New House Batteries and New Issues

SherylandPat · 03-27-2016, 05:18 PM

I have a 1999 Winnebago Ultimate Freedom 40JD. It had been in the shop for an engine replacement and when we got it back we noticed the house batteries really needed to be replaced.

Today I put in 3 large deep cell batteries and while doing this I noticed the inverter wasn't completely hooked up and the ground cable - or at least I think it was a ground because it was attached to something on the wall inside of the battery cabinet.

I connected everything the same way I thought it came off and now I'm having issues.

My generator wont start, Refrigerator is saying it's not getting enough DC and the basement air conditioner wont turn on.

Fuses all look good but I'm wondering if there's additional places I need to check?

Any ideas or suggestions would be a huge help!!

Ranger Smith · 03-27-2016, 05:23 PM

My ultimate was connected to a thing in the side wall and it was a fuse. It was a 300A i believe.

nothermark · 03-27-2016, 05:26 PM

Get out a voltmeter and start checking. Nothing beats data. ;-)

garbonz · 03-27-2016, 05:28 PM

Sounds like a bad ground

SherylandPat · 03-27-2016, 05:36 PM

How do I know if that fuse is bad?

SherylandPat · 03-27-2016, 05:37 PM

The meter shows 110 coming from the inverter and shows the 3 batteries are putting out 110 volts. Should I check elsewhere?

FIRE UP · 03-27-2016, 05:58 PM

Quote:

Originally Posted by SherylandPat

The meter shows 110 coming from the inverter and shows the 3 batteries are putting out 110 volts. Should I check elsewhere?

"The 3 batteries are putting out 110 volts" huh????? Your batteries should be putting out 12 volts DC, not 110 AC. One of the first things you need to do is, follow ALL the ground cables from the house batteries to where they lead. In most cases, those ground/negative battery cables will lead right to the frame of the coach. You need to make sure that each and every connection, that has anything to do with all those negative cables, is clean and tight.

And, as far as a fuse is concerned in the main positive house battery cables, many times there is a 100, maybe 200 amp fuse, not far from the house batteries right in line with the main positive house battery cable, that leads to the Inverter. You need to make sure that, those connections are clean and tight too.

But, be ultra careful here. You're dealing with a ton of battery voltage. If you find that ultra large fuse, and you think it's loose or dirty or both, then disconnect the house batteries at the posts and, un plug the coach from shore power. That way you've eliminated voltage from either direction, leading to that fuse.

Let us know what you find.
Scott

grtharris · 03-27-2016, 06:51 PM

SherylandPat, Here is a link to the battery connection drawing for your coach. I colored up this view below to help a little. The fuse is a 300 amp fuse. The easiest way to check the fuse is to check for a voltage drop across the fuse. Good fuse 0 VDC bad(open) fuse 12VDC. Also check you meter 110 volts at the batteries???
If you need to change the fuse remove the ground wires from the coach batteries and remove shore power. Like FIRE UP said there is a ton of current in those batteries if you short someout there will be SMOKE!!
http://www.winnebagoind.com/diagram/1999/129902.pdf

FIRE UP · 03-27-2016, 08:09 PM

Quote:

Originally Posted by grtharris

SherylandPat, Here is a link to the battery connection drawing for your coach. I colored up this view below to help a little. The fuse is a 300 amp fuse. The easiest way to check the fuse is to check for a voltage drop across the fuse. Good fuse 0 VDC bad(open) fuse 12VDC. Also check you meter 110 volts at the batteries???
If you need to change the fuse remove the ground wires from the coach batteries and remove shore power. Like FIRE UP said there is a ton of current in those batteries if you short someout there will be SMOKE!!
http://www.winnebagoind.com/diagram/1999/129902.pdf

Hey Grant,
You have me confused about something here. I'm not the sharpest tool in the shed by far but, if I were to check that fuse, while the batteries are connected, I should get 12V at one end and, 12V at the other, correct? If the fuse is blown, and the coach is NOT plugged into shore power, I should get ZERO volts on the other side, correct?

And that pre-supposes that the Inverter/charger or, converter has has been disconnected due to un plugging of shore power, correct?

What I don't understand is the "voltage drop" good fuse "0" and bad fuse "12v" thing. I'm probably not seeing the big picture here.
Scott

twinboat · 03-27-2016, 08:16 PM

What I don't understand is the "voltage drop" good fuse "0" and bad fuse "12v" thing. I'm probably not seeing the big picture here.

___________________________________

It is just another way to check for an open fuse.

If you touch each side of the fuse holder with the probes, the meter will read volts if the fuse is bad, by completing the circuit.

nothermark · 03-27-2016, 08:29 PM

It sounds like you have a 12 VDC problem if the refrigerator is complaining. I'd put the negative probe on the chassis and start measuring each battery post to ground. It should be less than a volt to the chassis and somewhere above ~12.6 on the positive side then no noticeable drop as you move through the house disconnect relay. What you are looking for is changes. The actual voltage will depend on the state of charge of the battery and the charger.

grtharris · 03-27-2016, 09:18 PM

FIRE UP , sorry about that, a good fuse will have zero are very close to zero resistance so as current flows through the fuse you will not see a voltage reading (no voltage dropped across the fuse). If the fuse is open it will have infinite resistance and the meter will read the applied voltage to the circuit(all voltage dropped across the fuse). The advantage of checking a in circuit fuse this way is you do not have to worry about any back feed voltage. Other good way is to remove the fuse and measure the resistance. My concern was feed back from capacitors in the inverter.

FIRE UP · 04-03-2016, 01:54 PM

Quote:

Originally Posted by grtharris

FIRE UP , sorry about that, a good fuse will have zero are very close to zero resistance so as current flows through the fuse you will not see a voltage reading (no voltage dropped across the fuse). If the fuse is open it will have infinite resistance and the meter will read the applied voltage to the circuit(all voltage dropped across the fuse). The advantage of checking a in circuit fuse this way is you do not have to worry about any back feed voltage. Other good way is to remove the fuse and measure the resistance. My concern was feed back from capacitors in the inverter.

Grant,
I surely appreciate you getting back to me on this. I've done a bit of electrical work and, normally if I have what could be a potentially bad fuse, I simply check for 12VDC at either end. But, on that large one, between the battery and the inverter, like I stated earlier, I'd have to disconnect the battery to eliminate the voltage entering it from that end and, I'd have to make sure the inverter/charger was disconnected too, to stop any voltage coming into that fuse, from that direction. Then I'd just the ohm setting on the meter at that point. I think we're on the same page here. Thanks again.
Scott