Battery Charging while towing

[Tomahawk]

I have felt for a while my batteries were not charging fully while towing. On a recent trip, the batteries were connected to shore power for days before leaving. We left the night night before and spent the night in a hotel outside of LA. The next day we drove 4 hours to Sequoia. When we arrived, I checked the batteries, and they were sitting 12.5 volts. Seemed a little low to me. After a night in the trailer the voltage was 12.4V. The next we returned to the trailer around 7:30. The SA panel was in the sun from about noon to 5. The battery voltage was 12.7V. After several days of monitoring the batteries they were consistently at 12.7 after charging with the panel. The day we left, we left early before the panel was in the sun, we drove home 6 hours and I put the trailer in the driveway immediately. I plug back into shore power and the converter/charge started working hard to charge the batteries. The fane was running and that was the first time I have ever heard it run. I checked the truck and the 12V power has power supplied.
Thoughts?
Thanks,

[ALLOY]

When charging (solar or converter) the voltage should be around 13.5-14.4V.


The battery manufacture will have details on the charging parameters. Same goes for the solar controller and converter. They all need to be in the same range.


Edit:The voltage drop (wire + connections) from the tow vehicle may not allow a high enough voltage to charge the trailer batteries.

[Bigfin]

Check out Progressive Dynamics and their converter replacements. Made all the difference in my battery charging. The TV does not have the ability to do the job, for various reasons. Search for PD in the appropriate forums. Cheers!...

[Old-Biscuit]

Truck Charge line can maintain a trailer battery while in transit but due to its 12 gauge and length of wire it would have a tough time Charging a trailer battery

Want to Charge....run 10GA wire

[Dave Pelletier]

Charging from the TV is minimal to nothing in most cases. A better way to charge while driving is to get a DC to DC charger.

https://thewanderful.co/blog/what-is...is%20different.

[Marine359]

Originally Posted by Old-Biscuit

Truck Charge line can maintain a trailer battery while in transit but due to its 12 gauge and length of wire it would have a tough time Charging a trailer battery

Want to Charge....run 10GA wire

The 7-pin will give you (typically) about 4-5 amps under normal driving conditions. That’s enough to service a 12v compressor fridge, or float charge your FLA if the FLA has already gone through bulk and absorption. Not enough amperage for bulk. When I travel with my LFP @ 100% SOC, the 7-pin will keep my fridge cold without a dc/dc charger, and I will arrive at 100% SOC.

[Dave Pelletier]

Originally Posted by Marine359

The 7-pin will give you (typically) about 4-5 amps under normal driving conditions. That’s enough to service a 12v compressor fridge, or float charge your FLA if the FLA has already gone through bulk and absorption. Not enough amperage for bulk. When I travel with my LFP @ 100% SOC, the 7-pin will keep my fridge cold without a dc/dc charger, and I will arrive at 100% SOC.

Good info; just a reminder that different TV's may have different results.

Dave

[xc-mark]

I can confirm the 3~5 amp charge with any factory set up ,however you will NEVER get more then 50/60% of a full charge . You cant get more then 13.6 volts at the RV battery. You need 14.2 ~14.8 volts to get to full charge. I have installed a 18 amp DC to DC Victron Orion . They accept low voltage power and put out three stage charging to the voltage you program it for. So it will accept 11 volts on the input side and still put out 18 amps at 14.4 volts (also protects the car alternator for Lithium systems). Any DC to DC charger larger then this will not be compatable to use with your RV 7 way plug , the car side amps would burn the plug and wires.

https://www.amazon.com/Victron-Orion...ps%2C77&sr=8-4

[Dave Pelletier]

Originally Posted by xc-mark

I can confirm the 3~5 amp charge with any factory set up ,however you will NEVER get more then 50/60% of a full charge . You cant get more then 13.6 volts at the RV battery. You need 14.2 ~14.8 volts to get to full charge. I have installed a 18 amp DC to DC Victron Orion . They accept low voltage power and put out three stage charging to the voltage you program it for. So it will accept 11 volts on the input side and still put out 18 amps at 14.4 volts (also protects the car alternator for Lithium systems). Any DC to DC charger larger then this will not be compatable to use with your RV 7 way plug , the car side amps would burn the plug and wires.

https://www.amazon.com/Victron-Orion...ps%2C77&sr=8-4

That's the info I was looking for. Again, I'd caution that SOME newer vehicles are programmed to stop charging batteries when the starting battery has reached full charge - not sure if every tow vehicle will provide even 3 amps ALL the time....this is what I've been told; any thoughts?


Dave

[twinboat]

Originally Posted by Dave Pelletier

That's the info I was looking for. Again, I'd caution that SOME newer vehicles are programmed to stop charging batteries when the starting battery has reached full charge - not sure if every tow vehicle will provide even 3 amps ALL the time....this is what I've been told; any thoughts?





Dave

Alternators can't just stop charging the battery.
Some charging, at least a maintance charge, has to happen to support the electrical operation of the vehicle.
As you turn on accessories , the amp draw rises and the alternator output increases to compensate.
A connected charge line is that kind of draw on the system and it will compensate for it.

[Dave Pelletier]

Originally Posted by twinboat

Alternators can't just stop charging the battery.
Some charging, at least a maintance charge, has to happen to support the electrical operation of the vehicle.
As you turn on accessories , the amp draw rises and the alternator output increases to compensate.
A connected charge line is that kind of draw on the system and it will compensate for it.

Makes sense; my Jaguar did some funky thinks with charging output but I didn't tow with it.

[carybosse]

I haven't read the specs on my Silverado, but maybe if my insomnia gets worse...

On my Colorado, the alternator was variable in nature. In TOW/HAUL mode, it was kicked up a notch. Would expect the SIlverado to be similar.

I think there is a 30 Amp fuse on this, but of course, it all depends on what the trailer pulls as to how much is provided.

[ArtJoyce]

Are you running the fridge on DC when towing?

[Tomahawk]

Originally Posted by ArtJoyce

Are you running the fridge on DC when towing?

If that question is for me, then no.