Lithium Upgrade 2017 T@B Model S

kproctor

I want to convert the lead acid battery to Lithium.  Does anyone have a list or summary of all the components that require modification.  

webers3

I removed the lead acid battery from my 2017 320s and replaced it with Amphere Time Lithium. Since I did not replace the converter/charger there were no special components, I simply removed the FLA battery and replaced it Lithium. The converter/charger in my 320s will charge the Lithium to about 80% but that is not a problem since I can top it off to 100% with solar. Even at 80% I still have more capacity than I had with the original lead acid

pthomas745

Tell us what year trailer you have.  The newer trailers have a "lithium compatible" converter. 

kproctor

I have a 2017 Model S T@B.  I am interested in the impact of charging from the tow vehicle and the long term effects of only charging the Lithium battery to roughly 80%.  I do not have a solar set-up currently.

pthomas745

Most tow vehicles these days seem to do a lousy job of charging an RV battery, for many reasons.

For the lithium charging from your car, the "simple" solution is a DC-DC charger.

Here are a bunch of threads about DC-DC chargers, and some discussions about lithium charging, etc.

https://www.google.com/search?q=dc+dc+charger++site:tab-rv.vanillacommunity.com&client=firefox-b-1-d&sxsrf=AJOqlzXxTwrOJMYxy7qGVi41iypJQ38JWQ:1675013755968&ei=e67WY-XeOu3akPIPoMOQiAY&ved=0ahUKEwiliKy_qO38AhVtLUQIHaAhBGEQ4dUDCBA&uact=5&oq=dc+dc+charger++site:tab-rv.vanillacommunity.com&gs_lcp=Cgxnd3Mtd2l6LXNlcnAQA0oECEEYAUoECEYYAFDvCFjlK2DDM2gBcAB4AIABW4gBvgiSAQIyOJgBAKABAcABAQ&sclient=gws-wiz-serp

I handle my lithium the way Weber3 mentions: I use my lithium compatible solar controller and panel when I want to charge my battery.  If I'm at home, and I for some reason want to charge the lithium, I have a NoCo charger that is lithium compatible.

You can change out the converter for a "lithium compatible" model.  You should examine your camping style: if you are always at a full hook up site, you don't need a lithium.  If you are mostly camping with solar, you don't need a "lithium converter". 

Here is a battery "explainer" that goes over most of these things.  Find the section on "charging", and the statement "lithium batteries do not care if they are fully charged, and will last longer if they are not". 

https://www.solacity.com/how-to-keep-lifepo4-lithium-ion-batteries-happy/

kproctor

Thank you, your explanations are exactly what I needed.

Artie101

Happy I found this discussion tonight.  Thanks for starting it.

I have a 2016 T@B 320s Outback Edition.  I would like to do just this...change my FLA battery to a Lithium battery.  Does anybody know if I too can just make a straight swap and use my Renogy 100 watt solar panel to top it up when needed?   I read the attached article that seems to say not to have or keep it fully charged for longer life.  Thanks, that makes sense.

I also have a Noco that travels with us just in case we need it.  We do mainly full hook up sites, but I want to start doing some Boondocking and would like to join Harvest Hosts.  We'll be retiring in the not too distant future and I'd like to get some practice in now so we're ready for long trips in the future.

I currently have an older "Pow-R-Surge Advanced" 65ah FLA battery.  I would like to get a lithium 100ah battery, maybe with a built in heater, now that I have read up on charging, especially when 0 Celsius or below (we're in Canada).

We have a 2011 Subaru Outback 3.6R Limited that we tow with at this time.  We have the 7 pin connector and I am wondering if this is okay as is with a lithium battery as far as charging when we are driving to our next stop.  I read some posts on the DC-DC chargers and I'm thinking we might not need this.

Thank you in advance for any advice you can offer

pthomas745

Is your Subaru charging your battery now?  That would be the first question to ask about the DC-DC charger.  Then, work from there.

I have a 2017 Outback.  I just made a "straight swap."  You will need to measure the new battery and change the battery box, if you want the new lithium in a box. My 100ah lithium fit on the "back wall" of the front tub.  Keep in mind that the battery can sit in any configuration, except upside down. Stand it up on one end if that makes things fit better for you.  A 100 ah lithium (or any battery larger than the "Group 24" battery in your trailer now) will require more space, and if you want a box...you will need a bigger battery box.  So, make a note of the dimensions of the new battery and compare them with the old one.

I have a 100 watt Renogy panel, and an EpEver solar controller.  The controller is lithium compatible (it can provide the higher charging voltage that a lithium battery needs).  So, far, this setup has worked pretty well for me.  I do, however, have a propane fridge, so I don't draw much of the 90 or so available amp hours the lithium provides. 

Your stock FLA battery in your trailer now "may" have provided 40 amp hours of "usable" power.  (50 percent of the available amp hours for FLA is the "norm" for best battery life).  The 100 amp hour lithium can provide at least twice that much.  The "old" formula for solar wattage capacity used to be "match the battery amp hours to the solar panel wattage."  Which is fine when a trailer might use less than 15-20 amp hours a day.  A 100 watt panel could mostly recapture those amp hours with decent sun the next day.  If owners with 100 ah worth of lithium batteries were using 40 amps a day (with a 2 way fridge, for example) it may be advantageous to have 200 watt panels to more easily recapture those watts the next day or so.

subfreq111

@kproctor, as others have mentioned, you will have trouble charging to near capacity. In my 2018 320S, and your 2017, the built in DC converter is set for only a lead acid battery which tops off at a lower voltage (13.4-13.6)than Li(14.2-14.5). I looked into replacing the converter as others have done, but this requires replacing the entire control panel (WFCO) with a newer model WFCO or Progressive Dynamics makes one as well setup for Li. Instead, I decided to disable the original converter by pulling the bottom 40 amp fuse inside. I then permanently installed a single bank 10 amp Noco onboard charger in the electrical cabinet that is supplied directly from shore power when connected. The Noco can be set for different battery chemistries including Lithium. Between that and my solar setup, the Lithium batteries rarely drop below 90%. 

As for DC charging from your vehicle, as others have stated a DC-DC charger may be your best bet. The reason that so many here have very poor results charging from their vehicle is due to voltage drop from the source(alternator) to the RV battery. On vehicles that come pre wired for a 7-pin, I've seen mostly14 awg wire going to the +12V pin and a few with 12awg wire. While these are sufficient to carry the 15-20 amp loads that could be run, the voltage drop is considerable due to the fact it is running over 20 feet at best. In order for the RV battery to charge, you need a higher voltage incoming and if your alternator is putting out 14.1, by the time it gets back to the trailer, it may only be 12.8, or not enough to raise RV battery voltage. 

Artie101

@pthomas745 Thank you for that information.  Yes, the Subaru is charging the current battery even with the fridge running while travelling and keeping it full.  I have the 3 way fridge and an extra propane tank on the front. 

I do have a battery box now with the on/off switch on top and would like to have the same set-up when I get a lithium battery.  Can you please tell me what battery you are using?  Also, do you use a box and/or an on/off switch?

I figure I can always add an extra panel to bring it up to 200 watts if 100 does not work.

pthomas745

@Artie101 do you have a "battery disconnect" switch installed in the trailer? Or a "battery box" that has a switch attached to the box?  My 2017 has a battery disconnect mounted in the front tub.  I have an Ampere Time lithium in a battery box.  If you don't have an installed battery disconnect switch, there are many easy "battery switches" that attach directly to the battery.

The 100 watt panel will work fine, especially because of your three way fridge.  I find it pretty difficult to use a lot of power with my 3 way fridge, so 100 watts of solar works just fine for the amp hours I might use.  If your power needs are increased (medical devices, working on the road needing laptops, etc) 200 watts of solar may help replenish more quickly.

rcuomo

Artie, I had to update the controller on my Ren suitcase to maximize the charge potential to 100%. Fairly inexpensive upgrade and works perfectly. Here’s a link to my battery and inverter install. https://youtu.be/2KH4qSmmqD0

Yoshi_TAB

subfreq111 said:

 Instead, I decided to disable the original converter by pulling the bottom 40 amp fuse inside. 

Hi @subfreq111,

Isn't the 40 amp fuse in the converter the reverse battery protection that is used in case you hook up the pos/neg terminals opposite?  In my WFCO, the converter is the #6 30 amp fuse.

Also, I see you replaced the charger, but would you happen to know in a non lithium WFCO charger when it tops out at 13.4-13.6, does it continue to try and charge in bulk or absorbtion or does it move to float, even though the lithium battery may only be 85-90% charged.

Thank you

Artie101

@pthomas745 I have a battery box that has the disconnect switch attached to the top of it.  I am thinking that I can maybe reuse this.  I am interested in having a switch mounted in the tub and keeping my new battery in a box as you have. 

It sounds like a 100 watt panel ought to suit my needs just fine.

I'm wondering if you have some type of security for your battery as I have read that it is illegal to lock the tub with a propane tank inside but worry about someone coming along and stealing it.

Thanks again for all the info and for taking your time to respond.

Artie101

@rcuomo Thanks for the link.  That is very interesting.  I'll need to watch that a few more times as there is a lot of info there.  Keeping it inside is much more secure.  My suitcase came with a Voyager 20 amp charge controller.  Did yours and did you have to upgrade the supplied controller?

Thanks.

Slackers

Low $ way to secure your battery.  https://youtu.be/BE6oexCGUUk

pthomas745

I have a lock on my front box.  It has been there since the first day I owned the trailer.  It is not illegal to lock your front box.    (We have many posts on this issue, and there are a few restrictions for tunnels/ferries no one has ever found a law).  I also have a fairly thick bicycle type lock that weaves through the box and through the propane tank.

The only question about your existing battery box is whether or not your new battery will fit inside, so check over the measurements carefully.

AnOldUR

Out of sight, out of mind?

Found this storage shelf that fit the provided tray lips perfectly.
It covers the batteries and can't be removed without tools ...

rcuomo

Artie101 said:

@rcuomo Thanks for the link.  That is very interesting.  I'll need to watch that a few more times as there is a lot of info there.  Keeping it inside is much more secure.  My suitcase came with a Voyager 20 amp charge controller.  Did yours and did you have to upgrade the supplied controller?

Thanks.

Hi Artie, actually my Eclipse suitcase was from 2018 and didn’t come with the Voyager controller.  I believe it came with the first gen Adventurer controller that did not have Li capability. I replaced it this past summer with the Voyager 20a controller and as I mentioned it charges my 100a battery to 100%. I decided not to update the WFCO converter and instead purchased a separate Victron charger and I have installed SAE plugs in the outside tub and under the bed to charge both the LIFePO4 and AGM batteries. 

subfreq111

Yoshi_TAB said:

Isn't the 40 amp fuse in the converter the reverse battery protection that is used in case you hook up the pos/neg terminals opposite?  In my WFCO, the converter is the #6 30 amp fuse.

Also, I see you replaced the charger, but would you happen to know in a non lithium WFCO charger when it tops out at 13.4-13.6, does it continue to try and charge in bulk or absorbtion or does it move to float, even though the lithium battery may only be 85-90% charged.

Yes, fuse 7 is labeled reverse polarity protection. However, at least on my 2018, it is in fact the line connecting the converter's DC output to the DC circuitboard. The #6 30 amp fuse is the line connecting the circuitboard to the battery and tow vehicle at the front of the trailer. (Possibly labeled converter as this is the converter's charging path to the battery?) You can verify this by testing a DC appliance with each removed and will find that fuse 6 removes battery power and fuse 7 removes converter power. 

I don't know whether the charging profile would change on the older WFCO when lead acid target voltage is reached. I would suspect it would shift to float as a continuously rising voltage above range would indicate overcharging the lead acid battery. This is consistent with others' findings that the WFCO only charges Lithium to ~13.6, whereas my Lithium charger will top off to 14.5.

Yoshi_TAB

Hi, 

I've been spending a lot of time inside the WFCO as I'm moving over the converter/charger AC input to a transfer switch with my inverter install.  I have found a couple of mis-labels both on the AC and DC side.

Re; Charging ; This is my understanding..feel free to correct me if it's wrong.   If you look at the WFCO spec,they can put out 14.4 V, but the reason they will not do that when charging a lithium battery is because the circuit board logic will not boost its output voltage to 14.4V until a battery is at a lower voltage like a lead acid battery gets when discharged.  Since lithium batteries maintain a higher voltage even when being consumed, the circuitry of the WFCO never senses a lower voltage, so it will not kick up to the higher 14,4  voltage.  I was just wondering what stage the WFCO sits in after charging a lithium battery as far as it can go.  tks

sequimite

@subfreq111, I plan to upgrade to lithium in my 2016 320 S Max, and was contemplating the same solution--rather than upgrade the WFCO for lithium, disable the charge line from the WFCO and install a dedicated charger that would be active anytime we are connected to shore power. I will probably also install a DC-DC charger in the trailer on the 12V line from the 7-pin connector, but don't want to upgrade the wire on either side of the 7-pin connector.

I also have a suitcase solar panel, but it's only 80 watts, so won't contribute much.

SLJ

Same. Not changing out the WFCO. Installing a dedicated lithium charger that will run off shore power. Batteries will be switched off when shore power is connected as the WFCO runs everything AC and DC when connected to shore power. Also installing a DC to DC for lithium charging off the tow vehicle.