Battery charging while under way

[Camper_bob]

So, I've been thinking about a process or mod or something for quite some time regarding my battery.

I am thinking about this from the perspective of short over-night "wally world" stays during long road trips.

Since the truck doesn't really offer effective charging, I was thinking about ways to plug my generator into the trailer while under way. Let the on-board smart charger do the work for me and keep my battery topped off and in good condition so I can land at the next stop with a full charge. An added benefit would be that the fridge could run on AC power and save some propane (I'm using the gas anyway right, may as well save the propane).

One option would be to install a hitch receiver attached to the frame at the rear of the trailer and just plug the trailer into the 30A RV port on the genny. My receptacle is on the very rear street-side wall, so the cord run would be very short, and my receptacle is a twist-lock, so I wouldn't worry too much about the plug falling out. Also, the roof ladder is right there in the vicinity, so I could use that for additional support for the cord. Run the generator for a few hours and get the battery charged up while under way. In this scenario, I could even run the AC if I wanted and get the trailer cooled down ahead of my arrival at camp.

Another thought I had was to adapt the 50A plug down to a 20A and run an extension cord attached to the underside of the TT up to the generator in the bed of the truck.

Any thoughts on this? Anyone ever tried running a generator for a TT underway? With the potential for two days on the road this Fall, I worry about running the battery out between overnight stops and stops throughout the day.

 

[ctbailey]

Two days pulling and only two nights sleeping in the unit while getting to the destination will not flatten the house battery.

You're just using a tiny amount of house lights and a few runs of the water pump.

This sounds like a whole lot of (unnecessary) work. Once you hit Wally World parking lot, run the genny in the pickup bed for an hour. You're fridge only sips propane.


Craig Bailey
New England
2007 Chevy 2500HD crew
2015 Jayco Jayflight 32BHDS

 

[Rustic Eagle]

snip..... Once you hit Wally World parking lot, run the genny in the pickup bed for an hour. You're fridge only sips propane.......snip

That's what I would do if there was a concern about battery amp usage.

If the TT still has the OEM RV Marine/Deep Cycle battery, upgrading to a true Deep Cycle battery will provide increased amp capacity.

Another thought would be to incorporate a heavier gauge wire (by-passing the standard 7-pin charge wire) from the TV's engine compartment charging system back to the TT battery. The heavier gauge wire will produce more charging amps at the TT battery then the 7-pin connection.

Just thinking out loud.....

Bob

 

[Mustang65]

So, I've been thinking about a process or mod or something for quite some time regarding my battery.

I am thinking about this from the perspective of short over-night "wally world" stays during long road trips.

If you just want to use your TV to charge your TT battery(s), you can do what I did when we towed a TrailManor with a Honda Mini-Van. I ran a 4AWG from the rear 7 pin connector to the battery, where I connected it to a 20Amp breaker. I connected the breaker to the battery. I measured the output to the partially discharged TT battery and it was 14 amps. That was plenty to charge the battery.

You just need to supply a big enough pipe to get the needed charging power to the TT's battery, your alternator will provide the additional amps. I also replaced the wire on the TT's cable also.

Never had a low battery, I am spoiled now with SOLAR... allows me to keep the fridge running on AC while traveling (with the TT's inverter on). DW is happier since we do not use the LP for travel, I guess I am too.

Don

 

[Seann45]

For the amount of money and work involved in doing this I think you would be better off with a 80-150 watt solar panel on the roof..

 

[mike837go]

My advice is like baily and eagal's....


Several hours of driving will put more than sufficient power into the trailer's battery for a simple overnight.


If you leave your home with a topped up battery (you were plugged into shore power during preparations), you will arrive with a full battery.


As long as you just run lights, water pump and charge the phones, you won't use much electricity on the overnight. 2-3 hours of driving will recover that easily.

 

[Camper_bob]

The more I think about it, the more I see that you guys are right about keeping the battery topped up. I'm just worried that with the furnace running, I'll run the battery down further than my truck will be able to charge it back up. But at the same time, I should be at a park with power the second night, so I can just plug in to shore power there and be GTG.

I think also if I start out with a better battery, that might be a more worthwhile "upgrade". I'm still using the original dual purpose Interstate (that has been completely discharged at least once, and is at least 3 years old) that won't take a full charge. I was planning to replace the battery anyway, but I thought with a generator I could put it off a while longer.

So now I'm thinking I'll skip the generator completely (I don't have one yet) for now. I like the idea of getting more charging amperage with a thicker wire from the engine bay though. That might be something I could do pretty easily and could be more useful under other circumstances as well. I use the truck for hunting too, and there are a lot of things I could do with a nice charging wire at the rear of the truck...

I've got a lot of ideas rattling around in my head, and it helps me sort them out with input from this forum. So thanks for that!

 

[Jagiven]

From my experience if I have a 50% charge on my battery (12.0V) it takes about 6 hours of driving to fully charge the battery. The key when charging off the TV, is time, usually if I am staying in a Walmart parking lot, it’s a long days drive. So I am not worried about recharging the battery.

I have seen (heard) many times, in a Walmart parking generators connected to the TT. I just recommend parking away from others when doing such.

 

[Mustang65]

I think also if I start out with a better battery, that might be a more worthwhile "upgrade". I'm still using the original dual purpose Interstate (that has been completely discharged at least once, and is at least 3 years old) that won't take a full charge.

Just to give you an idea as to how much power your battery has left, take a look at the battery test (using a wind turbine dump load resistor) that I did on my original 85Ah battery that came with the TT 4 years ago. It has never been discharged below 12.0 Volts and has always had a charge on it. I used it for my work bench electrical projects and as a UPS supply for my home office. Even keeping it healthy, its age took a toll on it.

RVing with SOLAR battery Ah test

Since you only use the battery for over night stops, I would just purchase a 12VDC battery that has 100Ah (inexpensive Interstate 100Ah should do the trick), that should get you through the night with no issues. Interstate, Trojan, USBattery all have them. If you are thinking of longer stay overs, then you may want to look at other power sources, SOLAR , generators, more batteries....

The Honda rewire job took an afternoon to install.

Don

 

[haphapcamp]

Plus today's vehicles are not like when I first started driving when alternators were in the 40-63 amp range. Today 150 amps or more are the norm and don't some diesel rigs come with 2 alternators? I have never showed up anywhere without a full charge in my TT with my 145 amp alternator in my TV.

 

[Camper_bob]

Just to give you an idea as to how much power your battery has left, take a look at the battery test (using a wind turbine dump load resistor) that I did on my original 85Ah battery that came with the TT 4 years ago. It has never been discharged below 12.0 Volts and has always had a charge on it. I used it for my work bench electrical projects and as a UPS supply for my home office. Even keeping it healthy, its age took a toll on it.

RVing with SOLAR battery Ah test

Since you only use the battery for over night stops, I would just purchase a 12VDC battery that has 100Ah (inexpensive Interstate 100Ah should do the trick), that should get you through the night with no issues. Interstate, Trojan, USBattery all have them. If you are thinking of longer stay overs, then you may want to look at other power sources, SOLAR , generators, more batteries....

The Honda rewire job took an afternoon to install.

Don

Thanks! Yeah, I read about your test the other day, good info. My battery certainly hasn't been treated as good as the one in your test. Like I said, it's been completely discharged at least once, probably more than that. So, I'm planning to go with an upgraded battery. Probably a Trojan if I were to decide and order it right now today, but I'm still researching what I really want/need. I've been tossing around the idea of running dual batteries, but we so infrequently go without power, I don't think it's necessary. Same for solar. I like the idea, we just don't generally use the trailer that way. In fact, in almost 3 years, we have never spent a night in the trailer without some kind of shore power.

Plus today's vehicles are not like when I first started driving when alternators were in the 40-63 amp range. Today 150 amps or more are the norm and don't some diesel rigs come with 2 alternators? I have never showed up anywhere without a full charge in my TT with my 145 amp alternator in my TV.

My truck is a gasser, but it's a "Tradesman" and came with 2 160A alternators (designed for ambulance/firetruck use). So, yeah, I got the power, just need to see about getting it to the rear bumper. As it is, if I can get a good charge back on the battery after 6 hours of driving, that should be sufficient; my first day will be 8 hours (maybe more) and second day around 6, then we're on shore power for 4 days solid. I wish I had a second battery in the truck to drive an inverter, but that's a project for another time; perhaps a good use for the old TT battery after I replace it (in the short term, it'll be a good battery to "learn" with).

 

[Preacher87]

Camper_bob, if your truck came with the tow pack from factory, you're likely getting a good 15 amps of charge, if not more through your 7 way connector.
If this doesn't fill the bill, get yourself a winch connector.

You can pull several hundred amps through them when wired correctly. Wire it from your front batteries on a solenoid that is ignition controlled (so theres only power transfer when the engine is running) to the rear bumper, then run it the rest of the way to the trailer batteries.

 

[BuddyRay]

I've given this a lot of thought as well and my problem is with the excessive "intelligence" in the 2016 Ford (and probably other brands.)
The 'charge' wire from under the hood to my 7way is a 16 ga wire. There is no way that this wire will provide a decent charge no matter what alternator the truck has.
That wire is also a sensor wire that tells the onboard computer that the attached trailer has a battery. And it's deeply imbedded in a long and complicated wiring harness - no hope of tracing where the other end comes out.
If I replace or bypass this line I have no idea what impact this will have on the onboard computer. For example if I run a 6 or 4 ga wire from the TV battery to the 7way and cut the original wire, the computer will never understand there's a battery back there-and perhaps that won't matter-or perhaps it will upset the charge system.
And if I leave both wires connected - the onboard computer will see it's own battery on that line and think it has a trailer back there even when it doesn't.
I do think running a completely separate circuit back through its own connection (such as a winch connector) might work.
I just think it is a shame Ford doesn't understand the need for a good stiff charge line.


Sent from my iPhone using Tapatalk

 

[Mustang65]

I've given this a lot of thought as well and my problem is with the excessive "intelligence" in the 2016 Ford (and probably other brands.)
The 'charge' wire from under the hood to my 7way is a 16 ga wire. There is no way that this wire will provide a decent charge no matter what alternator the truck has.

If I replace or bypass this line I have no idea what impact this will have on the onboard computer. For example if I run a 6 or 4 ga wire from the TV battery to the 7way and cut the original wire, the computer will never understand there's a battery back there-and perhaps that won't matter-or perhaps it will upset the charge system.
And if I leave both wires connected - the onboard computer will see it's own battery on that line and think it has a trailer back there even when it doesn't.
I do think running a completely separate circuit back through its own connection (such as a winch connector) might work.
I just think it is a shame Ford doesn't understand the need for a good stiff charge line.


Sent from my iPhone using Tapatalk

To ease your mind the F150 uses the blue wire (brake controller) to determine if there is a trailer connected to the TV (sees the resistance from the TT's brake circuit). The Trailer's 12VDC charging wire goes to the trailer charging relay under the hood (the one you need to install, for some reason Ford does not install it and leave it in the glove box). The relay is activated by the ignition switch. There is no computer connection to this charging circuit. As for charging the TT battery, if the TT's battery voltage is lower than the TV's battery voltage it will pull the TV battery lower and the trucks alternator voltage monitor will increase the Voltage/Amps to the 12VDC trucks battery, which also charges the TT's battery.

Don

 

[BuddyRay]

Thanks Don, but your information is out of date. 2014 was the last year Ford used a charging relay that had to be installed.
They changed in 2015 and again in 2016 they changed pretty much all the electronics behind the dash to a Ford engineered solution (they used to use a Microsoft Solution).
The result is that the whole system is much more integrated and much more complicated. I know it uses more than the brake line - because it can detect my boat trailer (5 pin) or a U-Haul trailer (4-pin) neither of which have a brake line or a charge line. It appears to be detecting all three (lights, brake and charge) and determining what type trailer you have based on what it finds. It then configures a bunch of stuff in the electronics based on that determination.
That makes it scary stuff to start changing wiring.

 

[Mustang65]

Thanks for the update, I have to go to Ford for my oil change next week, so I will see if the parts guy will print me out a new wiring diagram. I will take a look at it and see what the options may be

Don

 

[Camper_bob]

I'm not sure my RAM is as smart as that Ford BuddyRay is talking about.

I'm still thinking perhaps the best and simplest solution I have is to run a charge wire directly from the front engine bay to the rear. If I went directly off one of the alternators, I wouldn't have to worry about discharging the current battery right? It would only work if the truck was running? I guess I still have a lot of research to do here ...

I've been toying with the idea of making a plug to terminate at the rear like Preacher87 mentions. This would allow me to use whatever I want back there. I could plug in a winch, I could charge my battery, I could plug in an inverter (we have a water pump that we use at the ranch this would work perfectly for); the possibilities are nearly limitless.

 

[Preacher87]

(snip)

I've been toying with the idea of making a plug to terminate at the rear like Preacher87 mentions. This would allow me to use whatever I want back there. I could plug in a winch, I could charge my battery, I could plug in an inverter (we have a water pump that we use at the ranch this would work perfectly for); the possibilities are nearly limitless.

*cough cough* Jumper cables *cough*

 

[Camper_bob]

*cough cough* Jumper cables *cough*

LOL!! Funny you should say that. My brother recently did exactly that!! I think I'll hit him up for ideas.

His was so that he could run a winch on a trailer. He likes to resurrect "dead" cars, so he often has to pull them up onto his flatbed trailer. So he "fashioned" a set of jumper cables to run his trailer-mounted winch to make that process easier.

 

[M&A]

Plus today's vehicles are not like when I first started driving when alternators were in the 40-63 amp range. Today 150 amps or more are the norm and don't some diesel rigs come with 2 alternators? I have never showed up anywhere without a full charge in my TT with my 145 amp alternator in my TV.

X2