Modifying 2021 17MKE to Lithium 100a batteries

[Pete & Pat]

Apologies in advance for the lack of knowledge on my part, as I'm new to this. I'm planning on modifying my battery systems to replace two 12v lead-acid with LiFePO4 100a batteries. I've been trying to put together as much information as I can,including a post on the same topic from July 15, but have some questions as I'm awaiting some info from Grand Design service folks.

1. Where is the voltage converter located on the rig? I've read in the forum on larger units it's located behind the aft wall of the pass through, but before I take it apart, I'd like to be certain.

2. What is the best type of voltage converter to use with the Lithium batteries? Does that require additional equipment related to battery monitoring or charging?

3. Are larger wires required from the battery to the converter than are supplied with the original equipment? Existing original wires seem fairly small in gauge.

4. Any concerns about whether the Lithium batteries are compatible with on-board equipment?

Thanks, Pete

[acoleman43]

Apologies in advance for the lack of knowledge on my part, as I'm new to this. I'm planning on modifying my battery systems to replace two 12v lead-acid with LiFePO4 100a batteries. I've been trying to put together as much information as I can,including a post on the same topic from July 15, but have some questions as I'm awaiting some info from Grand Design service folks.

1. Where is the voltage converter located on the rig? I've read in the forum on larger units it's located behind the aft wall of the pass through, but before I take it apart, I'd like to be certain.

2. What is the best type of voltage converter to use with the Lithium batteries? Does that require additional equipment related to battery monitoring or charging?

3. Are larger wires required from the battery to the converter than are supplied with the original equipment? Existing original wires seem fairly small in gauge.

4. Any concerns about whether the Lithium batteries are compatible with on-board equipment?

Thanks, Pete

Welcome Pete! I hope you find this forum helpful.

I'll try to answer your questions and let smarter people correct anything

1-The AC to DC converter is likely part of your main distribution panel in the back of the RV in the kitchen area.

2-THe converter only converts AC to DC. It does not interact with the batteries. However, most factory systems will have a converter/charger. This is an all-in-one unit that converts AC to DC AND charges the battery from the AC coming into the RV. There's a good chance this is what you have. Saying this, any charger that is compatible with lithium will work. A lot of current chargers will automatically sense what battery type it is charging and switch charging algorithms to the correct profile. If you can locate your distribution panel and get a model number, that will be very helpful.

3-The size of wire is determined by the maximum voltage and current running through the wire/cable and the length of the wire/cable. You would have to know the max discharge capabilities of the batteries and the distance from the batteries to the distribution panel.

4-The onboard equipment doesn't care what type of battery is supplying the electricity, the equipment only cares the voltage that is being supplied. All your equipment should be 12v, and your batteries should be 12v so it won't be an issue.

[ncitro]

Pete & Pat AC Coleman has given you some answers but here is some additional advice. The existing wiring will be fine for a lithium converter as long as you get one the same size as your factory (probably 55 amp). With that much battery it would not be a bad idea to go with a larger converter, this would give you shorter run times on a generator to recharge if you use one. If you increase the size you will want to increase the wire size as well. In that case what most of us do is move the converter to the battery bay, this shortens the wire run from the converter to the batteries, so there is less voltage drop, and less wire to buy. Leave the factory wiring in place to feed the DC panel, and just unplug the factory converter and leave it there as a spare. You can then run an extension cord from the outlet the factory converter is plugged into to your new converter and you should be all set.

No battery monitor is required, but it is recommended. Without one it is basically like driving without a gas gauge. I am partial to the Victron BMV or Smart Shunt, but there are other options as well.

[TucsonJim]

Pete & Pat AC Coleman has given you some answers but here is some additional advice. The existing wiring will be fine for a lithium converter as long as you get one the same size as your factory (probably 55 amp). With that much battery it would not be a bad idea to go with a larger converter, this would give you shorter run times on a generator to recharge if you use one. If you increase the size you will want to increase the wire size as well. In that case what most of us do is move the converter to the battery bay, this shortens the wire run from the converter to the batteries, so there is less voltage drop, and less wire to buy. Leave the factory wiring in place to feed the DC panel, and just unplug the factory converter and leave it there as a spare. You can then run an extension cord from the outlet the factory converter is plugged into to your new converter and you should be all set.

No battery monitor is required, but it is recommended. Without one it is basically like driving without a gas gauge. I am partial to the Victron BMV or Smart Shunt, but there are other options as well.

Just a few updates:

The converter on the '21 17MKE is integrated with the power distribution panel. And since this is an Imagine, there is no "battery bay" since the batteries are on the A-frame. According the the parts look up page, the 17 MKE has a 35 amp converter which is a model WF-8735. I believe there are lithium dedicated replacements that can be substituted in your unit.

Jim

[TucsonJim]

WFCO sells a model called the WF8735LiS which can be used as a direct replacement for your current WF8735.

https://wfcoelectronics.com/product/wf-8735lis/

[Pete & Pat]

Thanks all for the quick and detailed responses. We'll see how it goes.

[Jack61]

I just put two Battle Born 100 AHr batteries in my 2022 17MKE. I utilized the small jog in the passthrough storage area to place the new batteries.





Just as a precaution, I used 4 ga wire. The wires still need to be dressed. I'm going to clip them to the ceiling of the passthrough compartment. The connections to the main system are made behind the wet center on the opposite side of the compartment. In order to not re-wire anything I didn't have to, I left the original battery terminals (taped off) inside an empty battery box on the tongue. The positive lead is connected to the battery side of the battery disconnect switch. The negative side is connected to the battery side of the furrion shunt that came with the solar package.

I also need to make a face plate for the Victron 712 battery monitor that I added to the setup. It is installed on top off the battery box. I'm going to put a faceplate above the left side of the battery box and just cut a hole to mount the monitor gauge.

Camped for the first time this weekend and tested out turning off the connection to shore power. The Victron monitor told me I was drawing 9 amps when the refrigerator was running and that I had about 36 hours of runtime remaining. It was a cloudy day so the solar wasn't contributing much. An engineer with Battle Born ran some numbers for me and stated that if I would add a second 165W panel to the roof I should be able to run the refrigerator without needing a generator backup.

I am by far no expert but with the help of the guys on this forum I was able to complete the job! (Thank You !!)

If you want an amateur's take on the process, feel free to message me.

Jack

[Pete & Pat]

Thanks for the helpful comments and pics Jack.

[Jlawles2]

Jack61 Jack, nice place for those batteries.

For safety, have you considered using https://www.amazon.com/Team-Performa...s%2C131&sr=8-6 or https://www.amazon.com/Team-Performa...s%2C131&sr=8-6 on the tongue as a place to "PARK' the cables?

[Jack61]

Jack61 Jack, nice place for those batteries.

For safety, have you considered using https://www.amazon.com/Team-Performa...s%2C131&sr=8-6 or https://www.amazon.com/Team-Performa...s%2C131&sr=8-6 on the tongue as a place to "PARK' the cables?

Very good idea ! Thanks.

[David Smith]

When increasing your solar wattage remember the panels have to be identical for best performance. A matching 165W Furrion solar panel is ~$500-$600. You can buy 2 175 watt (350 total) for less the $400 from Renogy.