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I BEgan · 08-24-2008, 11:21 AM

While on a road trip to the Oregon Coast last week, my univolt abused battery finally gave up the ghost. I had been limping along with it's poor performance and relying on either my generator or shore power and primarily used the battery only while operating the jack. When even this was too much, I figured it was time and picked up a new Exide Nautillus Gold (675 mca, 182 min reserve, 550 cca, 182 rc, 105 amp/hr). To hear my water pump hum along without shore power was very foreign to me.
The next morning, my wife was getting ready while I got our gear together and unhooked our campground connections. Seconds after running off of the battery, the water pump kicked on and blew the main 40 amp fuse. I think she had a few lights on besides the pump. I changed the fuse, tested it and off we went.
Similar situation the following morning only this time when the power kicked off, the fuse was OK and I cannot figure out why. Everything functions normally while connected to shore power. The battery is fully charged and producing around 13 V. I am getting the same voltage at the fuse box. All fuses have been tested as good. When I attempt to turn on the compact florescent ceiling lights they blink as if they are getting a spike of juice.
I am running an 60 amp Intellipower with Charge wizard.
Any info is greatly appreciated. I have a multi-meter but only know enough to be perplexed.
Thanks,
Brandon

Excella CM · 08-24-2008, 02:44 PM

I'd vote for a loose connection somewhere around the battery cables.

mustang · 08-24-2008, 04:41 PM

I wonder if your pressure regulator on the water pump is set to high, and when your hooked to shore power you have the extra oomph to hit what your regulator is set at but on the battery power you never acheive this so the pump is on pushing hard (seeing spikes in the lighting) as it cycles until the fuse pops because it over heats. low amperes high volts will cause that scinerio, My weak battery (9 years old or so) causes the lights to flicker when pump is at the high end of pressure setting. Just my thought. good luck I am intrested in the cause. Is the battery to small? do a load test also. I am not sold on exide or interstate. they used to be a good battery, but I have seen recent issues. I chose NAPA or New Castle and heard good things about A/C voyager.

I BEgan · 08-24-2008, 06:50 PM

I checked the cable connections right away, so I can rule that out.
I am wondering about where the negative cable from the battery gets grounded. I'm thinking a bad ground could be the culprit.

I am interested in the water pressure theory. I did mess around with the pressure regulator a couple of days ago to compensate for extreme pressure at a campsite. At the time, I thought this would only affect the water coming from the fresh water inlet (hose). Is there a regulator off of the water pump or is the pressure regulator where the water comes into the trailer one and the same? BTW, I am still running the original water pump.

Excella CM · 08-24-2008, 07:00 PM

You need to check the high pressure limit switch on the pump itself. The pressure regulator for city water is not electrical.

I BEgan · 08-24-2008, 08:01 PM

Will do. This still doesn't get me up and running though. Again, even though all of my fuses checked out through resistance tests, nothing works while being powered only through the battery.
Any ideas?

Lumatic · 08-24-2008, 08:55 PM

If you find a source for 40 amp AGC fuses (the size for car fuse boxes, about 1 1/4"x 1/4" ) at a regular price let us know. I have tried auto parts and audio with no luck. The highest I can find is a 35. I am now using a auto reset breaker.

I BEgan · 08-24-2008, 09:15 PM

Quote:

Originally Posted by Lumatic

If you find a source for 40 amp AGC fuses (the size for car fuse boxes, about 1 1/4"x 1/4" ) at a regular price let us know. I have tried auto parts and audio with no luck. The highest I can find is a 35. I am now using a auto reset breaker.

I picked up half a dozen yesterday at my local RV store. Worst case scenario, you could buy them there www.statetrailer.com I am certain I have found them at Autozone before as well, though.

olddog299 · 08-24-2008, 09:54 PM

Quote:

Originally Posted by Lumatic

If you find a source for 40 amp AGC fuses (the size for car fuse boxes, about 1 1/4"x 1/4" ) at a regular price let us know. I have tried auto parts and audio with no luck. The highest I can find is a 35. I am now using a auto reset breaker.

I found them here pretty cheap:

http://www.terminalresolutions.com/s...GC-Fuse/Detail

I BEgan · 08-25-2008, 06:08 PM

Thanks in advance!

mustang · 08-25-2008, 06:12 PM

I didnt catch your battery age, but a weak battery could cause the pump not to be able to acheive regulator pressure. Regulator on the pump, not city water into trailer You have a high limit and a lowturn on.

mustang · 08-25-2008, 06:15 PM

I see battery is new adj regulator on pump ( high limit) turn it down a touch

Ramp · 08-25-2008, 06:35 PM

The onboard pump bypasses the regulator only city water is regulated. If you blew a 40 amp fuse it is most likely a short to ground. I would start by taking the fuse out that feeds the compact ceiling lights. If you take one fuse at a time out untill the problem gose away you can narrow it down.

I BEgan · 08-27-2008, 09:05 PM

Quote:

Originally Posted by Ramp

The onboard pump bypasses the regulator only city water is regulated. If you blew a 40 amp fuse it is most likely a short to ground. I would start by taking the fuse out that feeds the compact ceiling lights. If you take one fuse at a time out untill the problem gose away you can narrow it down.

I think you are correct about the short to ground. Again, I am reading 12.9V after the fuses, so it must be the ground, right? How do I trace this? Again, I have zero function of anything unless I am on shore power. I have figured out that the "spiking" of the compact ceiling lights was probably residual power from the inverter as it doesn't work after a while.

I BEgan · 09-06-2008, 10:31 PM

Just to wrap up this thread, it turned out that I had mistakenly replaced the ground fuse with a 40 amp replacement used for the battery & tow vehicle instead of the 50 amp needed.

Thanks for everyone's input!
B

Inland RV Center, In · 09-07-2008, 06:49 AM

Quote:

Originally Posted by Lumatic

If you find a source for 40 amp AGC fuses (the size for car fuse boxes, about 1 1/4"x 1/4" ) at a regular price let us know. I have tried auto parts and audio with no luck. The highest I can find is a 35. I am now using a auto reset breaker.

We have the larger size univolt fuses rated at 40 and 50 amp. We also have the MDM 40 fuses as well.

Andy

69AmbassFl · 09-07-2008, 09:33 AM

I had the same problem with my 69 as everything would work while plugged in to shore power but with the battery nothing would work. I found the ground side from the battery had a blown 40 amp fuse. Changed the fuse and all worked again. On my 69 both the pos and the neg side has 40 amp fuses in the fuse panel. I have since taken out the original type fuse panel and went to an audio install shop and bought maxi fuse type holders so the fuses are more easy tio come by.