Battery voltage drops!!!

[bc_canuck]

I have a 2015 Jayco Pinnacle with a residential fridge. When I am plugged in to shore power and have fully charged batteries (two of the biggest Trojan 6 volts that I could fit in the battery cases) my voltage readout is 13.2/ 13.3. After driving for 4 to 5 hours my readout has dropped to around 12.3 to 12.4 volts. I thought that it should at least maintain my full charge running off my truck charging system. When we then dry camp overnight my LOW voltage alarm starts to beep usually around 5 am and of course wakes me up. I did not spend 100K to have a very fancy alarm clock. Any suggestions would be appreciated. Thanks .

[Gdetrailer]

smkettner wrote:
Generally you should have 4x GC2 for a residential fridge application. Especially if off grid 18+ hours. Maybe 2x L16 if you have the headroom.

With everything off, your batteries should be resting at ~12.6 volts... plug into the running truck to verify voltage pops up at least 1/2 volt to show the connection is working.

Next I assume you are charging on generator when off grid. What converter is doing the charging? And what is the charging voltage? Voltage should steadily rise to at least 14.2 volts during the first 30 to 90 minutes of charging. You should continue charging at least 60 minutes after battaery is above 14.2 volts.

You did not mention solar? I recommend 500+ watts if you are off grid with a residential fridge.

Not necessarily true.

I can easily go 20-24 hrs without any problem with ONE pair of GC2 batteries and still have plenty of capacity leftover.. And that is with running a 30K furnace overnight which draws 10A while it is running..

I suspect the OP has a charging issue or other phantom draws or perhaps both..

Additionally the OPs fridge may have other things going which may contribute to excessive battery draw like electric door heaters which reduce sweating around the door.. My fridge does not use electric door heaters which saves me a lot of battery draw..

[MEXICOWANDERER]

RJsfishin wrote:
I can hear the salesman now,......"yes, for 100 thousand, it should work for dry camping"

You do know the reason they make RV propane fridges ??

¡Si!

To hurl out the door. They make great landfill.

[re_tired]

Wouldn't hurt to make sure you have 12V at the truck's connector for that pin. My truck has a fuse just for that wire. I might not notice for a long time if it blew for some reason.

[time2roll]

bc canuck wrote:
I guess that maybe one night dry camping I just might get by with running my Onan genny 'till mdnight peeing everyone off that is within 50 yards.

Probably a WFCO converter slow charging at 13.6 volts.
Need to replace with three stage that actually works.
Progressive Dynamics or IOTA.

[bc_canuck]

Thanks to all replies. The batteries are the T125 Trojans which I think will give me 240 ah. Originally we had 2 12v group 24 c which did not have enough to power a flashlight overnite. The factory said that they recommended at least group 27c batteries surprize no room I could not fit them because of lack of space thats why I got the Trojans. I guess that maybe one night dry camping I just might get by with running my Onan genny 'till mdnight peeing everyone off that is within 50 yards.

[re_tired]

Just used my voltage drop calculator. 12 volts on 12 gauge wire will drop .8 volts at 8 amps on a 30 foot run. The truck is referencing its own battery and charging accordingly. So, the trailer battery is never going to get enough voltage or current to do more than a trickle charge.

I also checked my truck and see that it has a 30 amp fuse on that wire to the connector. That's interesting. A chart shows you can only get 30 amps at the end of a 10 foot long 12 gauge wire at 12 volts. In other words, if there was a short maybe 25-30 feet away in the RV on that line, it would probably never blow the truck's 30 amp fuse.

[RJsfishin]

I can hear the salesman now,......"yes, for 100 thousand, it should work for dry camping"

You do know the reason they make RV propane fridges ??

[RoyB]

You need to make sure the truck is charging your batteries... You should read 12.6-7VDC across the battery terminals for a fully charged battery setup with out shore power running (not 13.2VDC as you listed)

Then when you start up your truck this DC VOLTAGE should jump up to 13.2VDC to 13.6VDC telling you the alternator is charging your batteries.

Like the others on here have stated your DC CHARGE from the truck through the small 7-way charge connection will probably only give you around 6-8AMPS of charge current...

That is just a tad more than trickle charging...

Roy Ken

[MEXICOWANDERER]

You have an electrical situation very similar to me and the first Ms Mex.

I earn X Dollars and she spent X, plus healthy vigorish.

Your charging is not providing enough power. Simple.

Troubleshooting is required. not so simple but like the bank yelling in my ear, it's something that must be fixed right away. My fix cost me a hell of a lot more than what your fix is going to cost.

[Jpatrickc]

I don't think it is a problem with the alternator as much as the wiring from the truck to the rig not being heavy enough to handle the current demand. The voltage drop from the truck fuse block to the RV battery is probably enough to require the RV battery to make up the difference.

Typically I can only get about 15 amps of charge current from my truck to my RV when the RV battery is low. If I use the Progressive Dynamics PD9260 converter on the same battery I get 40-45 amp charge.

The solution is to run a heavy cable from the alternator to a high current connector at the back of the truck and a mating connector and cable to the RV battery ( With an appropriate fuse at both the alternator and RV battery for short circuit protection). I have not done this yet but I plan to before I begin full timing in a few years.

Pat

[time2roll]

Generally you should have 4x GC2 for a residential fridge application. Especially if off grid 18+ hours. Maybe 2x L16 if you have the headroom.

With everything off, your batteries should be resting at ~12.6 volts... plug into the running truck to verify voltage pops up at least 1/2 volt to show the connection is working.

Next I assume you are charging on generator when off grid. What converter is doing the charging? And what is the charging voltage? Voltage should steadily rise to at least 14.2 volts during the first 30 to 90 minutes of charging. You should continue charging at least 60 minutes after battaery is above 14.2 volts.

You did not mention solar? I recommend 500+ watts if you are off grid with a residential fridge.

[CarnationSailor]

My Rushmore comes with a residential refrigerator and 700 watt dedicated inverter, but we went with the RV refrigerator option so we could dry camp without having to run the generator all the time.

Since the dealer removed the residential frig, but left the inverter installed, I sometimes use the inverter instead of propane when on the road. After about 5 to 6 hours on the road, my two 6-volt batteries will be down 30% to 40% when we get to the campground.

Just another instance of the truck's alternator not being able to keep up with the battery draw.

[Coolerman]

Would also help to know what other loads are pulling the batteries down. There are lots of small things that add up to a large draw. (CO2, carbon monoxide detector, the converter itself, tank monitors those kinds of things) add in a large fridge and it's no wonder the battery is down when you get to camp.

My Nissan Xterra "charge wire" was only 14ga! WAY too small for charging a battery located 20' away. I ran an 6ga wire, (even that is too small if the battery is really down) but since we go on LONG trips, it works out fine.

As stated measure the voltage at the truck battery (with the truck running preferably at about 2000 RPM to simulate driving) them measure the voltage at the camper battery. Bet you will find they are different by over .5 volts. That low and the camper battery can never fully charge. You need to run larger wire to eliminate the voltage drop.

[CA_Traveler]

You might get better input if you post the refer, charger and battery model numbers as there are many variations. What is the refer draw, charger capability, etc.

[CA_Traveler]

For every AC amp that the refer uses the inverter will draw about 11A DC. There is little or no charging while you drive and checking RV battery voltage with TV in high idle would be a start. It's a long run from the TV battery to the RV battery and the wiring may be inadequate for the job.

For night time you either have to much load or inadequate batteries for a res refer.

Example: With a 22A DC draw you would use 22A*5hr = 110Ah or almost 50% discharge. Adjust this for the actual draw and refer duty cycle.

Plus even when the driving charging works as it should you may not get 100% charged batteries but closer to 90% charged.

A lot of guessing in the above numbers. Do a energy audit and find out what your power usage is including refer, lights, etc.

It would not surprise me to find out that your usage exceeds the battery capability but that is speculation on my part. Solutions might include more batteries, better charging, gen or solar.