dc power not turning o

[Dean and Mary]

Imelda, Thanks for the update, and I’m glad you’re able to get home with things as they are. Just a quick reminder—the jacks don’t receive their power from the converter, but more of a direct connection from the batteries through the 60 amp Optifuse shown in my above image. 

[jd1923]

1 hour ago, Imelda said:

the 60A fuse is good just checking the low resistance (not the voltage but I will) across it.

Does this mean the "fuse is good?" it's certainly not a conclusive test and it doesn't mean there's a 12V source connected to the breaker. +12V on the source side of the breaker shows you have connection to the batteries. +12V on the load side shows the breaker is closed providing a power connection to the bus.

1 hour ago, Imelda said:

I am starting to suspect the converter.

A dead (or disconnected) converter will only keep you from recharging batteries when connected to shore power. A running converter is not required to operate lights, the jacks or anything else 12VDC. Converter status is independent of these 12V loads getting power from the batteries.

[jd1923]

4 hours ago, Dean and Mary said:

jd, thanks for sharing the photo of your original 12‑volt distribution. It’s definitely cleaner than what my original setup looks like. I’ve attached a photo of mine—minus the 8‑gauge input wire. I’m in the middle of replacing everything and wanted a picture before I completely disassemble it.

On my install, there are two wires on the input side of the Optifuse (not counting the main 8‑gauge battery feed that’s been removed). I haven’t traced them yet, but I suspect one may be for the breakaway switch. I don’t want to hijack the thread until the main issue is resolved, but identifying these wires would save me some time.

Dean, WOW! I've seen some strange wiring but what happened here? Did they run out of buses on install day? The installer just bolts everything to the breaker, OMG! 🤣

BTW, this is the famous Optifuse! Many of these have failed, so that OTT has stopped using them! Search the Forum for keyword Optifuse. I'd be surprised if this isn't the answer to the issue of this thread, since everything not working, lights, jacks etc. is connected to this breaker. Do yourself a favor with your upgrade and replace the Optifuse breaker with an 60A ANL fuse and holder. Oh, and add a +bus, LOL!

Back in 2016, OTT used Bussman breakers (at least on our hull). They installed a 40A for all 12VDC lighting, jacks, etc. (pictured above) and a 30A Bussman for the rooftop solar. Keeping things standard, I purchased a 35A Bussman breaker to protect the Victron MPPT 100|30 SC that I added for our 400W Renogy suitcase solar.

Three Bussman breakers, 2 of them 11 years old, the new one 2 years old, no issues. ANL fuses are more reliable as you certainly know when they are blown (always have a spare). Fuses will blow when there's too much current on either side of the fuse. Breakers are directional, so they only protect on the load side of the breaker.

I have no idea what your two black wires are on the source side of your breaker. Trace them back if you can. If not, I'd wire them to a new bus with everything else. I have no wires before a breaker anywhere, meaning power to the breakaway switch on our hull does pass though the 40A breaker (OTT had not wired this to code). I know the breakaway switch works because I pull it to test for amperage to the brakes.

When I moved these breakers to the dinette area, I found the wiring from the jack fuses to all 3 jacks ran towards the dinette area first (was surprised since one jack is right there and the curbside jack is another direction). I removed all that excess wire and removed 3 butt connectors on each of the 3 wires along the way. I crimped one fresh butt connector on each of 3 much shorter wires to clean things up. 😎

Edited Saturday at 06:47 PM by jd1923

[jd1923]

20 hours ago, Hokieman said:

Did you see the manual?   It’s got over a dozen diagrams in it, I just did a snip of one of them.   Most of the circuits are shown. 

Thank you. I had not checked out the 2019 Oliver Manual before. I just downloaded a copy. I see many differences comparing our older hull but still can be helpful.

[Dean and Mary]

6 hours ago, jd1923 said:

Dean, WOW! I've seen some strange wiring but what happened here? Did they run out of buses on install day? The installer just bolts everything to the breaker, OMG! 🤣

BTW, this is the famous Optifuse! Many of these have failed, so that OTT has stopped using them! Search the Forum for keyword Optifuse. I'd be surprised if this isn't the answer to the issue of this thread, since everything not working, lights, jacks etc. is connected to this breaker. Do yourself a favor with your upgrade and replace the Optifuse breaker with an 60A ANL fuse and holder. Oh, and add a +bus, LOL!

Back in 2016, OTT used Bussman breakers (at least on our hull). They installed a 40A for all 12VDC lighting, jacks, etc. (pictured above) and a 30A Bussman for the rooftop solar. Keeping things standard, I purchased a 35A Bussman breaker to protect the Victron MPPT 100|30 SC that I added for our 400W Renogy suitcase solar.

Three Bussman breakers, 2 of them 11 years old, the new one 2 years old, no issues. ANL fuses are more reliable as you certainly know when they are blown (always have a spare). Fuses will blow when there's too much current on either side of the fuse. Breakers are directional, so they only protect on the load side of the breaker.

I have no idea what your two black wires are on the source side of your breaker. Trace them back if you can. If not, I'd wire them to a new bus with everything else. I have no wires before a breaker anywhere, meaning power to the breakaway switch on our hull does pass though the 40A breaker (OTT had not wired this to code). I know the breakaway switch works because I pull it to test for amperage to the brakes.

When I moved these breakers to the dinette area, I found the wiring from the jack fuses to all 3 jacks ran towards the dinette area first (was surprised since one jack is right there and the curbside jack is another direction). I removed all that excess wire and removed 3 butt connectors on each of the 3 wires along the way. I crimped one fresh butt connector on each of 3 much shorter wires to clean things up. 😎

Thanks for the detailed response. I agree—the wiring is a mess, and that’s exactly why I’m redoing all of it. I did not know about the failure rate of the Optifuse. I’m also curious about the maximum of three wires on a lug, and why there are two connections ahead of the Optifuse. For my upgrade, I’ll be using the Victron Energy Lynx Distributor with ANL fuses.

[Snackchaser]

21 minutes ago, Dean and Mary said:

why there are two connections ahead of the Optifuse.

Those are probably the emergency breakaway switch for the breaks and the CO monitor.  They take a direct feed from the battery.  

[Dean and Mary]

1 hour ago, Snackchaser said:

Those are probably the emergency breakaway switch for the breaks and the CO monitor.  They take a direct feed from the battery.  

Thanks Snackchaser, that makes sense. 

[Imelda]

i got back home fine and with a voltmeter i did some more checking and there is 13V coming out of the batteries, I checked but there’s no 12 V on either size side of the optifuse. The fuse is good as i checked with ohmmeter. There is a one amp in line fuse I also checked it’s good also. the 2000 inverter is turning on fine and turning on the microwave and all the stuff that runs off the AC so it’s puzzling why there is no 12V DC power in the trailer. there has to be a  bad fuse or switch somewhere. I am going to try to reach out to OTT but it usually takes them a while to get back to me. any other ideas?  could a fuse be blown in the inverter. 

[Snackchaser]

2 hours ago, Imelda said:

 I checked but there’s no 12 V on either size side of the optifuse.  The fuse is good as i checked with ohmmeter.

I'm a little confused because you've said there is no power on either side of the optifuse, but you've also said that it tests good?  Also, you mention a 2000 watt inverter, where you talked about a converter before.  These are different things and wired differently.  BTW, a 2000 watt inverter should have another ~200 amp breaker or fuse between the inverter and battery.  That's not the problem, but you should be aware of it.  Mine is mounted on the vertical wall above the inverter.

At any rate, the battery and/or the inverter both feed the 12 volt panel (and jacks) via the 60 amp optifuse breaker.  Re-check it for 12v from each terminal to ground.  There are grounds all over the place in that area, the jack post, trailer frame, or the inverter chassis will work.  If there is voltage on the line side, but no voltage on the load side, then you have a bad breaker.  These breakers are readily available, and the failure rate is pretty low for the millions of them out there.  

Edited 4 hours ago by Snackchaser

[jd1923]

On 10/9/2026 at 5:44 PM, Hokieman said:

I saw a previous post from you that indicated you had LiTime batteries installed by a technician. Did they by chance install an ANL fuse or a circuit breaker?

3 hours ago, Imelda said:

i checked but there’s no 12 V on either size side of the optifuse.

There must be a direct positive (+) battery connection to the Optifuse. Geoff ask you to retest, but when you're certain there is no power on the battery side of the breaker (or both sides) then the +battery cable feeding the Optifuse is either 1) disconnected, 2) switched OFF or 3) has an added inline fuse that is blown. You must have an open circuit for there ot be no power on "either side of the optifuse."

OTT in their OEM build did NOT add a switch or redundant inline fuse in this circuit. The Optifuse is the breaker that protects your batteries from shorts in ALL DC lighting and appliances (all DC loads).

If you have anything but a solid stretch of 6 or 4 AWG between the Optifuse and your batteries it must be an aftermarket installation, perhaps something was added during April 2025 when you had LiTime batteries installed.

Your solution is simple. Just follow the battery cable from the Optifuse to the batteries. Given your Optifuse is under the streetside bed, the cable will run a whole 5 ft total, first under the pantry area, then up through a drilled hole/grommet into the battery bay, then connected to a positive battery terminal. Your "Tech" could have added a +bus somewhere interior, if so test for +13V there.

But if the retest shows +13V on the battery side, but NOT on the load side of the Optifuse, then replace the Optifuse with a 60A ANL Fuse.

There are no other possible causes for the full loss of DC power in the Oliver.
You either have an open circuit in the battery cable or a bad Optifuse breaker.

 

 

Edited 3 hours ago by jd1923

[Imelda]

i think i checked all the fuses on the 12V line and they appear good but there is this connector on both the positive and negative wires coming from the batteries to the fuses and i wonder if they are open circuit.  I have never seen this type of component before. is it a connector or fuse or what but it goes to the fuses where i cannot get any voltage reading of any kind even though the fuses test good  what is this type of connector for?