Solar and Lithium Battery Installation

[macnut]

We added solar and lithium batteries in April. AM Solar in Springfield OR did the installation and I’m really happy with the result.
Al

https://mobilemosers.com/2023/05/27/...-installation/

[johnbro27]

Nice write up.. Thanks for sharing.

[macnut]

Thanks! I think the most important part was the upfront planning with an electrical engineer.

[Flying E]

I have a couple of questions about the Victron Cyrix-Li-ct that was installed. Does this give you the ability to bridge both batteries for staring if the chassis batteries are low? Is the alternator charging the Li batteries while driving? Is the chassis battery being charged when plugged in?

[macnut]

Originally Posted by Flying E

I have a couple of questions about the Victron Cyrix-Li-ct that was installed. Does this give you the ability to bridge both batteries for staring if the chassis batteries are low? Is the alternator charging the Li batteries while driving? Is the chassis battery being charged when plugged in?

Yes to all of those questions. I also had them install an on/off switch to it, as an extra precaution so I don’t overwork the alternator if the batteries are really low when I start a long drive.

[Cam Jack]

That is the same spot that I want to install Lithium batteries on my 2022 3014.

I currently have a 2000 watt inverter and a 60 amp MPPT solar controller installed on the lower portion of the bay.

I've recorded temps close to 140 degrees in the lower portion of the bay.

The upper shelf has recorded 160 degrees. I started watching the temperature because after one long summer drive, I removed a box i had stored on the upper shelf and was extremely hot. Almost to the point of burning my hand.

I'm fully aware of what a BMS does, but I'm worried its just a too hot location for the Lithium batteries. Not sure if a fan would accomplish anything due to the heat is coming from the shelf itself.

1) Does anyone else use that location or has recorded those temps that I have seen?

2) Any Ideas on lowering the temperature?

Nice install, but don't forget that switch on a long drive if the batteries need a lot of charge. My preference is a DC to DC charger. Has worked well on a previous RV. As I get older, one less mistake to make.

[macnut]

Cam Jack, I appreciate your post! I’ll be taking temperatures there while on the road tomorrow and will let you know what I find.

I’ve already talked to AM Solar and while it may not be a safety issue, I would be concerned if it reduces the life of the battery in the long term.

I may have them relocate the batteries to the bay between the hot water heater and the water tank. On the water tank side.

I may also try installing heat shield along the outside of the bay to see if that makes a difference. I would probably want that regardless of where my batteries are, just because I don’t want the needless heat coming into the bay.

Once again, I’ll keep you posted!

[Cam Jack]

I like your shield idea!

I just looked under the bay. The Cat is just below the pass through. That make since for the excessive heat in that bay.

A friend who used to fabricate headers is helping me with a shield/installation idea.

That location is by far best spot for the shortest wire run to the inverter. I'll keep you advised when I install it and check the temperature.

I'll be driving to Oshkosh in July from California. I'll get good data then.

A 2023 3014 was park next to me. The Cat was in the same location as mine.

[macnut]

CamJack, that’s awesome that you have someone to work with on the shield idea. Here’s the best photo I could get of the area. I tried to draw where the compartment is and yes, it’s right over the catalytic converter!

Please let me know anything you find about the heat shield!

I was thinking of sticking this reflective shield right over that point. Theoretically it should help!

Design Engineering 010392 Reflect-A-GOLD High-Temperature Heat Reflective Adhesive Backed Sheet, 12" x 24" Sheet https://a.co/d/di2SIzk




Hopefully we can solve this as I’d hate to give up another bay for storing the batteries!

Btw, I did check my battery Bluetooth app, and there were no event recorded for over heating. So at least that’s good, considering I drove 500 miles from Grants Pass to the SF Bay Area, and then another 500 to Las Vegas. It was in the high 80s driving to Las Vegas.

Al

[macnut]

Btw, the catalytic converter is on the left I. The photo (looking towards the rear of the coach). The cylinders on the right are part of the Liquid Spring installation.

[macnut]

Ok, I just finished driving from North Las Vegas to Bakersfield, about 300 miles in 5 hours, starting at 1pm and ending at 6:10pm.

I drove 60-62 the entire way, but a little slower up the mountain passes and a little faster down.

The weather was warm, in the 90’s most of the trip till I started up the Tehachapi’s then it cooled to about 80.

There was a strong 20+ mph headwind almost the entire drive, which reduced my normal 8.4mpg to 7.4mpg!

I only stopped for a quick restroom break.

Here is the temp data directly from the battery over the catalytic converter. The other battery was generally about 2 degrees cooler.
Start: 90
After 1st hour: 95
After 2nd hour: 99
After 3rd hour: 102
After 4th hour: 106
After 5th hour: 108 (107.8, actually)
It stayed there until I arrived.

It was 107.8 at the top of the Tehachapi and never moved after that. Probably because there was more downhill and it cooled to the low 80’s.

The inside of the compartment started at a little over 90 degrees and went up to about 110 pretty quickly, then went up and down between 110 and 120ish. It went down when going down the passes and up when climbing. I think the strong headwinds contributed to a higher temp, but I wasn’t towing this time, which helped.

So, what I make of this is that the heat shielding under the compartment is helping, but should be improved.

Also, I think the batteries themselves must be insulated pretty well to start so much lower than the compartment it’s sitting on after 5 hours.

I’m thinking I’ll keep the batteries where they are but add additional heat shielding to the bottom of the metal shielding Newmar provides.

Here the one I’m thinking of right now. The other one could only take 800 degrees, but this one is much higher. Even if it takes the temp down another 10 degrees it would be worth it.

BSTFLEX Reinforced Lava exhaust Heat Shield Mat 12 Inch x 24 Inch with adhesive Backed Resistant High-temp (12'' x 24'')… https://a.co/d/dAvorRw

What do you think?
Al

[macnut]

Wow, I think that was my longest post ever!

[macnut]

Here’s a graph of the compartment temperature taken right beside the battery over the catalytic converter.

[Cam Jack]

Good information.

Is your temperature monitor actually laying on the top shelf where the batteries sit?

Sounds like your trip had somewhat good airflow. I noticed the higher temps in traffic and definitely driving up passes.

My friends idea with the extra insulation would be two parts. Attaching some type of blanket like your idea and also an aluminum shield with airspace between the Al shield and blanket.

Looks like i don't need the internal battery heaters!

I hope someone else has relocated the batteries into that spot and will comment.

I'll have to take a closer look at a 2023 and see if it has more insulation than my 2022. Newmar went from a 22K chassis to a 24K chassis in 2023. Maybe a little more distance from the Cat to the box.