I was told this buy someone at an RV business......sounds like BS.....but I know shinto about vehicles........So I put this claim to you guys. BS or no BS?Also, while we're at it, same guy:The BMS in lith batt's is a big drain on the batt's.....BS or no BS?Edit: Mod's- If this is best put elsewhere, please go ahead and move. :)

It depends on what is hooked up. This post has the details.https://www.thedieselstop.com/threads/2017-f450-not-charging-trailer-batteries.623818/I don’t know about a problem with lithiums. People say they charge them driving. I think that’s closer to BS.

Bert the Welder wrote:Also, while we're at it, same guy:The BMS in lith batt's is a big drain on the batt's.....BS or no BS?Complete BS.I have a pair of Battle Borns that I pulled out of an RV when I sold it in March. They have been sitting in a heated space since March, with no charger on them. I checked the voltage about two weeks ago, they are sitting at 13.2.

There is a delay - when starting, approximately 45 seconds elapse before the alternator is applied to the battery system.It's been years since I last checked this, but it could easily add to the pot of misunderstanding when sourced from an RV dealer.

Ford has several charging systems and so far is the only manufacturer who puts disconnecting relay on trailer charging wire. Early Powerstrokes with7.3 engine would not start charging till couple of minutes after engine start. That was due charging voltage killing glow plugs, so instead of making better GP, they solved it by running the engine on battery power till GP would be no longer needed. That was pretty annoying for me, when I had my truck sitting for months and occasional engine starting was actually killing the batteries, instead of charging them. Newer trucks have it improved. but each designated aux battery charging on diesel will have delay timer.

Bert the Welder - Ford's website has access to manuals / upfitter or body builder information etc. - but generally the little blue "charge wire" is not capable of carrying the significant amperage required to charge batteries in less than days... LiFeO4 batteries can accept charge at very high rates that can overload an alternator if the charge rate is not regulated. I am looking at using a DC-DC charger to charge batteries from the engine alternator. Watch the input requirements of these vs your alternator capacity. Ray on the "Love Your RV" u tube channel installed one and shows how they work. Their RAM truck has a high amperage connection terminal under the hood. A rule of thumb we used in heavy trucks was to not exceed 50% of alternator capacity when adding stuff like inverters and fridges etc The alternator does not put out full capacity at low rpm / idle. I have found solar to be pretty much useless in western Canada in winter. Because of their fast recharge capability lithiums are particularly suited to "mechanical" charging I'm thinking.

"Newer" Ford trucks don't charge house batt's? | Good Sam Community

71 Replies

deltabravo
Nomad
Dec 20, 2020
noteven wrote:
but generally the little blue "charge wire" is not capable of carrying the significant amperage required to charge batteries in less than days...

Yep, the factory charge line is typically only 12AWG wire.

I did this upgrade for higher amp charging a few years ago.
deltabravo
Nomad
Dec 20, 2020
Bert the Welder wrote:
I am looking at using a DC-DC charger to charge batteries from the engine alternator.

This is what I'm going to use
toddb
Explorer
Dec 20, 2020
I found the brake thing to be true on my '15 350. I use an victron orion 12|12 9a dc-dc charger. It suits my needs for a small charge to keep up with the compressor fridge and utilizing the factory truck and camper wiring.
Bert_the_Welder
Explorer II
Dec 20, 2020
So lets push our luck that this one is granted entry to this thread too.....

Mr. Wizard: I'll not put you through further questions from a pea brain. But would ask if, since you have obvious knowledge in this area, you've seen a video or website that has a good, straight forward explanation on the how's, what's and why's of truck to TC charging systems, suitable for the rank beginner?

Much appreciated!
Bert_the_Welder
Explorer II
Dec 20, 2020
OK.... Thanks Mr. Wizard. I have a long reply typed out with questions, but keep getting formatting complaints. So I'm going to give up before I send the laptop out the window......
I just really need to give up ever understanding this stuff.....
Time for a sedative......

*Edit: Well, at least this one got through......
Buzzcut1
Nomad II
Dec 20, 2020
Bert the Welder wrote:

Agree, but check the wire going from your engine back to the camper plug. If it's way undersized, as is often the case, nothing else matters until that gets an upgrade. You can't blow a golf ball through a garden hose..... :)
.

That's the reasoning behind why lance recommends skipping using the trucks wiring harness and trailer plug and running 8 gage wires directly from the battery (positive and negative) through a 40 breaker and into the Lance bed plug at the front of the bed. Bigger pipe shorter run.
Bert_the_Welder
Explorer II
Dec 20, 2020
riah wrote:
I think its more related to the truck electronics than to the batteries, as charging the camper batteries off the truck is an issue with lead acid batteries as well! We had similar issue with charging our typical auto batteries (lead acid) we were using for our TC solar system. We too thought we should be able to charge them off the SD F350 as it had a second alternator, but it didn't seem to work very well. So now we are looking at the DC-DC charger option so that when we get our LiFePO4 replacement batteries we will be able to keep them charged when it's overcast and we are driving, as that seems to be a missed opportunity for us currently without it.

Agree, but check the wire going from your engine back to the camper plug. If it's way undersized, as is often the case, nothing else matters until that gets an upgrade. You can't blow a golf ball through a garden hose..... :)
That's a lesson I gleaned from folks here. It's all a system. Look at each section, start to finish and can each component along the way handle what the previous one is throwing at it.
And I also learned that camper electrical is better left to someone else. The tough part is finding that someone else that is trustworthy....
billtex
Explorer II
Dec 20, 2020
The “delay” is interrupted when you step on the brake pedal. A fail-safe Ford built into the charge system.
theoldwizard1
Explorer II
Dec 19, 2020
riah wrote:
So now we are looking at the DC-DC charger option so that when we get our LiFePO4 replacement batteries we will be able to keep them charged when it's overcast and we are driving, as that seems to be a missed opportunity for us currently without it.

A second alternator is really only useful when your vehicle has very heavy loads (additional lighting, electric powered hydraulic pumps, etc).

A DC to DC charger is the only way to fully recharge a RV house battery bank. And they do not need extra heavy duty wire !
theoldwizard1
Explorer II
Dec 19, 2020
Bert the Welder wrote:
Thanks. I'll look him up and try to find the vid's. It certainly seems like having something like the DC2DC is needed for the "new" type batt's.

First, I worked for Ford designing Powertrain Control Systems for over 30 years until 2007, so I DO KNOW what I am talking about. Yes, I am sure things have changed since then and different manufacturers do things a bit different.

Second, there are really two issues here. Is the alternator capable of putting out sufficient voltage and current to charge a RV "house battery bank" (1 or more batteries wired for 12V nominal) AND are voltages directly from the alternator "optimal" for recharging a house battery bank.

Almost all vehicles built after about 2000 have some type of "smart charging" system. Theses systems are designed to only replace the amount of energy used to start the vehicle and not let addition loads cause the starting battery to discharge. In simple terms, immediately after starting, the voltage at the starting battery will be about 14V. Within about 5-10 minutes, that voltage will drop done to about 13.2V at the starting battery. Even with the heaviest gauge wire you can install, you are not going to get more than about 13.2V at your house battery bank ! This is not sufficient to recharge a house bank that is below 80% SOC !!

Different battery chemistries require different voltages for optimal and complete charging. Flooded lead acid is different than AGM is different than LiFePO4.

A DC to DC charger, install close to your RV's battery bank, will BOOST the incoming voltage and apply the correct voltage to your battery bank !

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"Newer" Ford trucks don't charge house batt's?

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