No 12 Volt From Battery

[72NewbsOver]

So I've searched every where on the forums to no avail so I figured I'd finally post.

We have a '72 Overlander 27. We took her on our maiden voyage and when we arrived we no longer had 12 volt power from the Battery. We have it when plugged into the tow vehicle, but that is it. I replaced the battery after realizing the previous became overcharged hooked up to the converter (or inverter I get confused what it's called). It has the original univolt fuse box and I replaced all the glass fuses and still no solution.

My only idea is that the battery somehow became ungrounded. If this is the issue, how do I fix it? If not, what else could it be?

[TheHandyDan]

A multimeter will tell you if your battery has 12V or not. If you have zero volts at the battery (between the + and - terminals) then you have a bad battery.

If you have 12V at the battery but nothing works, then I suspect your grounding wire to the frame has come loose. Your battery's green grounding wire probably goes to the frame somewhere and all your negative lines connect to the frame eventually too. That could be anywhere though but look around the bolts in your A-frame area (like your safety chains), that's where mine went.

[72NewbsOver]

I was hoping it would be grounded to the a frame, but the battery is all the way in the rear.

[HowieE]

It does not matter where the battery is you start there. Charge the battery overnight with a battery charge, not the univolt. Once check the voltage across the battery posts. If the battery has voltage then check from the positive terminal to the trailer body or frame. If you see voltage there you have checked the ground side. Now go to the fuse panel and check from the positive wire feeding the panel to the trailer body. Where ever you lose the indication of voltage defines the problem.

If these test check OK plug the trailer and check the output of the univolt. The voltage should be higher than the voltages you read from the battery alone.

In any case I would replace the univolt with a more up to date charger that does not have the likelihood of cooking your battery.

[72NewbsOver]

The charger has been replaced with a powermax charger to charge the battery, it's just the fuse box of the univolt being used.

[72NewbsOver]

Also, is it normal for the converter to be connected directly to the battery?

[DKB_SATX]

Originally Posted by 72NewbsOver

Also, is it normal for the converter to be connected directly to the battery?

My Argosy was already somewhat modernized when I got it, but its connection between battery and converter is "indirectly direct." The leads from the battery and converter are attached to the same respective (+/-) posts on the fuse block. So, if the converter's off, the battery powers the 12v system, if the converter's on and the battery's inline the converter powers the 12v and charges the battery, and if the battery is out of the loop the converter just powers the 12v systems on the trailer.

You don't appear to have answered the question about whether your battery is stone-dead or if it has normal voltage that's just not getting into/through the fuses. If you're still using the old glass-fuse block on the Univolt and the battery itself is OK, that's the first place I'd look. Over time one or more of the rivets attaching the fuse holders to the bus can become loose and lead to an unreliable connection.

[72NewbsOver]

It's a brand new battery with normal voltage. I have replaced all the fuses and have 12 v when plugged into the truck. I had planned on updating the fuse panel to a more modern one but what to make sure this one works and it isn't a grounding issue.

[DKB_SATX]

Originally Posted by 72NewbsOver

It's a brand new battery with normal voltage. I have replaced all the fuses and have 12 v when plugged into the truck. I had planned on updating the fuse panel to a more modern one but what to make sure this one works and it isn't a grounding issue.

OK... have you checked continuity across the fuse block? (not across the individual fuses, but from the + lug on the bus to the load side of the fuse block (with a known-good fuse installed.) That'll tell you if there's a problem like the one I described earlier. Also, have you verified that there's +12v at the end of the battery cable where it attaches to the fuse block? Especially if the battery is some distance from the fuse block there may be an inline fuse in the cable that's open.

It's just an iterative process of checking for voltage and continuity until you find the break(s). If you have 12V everywhere when hooked to the trailer and the battery is good, it's most likely a problem with one or both of the battery cables so that's where you should start.

[SuzyHomemakr]

If you need a (or another) multimeter, I highly recommend this one from Harbor Freight:
Digital Multimeter - Save on this 7 Function Digital Multimeter

It's dirt cheap, so it can ride around in the Airstream as a spare. Also, it measures up to 10 amps of DC current, so it's great for tracking down all of those vampire drains on the system.

[72NewbsOver]

Thanks everyone for the feedback and suggestions. So after looking at the manual, I noticed there was a 50 amp glass fuse connected to the negative cable. After struggling to reach it since it was behind the univolt, I replaced it and of course that was the issue.

So my next question, what is suggested to replace the old fuse panel with a modern one?

[jbxx]

Originally Posted by SuzyHomemakr

If you need a (or another) multimeter, I highly recommend this one from Harbor Freight:
Digital Multimeter - Save on this 7 Function Digital Multimeter

It's dirt cheap, so it can ride around in the Airstream as a spare. Also, it measures up to 10 amps of DC current, so it's great for tracking down all of those vampire drains on the system.

I think this is the one that you can get free if you look for the coupon.
It's a POS but it does work. Free vs $170 or up for a Fluke.

[jbxx]

[QUOTE
So my next question, what is suggested to replace the old fuse panel with a modern one?[/QUOTE]

How about one of these, 50 A circuit breaker manual reset:
Del City - Item #: 76950

[HiJoeSilver]

I used this fuse panel, absolutely love it!
https://www.bluesea.com/products/502..._Bus_and_Cover

Also manual resettable 50a breakers.

[HiJoeSilver]

Link to breaker on amazon,

http://www.amazon.com/gp/aw/d/B0024J...F1L&ref=plSrch

I like the fuse panel because it's neat organized. Positive and negative terminals for connecting lots of circuits. Plus main pos and neg posts for battery connections.

Lots of options though.