Let's design a Lithium Battery system.....

zgfiredude

I have a 2020 T@G 5w Boondock. My original Interstate Deep Cycle battery is toast (suprisingly), so I am going to take the Lithium plunge.

I will likely get a Renogy 100ah smart battery as a replacement, but want to know if there are other components that can/should be upgraded as well. Currently I have a Victron 75/10 charge controller and the factory solar panel on the T@G. I have read several of @JamesDow 's posts so I have some solid basis of thought, thanks James! I will likely add a 100 watt solar suitcase into the mix as I can use it with the T@G and with my Jeep (aux battery addition coming after the trailer gets squared away). That will likely have a 50 to 70ah lithium or AGM battery added to support a fridge in the Jeep......I do not yet have a fridge in the T@G, but that will come as well.

So I'm looking at two lithium batteries, two fridges, 1 solar suitcase, etc all in due time. The trailer upgrade will come first, likely with a fridge then the Jeep can come a bit later.

But, what do I want to make this a bombproof system?

Landpaddler

We use a Lion Safari UT 1300 that we got with the 2021 Tag xl boondock. Last trip it never got below 80% and we were using an electric blanket at night. No fridge yet but I think it will run it as long as we have decent sun.

JamesDow

Here are my initial quick thoughts.
Sketch out what you want on paper.

Get a solar suitcase that contains a solar controller. The10 amps of the Victron may/will not be enough. A solar suitcase with a controller could be used directly to the Jeep without the trailer. Depending on your existing solar T@G wiring, the solar suitcase may need some sort of simple solar branch connectors to be used to connect up parallel to the trailer. If your trailer solar is directly wired to the battery through to solar controller and an existing SEA plug exists and is unused, the solar suitcase could be plugged directly into the SAE plug. This would put the solar panels in parallel. (double-check the polarity of the SAE wires)

If your T@G did not come with a SAE connector going directly to the battery, (located on the front tongue box) you will need to get one. You will need one SAE for the T@G and one SAE plug for the Jeep. Again, double check the polarity of the SAE connectors. On my T@G it was reversed so the wires going to the battery needed to be swapped.

You may want to include some sort of battery monitor into your mix. My Renory battery was matched to one that connected directly using a standard computer style Cat5 cable.

A battery charger may be of use with the Jeep setup. That would allow for charging independent of solar or vehicle alternator.

Make sure to get enough wire extensions so the solar suitcase can be positioned in various locations throughout the day to best collect the sun's power. (10-15 feet should be enough).

While a lot of my equipment, came from Renogy, don't discount other sources for batteries. Some depends on your camping needs (i.e. - extreme hot or cold)
Will Prowse on YouTube has some good information.

If you are buying from Renogy, I strongly suggest purchasing directly from them, otherwise the warranty may not be good. They will match on-line pricing from sources such as Amazon. Typically quick and free shipping.

If it was me, I would go with an inexpensive lithium battery over an AGM battery. I am very weight conscious with my setup.
 
Best of luck!

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https://youtu.be/KvCdo0cs99w

SueBHunny

I agree on the solar suitcase with a controller. My Renogy solar suitcase came with a built in controller, and when I upgraded my battery to a LiFePo it was as as easy as just switching the battery input on my solar suitcase after installing the battery (which was also easier than anticipated).

zgfiredude

Thanks for the help and suggestions. I wondered IF the current charge controller was "enough" I'll look at replacing that. Is 20 amps enough? Am I just looking at replacing that because of the addition of the solar suitcase? If so, if the suitcase has a built in controller then why? I'm confused here.

I follow the logic of the solar suitcase with built in controller, makes perfect sense for dual use. I DO have the SAE plug already on the trailer, and now realize that that connection is "unmetered" so to speak, so the built in controller covers that base.

The charger for the Jeep is a thought that I hadn't had. So what we are saying here is that the Jeep aux battery could then charge by shore power (via this charger) and solar via the suitcase, correct? This is keeping the Jeep aux battery completely independent of the Jeep's electrical system which is clean and simple. IF I were to want to add charging while driving for the Jeep aux battery that would be by dc/dc charger?

Great input so far, thanks. I'm a fan of the two systems being somewhat independent of one another.

Are there any concerns/issues with the new battery in the trailer charging from the Jeep while in motion? I'm thinking not other than it may not get to 100% charged as you've previously discussed.

JamesDow

@zgfiredude
Having two controllers is a bit redundant, but that is what you are going to need for the trailer and Jeep. You are not looking to just replace your current 10Amp Victron.
If you just had one solar controller (tied to the T@G), you would never be able to charge the just Jeep auxiliary battery without the T@G. I think you want the flexibility to charge the T@G and/or the Jeep together or separately. Even without the Jeep stand-alone setup, the solar suitcase would allow you to park the T@G in the shade under a tree and use the suitcase (positioned in the sun) along with the T@G solar panel to charge up the T@G system. With a solar suitcase containing a solar controller, you could simply just plug it into your SAE port and run your two solar panels in parallel. That would increase the speed of charging the T@G battery, allowing flexibility of maximum sun exposure into at least one or both panels.
» I noted today that the difference in the Renogy solar suitcase without and with a controller is only $9. I would jump on that now (very soon) if that is the brand you desire. Keep in mind, you could also get a folding panel (non Renogy) with a controller built in, which may be lighter. You may have to get an adapter to make it work, but it is also a consideration.
As for a battery charger, yes, it could charge any battery via shore power completely independent of the Jeep's electrical system. I have at times, charged my T@G lithium battery via the SAE port with a stand-alone battery charger. That eliminates the hassle of getting to the battery posts. (It is a bit of a wiring mess)
As for charging a lithium battery from the Jeep, check the Jeep's voltage output while driving.
If you wanted to add charging of the auxiliary tow vehicle battery while driving, you could run a separate line from the positive cable, or even just plug into a standard 12-volt port in the Jeep. If you measure your Jeep's output while driving, you will likely find it is in the range of 14+ volts. Use a voltmeter or a simple 12-volt port cigarette adapter meter to check. If you are running at 14-volts or above, then I see no need for a DC-DC converter. For me running a line directly from my tow vehicle battery to my T@G lithium battery, I get about 11% increase in state-of-charge for every 200 miles driving. No need for DC-DC converter. The one thing to be aware of is that the lithium battery will charge the tow vehicle battery when the tow vehicle is off when directly connected. This is due to the fact that lithium stores voltage at a higher level than lead acid batteries do. Simply, power will flow towards the lower voltage system. I have a simple switch on mine to disconnect the setup. I could just as easily just pull apart my 7-pin connection, but "click" and I am done. What happens the tow vehicle and T@G are parked together for an extended period? The tow vehicle battery gets charged and the T@G battery loses some charge. Not a big deal, but I want all the charge possible kept in my T@G battery. Bottom line, try a direct line first and if that does not charge the auxiliary battery in the Jeep, you may need the DC-DC converter. All the DC-DC converter does is increase the voltage up to 14+ volts so a lithium battery can be charged. I could potentially get to a state-of-charge simply by driving a long distance, but keep in mind if a refrigerator is on, power will be used up in the process, so getting to 100% would take some miles.
 

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zgfiredude

I follow all of that @JamesDow , I was just trying to clarify your original thought that the Victron @ 10 amps might be insufficient. I'm totally good with the two independent solar panels and controllers as we have indicated.

1. So your "direct line" to the T@G battery is via the 7 pin trailer connection, yes? If so, then I have that in place already via the factory tow harness, but can certainly verify the charge rate once installed. Seems like that's a "why not" kind of thing even though I'll likely maintain the T@G battery via shore power when stored at home.....it lives in the garage.
2. I follow the charging rate being reduced if a fridge is live in either vehicle, not an issue. Thanks for the explanation on the Lithium to Lead Acid back charging.
3. What is your thinking on the Lithium wanting/needing heat. I live in western Colorado, and we are often out camping at sub 32 degree temps overnight. So as I understand it, the Lithium will not want to charge at those temps, but will discharge then. Do you think the heated version of the Renogy is something I should be looking strongly at? I know you can externally heat them, but it looks like cost wise they are similar. Will those temps harm the battery, or only keep it from charging/discharging? I have NOT researched this question.

I am thinking that Phase 1 is a 100ah Lithium for the T@G, and a 100 watt suitcase w/controller for additional supply. The fridge for the T@G will come in here as well. Then, Phase 2 will be the battery, the second fridge and solar connections on the Jeep.

JamesDow

@zgfiredude
Yes my direct 12-volt line from my tow vehicle runs through my 7 pin trailer connector. As for maintaining my lithium battery at home, I just put the battery in "shelf mode". It will hold charge for months without issue. I just plug in a few days before a trip with the refrigerator on and charge will go up to 95%+ state-of-charge.
As for the need for self-heating function, my answer would be no. (Renogy - $765 vs $510).
The non-heated Renogy will charge down to 0°C (32°F). After that the Battery Management System (BMS) will cut off charging protecting the battery.
I placed my battery in a group 27 battery box and installed foam padding on the bottom and sides. The foam protects the battery from rough roads as well as insulating the battery from cold and heat. As a lithium battery is discharged through use (refrigerator, USB charging, fan, lights, etc.) it will automatically produce some heat in the process. The foam will hold in the heat and assist in the charging process below 32°F. Also keep in mind that the charging will be during the day via solar when temps naturally increase. I would save the $255 unless you really will be camping extended periods in the mountains.
Keep in mind that current Renogy discount "sales" may be limited in time. You can also get 5% off by signing up for promotional marketing.
 
Decision time.
Now get to work at spending money, creating income for others and more jobs.

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https://www.youtube.com/watch?v=EaiwxDUY9ho

zgfiredude

Thanks! I'm on the shopping spree shortly!!

danp

I guess I am lazy but willing to spend the money. It is more than likely on this site somewhere but I would like the definitive answer on what to do to replace my battery and be somewhat self-sufficient for a weekend up to seven days. My original battery for a 2017 tag is on it's way out and I need to replace. I don't know enough to know what the best way is to go. Lithium and solar seem to be the way. JamesDow seems to have the answers. True.

zgfiredude

True.

@JamesDow is the man......IMHO, you can do any of the different battery chemistry types.....Flooded, AGM, Lithium. You will get what you pay for. If you NEED to go 7 days and have only factory solar to replenish the battery, AND have moderate electrical demands (fridge +) you really need to budget for lithium and size the Amp Hour capacity according to your needs/budget.

That's my unsolicited opinion after my research and fumbling about.