A little solar advice

[caissiel]

I have increased the power wire from the truck batteries to the trailer plug to 10 ga. wire and with both alternator I only got 23 Amps same as the power plant did through the converter. The original switched wire did not supply enough power to charge my trailer batteries properly on the road. Might work for one battery but not 3.

So for me it was a no brainer that a 200 watts solar system would do the job.
Since the installation I see 14.7 volts and 100% battery charged by noon. Something that I never saw before.
The solar panels for me do most of the work, and serve the unit very well with 3 batteries.
Now I never unplug the truck as the solar panels keep the batteries at max power.

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[wdk450]

As someone experienced in electrical stuff, I think the main limiting factor on how many amps can be delivered to the trailer from the tow vehicle is the amperage capacity of the standard umbilical cable connectors (10A.?). I think that the truck wiring engineers then wire to that limit. I have heard of owners custom wiring their own connections to the truck battery/alternator, and these mirror the dual battery charging systems used in motorhomes; with a self-resetting circuit breaker near the truck battery connection, a new large cable from the battery to the rear of the truck, a connector capable of the maximum amperage allowed by the circuit breaker to the trailer (along with a same sized cable and connector for the ground return current), and another section of large cable (and ground cable) to the trailer's battery. Some even do not trust the truck's frame for the ground return and wire the charging ground cable all the way to the truck's battery.

 

[dave10a]

Well at the theoretical max from my truck alternator is 25 amps because of the circuit breaker in the TV and 16 amps from the solar panel. That's 41 amps theoretical. In reality its near 20 amps from the truck and near 12-13 amps from the solar panel which give approx 30 amps total on a clear sunny day. My 4 agm type 24 12 volt batteries are rated at 440 amps-- so at 50% charge that is 220 amps. Therefore at 100% charge efficiency I need 220 amps pumped into the batteries which would take 7hrs on a good day while driving. Unfortunately the batteries don't take a charge at 100% efficiency and is more like 80-90%+ I would guess.

 

[scottyb]

Interesting topic. I've often wondered how many amps are supplied from the TV. I also have dual alternators but it sounds like the limiting factor is the wiring, not the alternator? I have 4 6V batteries which gives me 450 Ah. I am running an el cheapo inverter to run a wine fridge during travel. My batteries are usually topped off beginning a trip and I assume the charge from the TV overcomes the drain for the wine fridge and keeps them topped off. It sound like if I pulled the batteries down to 50%, it would take many hours to replinish their charge, while at the same time using the fridge. Do any of you use an AGS. It seems to me that it would be nice to have, especially if you have a residential fridge.

 

[Jimsryker]

I have 4 6V batteries which gives me 450 Ah.

Hey Scottyb. Thinking of going to 6 volt myself. Kind of off topic, but can I ask where you locate your batteries? My 3010 has a battery area in the front by the gen. but I'm doubtful it can handle 4 batteries. Then there are my concerns regarding overall weight capacity of said area. Have you changed the location? Using a slide out tray? Sorry I don't know the configuration of the 4100, so all my questions may seem inane. Anyone please feel free to pipe in here....

 

[scottyb]

Hey Scottyb. Thinking of going to 6 volt myself. Kind of off topic, but can I ask where you locate your batteries? My 3010 has a battery area in the front by the gen. but I'm doubtful it can handle 4 batteries. Then there are my concerns regarding overall weight capacity of said area. Have you changed the location? Using a slide out tray? Sorry I don't know the configuration of the 4100, so all my questions may seem inane. Anyone please feel free to pipe in here....

It is tight but I have them in the front compartment in 2 boxes made for 2 6V each. I did this because I started out with two and added two more later. I don't have any pictures but here is the way I would have gone if I started out with 4. Quad 6V Battery Box . It gives you the dimensions you need.

 

[dave10a]

Interesting topic. I've often wondered how many amps are supplied from the TV. I also have dual alternators but it sounds like the limiting factor is the wiring, not the alternator? I have 4 6V batteries which gives me 450 Ah. I am running an el cheapo inverter to run a wine fridge during travel. My batteries are usually topped off beginning a trip and I assume the charge from the TV overcomes the drain for the wine fridge and keeps them topped off. It sound like if I pulled the batteries down to 50%, it would take many hours to replinish their charge, while at the same time using the fridge. Do any of you use an AGS. It seems to me that it would be nice to have, especially if you have a residential fridge.

The wire size definately is a limiting factor. However the demand for the batteries is variable depending on the charge required. Batteries are like a huge variable resistor as they charge up they demand less current because the internal resistance increases. However if the wire size is small the the voltage drop between the load and source increases allowing less power (watts) to the battery. I am not sure where Ford sense the voltage for the alternator output, but the closer to the load or 7 pin connector the better because the alternator will increase the voltage to compensate for wire loss, or in the case of a blocking diode the .7v loss across a silicon diode. In any event the 12 gauge wire is adequate in most cases. BTY measuring the charge current to a battery is could be fools errand unless one knows what the battery charge is and what is required. I just checked the Ford wiring and the black and white charge wires at the 7 pin connector are 10 gauge wires.

 

[Jimsryker]

It is tight but I have them in the front compartment in 2 boxes made for 2 6V each. I did this because I started out with two and added two more later. I don't have any pictures but here is the way I would have gone if I started out with 4. Quad 6V Battery Box . It gives you the dimensions you need.

Awesome. Thx Scottyb. I just found your comments on another thread regarding this topic and even better, Recumbents rig and TV are identical to mine. I like this box as it's fairly low profile compared to a Noco. Now I just have to spring for 4 T-145 Plus Trogan's! Oh well, the 5 Goodyear G614's hurt worse!

 

[scottyb]

Awesome. Thx Scottyb. I just found your comments on another thread regarding this topic and even better, Recumbents rig and TV are identical to mine. I like this box as it's fairly low profile compared to a Noco. Now I just have to spring for 4 T-145 Plus Trogan's! Oh well, the 5 Goodyear G614's hurt worse!

All are money well spent. BTW, my rig has a steel plate floor under the batteries. I am seeing no bowing or sagging and it seems to be very solid.

 

[caissiel]

My 2005 F250 trailer wire was way under 10 ga. Looked more like 16 ga. It also did not have a 30 amp breaker as I recall. Also the wires would have gone to there rear of the 8ft box and back to the front at my 7 pin location. I ran the 10 ga direct from battery on driver side pass the cab and 3 ft in the box in the front of the 5th wheel location, where it's an easy plug in location that I always have in all my TV.
I did modification because I always had a 10 ga system on my previous trucks.
I also observed that trailer batteries charged much faster if truck batteries were also at lower drain.
Solar is the only way the trailer batteries get full charge during the day. No way I could drive long enough to charge fully and use to kill my batteries on long trips without long CG stops. And that only charged them to 65% as I found out after solar installation.

Also looked to replace my Trailer wire and local supplier have no 7 part wires that have 10 ga power and ground wire. So beware if doing a wire repair.

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[dave10a]

Looks as though Ford made improvements to the wiring since 2005.