DC Power Issues with new Big Country 3965dss

[bishgeo]

Ready to burn this thing already. Lost all 12 v power first night in it. Checked all 110 power first. Good there tore storage comp panels out to get to converter. Found 3 blown fuses in converter. Put everything back together seems ok. Un hooked shore power Monday morning dead as a door nail. Drove 8 hours to pigeon forge still dead. Voltage in display for leveling shows 11.86 v. Dealer put 2 new batts in on delivery. 😡😡

 

[danemayer]

Re: New owner big country 3965dss

Hi bishgeo,

Welcome to the Heartland Owners Forum.

Sorry to hear about your problems. The fuses on the Power Converter protect against polarity reversals - meaning that they blow when the batteries are connected with the wrong polarity (dealer error?). Usually the polarity reversal is noticed pretty quickly and corrected, but the Power Converter doesn't have any output until the fuses are replaced.

It's also possible that the 12V DC mini-circuit breaker between batteries and Power Converter has also tripped. It has a manual reset. If that's the case, after replacing the fuses on the Power Converter, your interior lights and 12V DC devices would all work as long as you were on shore power. But as soon as you unplug, there's no path from the battery to those lights and devices - so everything goes dead.

In that condition, the batteries will continue to operate the levelup system, slides, and residential refrigerator (if you have one), but the batteries will not be recharged enough to keep up with demand.

Check near your batteries for a row of mini-circuit breakers covered by a red rubber boot. The pictures I've attached will help you find the manual reset breaker. Yours may look a bit different, but if you look for the thicker wires, you'll be in the right area. There's a teeny tiny button on one end of the manual reset breaker. After pressing it, if on shore power, you should see the voltage in the levelup readout jump up to over 13V.

Some trailers built over the past year now have 80 amp breakers with manual reset. They're larger and usually have a square form factor, rather than the smaller rectangular ones in the picture.

Our owner-written Electrical user guide has diagrams and photos along with detailed explanations that you may find helpful.

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On edit: after reading about your TV problem, I'm wondering if your trailer experienced some type of shore power problem that damaged some of your devices. Are you using an Electrical Management System (EMS) to protect against overvoltage, low voltage, open neutral, etc? They sometimes called surge protectors, but do much more to protect the trailer.

 

[bishgeo]

Re: New owner big country 3965dss

No power across this.

 

[cookie]

Re: New owner big country 3965dss

When you checked that fuse did you put one probe of your meter to ground and the other to each lug, one at a time?
No 12 volt on either lug?

Peace
Dave

 

[danemayer]

Re: New owner big country 3965dss

No power across this. View attachment 59593

To clarify, if you mean that putting the red meter lead on the left side connection, and the black lead on a known good ground, you get 12V DC, but moving the red lead to the right side connection, you read 0V DC, then that fuse is blown. That would prevent getting any battery charge to the interior and would prevent you from getting the batteries charged.

But if you're measuring across those 2 connections, you should read 0 as there is no difference in voltage potential.

 

[bishgeo]

Re: New owner big country 3965dss

Used test light grounded to battery ground. No power on one side.

 

[justafordguy]

Re: New owner big country 3965dss

Sure sounds like it's blown. The question now is why?

 

[bishgeo]

Re: New owner big country 3965dss

$7.95 part &138.00 service call. 😡😢

 

[danemayer]

Re: New owner big country 3965dss

$7.95 part &138.00 service call. 😡😢

And what remains is to find out what caused this fuse and the fuses on your Power Converter to be blown. I'd be asking who did what to your electrical system and I'm wondering about the dealer putting in 2 new batteries on delivery.

 

[sengli]

Re: New owner big country 3965dss

My 100 amp fuse was also blown. I replaced mine today after reading this thread. I hadnt tried the inverter for the fridge yet. Got everything connected and tried out the inverter, to power the fridge. It worked O.K and acted like it was fine. I think my fuse got zapped when the dealer had this on his lot, with marginally charged batteries, and tried to use the inverter. Low voltage means high current for a given load.

So when the fridge on, and the inverter running, the measured voltage was 12.3, does that seem about right?

So what does everyone think, about replacing the 100 amp fuse, with a reset-able circuit breaker of the same amperage rating?

 

[bishgeo]

Re: New owner big country 3965dss

That may work we came from myrtle beach to pigeon forge with no 12 v power and fridge off. Fridge was still good and cold when we got here. I don’t see any need to even run it on inverter.