House Batteries - Inside or Under the Van?

Drizzt · 01-15-2022, 11:44 AM

Greetings fellow van nerds!

Been digging around for threads on this topic and haven’t found any. I recently got into an argument with an EE over it; he just kept saying “water and electricity don’t mix.” Well no sh!t genius but the second engine battery is already under the van so riddle me that Batman... But that conversation got me to (probably over-) thinking if there was some major red flag that I’m missing.

Originally I’d planned on mounting them under the van behind the rear axle like I’ve seen on most of the E-Series SMB’s when I was at SMB Texas. But I’ve been kicking around the idea of having them inside the van as they would fit above the wheel wells fairly well (these would be LeFePO4 so no venting issues). My plan for under van batteries includes fabricating some plates to protect them from direct water spray, but they wouldn’t be waterproof if one was to end up going through a deep enough “puddle.”

I like the idea of keeping them under the van for maintaining more precious space inside the adventure wagon, but under the van is also a real pain in the a$$ to get at the batteries (the amount of swearing needed to service the second engine battery always amazes me). I’m not sure that inside mounted would make servicing any easier as you’d have to pull out damn near everything to get to them (I have a permanent raised bed with ‘garage’ underneath for toys) but there would also be one less set of holes to drill through the floor which has appeal. There would also be less cable run if they were inside as well.

I realize this is a pretty open ended topic but interested in anybody’s experiences with each, especially if there is some major issue with under van mounting that I’m not seeing.

Thanks, y’all.

David

Lilnuts2 · 01-15-2022, 11:53 AM

Inside is the way with lithium's. They can't be charged when it's below freezing. They can be mounted on their side or even upside down. There is no reason to have awesome access, because you never touch them. Shorter cables is always good. They are so much lighter that handling them in a tight space is not bad at all.

I love my lithium's.

ShuttlePilot · 01-15-2022, 12:13 PM

I second everything Lilnuts2 said. Unless you are installing a 12kwh 10 battery system like you see on Instagram every day in sprinters there is no need to mount outside with lithium. I wouldn't even consider mounting lead acid in the location I put my pair of battleborns. This was mostly wasted space before and doubled my capacity over the 4D lead battery hanging under the van. I'm very happy with all of it.

p.s. I quit arguing with engineers long ago, I just say," your right" and move on. I learned that from Chris Voss Chief hostage negotiator.

- Eric

bigriver · 01-15-2022, 02:19 PM

Timely topic for me as I am working on the same issue. I'm replacing two 4D 210 AH AGM's with a single 200 AH LiFEPo4. Same useable at about 30% the weight. My existing bats are frame mounted under side door and in front of spare tire. I have measured every which way and not been able to find the interior room for the new battery and still be able to pack as we do for extended Baja trips so under the van it goes. With Lithium there is not only the charging issues with cold (managed hopefully by the BMS) but also heat related issues in terms of battery longevity. Scalf pointed this out to me and my additional research confirms this fact. Since I need to replace with the existing 4D form factor in order to use the existing under side door housing I'm kinda stuck as to what's available - and whatever I end up with will be under the van. We'll see how that works out.

1der · 01-15-2022, 03:07 PM

I also have been giving considerable thought in switching to Li and how to make it work for our extended winter camping as well as rest of the year.

Currently the two 170Ah each AGM/s are mounted aft of the rear axle and forward of the basement box. This is a great location in the EB that is not available in the RB.

Because we have a walkthrough layout I have been strongly considering cutting another access port in the floor in the center aisle above the existing battery location and enclosing that space with an insulated box to hold the Li battery or batteries. This space could receive a small amount of ducted heat from our Espar heater and I would likely use the heated batteries as an additional safety factor.

Depending on the number of batteries it could add an additional underfloor storage space as well.

Lithionics makes a nice heated 315Ah w/ 20" x 10" x 6" dimensions. A single one of these would increase our usable amp capacity by 60% and would fit easily in the box I could install in that area.

The important part for us is making sure the batteries can be charged when it is below freezing outside while maximizing interior space.

ONE other consideration that I feel is often overlooked in these Li setups is how to charge the starter batteries (which need to be AGM because of temperature consideration) from the solar panels or shore power based charger . Not an easy elegant solution for this, at least that I have found. Having all the batteries as AGM's, dual battery bank charging was an easy solution using a bi-directional isolator. The DC to DC chargers are not bi-directional and the AGM's have a different charging profile than the Lithium. So, the starter batteries are reliant on the alternator for charging or a separate charging system (from solar/ shore) needs to be incorporated into the system and dedicated to the AGM starter batteries.

bigriver · 01-15-2022, 03:18 PM

O000h... Ray... that is an interesting battery. If I can wrangle a couple more inches above my existing 4D that could work in my application. The specs show a heater feature "Internal Heating Kit: Permits Charging as low as -20C/-4F" that would certainly help with either of our applications.

Thanks for the tip

bigriver · 01-15-2022, 03:21 PM

Oh - right - $4,500 - figures ... got excited there for a second Heh

1der · 01-15-2022, 04:09 PM

Check w Scalf77 re the Lithionics, I think he has a relationship established w them.

yep, not cheap but the 4D Lifeline AGM batteries are pushing $700 a piece, now.

KDB · 01-15-2022, 08:11 PM

Sounds like a quite a few of us are getting off the AGM's and into heated Li. Put your batteries inside if you have the ability too. COld weather (as in teens and below) and even your lead acid's will struggle with their voltage output and wont easily take charge. Warm batteries are ideally what your looking for at all times. I intend to upgrade to 2 100A battleborn heated Li's from 2 100A AGM's. The additional useable amperage and quicker solar charge of Li batteries has me ready to make the change.

pjpvi · 01-15-2022, 08:16 PM

Quote:

I have been strongly considering cutting another access port in the floor in the center aisle above the existing battery location and enclosing that space with an insulated box to hold the Li battery or batteries.

That's a great idea Ray as my AGM's are in the same location, and like all of you, I'm looking at Li after these AGM's die (should be in the next year or two). Can't wait to see what you all come up with so I can learn from your successes.