Winnebago 2301BHS Solar Project: Questions

[Sentry]

I am attempting to upgrade the Solar to my Winnebago 2301BHS. I am also attempting to get this done by March 11, when we take off to hopefully use all this in the desert..



We have:

4 Battle Born Batteries (100ah ea)
2 10 Ga. Roof Entry boxes just in case.
Dicor Sealant
Everbond Tape 2" may get wider.

60 amp ANL fuse for Shunt





We have on the way:

4 175 Watt Solar Panels


20ft of 10 awg wire for Solar Panels (both Black and Red) to go from panels to combiner box.



Solar Combiner Box



6 ft of 10 awg wire to go from combiner box to charge controller


Victron Charge Controller 100 | 50

Progressive Dynamics Replacements WFCO RV Power Centers 55 Amp Lithium Converter


SmartShunt 500A/50mV

[Sentry]

So, looking at diagrams.... I am seeing where some suggest a multitude of things in the mix.



I am not doing inverter controller at this time. I am not trying to charge this from the vehicle.



However.... Battle Born, sent me a diagram with an inverter charger in it, and a Battery Guardian in it.... I was told delete the inverter charger, but not the Battery Guardian... I do not see where I need that device at this time.



Is the vehicle alternator charging the trailer batteries?


I am also trying to figure out... Bus Bars, fuse sizes....


Any help is appreciated.


When I spoke with one individual at Battle Born, he suggested I purchase the Charge Controller, the Shunt and a 60 amp fuse.



I was also able to email another individual at Battle Born, however... I'm guessing because they are very busy people, they speak quickly on the phone, and give very little info in email.

[creativepart]

Originally Posted by Sentry

I am not doing inverter controller at this time. I am not trying to charge this from the vehicle.

I'm guessing this is a typo and you mean "inverter/charger?"

Originally Posted by Sentry

I was told delete the inverter charger, but not the Battery Guardian...

I'm not sure what a Battery Guardian is... so I looked it up and it appears to be a battery disconnect. Again, I'm unfamiliar with this one but most folks use a standard rotary disconnect, aka "salesman's switch."

Originally Posted by Sentry

Is the vehicle alternator charging the trailer batteries?

Yes... your tow vehicle will charge your house batteries as you tow the trailer. Many feel this isn't an issue, others disconnect the TV's charge line or use some other device like a DC to DC charger to provide a more appropriate charge profile to your batteries. You need to simply be aware of this issue and make your own mind up how to proceed. Lots of info online about this.

Also, you make no mention of where you plan to put 4-group 31 batteries on your rig but we would assume you are putting them in the forward compartment of the the TT. So, don't forget you'll need some way to hold the batteries in place up there.

[Sentry]

Originally Posted by creativepart

I'm guessing this is a typo and you mean "inverter/charger?" yes. Inverter/ Charger which I will not be doing at this time.



I'm not sure what a Battery Guardian is... so I looked it up and it appears to be a battery disconnect. Again, I'm unfamiliar with this one but most folks use a standard rotary disconnect, aka "salesman's switch." Does that Mean, don't get it?



Yes... your tow vehicle will charge your house batteries as you tow the trailer. Many feel this isn't an issue, others disconnect the TV's charge line [How do you do that?] or use some other device like a DC to DC charger to provide a more appropriate charge profile to your batteries. You need to simply be aware of this issue and make your own mind up how to proceed. Lots of info online about this. So something is needed, even though I am not intending to change the batteries via the alternator...?

Also, you make no mention of where you plan to put 4-group 31 batteries on your rig but we would assume you are putting them in the forward compartment of the the TT. So, don't forget you'll need some way to hold the batteries in place up there.

The batteries and all components of the solar system (except the panels) are intended to go under the master bed mattress compartment. Not the pass through, but the box under the mattress in the master bed area.

[creativepart]

OK, you didn't ask any questions... but you also didn't say how you plan to wire they system. Series? Parallel or a combination of Series/Parallel.

I ask because of the 10ga wire you plan to use between your combiner box to the charge controller.

[Sentry]

Originally Posted by creativepart

OK, you didn't ask any questions... but you also didn't say how you plan to wire they system. Series? Parallel or a combination of Series/Parallel.

I ask because of the 10ga wire you plan to use between your combiner box to the charge controller.

There is a lot I do not know off the cuff... I am learning. Capable of doing. But learning.



I will be wiring in Parallel.



Currently I have one roof access for solar wires, I am thinking I will have to do, one more. What does it look like under there?

[Sentry]

Yes, I kind of need my hand held through this... I know enough to be dangerous.. Not enough to not start a fire.

[Fred 2106DS]

Originally Posted by Sentry

Yes, I kind of need my hand held through this... I know enough to be dangerous.. Not enough to not start a fire.

I’ll try and help as best I can. Let’s take this one step at a time. I see this as a 4 step project.

• Install your solar panels and run the output into your under bed storage area.
• Run the OEM battery wires from the tongue back into your under bed storage area.
• Replace your OEM converter/charger with your new lithium converter/charger.
• Tie everything together with your batteries, shunt, busbars, solar controller etc. in your under bed storage.

Is this list generally what you’re looking to accomplish?

If so, starting with your solar panel install, what is currently on your roof? From your previous posts there appears to be at least one solar gland, do you know what the wire size is and where it exits down below?

If the gland is wired with 10 AWG, then to simplify this portion of the install, assuming you’re only using four 175 watt panels, you may want to consider wiring your panels in a series/parallel configuration. This way you are only pushing 20 amps @ 36-44 volts off the roof, which 10 AWG can easily handle.

If you go with a parallel only setup and combine the 4 pairs of wires in a roof top combiner box, minimally you should run 8 AWG from the combiner box to your under bed storage, 6 AWG would be better. In this configuration you are pushing 40 amps @ 18-22 volts off the roof.

The second step, running/extending your battery wires back into your under bed storage is easy enough. Just use at least the largest sized wire that is currently being used, probably 6 AWG. When I brought my wires back into the pass-thru, I terminated them in a junction box and extended them from there. Here is a link to that post.

The third step, replacing your OEM converter/charger with your new lithium converter/charger is a straight forward swap, nothing extra to do here.

The fourth and final step, tying everything together, shouldn’t be too complicated. I looked at a couple of Battle Born’s wiring diagrams and they are straight forward diagrams.

You stated they want you to use a Battery Guardian, which a low voltage auto disconnect switch. This makes storing your camper with the batteries installed more or less idiot proof. If your battery voltage drops to 11.5 volts, it will shut off all loads to the batteries. You can accomplish the same thing by installing a manual disconnect switch, but you need to remember to use it when you want to disconnect all loads, such as when in storage, and then turn it back on again when needed. The Battery Guardian is more or less an install and forget it piece of equipment.

As for the question of your tow vehicle charging your trailer batteries; Yes, your tow vehicle will send a charge to your trailer batteries. Will it hurt anything after installing LiFePO4 batteries due to their lower internal resistance, I honestly don’t know. This week I’m planning to run tests using my Tundra and camper to see if there appears to be a problem, at least with my setup and vehicles.

I haven’t seen a problem to date, I’m using a DC to DC charger in addition to the 7-pin connecter and solar panels to send a charge to my batteries when we are traveling. I plan to draw down my camper batteries to 60% and disconnect all charging inputs except for the 7-pin connector and see what the voltage and amperage draw is through the 7-pin connector. Then I’ll disconnect the 7-pin connector and connect the DC to DC charger and take the same readings. As a final step, I’ll connect both the 7-pin and DC to DC charger and see what those individual and combined readings are. I’ll also take readings of the alternator output before and during these tests.

What other questions do you have?

[creativepart]

^This. Fred has good advice.

The reason I asked about wiring is that 10ga is suitable for 30amps - which means about 450w of solar. You’re planning on 700w of panels. You can increase the wire size or wire your panels to increase the voltage and reduce the amps.

It’s good you are asking questions now. From the sounds of things you might be better off doing more research and investigation before buying everything. This will increase your confidence in the equipment and materials you purchase. It’s good to take suggestions from suppliers like BB but it’s best to understand the subject enough to decide if it’s something you want to use, not just following suggests from venders.

[Sentry]

I’m going to just do this.

https://youtu.be/JMqtVBN26NQ

Granted we will only have four 175 watt panels for now totaling 700 watts.

We are currently waiting on wire and charger/ inverter.

Instead of drilling new holes in roof, I’ll be using combiners on the roof to bring down two wires. Need to check gauge of wire coming down.

Daunting project to be sure.

[Fred 2106DS]

Originally Posted by Sentry

I’m going to just do this.

https://youtu.be/JMqtVBN26NQ

Granted we will only have four 175 watt panels for now totaling 700 watts.

We are currently waiting on wire and charger/ inverter.

Instead of drilling new holes in roof, I’ll be using combiners on the roof to bring down two wires. Need to check gauge of wire coming down.

Daunting project to be sure.

Good luck! Let us know how it turns out.

[Sentry]

Originally Posted by Fred 2106DS

Good luck! Let us know how it turns out.

I still have to do as you said which is disconnect battery cable and move to converter.
That’s kind of what led me to current decision.

[Sentry]

Not disregarding advice given. Just busy.

[johnevans3]

FRED, please post your results on your test especially the data on the 7 pin load test!!!
With 1 lithium battery on my 2106 FBS, I am hopeful that I won’t have to do the dc/dc charger route and just use the 7 pin connection. I am not trying to significantly charge the battery as I have other options for charging it. Thanks so much.

[Fred 2106DS]

Originally Posted by johnevans3

FRED, please post your results on your test especially the data on the 7 pin load test!!!
With 1 lithium battery on my 2106 FBS, I am hopeful that I won’t have to do the dc/dc charger route and just use the 7 pin connection. I am not trying to significantly charge the battery as I have other options for charging it. Thanks so much.

Will do. We've had nasty weather the last few days. I'm planning to run the tests tomorrow or Wednesday.

[Fred 2106DS]

Originally Posted by johnevans3

FRED, please post your results on your test especially the data on the 7 pin load test!!!
With 1 lithium battery on my 2106 FBS, I am hopeful that I won’t have to do the dc/dc charger route and just use the 7 pin connection. I am not trying to significantly charge the battery as I have other options for charging it. Thanks so much.

I ran the tests today using my 2020 Tundra and 2016 2106DS MM.

Spoiler alert, at least with my vehicle and LiFePO4 battery setup, I didn’t see any problems with amperage draw with just the 7-pin connector attached to my Tundra and charging the LiFePO4 batteries in the Micro Minnie. Nor, did I see any issues when using both the 7-pin connector and my 20 amp DC/DC charger together.

First, I charged my 200 Ah of Battle Born batteries in the MM to 100%. I then disconnected all inputs to the batteries.

Second, I added a load and drew down the batteries to 40% to simulate a somewhat depleted LiFePO4 battery. The voltage reading at 40% was 13.1 volts.

Third, I started my Tundra and left it warm up for fifteen minutes. I then measured the alternator voltage and amperage output at the Tundra’s battery while idling with nothing connected to the Tundra. The alternator output readings were 13.87 V @ 9.5 A.

Fourth, with the Tundra idling, I connected the 7-pin connector from the MM to the Tundra and measured the voltage and amperage entering the LiFePO4 batteries and also measured the voltage and amperage output from the alternator at the Tundra’s battery. The readings at the LiFePO4 batteries using the 7-pin connector were 13.13 V @ 2.61 A. The alternator output readings were 13.46 V @ 12.1 A.

Fifth, I ran the same 7-pin connecter tests with the engine at 2000 RPM. The voltage and amperage entering the LiFePO4 batteries was 13.65 V @ 4.6 A. The alternator amperage output was 12.6 A. I forgot to measure the alternator voltage, but I wouldn’t expect it to be a problem.

Sixth, I ran the same tests at idle with my 20 A DC/DC charger connected, along with the 7-pin connector also being connected. The alternator output readings were 13.31 V @ 29.2 A. At the input side of the DC/DC charger, the readings were 12.84 V @ 25.4 A.; and the output readings of the DC/DC charger were 13.66 V @ 19.3 A.

Based on the above readings, I don’t see an amperage issue when using the 7-pin connector with LiFePO4 batteries, at least with my setup. The amperage draw through the 7-pin connector seems minimal even when connected to a somewhat depleted LiFePO4 battery.

One thought I had after running these tests on the 7-pin connector, I wonder if my Tundra limits the current through the 7-pin connector being that its factory equipped for towing.

Fred

[tinglett]

Originally Posted by Fred 2106DS

I ran the tests today using my 2020 Tundra and 2016 2106DS MM.

...

Fifth, I ran the same 7-pin connecter tests with the engine at 2000 RPM. The voltage and amperage entering the LiFePO4 batteries was 13.65 V @ 4.6 A. The alternator amperage output was 12.6 A. I forgot to measure the alternator voltage, but I wouldn’t expect it to be a problem.

Sixth, I ran the same tests at idle with my 20 A DC/DC charger connected, along with the 7-pin connector also being connected. The alternator output readings were 13.31 V @ 29.2 A. At the input side of the DC/DC charger, the readings were 12.84 V @ 25.4 A.; and the output readings of the DC/DC charger were 13.66 V @ 19.3 A.

Based on the above readings, I don’t see an amperage issue when using the 7-pin connector with LiFePO4 batteries, at least with my setup. The amperage draw through the 7-pin connector seems minimal even when connected to a somewhat depleted LiFePO4 battery.

One thought I had after running these tests on the 7-pin connector, I wonder if my Tundra limits the current through the 7-pin connector being that its factory equipped for towing.

Going back through this thread, I think I had a little ah-ha moment based on this test that Fred did with his Tundra. I am very certain that the current is limited, but perhaps not on purpose, but due to the wiring gauge of the harness as well as the charging profile the vehicle will produce. I very much doubt you are ever going to see over 13.65V or so. Certainly you won't ever see the 14.4V that you'd like to have into your lithium batteries.

So here's the ah-ha moment. Note what the DC-DC charger does. It can produce a higher voltage! It took a 12.84V input voltage and gave the batteries what they wanted. And look at that current! Ok, I'm a little excited by this thought . That is, I was thinking all along the DC-DC charger would protect the alternator (and that I don't need that), but I wasn't considering the charger would actually (greatly) improve the charging situation. I'm liking that thought!

I don't mean to hijack this thread, but thought I should point it out. Perhaps this is obvious to many, but it's new to me. I'm thinking it's the real reason to get a DC-DC charger.

[Sentry]

Yesterday, I removed the front A/c and replaced it with a Maxxair fan remote unit. I was able to pull the 120 line through with 12 volt wire attached. Found it was best to push from one side and pull from other to not chew up the 12 volt wire.
Backed my truck up next to trailer wife and daughter passed the A/C down to me and son standing atop bed cover.
Hopefully dicor did ok through the night.

[Sentry]

I used 1/2” plywood to build up the interior of the under bed cargo area.
Going to play Tetris under the bed with Victron components and batteries today.
Still waiting on charger inverter. So not sure about mounting anything just yet.
Still running lead acid battery until then.

[Sentry]

I suspect, I will have to remove the inside panel at the front of the trailer to get to the solar panel wire.
As that is where the schematics show it runs.

It’s also where the PWM is. I’m guessing I will have to run new wire for length. Another pull behind, but hopefully easier in this case.