12v not working

[Paul]

Hmmm, my converter protection fuses are 30A. I'm not sure if that's because shore power is 30A max or if that fuse rating is just a coincidence. BTW, check the radio's own fuse, 5A??; one has to remove the radio to get at it. Regards, GK

The fuse will be sized for the gauge of wire and the device it protects. It is possible Paul's fuse was replaced by someone who didn't want the 30 to blow (when in fact it was designed to).

I ordered the trailer brand new and took delivery of it the same day it arrived to the dealer so I think they were installed by livin lite but I guess the dealer could had the time to change them. The fuse that is closer to the battery is also 40a weird. Should I replace them with 30a?

[Pinstriper]

Hmmm, my converter protection fuses are 30A. I'm not sure if that's because shore power is 30A max or if that fuse rating is just a coincidence. BTW, check the radio's own fuse, 5A??; one has to remove the radio to get at it. Regards, GK

The fuse will be sized for the gauge of wire and the device it protects. It is possible Paul's fuse was replaced by someone who didn't want the 30 to blow (when in fact it was designed to).

I ordered the trailer brand new and took delivery of it the same day it arrived to the dealer so I think they were installed by livin lite but I guess the dealer could had the time to change them. The fuse that is closer to the battery is also 40a weird. Should I replace them with 30a?

You'd have to know whether it was intended to be 30 or 40. Wire gauge plays into it, also what is the rating of what else is connected.

I was just trying to explain why one might have a 40 in place if in fact it was supposed to be a 30 (which would need confirmation beyond GK's assertion)

[GrampaKilt]

Okeydokey. My converter is a Progressive Dynamics 4045KV, an older model for sure. The 45 refers to 45 Amps. But what does 45A refer to since, the 110V side is rated for 30A AC and "the DC section has 12 branch fuse holders, two wired to accommodate 30 Amp fuses, ten more with a maximum rating up to 20 Amps each". Aaaah! Exactly what is being protected by those 2 30A fuses? All the other 12V branches? (Since they do insert at a separate location in the DC section.)

While I'm at it, probably one of this forum's vaunted gurus can answer this question. Up to what size inverter can I install given the following: I have 2 6V Trojans, a 60A fuse off the positive terminal (not sure now why I did that), a 50A shunt off the negative for my battery monitor (again, not sure why I went with such a low amperage)? Please and thankyou! GK

[DavidM]

Paul: Are the 40A fuse(s) that you are talking about in a pair and not part of the coach's DC fuse line up? Then they are to protect the converter from reverse polarity from a bad battery hookup. Check the polarity with a meter.

Grampakilt: You can put as big an inverter as you want as long as you wire it directly to the battery with the appropriate size wire and protected by an appropriate fuse. Not sure why you now have a fuse in the negative circuit. It isn't required.

Also consider what you are going to power with the inverter. If the TV only then it can be a small 200-300 watt unit and wired with 10 gauge wire and a 30A fuse to protect it. If you also want to power the microwave then it needs to be a 2000 watt inverter connected with at least #2 wire but bigger if it is far away, protected with a 200A fuse.

David

[GrampaKilt]

Thanks for your mentorship DavidM! Clarification (I think) it's a 50A shunt on the negative side.

Also can you explain to me (again??) why I put a 60A fuse off my positive?

I'm thinking of a 1000W inverter; plenty to run a blender or those projectors my grandchildren now have. Have you noticed the prices for true sine wave inverters have plummeted? Hence my interest in the install. (Just installed a 1000W in my son's tent trailer--3 teen grandchildren, 10 phones or gadgets, everyone clamoring for charging ports...made sure to use #4 wire.) GK

[DavidM]

Oh, I think you mean a 500A shunt. That is the typical rating for RV/boat shunts. I think they produce 50 mV of voltage drop at 500A and that voltage drop is used by the battery monitor's electronics to figure the current going through them. If it sees 1 mV then the current is 10A.

The 60A fuse on the positive side is to protect the wire, probably #10 gauge.

David

[Merlin]

I had a very hard time finding a 40a fuse locally, all I could find was 30a. I could have looked harder though just went to 3 stores. I decided to order a pack on amazon. I went to Canadian Tire and got a AGM group 24 battery. I didn't wanted to go up in size or switch to 6v batteries since I didn't wanted to change the box etc. and a group 24 is enough for my need but I decided to upgrade to AGM.

My radio is not working though I though maybe it was because of the blown fuse or that the old battery wasn't charged enough but it still doesn't work with the new battery, everything else work fine.

Paul, just so I am clear, everything electrical in your camper now works fine, except for the radio?

[GrampaKilt]

DavidM, thanks to forum, I rewired the mains with #6 or #4. I found it very difficult to squeeze the gauge into the converter's terminals. Attached is a pic of my 50A shunt. I've discovered it's no longer manufactured and a 100A shunt is the lowest sold.

Another question therefore regarding an inverter (1000W). May I ground the inverter to chassis or must I run back to the negative. And if so, before or after the shunt??

Thanks again, GK

[DavidM]

Answering your questions a little out of order:

You really want all loads to be on the shunt, so wire a new inverter after the shunt, except see below.

But that brings up another problem. The shunt is presumably limited to 50A (never heard of one that small) and a 1,000 watt inverter will pull more DC than 50A. So either get a new shunt or wire the new inverter before the shunt, but if you do that your BM will not read the true amp hours.

I would never, ever rely on a chassis ground to supply the negative DC circuit for an inverter. Too high a current and lots can go wrong with steel connections. Wire the inverter with + and - wires back to the battery (or shunt as above). Inverters also need to be grounded from their chassis to the RV's chassis but only with 8 gauge wire typically and that ground is meant for safety, not to supply DC power.

PS: Having issued that warning, the 100A starting circuit for my new MHs starter uses the chassis as its negative and it wasn't even hooked up as delivered. It worked because the generator chassis was bolted to the MH chassis providing a return circuit. Go figure. I did connect the unconnected ground wire to the MHs chassis.

Edit: I searched on Amazon and did find a BM with a 50A shunt but it reads in milliamps, not surprisingly. Here is one that I installed in my new MH and has a 500A shunt and has a nice round display, a bit like the Victron for 5X the price: https://www.amazon.com/gp/product/B0824X5MKM/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

David

[Paul]

I had a very hard time finding a 40a fuse locally, all I could find was 30a. I could have looked harder though just went to 3 stores. I decided to order a pack on amazon. I went to Canadian Tire and got a AGM group 24 battery. I didn't wanted to go up in size or switch to 6v batteries since I didn't wanted to change the box etc. and a group 24 is enough for my need but I decided to upgrade to AGM.

My radio is not working though I though maybe it was because of the blown fuse or that the old battery wasn't charged enough but it still doesn't work with the new battery, everything else work fine.

Paul, just so I am clear, everything electrical in your camper now works fine, except for the radio?

Yes exactly everything work fine now except the radio

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[Merlin]

I had a very hard time finding a 40a fuse locally, all I could find was 30a. I could have looked harder though just went to 3 stores. I decided to order a pack on amazon. I went to Canadian Tire and got a AGM group 24 battery. I didn't wanted to go up in size or switch to 6v batteries since I didn't wanted to change the box etc. and a group 24 is enough for my need but I decided to upgrade to AGM.

My radio is not working though I though maybe it was because of the blown fuse or that the old battery wasn't charged enough but it still doesn't work with the new battery, everything else work fine.

Paul, just so I am clear, everything electrical in your camper now works fine, except for the radio?

Yes exactly everything work fine now except the radio

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Great. It seems the radio fuse must have blown. If you can find and replace it, you should be all set.  Check the fuse panel for a blade fuse for the radio. If it's good, there may be a separate inline fuse in the radio or the wire going to it.

[Merlin]

Thanks for your mentorship DavidM! Clarification (I think) it's a 50A shunt on the negative side.

Also can you explain to me (again??) why I put a 60A fuse off my positive?

I'm thinking of a 1000W inverter; plenty to run a blender or those projectors my grandchildren now have. Have you noticed the prices for true sine wave inverters have plummeted? Hence my interest in the install. (Just installed a 1000W in my son's tent trailer--3 teen grandchildren, 10 phones or gadgets, everyone clamoring for charging ports...made sure to use #4 wire.) GK

Your getting great advice from David. My only suggestion is for device charging. It's inefficient to invert 12vDC to 120vAC then convert back to 5vDC for usb charging. Better to simply go 12v to 5v with something like this.

https://www.amazon.com/Charger-Adapter-Identification-Multi-Protection-Charging/dp/B0779D7DFG

[GrampaKilt]

Paul, I apologize for somewhat hijacking your thread with my questions. On the other hand, I think the answers have been very clear and informative for all. As for the shunt, I had a hunch the low A rating would come back to haunt future electrical plans. And the 500A shunt was just a few dollars more. Called penny foolish? Not all my decisions have been that way; after all, in 2014 I did spend about 7K more for my beloved and 'generational' CL. GK

[Paul]

Paul, I apologize for somewhat hijacking your thread with my questions. On the other hand, I think the answers have been very clear and informative for all. As for the shunt, I had a hunch the low A rating would come back to haunt future electrical plans. And the 500A shunt was just a few dollars more. Called penny foolish? Not all my decisions have been that way; after all, in 2014 I did spend about 7K more for my beloved and 'generational' CL. GK

I am glad you did it has been very informative!

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[Paul]

I was able to fix my radio! There was a fuse behind it that I replaced