My inverter installation

descott12

Hello all,
I wanted to post this in case somebody else is trying to do the same thing. When the dealer told me the "Lithium upgrade" with the inverter was an additional $7500 I said that is a "big no thank you" and I did it myself.

I replaced the single Battleborn 100AH battery with 2 LiTime 100AH self-heating batteries in parallel. I used a Renogy 2000W inverter with remote on/off switch. I installed a standard outlet and I ran a short extension cord from the inverter to the microwave so I can easily run the microwave when away and disconnected.

The installation was conceptually easy but working in the small confined spaces is tough and dealing with 2/0 battery cables that don't bend is also very tricky but I got it to work well. The whole thing was just about $1000.

Here are the major parts:

2025-06-21 - updated parts list
Bus bars - $24 - https://www.amazon.com/dp/B0BYMNL4YX

Self-heating LiTime 100AH battery - $320 each - https://www.amazon.com/dp/B0DBL9ZKHV

250A fuse - $15 - https://www.amazon.com/dp/B079ZK1GYL

250A class T fuse - $24 - https://www.amazon.com/dp/B0D7PG2PSP

2000W Renogy Inverter - $240 - https://www.amazon.com/dp/B07H9SXV61

Battery/inverter disconnect switch - $13 - https://www.amazon.com/dp/B08YXGXW2W

Cables from BatteryCablesUSA $110

I have attached a schematic and 4 pictures of:
1) The batteries are at the bottom of the image. They are under the passenger side couch where the original battery was. You can see the bus bars in the center horizontally and the cable with the fuse coming from the inverter that is off image on the right side.  Note that the + terminal on the right battery is not hooked up yet as I am charging the left battery and you are not supposed to hook them in parallel until both are fully charged (or at least somewhat equal).
2) The inverter to the left of the AC unit.
3) The new outlet installed in the bulkhead to the AC unit compartment
4) And the new yellow extension cord running up the the microwave

Please let me know if you have any questions or if any of the gurus out there spot something that I did wrong.  I realize now that I probably need to add a fuse on the inverter AC output.

donmontalvo

A couple questions, since you asked.

Have you considered a 250A Class T, to avoid the possibility of an arc?

Also are the +/- wires going from the batteries to the busbar the same length? I only ask because I see the battery on the right does not have a + connection, and I see a + cable that isn't connected but much longer than the + cable on the battery on the right.

descott12

donmontalvo said:

A couple questions, since you asked.

Have you considered a 250A Class T, to avoid the possibility of an arc?

Also are the +/- wires going from the batteries to the busbar the same length? I only ask because I see the battery on the right does not have a + connection, and I see a + cable that isn't connected but much longer than the + cable on the battery on the right.

Hello, I don't even know what a Class T is????  Please explain.

The battery cables to the bus bar were all SUPPOSED to be the same length but I had an issue getting them all to fit as they are so stiff and non-bendable so I had to subsitute that long one. I plan to change it out for one that is the same or a similar length.  They are all supposed to be 8 or 9 inches.

Yoshi_TAB

Hi,

When I put a 2000W inverter in my 320, a Class T was highly recommended from various sites I researched.  It is considered the gold standard for fuse protection for  higher amp circuit protection because of its rapid responce time time and its ability to eliminate any arc flash  if/when the fuse blows.  The con is they take up more space and the fuse itself is more costly than others.

A switch to isolate my inverter was also recommended when I installed my inverter.  It did come in handy when needing to isolate the inverter from the 12V source during maintenance /troubleshooting.

descott12

Thanks guys. I just ordered a T class fuse and a cutoff switch. Thanks for the advice. Now I will need to order some new cables to integrate all this and luckily I realized the cutoff switch terminals are M10

Yoshi_TAB

Hi,  From my experience (and you may already know)  Windy Nation,  makes very nice flexible welding cables and has an Amazon store front.  That made it much easier to return cables when I  bought the wrong length and end fittings (which happened a lot  as I designed my system and made changes).  I also bought some from battery USA (as you did) who has very good cables and prices.  One other thing, I bought a small computer type fan to put next to the inverter as added cooling .  I know the inverter has a built in fan, but wanted some extra cooling as heat is your enemy.  One more thing..make sure you buy good fuse brands such as Blue Sea and watch for knock offs (again sorry if you are already aware).  A bit more money, but not worth cutting corners in this area.

donmontalvo

descott12 said:

donmontalvo said:

A couple questions, since you asked.

Have you considered a 250A Class T, to avoid the possibility of an arc?

Also are the +/- wires going from the batteries to the busbar the same length? I only ask because I see the battery on the right does not have a + connection, and I see a + cable that isn't connected but much longer than the + cable on the battery on the right.

Hello, I don't even know what a Class T is????  Please explain.

The battery cables to the bus bar were all SUPPOSED to be the same length but I had an issue getting them all to fit as they are so stiff and non-bendable so I had to subsitute that long one. I plan to change it out for one that is the same or a similar length.  They are all supposed to be 8 or 9 inches.

I honestly didn't know what a Class T was until the past few months either. Baptism by fire, learned a TON over at the Victron Energy page on Facebook. The experts there told me I should ask Battle Born what the "Interrupt Rating" rating recommendation is for their two batteries. I was shocked to learn that the recommendation could only be met using a Class T fuses. They recommended an MRBF on the battery positive posts, and the Class T as close as possible to the positive post on the battery that connects the parallel array to the positive busbar.

My two 12V 100ah LiFePO4 batteries sit side by side. The two wires used to configure the parallel array connect the two batteries to each other (one positive; one negative), they are the same length. The two wires that connect the parallel array to the busbars are also the same length (one positive; one negative).

The caveat, installing the Class T fuse, in it's 7" holder, directly to the MBRF on the battery leading to the two wires that connect the parallel array to the busbars ARE still the same size.

Thermal images show no heat issue, even when taxing the limits of the kit, and Battle Born and Victron experts all OK'd my schematic.

donmontalvo

Yoshi_TAB said:

One other thing, I bought a small computer type fan to put next to the inverter as added cooling.

I put a USB fan in the compartment where I installed my inverter, goes on/off when the inverter does. Thermal images showed it didn't really cool things down. I added a second fan on the other side of the component, so one blows air in, and one blows air out. Temperatures became much, much more reasonable. Just a thought.

donmontalvo

descott12 said:

Thanks guys. I just ordered a T class fuse and a cutoff switch. Thanks for the advice. Now I will need to order some new cables to integrate all this and luckily I realized the cutoff switch terminals are M10

Pretty sure you figured this out, but Class T fuse holders come in sizes to match the AMP rating of the fuse, and are specific to the vendor's Class T fuses.

descott12

Hello all,
Thanks to the comments and suggestions above. I have made the changes and update my original post. I replaced the fuse with a class T fuse, added a cutoff switch for the inverter input and I made sure all the battery cables to the bus bars as the same length. The system works quite well and it is pretty easy so anybody should be able to make the upgrade. Sure beats the $7500 "Lithium battery upgrade" that the dealer was charging.

donmontalvo

descott12 said:

Hello all,
Thanks to the comments and suggestions above. I have made the changes and update my original post. I replaced the fuse with a class T fuse, added a cutoff switch for the inverter input and I made sure all the battery cables to the bus bars as the same length. The system works quite well and it is pretty easy so anybody should be able to make the upgrade. Sure beats the $7500 "Lithium battery upgrade" that the dealer was charging.

Nice work!

I moved my "connect the two LiFePO4 batteries to busbars instead of each other" to-do list item up the list, because of you.

descott12

donmontalvo said:

Nice work!

I moved my "connect the two LiFePO4 batteries to busbars instead of each other" to-do list item up the list, because of you.

Yes, the bus bars make the system so much easier to build and maintain.

Yoshi_TAB

Hi @donmontalvo

Where do the small red wires in front of the main positive terminals go to?  I believe they are connected on the battery heat enable terminal , but where does the other end go to? TY

donmontalvo

Yoshi_TAB said:

Hi @donmontalvo

Where do the small red wires in front of the main positive terminals go to?  I believe they are connected on the battery heat enable terminal , but where does the other end go to? TY

It is outlined in my schematic. Right-click on the schematic on the top of my blog page to see the details.

https://donmontalvo.com/2025/05/02/coming-up-for-air/

PS, unfortunately this forum downsamples schematics making it impossible to read, so the URL provides a path to an easily readable schematic.