Charging circuit on Silverado 2500 HD

[oeeman]

Merry Christmas to all!

I have a 2007 SILVERADO 2500 HD. I'm pulling a 2012 3400 RL. I start my trips with a fully charged battery, the battery switch on, a fuse in the truck charging system and my meter that I installed in the trailer giving battery charge and discharge info (thanks to this forum!) shows some charge amps while connected to truck with truck running. Standard fridge and other items in trailer - no modifications.

After a day of travel (8 - 10 hours) the inverter in the trailer is flashing at the 50 - 90 % level. I'll admit I don't know the voltage level when this happens. Everything works but I would think after 8 hours of freeway driving the battery would be back up to full.

I've read in the forum that the charging circuit is a "trickle" charge and that makes sense. However trickle is a relative term. So anyone know what the truck should be able to generate?

Question is for others is if they have found that the charging circuit on the 2500 was light for the bigger trailers and may have had to have the wiring upgraded to get enough juice back to RV battery. I believe the fuse in the charging circuit is a 30 amp fuse if it was doing 10 amps for an 8 hour day that would be enough to charge it.

Anybody had similar issues and generated a fix? Comments?

[Our3231CK]

I have a 2016 chevy 3500HD and have experienced the fuse blowing in the truck if the battery gets to 50% prior to plugging in to drive, after boon docking, this doesn't sound like your issue. You can also check that fuse in the truck.

I'll run the generator in the morning for 20 minutes to recharge.

Are you driving with the fridge on? and other things like fans or lights?At most your getting 3A to trickle charge.
I also replaced my standard battery with an AGM after 2 years and haven't had any problems since with mine.

[rames14]

Think of trickle charges as somewhere around 5 amps. If you have a residential fridge, you may be drawing about 3 amps AC/hour. But, to get DC to AC, you go through an inverter. Ohms law is watts=ampsxvolts. So, your fridge is 3 x 120 = 360 watts. 360 watts / 12 volts = 30 amps on the battery side. So (let’s forget all the things running other than the fridge like CO detector), you are using 30 amps per hour and charging 5 amps. If you have two traditional 12v deep cycle batteries, they are typically 88 amps, of which you can use 50% each without damaging the battery. So, you have 88 usable amps. This is generalization. Fridge usage will depend on outside temp, exact fridge you have, settings, etc. owning an RV is a learning curve. Hope this helps.

[rames14]

The second part of your question (and I used residential fridge as an example) has a number of solutions. If your concern is just less battery drain, turn off your fridge. It will stay cool for that period of time. Second, and cheapest, is add more battery. Third would be add DC/DC charging. I use a smart BIM with 2/0 wire front to back. Others use the Renogy system. You can search DC/DC charging and find lots of options. Mine was about $850 if I remember correctly.

[AZ Traveler]

Kevin,

Are you running your reefer on gas or electric? A RV reefer on electric is a power hog and will run your batteries down. What are you running with the inverter?

[oeeman]

when I bought the truck, I had no charging and traced it down to the fuse blown. I replaced that and haven't had any trouble since. It is not a residential fridge but the one that came with the trailer, a dometic model that I run on propane while traveling. Don't run anything else that I'm aware of (other than normal parasitic draw). The concern is that I will be traveling to AZ. I normally would stop in a park at least once but won't be this time. Looks like I'll have to adjust my thinking or get a charging circuit. Anybody ever run a generator in their truck bed and used that while driving to charge the batteries?

[jimcol]

We have made some 16 hour pulls with both a Ford & a Ram running the refrigerator on gas and the few parasitic drains. Never had the battery discharge to where it wouldn't keep the fridge running. We do not have an inverter. Does the 50-90% flash on your inverter say the battery is down 10% or 50%? Until you know that, your interpretation of the data may be raising a concern for an issue that doesn't affect your refrigerator.

[oeeman]

I just realized that I mispoke in my original post, my apologies. I am not running the fridge on the inverter. Just the normal trailer circuit and the CONVERTER is what is showing the reduced battery level of 50 - 90 %. Based on the comments I think I will need to do some testing in the driveway prior to leaving to verify the amp draw of the system with the refrigerator on and the charge from the truck.

Jimcol,

I think you may be right I need to understand the actual draw better. I will pay closer attention to the battery meter I installed concerning voltages, etc. to get a better understanding. I can also manage the reefer better. It is cold for a lot of the drive so may be able to turn it off also.

[RVDH]

I have a 2008, no problems with a residential frig and inverter. One thing I did find out is that there's a wire under the hood that wasn't hooked up, once I did that it worked fine

Originally Posted by oeeman

Merry Christmas to all!

I have a 2007 SILVERADO 2500 HD. I'm pulling a 2012 3400 RL. I start my trips with a fully charged battery, the battery switch on, a fuse in the truck charging system and my meter that I installed in the trailer giving battery charge and discharge info (thanks to this forum!) shows some charge amps while connected to truck with truck running. Standard fridge and other items in trailer - no modifications.

After a day of travel (8 - 10 hours) the inverter in the trailer is flashing at the 50 - 90 % level. I'll admit I don't know the voltage level when this happens. Everything works but I would think after 8 hours of freeway driving the battery would be back up to full.

I've read in the forum that the charging circuit is a "trickle" charge and that makes sense. However trickle is a relative term. So anyone know what the truck should be able to generate?

Question is for others is if they have found that the charging circuit on the 2500 was light for the bigger trailers and may have had to have the wiring upgraded to get enough juice back to RV battery. I believe the fuse in the charging circuit is a 30 amp fuse if it was doing 10 amps for an 8 hour day that would be enough to charge it.

Anybody had similar issues and generated a fix? Comments?

[twindman]

I have traveled 120,000 miles in the last 15 years and never had a battery problem while towing and always have the RV frig on gas the whole time.

[rames14]

Oeeman, I may have missed it but what are you running for a battery - type and quantity? I know a lot of people have started with just one battery.