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

time2roll wrote:

noteven wrote:
I have a question:

If I have 2 x 100ah LiFeO4 house batteries with a charge rate spec of "1C" sitting at 20% after a rainy few days in the forest, how long does it take to charge these batteries via the truck engine when I start up and drive away, using the "7-way" connection?

I figure a 40amp DC-DC charger recharges them fully in 4 to 4-1/2 hours.

Only trouble is most 7-pin connectors have OEM #14 wire and a 40 amp fuse. Good chance that 40 amp DC-DC will pull 50/60 amps and open the fuse resulting in no charge. I recommend 20 amp DC-DC if using the OEM 7-pin connection.

I didn't word that right - how long will the standard 7 way pin system take to recharge Li batteries?

Twenty year old camper, that’s how big the battery box is. It will only hold one battery, and a group 31 is the biggest that will fit. It is an AGM, so I don’t have to pay much attention to it. It would take some major remodeling to install a bigger box.

I’ve had an idea rolling around in my head for years of redesigning the step up into the overcab bed to include a a second big AGM battery there. That’s pretty doable for me, as we need the step anyway. But you know. $$$, time, effort, blah blah. :W

Oh, and if I were to do that, the battery I’d put there probably wouldn’t be THAT much less than $450. Might even be more, and I’d still need a good way to charge it while driving. I might not need 30 amps though, having more depth with two batteries.

:):)

Maybe I missed it-why a single battery? Just adding another battery will address a lot of your power needs. That’s even less $.

I think I’ve explained my needs pretty clearly, and what lead me to the Redarc charger. Solar won’t scratch every itch, and I don’t claim a B2B charger will either. Especially if your style is to drive a few hours to a destination, then that’s where you are for XX number of days. But if your traveling style includes a fair amount of driving just about every day, why WOULDN’T you take advantage of the charging potential you can harvest from the truck? It’s not like it hurts the fuel mileage, or is killing the alternator. And remember, I mentioned that my Redarc has a solar input built in. I could have bought a B2B that doesn’t have a solar input, but I chose this one because it does. Does that sound like I’m avoiding solar? I just haven’t installed it yet.

What kind of solar system would I have to install to get a minimum of 30 amps of charging potential so my single group 31 battery doesn’t get flattened by the fridge? That works regardless of what the weather is doing? That works at night? For about $450?

There’s not an abundance of available room for solar panels or more batteries on my camper. Yes, I could shoehorn some in here and there, but there’s only so much I’m able and willing to do on that front. Now that lithium is more of a viable option, I could maybe do it with a single panel of the right type, a battery pack of the right size, and an MPPT controller that has both a solar and a B2B input. But not for $450. And there’d still be that bad weather and night thing.

Keep in mind that I said we don’t always know where we’re going to spend the night. Most of the time we don’t, and I need to be able to camp totally without hookups for at least a few nights on a moment’s notice. Do we always dry camp? No, we go with the available and convenient options where we are, but I need dry camping to always be an option. Not having to immediately turn on the built in generator that’s convenient but isn’t quiet, or drag out and hook up the Yamaha 1000 that’s quiet but isn’t convenient, so I can charge the battery up before going to bed is priceless to me.

:):)

It’s amazing the trouble some Folks go through to avoid getting solar panels and AGM’s. I have not opened my battery compartment-literally -in probably 6 or 7 years.

B2B chargers need to be as close to the battery they are charging as possible. No sense boosting the voltage to just run it through a long circuit that induces voltage loss.

I put mine under the galley sink, right next to the battery box that also under there. There’s about 18” of wire between the B2B output and the battery terminals.

:):)

noteven wrote:
I have a question:

If I have 2 x 100ah LiFeO4 house batteries with a charge rate spec of "1C" sitting at 20% after a rainy few days in the forest, how long does it take to charge these batteries via the truck engine when I start up and drive away, using the "7-way" connection?

I figure a 40amp DC-DC charger recharges them fully in 4 to 4-1/2 hours.

My Fords as far as I could check had all #10 charging wire and 30 amp fuse, or on 2017 breaker.
Breaker seems to be oversensitive, but I never really put meter on it.
Where would you put B2B charger? That will make big difference.
You can't draw 40 amp from 30 amp circuit.
30 amp time 4 hr gives 120 Ah (less heat loses) but charging amp are not linear.

noteven wrote:
I have a question:

If I have 2 x 100ah LiFeO4 house batteries with a charge rate spec of "1C" sitting at 20% after a rainy few days in the forest, how long does it take to charge these batteries via the truck engine when I start up and drive away, using the "7-way" connection?

I figure a 40amp DC-DC charger recharges them fully in 4 to 4-1/2 hours.

Doubt they’d ever fully charge via just the pigtail and no actual Charger.
However all this speculation, if one wants to figure it out, get an amp meter and see how your vehicle and and camper behave.

These are the cable size recommendations for installing the 25 and 40 amp Redarc chargers.



Just to get 4 AWG wires from the truck starting batteries, through a CB and ignition controlled solenoid, then under the crew cab and to the front wall of the pickup bed, I ordered 25 ft each of red and black fine stranded welding cable from TemCo. You’d be surprised how little of that cable was left over. The circuit length was just over 20 ft just to the plug at the front of the bed.

I had to order a little more cable to upgrade the wires in the camper umbilical cord to the battery. The total circuit length by the time I finished was just under 30 ft.

I don’t think you’ll be happy with the performance if you try to use the OEM circuit through the 7-way plug. You’ll either be blowing fuses or having an auto-reset CB constantly clicking off and on because it’s heating up.

:):)

noteven wrote:
I have a question:

If I have 2 x 100ah LiFeO4 house batteries with a charge rate spec of "1C" sitting at 20% after a rainy few days in the forest, how long does it take to charge these batteries via the truck engine when I start up and drive away, using the "7-way" connection?

I figure a 40amp DC-DC charger recharges them fully in 4 to 4-1/2 hours.

Only trouble is most 7-pin connectors have OEM #14 wire and a 40 amp fuse. Good chance that 40 amp DC-DC will pull 50/60 amps and open the fuse resulting in no charge. I recommend 20 amp DC-DC if using the OEM 7-pin connection.