak and cause low voltage problems with the unit. Mosture gets inside of them too just adding to the problems that can occur.

[Long Mike]

Tom, those fuses are the ones I use on all my equipment.

[sacnho]

I should have given a few more details originally.

I was not going to put anything larger than the called for 3 amp fuse. The 2 units I have are a Eagle 642 and a Eagle 320. According to a Eagle customer service rep the 642 uses 900 milli amps at most and the 320 uses 750 milli amps at most. I know that it is a simple matter and it is cheap insurance to put a fuse to each unit and that is probably what I am going to end up doing. Just curious as to if it is ever done with one fuse as long as both units are not over or under fused.

Fishing Rhino thanks for the heads up on the mini spade links. I did not know about those.