Journey with Confidence RV GPS App RV Trip Planner RV LIFE Campground Reviews RV Maintenance Take a Speed Test Free 7 Day Trial ×
 

Go Back   Keystone RV Forums > Keystone Tech Forums > Technical Corner
Click Here to Login

Reply
 
Thread Tools Display Modes
 
Old 06-05-2015, 08:31 AM   #1
Yosemitebob
Senior Member
 
Yosemitebob's Avatar
 
Join Date: Sep 2013
Location: Upland, CA
Posts: 425
Battery Fuse Size

OK, I have not found this info. What would be the size of the fuse if I was to install one in the main battery cable. I have two 6v batteries in series for 12v at 232 AH rating.
__________________
2015 Four Winds Super C, Class C Motorhome
4 - 100w mono solar panels with MPPT40 to charge four 6v batteries with 440amp hours.
Progressive Industries HW50c surge protector
1800 / 3600 inverter with auto transfer switch,
The bosses: My wife and two Labradoddles 80 lbs each
Yosemitebob is offline   Reply With Quote
Old 06-05-2015, 11:05 AM   #2
cb1000rider
Gone Traveling
 
Join Date: May 2015
Location: Texas
Posts: 101
Quote:
Originally Posted by Yosemitebob View Post
OK, I have not found this info. What would be the size of the fuse if I was to install one in the main battery cable. I have two 6v batteries in series for 12v at 232 AH rating.
You haven't found it because there isn't one in the main cable. I assume you're talking about adding one. I'd think that the max amps you'd be pulling would be starting the genset and running the inverter at the same time (for just a second) assuming you have an inverter. If it were me, I'd be looking into typical stereo equipment wiring - as they handle typical battery gauge wires and also have large fuses. Pulling a number out, I'd say 100 amps.
cb1000rider is offline   Reply With Quote
Old 06-05-2015, 11:14 AM   #3
chuckster57
Site Team
 
chuckster57's Avatar
 
Join Date: Jul 2014
Location: Modesto
Posts: 20,455
I wouldn't use a fuse, an automatic circuit breaker would be my choice. 100 amps seems high to me, factory uses 30A.
__________________

2012 Copper Canyon 273FWRET being towed by a 1994 Ford F350 CC,LB,Dually diesel.
Airlift 5000 bags, Prodigy brake control, 5 gauges on the pillar.Used to tow a '97 Jayco 323RKS.

Now an RVIA registered tech. Retired from Law enforcement in 2008 after 25+ yrs.
chuckster57 is offline   Reply With Quote
Old 06-05-2015, 12:06 PM   #4
Yosemitebob
Senior Member
 
Yosemitebob's Avatar
 
Join Date: Sep 2013
Location: Upland, CA
Posts: 425
Thanks guys wide space there 30 to 100. Ok, so here is my theory. All my electronics is up front with the battery. Solar which is only a 30a and it is fused, the remote electronics, which is fused, batteries (not), and a 600w linear which is fused, I want to use a fuse as for the simple reason it will melt (ANL type of fuse) if there was a fire up front disconnecting the battery by doing so. Leaving everything disconnected, perhaps I'm really over thinking this. I was not going to use the fuse as a link for electric as so much I was going to use it as a fuseable fire link, but didn't want it to break before that point.
You think I being over cautious.

Chuck, that is why I can't use a breaker type.
__________________
2015 Four Winds Super C, Class C Motorhome
4 - 100w mono solar panels with MPPT40 to charge four 6v batteries with 440amp hours.
Progressive Industries HW50c surge protector
1800 / 3600 inverter with auto transfer switch,
The bosses: My wife and two Labradoddles 80 lbs each
Yosemitebob is offline   Reply With Quote
Old 06-05-2015, 12:45 PM   #5
cb1000rider
Gone Traveling
 
Join Date: May 2015
Location: Texas
Posts: 101
Quote:
Originally Posted by chuckster57 View Post
I wouldn't use a fuse, an automatic circuit breaker would be my choice. 100 amps seems high to me, factory uses 30A.

You Sure? If he's got a 600 Watt inverter that's 600 watts / 12 volts = 50 amps. If he had a generator, I'd expect that thing to pull at least 30A when turning the starter. I haven't measured slide motors, but I'd expect them to be in the 10-15 amp range running...

All of this adds up, it's all got to flow through that "main" fuse... That being said, it really depends on the electronics in his trailer.

If it's low draw, you could put a simple analog amp meter on it and see what it draws peak.

Fuses should be configured so that they're not lower than 120% of the peak *expected* draw. Just remember that it's sum of everything "in use" at once.
cb1000rider is offline   Reply With Quote
Old 06-05-2015, 03:53 PM   #6
Yosemitebob
Senior Member
 
Yosemitebob's Avatar
 
Join Date: Sep 2013
Location: Upland, CA
Posts: 425
OK, so given the assorted electronics I have, that do run off the battery i.e., 600 walt linear, shortwave transmitter, a 1,000 w inverter arriving soon, generator, although it has it's own battery start, three slide motors, three vent motors, three separate landing motors, one in front and two in rear, MPPT20 solar charger, given all of them I could be at or over 100, but also given that I would never be able to start them all at one time anyway, I am going with a 60 or 80 amp fuse, which is the ANL type that can melt away if for some unfortunate reason I had a build up of heat in the front compartment.
__________________
2015 Four Winds Super C, Class C Motorhome
4 - 100w mono solar panels with MPPT40 to charge four 6v batteries with 440amp hours.
Progressive Industries HW50c surge protector
1800 / 3600 inverter with auto transfer switch,
The bosses: My wife and two Labradoddles 80 lbs each
Yosemitebob is offline   Reply With Quote
Old 06-05-2015, 04:58 PM   #7
JRTJH
Site Team
 
JRTJH's Avatar
 
Join Date: Mar 2011
Location: Gaylord
Posts: 27,154
Bib,

Maybe this isn't the "current technology" thinking, but a in line fuse on a main power line isn't necessarily intended to protect any specific component, rather it is intended to protect the distribution wire (cable) so it doesn't become overloaded and "melt down" creating a fire hazard. Think of it as the "main circuit breaker" in a house wiring system. Usually they are 200 amps or 225 amps, and then "after that breaker" the wiring divides and each circuit is further protected by additional breakers or fuses.

I'd think that if you're considering a fuse "at the battery cable" you'd want to determine the gage of that specific cable, protect the wire and then let the individual circuit fuses protect components further "downstream".

According to what I learned years ago, this is the "amperage capacity" for each DC wiring size based on a 15' run of wire:

4 ga 70 Amps
6 ga 50 Amps
8 ga 30 Amps

Keep in mind that these are "maximum recommended amperage" so you'd want to "step down" one fuse rating to protect the wire.

As an example. If the positive cable from the battery is 4 ga, consider a 60 amp fuse, if it's 6 ga, consider a 40 amp fuse and if it's 8 ga, consider a 25 amp fuse. That way the fuse will "blow" before the wire gets hot enough to cause any damage to the insulation. Also remember that this is for a 15' wiring run. A shorter run will handle greater amperage a longer run would handle less.

You aren't attempting to protect the "downstream components, any component supplied by that positive cable (on a branch line) should have its own "in line" fuse protection. Your "goal" in fusing the main cable is to protect that cable, so fuse appropriately based on the amperage that cable can carry for the total length of that cable run.

I hope this makes some sense rather than confusing the issue even further.
__________________
John



2015 F250 6.7l 4x4
2014 Cougar X Lite 27RKS
JRTJH is online now   Reply With Quote
Old 06-05-2015, 05:05 PM   #8
Yosemitebob
Senior Member
 
Yosemitebob's Avatar
 
Join Date: Sep 2013
Location: Upland, CA
Posts: 425
That makes perfect sense to me at least, as that is what I've been basing it on. My cable is 4/0, the fuse is 18" from the battery 6 additional feet to the breaker box. Downstream, each individual item has it's rated inline fuse. So, with all the info so far, I believe I'm headed in the correct direction.
Thanks all
__________________
2015 Four Winds Super C, Class C Motorhome
4 - 100w mono solar panels with MPPT40 to charge four 6v batteries with 440amp hours.
Progressive Industries HW50c surge protector
1800 / 3600 inverter with auto transfer switch,
The bosses: My wife and two Labradoddles 80 lbs each
Yosemitebob is offline   Reply With Quote
Old 06-05-2015, 05:11 PM   #9
JRTJH
Site Team
 
JRTJH's Avatar
 
Join Date: Mar 2011
Location: Gaylord
Posts: 27,154
4/0 multistrand cable (battery cable) 7 ft long will carry an easy 100 Amps at 12 volts, so if you're considering a 80 amp fuse to protect it, I think you'll be "golden" and the fuse is sure to "open" protecting the cable long before it gets hot enough to cause any physical damage to the insulation and expose your rig to any hazard. I think you're on the right track. Pictures when you're done ?????

Good Luck,
__________________
John



2015 F250 6.7l 4x4
2014 Cougar X Lite 27RKS
JRTJH is online now   Reply With Quote
Old 06-05-2015, 06:40 PM   #10
Yosemitebob
Senior Member
 
Yosemitebob's Avatar
 
Join Date: Sep 2013
Location: Upland, CA
Posts: 425
I'm told the fuse (80A) is in the mail, could not find it locally anywhere here.
__________________
2015 Four Winds Super C, Class C Motorhome
4 - 100w mono solar panels with MPPT40 to charge four 6v batteries with 440amp hours.
Progressive Industries HW50c surge protector
1800 / 3600 inverter with auto transfer switch,
The bosses: My wife and two Labradoddles 80 lbs each
Yosemitebob is offline   Reply With Quote
Old 06-05-2015, 09:42 PM   #11
bobbecky
Senior Member
 
bobbecky's Avatar
 
Join Date: Jul 2013
Location: Box Elder
Posts: 2,916
John brought up the main breaker in a house panel, and I think most people, including most electricians don't understand the purpose of fuses and breakers. First, the main breaker in a house panel is not intended to protect the house wiring, but is really there to protect the utility upstream from a failure in the main panel. The various breakers in a panel are intended to protect the panel from a circuit failure. So, in our RV's, a fuse or breaker in the 12 volt cable from the battery would be there to protect the battery from a failure in the cabling from the battery to the panel with the individual fuses. The small fuses in the panel are there to protect the panel from a failure in the 12 volt circuits. So, in sizing a fuse or breaker at a battery, the weak link is probably the cable, and then the battery. Most batteries can provide enough current to melt even a 4/0 copper cable pretty quick, before the battery were to fail. I would say, size the fuse as large as necessary to handle the maximum current that a 4/0 cable can carry without melting, and you will be good.
__________________
Bob & Becky
2012 3402 Montana
2012 Chevy 2500HD D/A CC
bobbecky is offline   Reply With Quote
Old 06-05-2015, 09:55 PM   #12
Yosemitebob
Senior Member
 
Yosemitebob's Avatar
 
Join Date: Sep 2013
Location: Upland, CA
Posts: 425
Some have questioned why I need a fuse where I'm putting it at all, and so far I've had some pretty darn good reasons why I should have one. Thank you for your input. I have a lot of electrical equipment and I if I can add one more link of safety then I will. When I'm done I will as John requested take a picture. Perhaps a picture will tell the story better than I. I'm now waiting for the fuse to get to me so I can finish.
__________________
2015 Four Winds Super C, Class C Motorhome
4 - 100w mono solar panels with MPPT40 to charge four 6v batteries with 440amp hours.
Progressive Industries HW50c surge protector
1800 / 3600 inverter with auto transfer switch,
The bosses: My wife and two Labradoddles 80 lbs each
Yosemitebob is offline   Reply With Quote
Old 06-12-2015, 12:24 PM   #13
Yosemitebob
Senior Member
 
Yosemitebob's Avatar
 
Join Date: Sep 2013
Location: Upland, CA
Posts: 425
My fuse came so I can wind this up now. In the picture you will see the MPPT20 near the top, just above that is a thermo switch, it closes the circuit to a fan at the bottom of the picture at 115 degrees and opens the circuit at 95 degrees. Attached to the top of this bay above the MPPT is the 600s linear and another thermo switch just next to that. Either switch will close the circuit if it gets too warm and cool the equipment down. About in the middle of the picture are two fuses, the vertical fuse 20a is for the solar controller, and the horizontal 80a is the main fuse inline with the battery. There is also an LED pilot light, which you can only see the wire loom which is in the upper right of the picture. This is hooked up to the small terminal that is connected to then load side of the solar controller. This gives me an LID red light mounted in the hatch cover and the controller turns this on turning dark time, it acts as a bulgar alarm, it's not really, but I used that circuit for that purpose to hopefully make someone that is thinking of stealing a little more apprehensive to do so. Same idea as some vehicles have on the dash where the LED flashes to give the attention to an alarm.

I can now leave my trailer battery cut-off switches on instead of turning them off. This will also give the battery and the controller a bit of exercise while in storage. I really like the new solar charger.
Attached Thumbnails
Click image for larger version

Name:	Solar Install-0813.jpg
Views:	305
Size:	97.4 KB
ID:	8796   Click image for larger version

Name:	Solar Install-0814.jpg
Views:	305
Size:	95.8 KB
ID:	8797   Click image for larger version

Name:	Solar Install-0817.jpg
Views:	239
Size:	93.2 KB
ID:	8798  
__________________
2015 Four Winds Super C, Class C Motorhome
4 - 100w mono solar panels with MPPT40 to charge four 6v batteries with 440amp hours.
Progressive Industries HW50c surge protector
1800 / 3600 inverter with auto transfer switch,
The bosses: My wife and two Labradoddles 80 lbs each
Yosemitebob is offline   Reply With Quote
Old 06-12-2015, 02:07 PM   #14
jsmith948
Senior Member
 
Join Date: Jan 2012
Location: Central San Joaguin Valley, CA
Posts: 2,117
Nice, clean, professional looking install. Really like your attention to detail.
__________________

Jack & Marty
2018 Laredo 298 SRL
2011 F-250 SB Crew Cab 4x4 6.7L
jsmith948 is offline   Reply With Quote
Old 06-12-2015, 06:13 PM   #15
Yosemitebob
Senior Member
 
Yosemitebob's Avatar
 
Join Date: Sep 2013
Location: Upland, CA
Posts: 425
Thank you Jack.
__________________
2015 Four Winds Super C, Class C Motorhome
4 - 100w mono solar panels with MPPT40 to charge four 6v batteries with 440amp hours.
Progressive Industries HW50c surge protector
1800 / 3600 inverter with auto transfer switch,
The bosses: My wife and two Labradoddles 80 lbs each
Yosemitebob is offline   Reply With Quote
Old 06-13-2015, 05:26 AM   #16
Cfoxtrot
Member
 
Join Date: Feb 2015
Location: Michigan
Posts: 55
Indeed a great install, you seem to have all the bases covered. Nice work Bob!

Chris
__________________

2013 Bullet 281BHS
2016 F150 SCREW 5.0
Cfoxtrot is offline   Reply With Quote
Old 06-13-2015, 07:51 AM   #17
Yosemitebob
Senior Member
 
Yosemitebob's Avatar
 
Join Date: Sep 2013
Location: Upland, CA
Posts: 425
Thanks Chris
__________________
2015 Four Winds Super C, Class C Motorhome
4 - 100w mono solar panels with MPPT40 to charge four 6v batteries with 440amp hours.
Progressive Industries HW50c surge protector
1800 / 3600 inverter with auto transfer switch,
The bosses: My wife and two Labradoddles 80 lbs each
Yosemitebob is offline   Reply With Quote
Old 06-20-2015, 09:24 PM   #18
Yosemitebob
Senior Member
 
Yosemitebob's Avatar
 
Join Date: Sep 2013
Location: Upland, CA
Posts: 425
Here is the final picture of the remote installed inside. Sorry I'm so late, I just forgot to post it.
Attached Thumbnails
Click image for larger version

Name:	Solar install-3645.jpg
Views:	173
Size:	91.2 KB
ID:	8869  
__________________
2015 Four Winds Super C, Class C Motorhome
4 - 100w mono solar panels with MPPT40 to charge four 6v batteries with 440amp hours.
Progressive Industries HW50c surge protector
1800 / 3600 inverter with auto transfer switch,
The bosses: My wife and two Labradoddles 80 lbs each
Yosemitebob is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump

» Featured Campgrounds

Reviews provided by

Powered by vBadvanced CMPS v3.2.3
Disclaimer:

This website is not affiliated with or endorsed by the Keystone RV Company or any of its affiliates in any way. Keystone RVģ is a registered trademark of the Keystone RV Company.


All times are GMT -8. The time now is 04:09 PM.


Powered by vBulletin® Version 3.8.9
Copyright ©2000 - 2024, vBulletin Solutions, Inc.