Need a pair of these for fusing battery

[WayneG]

I am reworking my house batteries to get less losses to the inverter and I am starting with fuses at the battery terminals to eliminate a 300A circuit breaker that I think has excessive internal losses.
I am also going to upgrade, simplify & shorten the wiring.

I found these nice fuse to battery post package on a UK website and a pair with fuses and covers is a bit over $50 (US) but shipping is $80!
Anyone see this or similar in the US?

[AWCHIEF]

I have seen those used on boats. Maybe someplace like West Marine might carry them.

[perryg114]

Can you get that fuse over here if you do blow one or it succumbs to corrosion?

Perry

[WayneG]

I looked over the marine site briefly and no luck, as for the fuse, it looks like a standard BUSS style fuse.

[WayneG]

This is the web site link in the UK
http://www.12voltplanet.co.uk/batter...ube-fuses.html

[Troutboy]

Is this the fuse going from battery to inverter?

If so I think the standard to use is a T-fuse, see link before.

Also, If your unit is original factory, it is likely the wiring is way to small, and you will get much better return and lower resistance by adding larger gage wire and a T-fuse...

Thanks

http://www.airforums.com/forums/f449...ml#post2012527

[alano]

Digikey has this stuff.

The terminal is found here, and the fuse is here.

In single unit quantities, the terminal is about $21 and the fuse about $8.

[perryg114]

After seeing the fuse close up, you don't want that right on the battery post. I would put it at the inside terminal end where it is protected from battery acid. Also it would take much less time to replace if it were in a terminal strip inside the trailer.

Perry

[WayneG]

Originally Posted by alano

Digikey has this stuff.

The terminal is found here, and the fuse is here.

In single unit quantities, the terminal is about $21 and the fuse about $8.

That one is vertical, the one I need is horizontal. I have very little clearance above the battery post in the slide out drawer, that is what makes this method attractive.
As for the installation, it is home brew wiring to a 1800 watt inverter,converter and solar gear inside the MH, the batteries are in a sliding drawer below the inverter.
This is my setup: http://theouterlimits.ws/projects/ai...lar/Page2.html The current battery/inverter section is about 1/2 way down the page.

As for putting the fuse right at the battery, acid/corrosion wont be the biggest concern, I will use a 300 amp fuse on each of 2 batteries, then the cables go 6" to the battery switch, so it is messy using any other method

[MelGoddard]

May I suggest that you 'Keep it Simple'?
Buy a single 300 Amp fuse, or a couple of in line 150 Amp fuses,("Lift truck fuses"), that bolt onto any terminal; and put it at the battery on the Neg. Terminal.
If you use 150 Amp, put one on top of the other, or at least in parallel.
This will give the whole house, protection from a 'dead short'. eg: a wrench dropped on the bare wire somewhere.

Perry's idea might be worth looking into also.

[66Overlander]

Originally Posted by perryg114

After seeing the fuse close up, you don't want that right on the battery post. I would put it at the inside terminal end where it is protected from battery acid. Also it would take much less time to replace if it were in a terminal strip inside the trailer.

Perry

First rule of circuit protection (i.e. fusing) is to put the fuse as close to the power source as possible to protect as much of the circuit (i.e. wire) as possible. For that criteria, on the battery terminal is perfect. Moving the fuse into the trailer would mean a chunk of wire was not protected against a short circuit. I wouldn't personally take that risk.

[greghoro]

Just brainstorming here.

How about combing a Top to Side post battery adapter with a
Blue Sea MRBF fuse holder set on its side?


Greg

[WayneG]

Originally Posted by greghoro

Just brainstorming here.

How about combing a Top to Side post battery adapter with a
Blue Sea MRBF fuse holder set on its side?

Greg

Thanks, but just like the Jameco part, there may be height clearance problems.
It is to late today, but tomorrow I will try and get photos to show the situation that I am dealing with on this battery drawer

[Ecodog]

Hi there Wayne,

Shorter wire runs and loss free connections are positive steps to improving your inverter performance, but are you measuring a significant voltage drop across the 300A breaker that would justify replacing it?

DG

[guskmg]

I can't tell you why, but my mine and others experience with protecting main battery cables, requires fuses within 18" of the batteries. It seems that in all the shorts that occurred the cables melted at that point. The only reason I can think of is the least resistance in the complete circuit during a short occurs at that point and creates the quickest heat in the cables.
guskmg

[Scoutx]

http://www.altecautomotive.co.uk/ind...?function=CART

With international shipping to US, 23.73 pounds or about $33.

If however you go here, you can get the terminal and some nice covers for them as well for 38.04 pounds or about $52. Makes the plastic covers about $10 each....but it's an option.

http://www.12voltplanet.co.uk/batter...ube-fuses.html


Cable to right

http://www.12voltplanet.co.uk/cover-...and-entry.html

Cable to left

http://www.12voltplanet.co.uk/cover-...and-entry.html

[WayneG]

On the voltage drop, my sine wave inverter shuts off at 10.5 volts. I had a Mr. Coffee running and after 5 min it would kick the inverter off, it was drawing between 80 to 90 amps and the volts were below 11.

I figure the wires should be good enough for 90 amps, but I will shorten and upgrade them to 1/0 to be sure. I think the main cause is the 300 amp circuit breaker, hence the switch over to fuses on each battery and eliminate the breaker.

Despite its rating, I do not fully trust the Blue Sea battery switch, but I will leave it in the circuit. I am also going to use a 1" x 1/4" copper bar on the battery minus lugs and will fasten the 500 amp current measurement shunt to the bar.

On the order shipping problem, I found out the shipping method I chose was going to use was some weird high speed international method. I redid that to airmail and now it is about 33 pounds for the pair and 13 pounds for shipping, totaling about $65 via PayPal. The order is on its way.

As to using some connector that goes vertical, the attached photo shows why I cant do that.
I am using Exide 27MDP batteries and the top of the post is just 1/2 inch from the lip of the opening of my battery drawer, so I do not have enough room to go vertical off the post

[WayneG]

Originally Posted by Scoutx

http://www.altecautomotive.co.uk/ind...?function=CART

With international shipping to US, 23.73 pounds or about $33.

They definitely have better pricing, but I already ordered mine from the other site this morning. A pair with fuses and covers and shipping it is about $65, a little high, but cheaper in labor/parts than trying to MacGuiver it on my own
I wish someone would pickup the product line here in the US, the low profile connection should work great for anyone with minimal clearance above the batteries.

[uncle_bob]

Originally Posted by WayneG

That one is vertical, the one I need is horizontal. I have very little clearance above the battery post in the slide out drawer, that is what makes this method attractive.
As for the installation, it is home brew wiring to a 1800 watt inverter,converter and solar gear inside the MH, the batteries are in a sliding drawer below the inverter.
This is my setup: http://theouterlimits.ws/projects/ai...lar/Page2.html The current battery/inverter section is about 1/2 way down the page.

As for putting the fuse right at the battery, acid/corrosion wont be the biggest concern, I will use a 300 amp fuse on each of 2 batteries, then the cables go 6" to the battery switch, so it is messy using any other method

Hi

Since we're talking about 2 batteries, I assume the engine battery is not part of this.

2 x 300A = 600A. Your batteries are *way* to small for that sort of load. The biggest load you show is the 1800W inverter. At 80% efficiency and 12V, that's going to pull 190A. It should get it's own dedicated cable, fuse it at 200 or 250A and move on. The rest of the "stuff" gets a fuse that makes sense relative to the load or charging current.

A few other notes:

If you are going to run batteries in parallel or in series, they should be "same same". You want the same brand, model, and batch. That gives you the best odds of keeping them equalized. Otherwise one will "hog" the charging process and one or both will eventually be damaged.

Your cross connect solenoid *could* move a lot of current. It is very unlikely the two battery banks are at equal voltages. If one is dead and the other fully charged, currents could be very high. Fusing this link is problematic. Sizing the solenoid is also problematic.

One solution for unlikely over currents is a fuse link. It's a bit of a pain to replace (= get out a wrench), but quite rugged. You see them in automotive and truck applications.

Bob

[WayneG]

Both of my batteries are identical, and about 6 months between being new.
True, I do not expect to ever draw 600 amps, but I do need to be able to jump to the chassis battery via the solenoid, in case it drains too low to turn the engine. The solenoid is automatic with the starter engaged and I added a switch to activate the solenoid to allow all batteries to be charged/discharged at the same time.

If I had my 300 amp fuse after the battery switch, that may work, but that also leave the wiring between there and the batteries unprotected.

With my planned setup of 300 amp fuses per battery, it should prevent any shorts from frying wiring, but at the same time it could allow a 600 amp gremlin path further up stream, so I guess I need to be sure each lighter gauge upstream circuit is properly protected.