Tapping 12V from the truck to charge Battle Borns

[howson]

Howard,

From your post #56 I believe this is an aux circuit on your truck which is powering down when the door is opened or when the vehicle is shut down, etc. If your not liking this operation, you could NOT use this circuit, and connect your DCDC ignition circuit to the marker/running light circuit. This is what I'm planning to do.

Jim

Yep, I'm going to give it a go. Super easy just to move the wire in the MICTUNING box. Then I can use the truck's light switch to turn off the D+ signal.

Even if I forget to turn off the Renogy DC-DC Charger prior to turning off the truck the power to the relay that passes battery power will deenergize when the truck is turned off. Only possible "gotcha" that I can think of is if the truck is in Accessory mode, I forget and leave the Upfitter switch for the Renogy on, AND I have the truck's lights on. That will send truck battery power (with the engine off) back to the Battle Borns--something I don't want to happen.

Post 48's schematic only needs a minor update to reflect the change. I'll do that soon. (I hope to swap the wire tomorrow if the weather cooperates.)

[Guest]

Howard,

I may not be clear on your setup. Are you planning to have a dual power circuit from the truck aux switch (from the overhead console) and also from the marker lights?

Jim

[howson]

Howard,

I may not be clear on your setup. Are you planning to have a dual power circuit from the truck aux switch (from the overhead console) and also from the marker lights?

Jim

No, not dual power. There's only one power circuit. Power comes from the truck's battery through a relay (controlled by an Upfitter switch in the truck cab). I can disconnect power going to the DC-DC Charger by turning off the relay.

The "other" 12v I'm referencing is the D+ signal required by the Renogy. (You'll have to read this thread again to fully understand.) Without that 12v D+ signal the Renogy does nothing with the power coming from the truck. I used the truck's original battery charge line in the 7-pin connector for the D+ signal in the original setup. Because of how Ford turns off the charge line when the truck's door is open or the International Space Station orbits overhead (sarcasm) it's causing chaos with the Renogy. Getting the D+ 12v signal from the running light circuit will be more consistent and easy to turn on and off.

Clear as mud?

Look again at the schematic in post 48. Just substitute running light power for the charge line power (clearly marked as the D+ signal) and you'll get it!

[Guest]

I got it Howard. I had thought the D+ was the relay controlled line from the truck. I believe we are thinking exactly in the same way to just run what is the DC DC ignition input ( your reference to D+) off the marker lights. I will be doing this but still need to understand if the draw on the DCDC can overcome my 7 pin charge line circuit protection. When I have a chance I will look up the drawings on my truck. Since I'm not running the fridge when driving ( I do like this) I'm hoping to use the power wire in the 7 pin to run the DC DC and the marker lights to energize what you are referring to as the D+ line.

Jim

[howson]

The charger setup is working flawlessly now that I am using the truck's light switch to trigger the D+ signal on the Renogy. (I moved the D+ signal wire from the charger post to the running light post in the Mictuning box as mentioned in a previous post.) Very easy to control when charging is activated using the light switch (for the D+ signal) and the relay (via an Upfitter switch) for the power transmission wires.

I have found that the right sequence to turn everything on is to first disable the Victron SmartSolar charger enable signal (using the Victron Connect app). Then apply the D+ signal by turning on the truck's lights. Then turn on Upfitter Switch 2 to allow the relay to pass power to the Renogy. I monitor the BMV-712 (again, using Victron Connect app) and can see the amperage going from negative (out of the battery to run the refrigerator through the inverter) to positive (back into the battery to recharge them AND run the refrigerator). I then re-enable the SmartSolar Charger Enable and solar is then added to the current flow (if any). Again, I can see this by monitoring the BMV-712 in the VictronConnect app.

On one day of this trip I didn't bother turning on the Renogy as solar was providing all that was needed to the camper to run the refrigerator and keep the batteries charged. On the other days it has been cloudy with a lot of rain. Almost no output at all from the solar array. (I'm in Atlanta at a campground and, as I write this, the solar panels are generating a whopping 27W. Rain, rain, rain....)

I am very, very pleased with the results of this mod. It's a really sweet setup if I say so myself.

[howson]

Final schematic:

[howson]

Some actual BMV-712 screenshots from today's tow home.

Screen Shot 1: Renogy off and solar off. Refrigerator is on (thus the amperage draw from the batteries).



Screen Shot 2: Renogy on, solar off. Note the 40A difference from the first picture.



Screen Shot 3: Renogy and solar on. Only getting 184W from my 1200W solar setup--overcast with spotty rain showers today.



Bottom line: If you have one or more LifePO4 batteries, a DC-DC Charger is something you should seriously consider. Shoot--if I'd installed the DC-DC Charger with the initial system I could have probably gotten away with two (versus four) Battle Borns and saved a wad of cash.

As documented in this thread, though, installing the Charger was not easy.

-Howard

[ncitro]

howson I am preparing to embark on this (made more difficult with a fifth wheel) and I had a couple questions. What size split loom did you go with for the 4AWG copper. I was thinking 1/2", 4AWG should be .20" each, so I was not sure if 1/2" would be big enough. I know sometimes that stuff can be hard to work with. Also I was considering the 60 amp version, but the book from Renogy only has sizes for shorter runs. With a long bed truck I figure my run from the front bay of the rig to the front of the truck to be 25 feet or so. I think since the book does not show a size past 8 foot, they either do not want you going that far, or the size becomes prohibitive. Was curious what your thoughts were. I am sitting on 400ah of lithium batts, with eyes on two more, so the additional charging capacity after a few cloudy days boondocking would be nice while driving. We had this exact situation a few days ago, left a friends driveway with 5% left. The truck and solar kept up, but it was pretty cloudy. We were headed to a park with hookups, so it worked out fine, but the extra charging capacity would be nice on those rainy cloudy days.

[howson]

howson I am preparing to embark on this (made more difficult with a fifth wheel) and I had a couple questions. What size split loom did you go with for the 4AWG copper. I was thinking 1/2", 4AWG should be .20" each, so I was not sure if 1/2" would be big enough. I know sometimes that stuff can be hard to work with. Also I was considering the 60 amp version, but the book from Renogy only has sizes for shorter runs. With a long bed truck I figure my run from the front bay of the rig to the front of the truck to be 25 feet or so. I think since the book does not show a size past 8 foot, they either do not want you going that far, or the size becomes prohibitive. Was curious what your thoughts were. I am sitting on 400ah of lithium batts, with eyes on two more, so the additional charging capacity after a few cloudy days boondocking would be nice while driving. We had this exact situation a few days ago, left a friends driveway with 5% left. The truck and solar kept up, but it was pretty cloudy. We were headed to a park with hookups, so it worked out fine, but the extra charging capacity would be nice on those rainy cloudy days.

I went with 1.25". It worked well with the Windy Nation 4ga wire (thick insulation).


I don't know the exact size, but super big heat shrink simplifies making the ends look nice.



If I'd stuck with my original goal (over a year ago) of just powering the refrigerator while towing, I could have gone with 1 Battle Born and a 2000W inverter and saved a wad of cash. Glad I have the setup I have, though, as it gives me a lot of flexibility while traveling. I *really* like this mod--just be aware it is time-consuming to get it "just right". There's plenty of opportunity to mess something up.

Edit: In that picture above there is small loom at the top near the connectors running into the larger 1.25" loom. Look closely and you can see where they join up. I had the small loom on hand so I don't know it's exact size.

The 40 amp is perfectly suited for powering the refrigerator as I've shown with the BMV screen shots. There's even a bit left over for the batteries. When the solar is cranking on a nice day I don't even bother turning on the Renogy. Having both makes it easy to select one, the other, or even both as charging options.

Feel free to ask away if you have any further questions.

[ncitro]

howson yeah I think the larger size would definitely make it easier to pull the wire thanks for the link.

As you know, I’ve replaced my fridge with a residential, because of that I think it uses less power when running off the inverter vs the a absorption. I agree though about having the choice of charger. Really it’s more and more clear to me that any approach to power management needs to be a combination of improved converter charger, solar, vehicle charging, and maybe even generator.

When I installed my solar last spring I debated about doing a DC to DC charger, but the effort needed to run the wires through the pin box to the front compartment caused me to blink and just do the solar. In the last year I’ve found that the solar does great most of the time, but on occasion (mainly a series of cloudy days) it has been inadequate. In those cases I would fire up the generator when we’d stop for lunch and top off a bit, but it would be nice to not need that for sure.

I’ve grown particularly fond of the 125 amp charging capability of my Magnum inverter/charger. While at the balloon fiesta last fall I found the lithium batteries took the full 125 amps right up to about 98 percent charge. That has cut down on generator run time significantly.

[ncitro]

howson So I embarked on this project over the weekend and wrapped up the truck side. In an unrelated issue, someone keyed my truck in February and I finally got to a body shop today to get it looked at. In order to fix the damage, they need to pull the bed off of the truck as they managed to damage the back of the cab a bit as well for good measure. When I ran the cable I did not have pulling the bed in mind, and am now faced with either pulling it down and tying it out of the way, and then rerunning it, or finding a way to put a plug inline to facilitate pulling the bed. I thought , while I have never had to have a bed pulled, it might be best to plan for that, so I should consider it. I bought extra Anderson connectors, do you know if they are weather tight that you would have one under the frame, connected all the time in rain, snow, salt, and god knows what else? I know the factory plugs under there have rubber seals around them, and the Anderson does not, so I am inclined to think its not, but I suppose since I have them I could use it and replace it down the road if it wears out.

Any thoughts?

[howson]

howson So I embarked on this project over the weekend and wrapped up the truck side. In an unrelated issue, someone keyed my truck in February and I finally got to a body shop today to get it looked at. In order to fix the damage, they need to pull the bed off of the truck as they managed to damage the back of the cab a bit as well for good measure. When I ran the cable I did not have pulling the bed in mind, and am now faced with either pulling it down and tying it out of the way, and then rerunning it, or finding a way to put a plug inline to facilitate pulling the bed. I thought , while I have never had to have a bed pulled, it might be best to plan for that, so I should consider it. I bought extra Anderson connectors, do you know if they are weather tight that you would have one under the frame, connected all the time in rain, snow, salt, and god knows what else? I know the factory plugs under there have rubber seals around them, and the Anderson does not, so I am inclined to think its not, but I suppose since I have them I could use it and replace it down the road if it wears out.

Any thoughts?

Wow--that stinks about your truck. Sorry you've got to deal with the hassle.

If it was me facing the problem of having the bed pulled, I'd remove the wire. In my case that's all the way from the 60A circuit breaker at the firewall to the back of the truck. I wouldn't be happy about it. I'm a moderator so I can't really express any stronger how I feel about that (language wouldn't be forum-friendly).

The alternative suggested could work, but connections tend to have some resistance, or build resistance over time due to corrosion. In a high-amperage, low-voltage line unnecessary resistance must be avoided. Given the environment the connection will "live" in, there's some probability of problems in the future due to corrosion.

Pulling the bed is (hopefully) a one-time event while you own the vehicle. Again--I'd remove the wire.

Guest (Jim), Cate&Rob (Rob), or anyone else--anything I may be overlooking?

[ncitro]

Wow--that stinks about your truck. Sorry you've got to deal with the hassle.

If it was me facing the problem of having the bed pulled, I'd remove the wire. In my case that's all the way from the 60A circuit breaker at the firewall to the back of the truck. I wouldn't be happy about it. I'm a moderator so I can't really express any stronger how I feel about that (language wouldn't be forum-friendly).

The alternative suggested could work, but connections tend to have some resistance, or build resistance over time due to corrosion. In a high-amperage, low-voltage line unnecessary resistance must be avoided. Given the environment the connection will "live" in, there's some probability of problems in the future due to corrosion.

Pulling the bed is (hopefully) a one-time event while you own the vehicle. Again--I'd remove the wire.

Guest (Jim), Cate&Rob (Rob), or anyone else--anything I may be overlooking?

Yeah it’s real bite. I could use a few voice four letter words, repair is quoted at $3,100. And get this I was parked at Fort Wilderness at Disney World of all places. I had put the truck up in the remote lot for a few days since we had company staying with us and I had them park at the site. Of ask the places I’d have thought it would be fine. I checked with them, no cameras or anything. They felt really bad, but nothing they could do to help. You have to go through a security gate to get in too. It’s not Fort Knox or anything but still. Sad comment on people.

You’re probably right. Since I’m fifth wheel I ran my cables up through a hole in the bed too, so I’ll have to take my Anderson connector apart as well. My body shop is really close to home, so I think I’d just pull the cable out back to the cab and coil it up underneath out of the way rather than unhook it back at the breaker.

[Guest]

Really unfortunate and sad that it would happen anywhere, much less at Fort Wilderness. It may be best to pull the wire out. This way the body shop will not damage it.

Hopefully better times are ahead,

Jim

[ncitro]

Really unfortunate and sad that it would happen anywhere, much less at Fort Wilderness. It may be best to pull the wire out. This way the body shop will not damage it.

Hopefully better times are ahead,

Jim

Thanks, I am leaning the same direction. I have never had to have a bed pulled yet, probably not likely it would need to happen again.