Battery Charging Question

[Oyah]

I suspect this question is in the forum somewhere, I just can't find it.

In a stock AS Classic, is the solar and battery setup capable of getting a charge from the vehicle alternator while it is running on the road?

Does the battery have the capability of taking a charge from solar, vehicle alternator, or generator depending on source availability? Thx.

[rmkrum]

IF the Airsteam has a standard lead-acid battery, either a standard 'flooded' one (has fill caps) or Absorbed Glass Mat (AGM) (no fill caps), it is capable of taking a charge from the tow vehicle alternator as well as solar or the convertor running on shore power. As the old saying goes, electrons are electrons, and the battery cares not from whence they came...

The one gotcha is that the tow vehicle needs to have its alternator and electrical system properly connected to the 'charge line' connector in the umbilical cable. Some Ford vehicles, for example, need a fuse and a relay installed to activate the charge line.

The other caveat is that not all tow vehicles have an ignition-operated cutoff relay to disconnect the charge line, and if you run down the Airstream's 'house' batteries, you can also run down the tow vehicle's 'starting' battery. With those vehicles, its a fine idea to unplug the umbilical cable from the tow vehicle. This depends on how the vehicle is wired, and varies quite a bit from brand, to model, to year...

[marter]

Originally Posted by rmkrum

Some Ford vehicles, for example, need a fuse and a relay installed to activate the charge line.

Sorry for the hijack but this caught my attention. Is my 2015 F150 one if those Fords? I remember reading something about this but didn't have our trailer then. How do I verify that I'm charging while hooked to the TV?

Thanks,
Mike

[OTRA15]

Originally Posted by marter

Sorry for the hijack . . .
. . .

The new search function in the blue box above works great, and "2015 F 150 trailer charging relay" returns these results:

https://www.google.com/search?q=2015+f+150+trailer+charging+relay&sitesea rch=airforums.com\

[rmkrum]

Originally Posted by marter

Sorry for the hijack but this caught my attention. Is my 2015 F150 one if those Fords? I remember reading something about this but didn't have our trailer then. How do I verify that I'm charging while hooked to the TV?

Thanks,
Mike

OK, I'm an all-Toyota guy, but the way I would tell is to hook up the umbilical to the truck and try it. Set up like this: Be sure its dark outside, or your solar charger is turned OFF. Disconnect shore power, but put the battery use/store switch in USE.

Start the truck, then put your multimeter across the Airstream house battery terminals and read the voltage. It may be somewhere around 13.8 volts or so. Note that reading. Then go shut off the truck, and see if the reading across the terminals drops back down quite a bit, to around 12.9 volts or less. The drop indicates the truck was trying to charge the battery before you shut it off.

And for the rest of the gang that will no doubt chime in, yeah, I could just measure voltage at the umbilical socket at the truck--but I don't remember which pin it is on.

This technique assures me that the truck is probably driving some current into the battery, which is shown by the voltage at the battery going up somewhat when the truck is running. This does assume your Airstream batteries are in reasonably good shape, and will hold a charge, and that the wiring from truck to Airstream is correct.

[uncle_bob]

Hi

The bigger question normally is "how much charging from the TV?"

There is a lot of fairly small ( number 10 maybe) wire between the alternator and your TT batteries. The voltage regulator in the TV is adjusting to make the starter battery happy. This generally means the TT battery looses out. Getting a few amps ( 10 maybe) is doing very well in most cases.

Bob

[waninae39]

its best to get a dc-dc converter between the TV and the trailer. That will isolate the two and provide on one way charging

[marter]

Originally Posted by OTRA15

The new search function in the blue box above works great

....if you're on a PC. It doesn't work so well on phone. It brings 94 pages of results.

But thanks for the help anyway.

Happy trails,
Mike

[marter]

Originally Posted by rmkrum

OK, I'm an all-Toyota guy, but the way I would tell is to hook up the umbilical to the truck and try it. Set up like this: Be sure its dark outside, or your solar charger is turned OFF. Disconnect shore power, but put the battery use/store switch in USE.

Start the truck, then put your multimeter across the Airstream house battery terminals and read the voltage. It may be somewhere around 13.8 volts or so. Note that reading. Then go shut off the truck, and see if the reading across the terminals drops back down quite a bit, to around 12.9 volts or less. The drop indicates the truck was trying to charge the battery before you shut it off.

And for the rest of the gang that will no doubt chime in, yeah, I could just measure voltage at the umbilical socket at the truck--but I don't remember which pin it is on.

This technique assures me that the truck is probably driving some current into the battery, which is shown by the voltage at the battery going up somewhat when the truck is running. This does assume your Airstream batteries are in reasonably good shape, and will hold a charge, and that the wiring from truck to Airstream is correct.

Thanks for the answer. Figured this would be the process, but I probably would have done this in daylight without thinking of the solar panel. I'm also looking for the pinout on the plug.

Thanks again,
Mike

[marter]

Originally Posted by waninae39

its best to get a dc-dc converter between the TV and the trailer. That will isolate the two and provide on one way charging

Can you point me to an example of this? I understand the concept but would appreciate an example.

Thanks,
Mike

[rmkrum]

Look on etrailer.com for umbilical cable plug and receptacle pinout diagrams. Standard 7 pin round connector with flat blade contacts is what you are looking for.

[marter]

Originally Posted by rmkrum

Look on etrailer.com for umbilical cable plug and receptacle pinout diagrams. Standard 7 pin round connector with flat blade contacts is what you are looking for.

Wow. Talk about lack of standards. I'll have to wait until I can hook the trailer up and check the batteries as you suggested.

I remember reading about this when I bought my truck. There was no bag with a fuse and relay, and pretty sure I saw those in the fuse block so the dealer must have put them in. But that was three years ago and I've slept since then so a little foggy on the recollection.

Again, sorry for the hijack OP. And thanks for the help everyone.

Happy trails,
Mike

[uncle_bob]

Originally Posted by waninae39

its best to get a dc-dc converter between the TV and the trailer. That will isolate the two and provide on one way charging

Hi

A DC/DC like:

https://shop.pkys.com/Victron-Energy...BoCsTYQAvD_BwE

( There are many others out there, this just happens to be what I use).

Works fine for a lithium setup with a built in BMS. They are quite happy to go for a long time at something like 14.2V. The DC/DC will pull the "whatever voltage" off of the TV and turn it into current limited fixed voltage on the output.

The gotcha comes when you go to lead acid batteries. They really want a stepped voltage. Running at 14.4 for a while is fine, but running at 14.4 forever is not good for them. Running at something like 13.6 is a compromise.( = what you should do with a DC/DC on lead acid). Running at 13.2 probably will not charge the batteries very well ( = they won't get full).

Wiring wise, the DC/DC gets fed off of the power wire from the umbilical. The output goes to the battery (through a fuse or breaker).

Lots of fun !!

Bob

[OTRA15]

Originally Posted by Oyah

I suspect this question is in the forum somewhere, I just can't find it.

In a stock AS Classic, is the solar and battery setup capable of getting a charge from the vehicle alternator while it is running on the road?

Does the battery have the capability of taking a charge from solar, vehicle alternator, or generator depending on source availability? Thx.

Wondering if you, as the original poster, have received the answers you were looking for?

Good luck,

Peter

[marter]

Originally Posted by OTRA15

Wondering if you, as the original poster, have received the answers you were looking for?

Good luck,

Peter

He shows being online yesterday about the time you posted this, Peter. Hopefully he'll respond if he didn't get the answers he was looking for. I do apologize for the hijack. One last post here and I'll stop.

@uncle Bob, thanks for the link and explanation.I have lead acid batteries so it sounds like it's a moot point. I assume if I don't stay plugged in when not towing I'm okay anyway.

@rmkrum, turns out I don't have the fuse and relay. And the pin out on my TV is embossed on the plug cover (+ is at 7:00 and - is at 1:00). Getting the trailer out of storage today today to get it checked and working before we head out this weekend.

Thanks to all,
Mike

[Oyah]

Originally Posted by OTRA15

Wondering if you, as the original poster, have received the answers you were looking for?

Good luck,

Peter

I believe the 2018 F250 SD w/tow pkg has the plugin wiring harness to power the TT. It has the dual heavy duty alternators.

Plan is to replace the 2 stock AGM/ lead batteries with 4 one thousand watt lithium batteries on a 2018/2019 Classic. It would be ideal if the battery charge can be topped off while driving. Portable solar panels will be connected in addition to the stock mounted solar panels to balance the 4K capacity while boondocking. A 3000 watt generator would be used as a back up or on hot days for AC.

The portable solar panels would allow me to adjust the position to optimize tracking the sun.

1. Can the batteries take a charge while driving or does it require mods?

2. What mods are required to add a connector to patch in portable solar panels?

3. Assuming the generator can produce more watts then is consumed by the AC, can the excess power be diverted to charge the batteries?

Is this a viable plan? Am I missing something?

Still trying to figure this out. Thx.

[uncle_bob]

Originally Posted by Oyah

I believe the 2018 F250 SD w/tow pkg has the plugin wiring harness to power the TT. It has the dual heavy duty alternators.

Plan is to replace the 2 stock AGM/ lead batteries with 4 one thousand watt lithium batteries on a 2018/2019 Classic. It would be ideal if the battery charge can be topped off while driving. Portable solar panels will be connected in addition to the stock mounted solar panels to balance the 4K capacity while boondocking. A 3000 watt generator would be used as a back up or on hot days for AC.

The portable solar panels would allow me to adjust the position to optimize tracking the sun.

1. Can the batteries take a charge while driving or does it require mods?

2. What mods are required to add a connector to patch in portable solar panels?

3. Assuming the generator can produce more watts then is consumed by the AC, can the excess power be diverted to charge the batteries?

Is this a viable plan? Am I missing something?

Still trying to figure this out. Thx.

Hi

Batteries are rated in amp hours rather than watts. You can get "one thousand watts" out of a battery the size of a C cell. You just can't get it for very long .

I'm sitting here in a 30' 2017 Classic with four 100AH lithium's in it. Just where they fit depends a bit on *which* floor plan / trailer you have. In our case two go into the battery box (and fill it completely). The other two are under the recliner center section.

A DC/DC converter is the only way to be sure your lithium's charge from the TV and you don't have weird issues. The batteries will run around $4,000. The DC/DC is just over $100. More or less it's roundoff error.

Connectors for solar depend a lot on how much you are trying to do. A 100W panel is different than a 600W setup. In both cases, a controller that will handle lithium properly is a real good idea.

Charging the batteries from the generator is very normal. Your charger / converter works the same off of the generator as off of the shore power.

More or less what most of us have done:

1) Swap out the charger / converter to something programable.

2) Swap out the solar charger to something that will handle more power and is programable.

3) Put in a battery charge monitor ( voltage is a poor way to check a lithium).

4) Drop in the batteries.

5) In many cases add more panels to the roof.

6) In some cases add a central "brain" to keep everything doing what it needs to do.

The 3,000W generator *plus* a bunch of portable panels is going to be a big/ heavy bunch of stuff to haul along with you. It's also going to be a task to get it all set up. That's why a lot of people go for the "more panels on the roof" approach.

Bob

[68 Overlander]

Originally Posted by Oyah

I suspect this question is in the forum somewhere, I just can't find it.

In a stock AS Classic, is the solar and battery setup capable of getting a charge from the vehicle alternator while it is running on the road?

Does the battery have the capability of taking a charge from solar, vehicle alternator, or generator depending on source availability? Thx.

Aren't you really asking...If I gang up on my batteries with multiple charge sources, which one is the boss and doing the most? The answers is not known unless you separate them other than the voltage applied to the batteries will be the highest of those connected to it and the amps being delivered will vary too. There are millions of people that roll these highways with multiple charging sources at the same time. If you have a modern TV, I don't think you risk draining your starting battery.
Somebody asked about checking to see of the TV was charging the trailer batteries. You can measure right on the 7 pin plug on the TV. If there is voltage on the charge line (prolly about 14 VDC) it is and will charge the house batteries.
That said, half of the people with a tow package have a blown 30 amp fuse in the engine compartment fuse block and complain their TV doesn't charge from the Alternator. It's an every day call. Check the fuse.

[uncle_bob]

Originally Posted by 68 Overlander

....
Somebody asked about checking to see of the TV was charging the trailer batteries. You can measure right on the 7 pin plug on the TV. If there is voltage on the charge line (prolly about 14 VDC) it is and will charge the house batteries.
That said, half of the people with a tow package have a blown 30 amp fuse in the engine compartment fuse block and complain their TV doesn't charge from the Alternator. It's an every day call. Check the fuse.

Hi

Ok, I checked the fuse / replaced it / re-checked the new fuse .... still nothing on the 7 pin while towing

There's a lot of magic in a modern car or truck. The days of things being easy to sort out are long gone. This module controls that module and all of a sudden, they no longer are happy with each other. The dealer replaces this or that, now it works. Why it broke ... nobody seems to know.

Bob

[68 Overlander]

Originally Posted by uncle_bob

Hi

Ok, I checked the fuse / replaced it / re-checked the new fuse .... still nothing on the 7 pin while towing

There's a lot of magic in a modern car or truck. The days of things being easy to sort out are long gone. This module controls that module and all of a sudden, they no longer are happy with each other. The dealer replaces this or that, now it works. Why it broke ... nobody seems to know.

Bob

Odd indeed Bob. There should be voltage at that charge line pin.