Replacing AGM with lithium in 2021 tab320 BD

immanence · December 2023

@Yoshi_TAB thanks!

The mini rocker was to switch off the battery, but I was worried about that amp rating. I'll have to shop around more there, as most of the switches have much lower amp ratings. I was hoping for something relatively low profile, and a rocker to match the rest of the interior switches.

LED is just the same diagnostic LED as you've posted, but I couldn't find anything smaller.

Fuse box holds a 30amp fuse.

I'll get some butt connectors, thanks!

Good call on the diagram! I'll slip one in near the battery or the WFCO.

Thanks for checking my work here!

immanence · December 2023

Here is a revised parts list based on @Yoshi_TAB comments:

Distribution Bar ($27): https://www.mcmaster.com/catalog/129/855/9290T12
High Current Rocker Switch ($28): https://www.mcmaster.com/catalog/129/1085/7395K28
LED ($5): https://www.mcmaster.com/products/led-lights/panel-lights-with-quick-disconnect-terminals-7/
Fuse block ($5): https://www.mcmaster.com/products/fuse-blocks/
10 ft black 8gauge battery wire ($8): https://www.mcmaster.com/products/wire/electrical-wire~/vehicle-wire-6/
10 ft red 8gauge battery wire ($8): https://www.mcmaster.com/products/wire/electrical-wire~/vehicle-wire-6/

I changed to a high current rocker switch, which is rated to 30 amps/125AC. I switched from the 6 gauge wire to 8 gauge automotive wire. Handles 51amps and saves some money. Probably easier to route too. I have some leftover butt connectors and heat shrink wrap from another project so those aren't on this list.

Yoshi_TAB · December 2023

Hi @immanence,

In looking at a few of your component selections a bit closer, they seem to be a bit atypical of what I've seen used for this type of build. I don't mean they won't work, just a tad different. Others can weigh in, but these are my thoughts. My comments are not meant to criticize, but to be helpful.

Distribution Bars; Normally I've seen separate positive and negative bus bars. I don't see why the two circuit with screw terminal type won't work, but I've only seen the one circuit with stud terminal type used.

If you plan to use the two circuit with screws, are you going to get the covers? They have them as an option. I would suggest them to protect the terminals from contact and a short. Are you going to use spade or ring terminals on the wires? I'm not sure but the #8 size screw for might be on the small size. But maybe not.

Switch: It only lists AC. I would get a switch also marked for DC. It also says for 10A. Am I reading it right? I don't think you are going to find a small 30 Amp switch. Have you considered the same type of OEM switch that can with your TAB but mounted inside to the left of the door as you walk in. Seems like a good place you can reach w/o having to go completely in your TAB.

Fuse blocks: What kind are you getting? If you click on the 30 amp capacity, the in line auto fuse holder for auto fuse comes up. Is that what you are using?

immanence · December 2023

Hi @Yoshi_TAB,

No worries, criticism is requested! I'm only ordering from McMaster-Carr because I thought this would be a reasonable place for a one stop shop/quality/price combo. But there may be better options! The website is kind of bad as they group components together though, so let me see if I can weed out the specifics better.

Distribution bar: your comment made me realize I had the 2-circuit bar selected. I don't think I need that, so I'm switching it out for this one: https://www.mcmaster.com/9290T32/

And that does have a cover available so I'll get that too: https://www.mcmaster.com/9290T27/

I see what you mean about the switch. Here is a version with a DC rating too: https://www.mcmaster.com/7165K29/

A little bit more expensive, but 30amp/30v. Since it is a 12v system, will the 30v be sufficient? I know you said the more amp rating the better, so if I need something more sturdy I can keep looking.

For the fuse box, I didn't like that the one I had selected was 12 gauge as the in line wires, so I switched to this one: https://www.mcmaster.com/8110K5/

20a-60a and with 6 gauge leads.

Thanks again for your attention to detail, I appreciate it. So many moving parts here.

Yoshi_TAB · December 2023

Hi @immanence,

For the switch, maybe something like this. It acts as a breaker for line protection and can be used as a switch to cut power to the battery. It would be hidden in the battery compartment.

Amazon.com: Hamolar 3 Pack 50A Auto Car Stereo Audio Circuit Breaker Fuse 12-48VDC Manual Reset Button Switch Fuses, with Wire Lugs Copper Washer : Automotive

Where do you plan to mount the switch? The reason I ask is if you plan to cut a hole somewhere in the finished wood, getting a clean cut , I found difficult. That switch has no cover/face plate (I think) to cover the cut area, if that makes sense. If cuttting into the wood for a exterior mount, I would try and find a switch with a face plate that would cover the cut area of the wood. If mounting behind the "scenes" its probably fine, but I would personally get one rated higher than your fuse size (30 amps).

You can mount this kind with just the knob showing. Also, I like having the battery switch :"standout" i.e bigger red knob: so you or someone else can quickly find it. Like a big red mushroom stop button in an industrial manufacturing environment.

Amazon.com: Jtron Battery Disconnect Switch Max.32V DC 100A Cont 150A INT Battery Switches for Boatsh for Car Off-Road Vehicle Truck Boat RV Marine(ON-OFF/100A) : Automotive

Everything else looks good.

immanence · December 2023

@Yoshi_TAB wow - I don't know why I didn't think of just ordering from Amazon. Everything is on there, and it works out to be a bit cheaper.

For an LED, would this work out okay: https://www.amazon.com/gp/product/B07P6L6FSF/ref=ox_sc_act_title_3?smid=A1FVLGW38BSVRT&psc=1

It says they come with resistors, did you put any resistors on your LED?

I think I'm just going to switch to Amazon and grab everything off there so I only have to order from one place!

I do like having access to the knob, so I can cut power/drain to the battery and let the solar do its work. Perhaps to the right of the WFCO would be the most accessible and close to the WFCO so I'd be using less wire. In fact this will be easier to access than the current switch in the tub when I have stuff packed in there!

I think I'm going to move the battery next to the AIR8 (if it fits, haven't actually plopped it in there yet), which will leave the passenger side storage fully clear.

Marceline · December 2023

I would get a proper battery cut-off switch.

https://baymarinesupply.com/blue-sea-m-6006-mini-battery-switch-on-off.html

I’ve had good luck buying stuff from Bay Marine Supply. I’m not sure of the quality of some of the stuff on Amazon.

Yoshi_TAB · December 2023

Hi @immanence

This is the LED light I used. I also read about the need for resistors, but in the Q & A for this light, users said they did not use/need a resistor so I also did not.

Amazon.com: PLUG-N-PLAY Instrument Cluster LED Indicator Light Dash Bulbs. Aluminum Pilot Lights. Color Acrylic Lens. Flush Panel Mount 5/16" 8mm 12V for Speedometer Odometer Tachometer (Black Bezel, Green LED) : Automotive

To the right of the WFCO is where my On/Off switch located.

I also placed my batteries next to the Air 8. For how we use our TAB, that area was less untilized then that next to the wheel well...but we all use our space differently.

Don't forget to use some sort of battery hold down to keep your battery from sliding around.

I agree with @Marceline about a proper battery switch and busbars. There are lots of name brands on Amazon. As mentioned, just need to check quality. Blue sea are high quality parts.

rickpool · December 2023

I was planning a LiTime 2x100 ah Mini install, but am now thinking a LiTime 1x230 ah with built-in low temp protection will actually make the install significantly easier (and operations less worrisome). Aside from battery cost, are there any other considerations that I should be contemplating before I head this route (e.g. reliability of the BMS, etc.)?

immanence · December 2023

Maybe of interest to @rickpool I just slotted the litime 230ah battery next to the AC. people often put smaller batteries here, but this one seems to be a perfect fit. See attached pic.

immanence · December 2023

Oops pic did not attach. Here it js

rickpool · December 2023

Thanks! This helps a lot. Plan to do the same now.

immanence · December 2023

@Yoshi_TAB do you know where the solar ties in? I should have asked this sooner, but does this maintain the function of the original wiring where if you turn the battery switch off in the tub I still charged via solar panel on top?

I just thought of this when connecting up the busbar and I was wondering where the mppt ties into the WFCO. I tried to follow the wires, but they go under the bathroom and then I assume loop back into the harness.

Bonus question: is there a way to tie in a solar suitcase here? I had a port on the outside, but I haven't explored where that goes yet. I think it is straight into the battery though, so I might be killing that port...

Yoshi_TAB · December 2023

Hi, @immanence,

Here is my wiring diagram. You may have seen it previously posted.

It shows how the solar is tied in when you move your battery (s) inside.

The MPPT does not connect to your WFCO. The OEM wiring configuration is that it goes from the solar panel, to the solar controller and then directly out to your battery compartment in the front tub.

To update the wiring for the solar controller and external plug:

Your solar controller has four wires going from it. One set (+/-) labeled PV goes to the solar panel. Leave those as is. The other (+/-) set goes out to the battery. You abandon (for now) the OEM positive battery wire on the solar controller and connect a new positive wire (with an inline 30 amp fuse) from the battery positive terminal of the solar controller to your busbar. (Negative does not change). This set up with allow the solar panel to send current to the solar controller and then to the positive busbar which is tied into your battery...charging your battery.

Bonus question answer

Now that you have an abandoned wire that goes from inside your Tab to the outside (from above), you can use it to connect to an external solar plug on the outside of your TAB. For the positive wire to the external solar plug, I used the exterior end of the abandoned wire (from above) to connect to the solar plug and the inside (of your TAB) end of the abondoned wire to the busbar. The outside wire should have an inline fuse. If not, be sure to add one. Now your solar plug is tied in fron the outside to the busbar using the abandoned wire. The inside end will most likely have to be lengthen with a butt connector to reach the busbar.

Hope this made sense..if not, please ask and i can mark up the diagram or re-explain.

Image: https://us.v-cdn.net/5021717/uploads/editor/qy/7wkzfwnbn6kd.jpg

immanence · December 2023

@Yoshi_TAB ahhh, very smart to use that abandoned wire!

This is the diagram I was working off of, but it looks like the one you just posted has a new inverter and some other new components (something at the top there?).

So working from this simplified diagram I can connect the battery positive from the MPPT to the busbar. And that abandoned wire (that used to go to MPPT) I can then connect to my solar suitcase input, directly into the same busbar. So really all of my input can go into the busbar and that will charge the battery? (With a fuse between each input and the busbar)

Here is where I have my new switch and busbar, which are close to the MPPT anyway:

I have most of the components installed and wire run, just need to connect the wires.

My fuses are 50amp resettable breaker fuses though, per a previous recommendation here. You specify 30amp here. Will the 50amp fuses work just as well?

Yoshi_TAB · December 2023

Hi, @immanence,

Sorry if I lead you a stray with the diagrams. The first one I posted was a "generic" drawing of how to move batteries inside without the need to cut any holes in your TAB.

The second is a more detailed with all the componebets I installed when I moved my batteries inside. At the same time I moved my batteries, I installed an inverter and transfer switch.

The wiring is the same, the second provides more details with all the changes I made.

For your set up, just ignore all the wiring for the inverter and tansfer switch.

Your description sounds right. Both positive wires from the solar controller and external plug get connected to the positive busbar, which in turn is connected to your battery and WFCO (via a switch).

Re: Fuses. 30 amp is sufficient for each circuit with 10 AWG wire. That is what I used everywhere except for the inverter circuit. The fuse.breaker combo I suggested was because I thought you were looking for a "hidden switch"connected directly to your battery. 30 amp protection is fine for all the individual circuits, including each solar circuit. All individual circuits should be protected by a fuse. Although a breaker can be used as a switch, that is not its main function. I did back off and suggested (in a previous post) a dedicated battery switch (after another poster also suggested it). I still would recommend a dedicated battery switch designed for repeated ON/OFF cycles which I think you did. A beaker can serve that function, but are not designed for that (IMO). Your switch location is the same as mine.

immanence · December 2023

@Yoshi_TAB Ahhh yes, I see - so that top component is the transfer switch? What is the role of the transfer switch in this setup? I was thinking about getting one for home use, but what power sources do you transfer between in the trailer? Is this for a more robust solar setup?

Ahh, shoot. I bought and installed 50amp breaker/fuses: https://www.amazon.com/dp/B095Z26JWM?ref=ppx_yo2ov_dt_b_product_details&th=1

Is 50amp oversized for this situation? In other words, is my potential surge limit too high?

I am not in the trailer now, but I believe the 2021 WFCO is WFCO WF-8735-AD, which if I look it up it lists it as 35 amps.

I can return the 50amp fuse breakers for 30amp if I need to. Or are these fuse breakers not even appropriate for this situation? I see they are commonly used by car audio folks. But I also see there are some more typical 30 amp in line blade fuses here: https://www.amazon.com/Febrytold-Gauge-Inline-Fuse-Holder/dp/B08QHKXD5N/ref=sr_1_1_sspa?crid=16I7SRUIUYHNH&keywords=inline+30+amp+fuse&qid=1702328540&sprefix=inline+30+amp+fus,aps,89&sr=8-1-spons&sp_csd=d2lkZ2V0TmFtZT1zcF9hdGY&th=1

immanence · December 2023

Ehhh - I like the cleanliness of the inline fuse holders anyway. I'm going to order some 30amp inline fuse holders and return the 50amp fuse breakers I got.

I'll just bide my time by soldering some ring terminals for now!!

Yoshi_TAB · December 2023

Hi @immanence

Your WFCO8735 is 35 amps, but that is the amp output (475W/13.6V) of the converter. Not the amps of any of the individual DC circuit/loads. Below is the spec. of the WF-8735. You can see for the six DC circuits (one for each fuse space), they are only rated for 2 x 30 amps and 4 x 20 amps.

Getting the 30 amp blade type fuse holder is a good choice. It matches the type of fuse in the WFCO so you have common fuse types. It's the same as what NuCamp provides as OEM between the battery and switch.

Re:Transfer switch. It's in the bottom right of the second diagram I posted. It is used in conjunction with an an inverter. It's just a box (see picture below) with a relay inside to automatically switch between AC shore power and AC inverter power for all the outlets in the camper. In the case of a RV, it allows all AC power outlets in the RV to be "live" when using an inverter (battery power). An inverter converts 12V battery power to 110 V AC power. So with a transfer switch, you can run all the 110V outlets when there is no shore power, but only battery power. Without a transfer switch , you are some what limited to the number and location of which AC outlets run on inverter power. Really just an extra convenience to be able to have all 110 outlets run off battery power. It was not hard to install while I was installing the inverter. We run our microwave for short spurts to reheat food, we have a hot water kettle for our morning coffee, charge electronics, etc. ....I know , I know..it's camping. But we go out for 2 months at a time and it's nice to have that feature..purely a luxery. But we all need some

Image: https://us.v-cdn.net/5021717/uploads/editor/5l/ov4bdr803ry0.jpg

immanence · December 2023

@Yoshi_TAB ahhh, that is pretty cool! Do you have two 100ah lithium batteries? How far does that get you?

That would be nice. I got one of those standalone power stations to fill that role, but it is obviously much smarter than the trailer batter and it wouldn't run the microwave or AC. Really just to charge a laptop when needed.

rickpool · December 2023

@Yoshi_TAB - Thank you for all of your insight and patience! :-) Quick question… your battery cut-off doesn’t cut-off Solar or Tow Vehicle charging… is there a strong reason one-way or another for this configuration? You previously clarified wanting power to the brakes, but am not sure whether to configure the cut-off upstream for the rest?

ckjs · December 2023

immanence said:

Ehhh - I like the cleanliness of the inline fuse holders anyway. I'm going to order some 30amp inline fuse holders and return the 50amp fuse breakers I got. ...

Did you find 30A inline fuse holders which actually use 10 gauge wire? The best I've seen use 12 gauge -> 20 amps.

Yoshi_TAB · December 2023

Hi @immanence

Yes, I have two lithium batteries that total the same capacity as your single. They work just fine for us with lots of capacity. No complaints on capacity.

Just to be clear, when I said AC in my post, it was for AC power, not the air conditioner. I have calculated if I was to run the Air 8 off batteries..with full batteries (and nothing else running) it would run for about 3-3 1/2 hrs...then they be dead :( The Air 8 consumes about 65 amps/hr. Very few campers of any size, can really run their air conditioning while boondocking and have solar keep up unless you have a lot of panels and "perfect sun exposure" to keep up.

I sized my inverter to run the microwave and hot water kettle (and my wife's hair dryer

) Anything that produces heat uses a lot of battery power, but for short spurts, it keeps up. Looking forward to see photos of your final set up.

Yoshi_TAB · December 2023

Hi @rickpool

Correct, no cut off switch for solar or tow vehicle charging. Don't see a need for that. I've looked at a lot of other set ups on different sites and don't recall seeing a cut off switch for those items. Plus you can turn off solar charging via the victron app. Or you can pull the fuse. You may have a need?

The dedicated line to power the emergency brakes is a personal preference on my part. I like knowing that I would not mistakenly leave a switch off while traveling making them useless in the unlikely event they are needed. I do have a fuse in line that I can pull if I need to disconnect power to them.

I am by far not an expert...just sharing what I've learned. You can also ask your question here. I post at these sites to get info. and solve problems The first one has many very knowledgeable people..mostly with big rigs, but very friendly and helpful. They have helped me with a bunch of electrical questions.

Solar Charging Systems | The RV Forum Community

Vehicle Mounted Systems | DIY Solar Power Forum (diysolarforum.com)

rickpool · December 2023

@ckjs, @immanence - Here are the 10 gauge, 30 amp blade fuses I purchased on Amazon…

DaierTek 10 Gauge Fuse Holder 12V for ATC/ATO Blade Fuse, Inline Fuse Holder 12V with 10 AWG Wires with 30A 40A Fuse Waterproof Fuse Holder for Automotive Car Marine -6pcs

https://a.co/d/76fYkj6

immanence · December 2023

@ckjs this is the pack I got, because I needed three. And I bought some separate 30amp fuses: https://www.amazon.com/gp/product/B0BRPW9KJ5/ref=ppx_yo_dt_b_asin_title_o01_s00?ie=UTF8&psc=1

Rickpool posted some too - a few options on Amazon, but I had the same problem when I was looking at McMaster-Carr. All of their 30amp options had smaller gauge wiring.

@rickpool You might know this already, but I like to have solar coming in even when the WFCO is turned off, because it eliminates battery drain and ensures the solar power is all going to the battery. If you needed to cut it off, I agree with @Yoshi_TAB though that I'd just pull the fuse.

rickpool · December 2023

@Yoshi_TAB - One “final” question before I start cutting wires. I am not currently installing an inverter, but want to accommodate this in the future; thus I am planning on running 2/0 awg from battery to both POS and NEG bus bars (with 225 amp fuse like yours). I see you tied your inverter NEG wire to the bus bar (which runs thru the shunt), but went straight to the battery for the POS wire… is there a compelling reason to skip wiring to the POS bus bar (e.g. to eliminate an extra 225 fuse)? Any other considerations?

Horigan · December 2023

One reason would be if you have a battery monitor that monitors current through the negative wire via shunt between the battery negative terminal and the negative bus bar.

SLJ · December 2023

Nothing should be connected to the actual negative of the batteries except the shunt. All negative connections should be after the shunt otherwise the monitoring won't be accurate. The negative wire to the shunt should be at least as large a gauge as the inverter wire. The inverter should be connected as close as possible to the positive and negative with the positive passing through the inverter fuse.

immanence · December 2023

Why do people add shunts - is it to have something more accurate than the MPPT?

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Replacing AGM with lithium in 2021 tab320 BD

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