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Discussion Starter · #1 · (Edited)
Hi all: I finally completed my power box revision/rebuild. I was running a tallish, narrow-ish wooden power box between the driver B and C pillars. I initially used a 95 Ah AGM, but switched to a Renogy 100Ah LiFePO4 self heating battery charged with a Renogy 30A DC-DC/MPPT charger and serving a Renogy 1000W PSW inverter. I've also included a Mean Well 24v/500W DC power supply to convert shore power into faux solar (far cheaper than charger/inverter) I had always planned to up my capacity to 200Ah and a 2000W inverter, and a 50A charger, but I decided to revise the box at the same time.

The old version of power box was around 7,590 cubic inches. I built it big enough to accommodate two batteries. I had two objectives for the redesign, in addition to the power upgrade: Reduce size (volume) as much possible and lower the height to fit under my bed platform should I lower it from its current waist level mounts.

Old:
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The new box came in about 400 ci smaller at 7,168 ci (16" x 14" x 32"). As some of you noted in my earlier musing about an 80/20 bed, I found there are pros and cons to wood vs. 80/20 vs. a hybrid (which I chose).

Here's box 2 rough fitted in the van. I used 1000mm 3030 Amazon knock-off 80/20.

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I had initially intended to mount all the components on an aluminum extrusion internal frame work, but I found that to be too wasteful of aluminum, so I shifted back to a shelf approach like Box 1. All the "serviceable components" (4 fuses and the DC-DC/MPPT) are on the top shelf so as to be easily accessible from the top.

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I was prepared to drill holes and use riv nuts to mount the box (it weighs 22# alone, just south of 100# including 52# of battery, 12# of Inverter and lots of 2/0 AWG Ancor cable). I was able to again avoid that by using the existing M8 holes in the interior metal side panel to mount the bottom and far left vertical components. The bottom rails of the box are a full meter long, and the extension to the right provides a path for 4 AWG positive and 2/0 AWG ground cables (actually double 4 AWG cables). I needed the 2/0-level ground for the house battery pack. The amperage draw on the house battery is fused at 75A, so the 4 AWG positive was plenty.

It's hard to tell from the picture, but the inverter and negative bus are on the bottom shelf (I set up the battery monitor shunt to work on the factory auxiliary battery because Renogy's DC Home app provides comprehensive bluetooth data for the batteries and DC-DC/MPPT charger).

Here's a couple of top views. I tried not to over-radius the 2/0 cable, but it was hard given my size constraints. I actually wound up using a double 4 AWG cable to achieve my ground due to constraints on the run back to the factory auxiliary battery.

Note that the batteries are locked down by the top cross bar, as well as two bars at the bottom and center of the stack. Very secure on bumps so far.

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Here's the forward driver's side of the box. I was able to fit a cover over the conduit cables running from the driver's seat pedestal. The lighted rocker switch is a new add that lets me turn off shore power (to silence the power supply fan) if I choose.

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Finally, here's a screenshot from the DC Home app. The Renogy batteries and DC-DC/MPPT talk to each other though ethernet ports, and Renogy has a bluetooth module and a powered ethernet hub (switch). 200 Ah means I can go long weekends with no solar panels.

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Finally, I am going to be testing out an induction plate. I expect my only cooking use in the van will be cold morning coffee before venturing out of my warm rolling home.
 

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Looks solid. I know this kind of thing takes a long time to plan and then assemble.

The only thing that came to mind when I looked at this was I wasn't excited about stacking the batteries on their side. For the most part in theory Lifepo4 batteries can be mounted in any orientation based on the general cell type not having sloshing liquid etc. I don't know much about these specific batteries and their internal structure, but I've opened several Lifepo4 batteries and have seen the insides. Not many of them appeared to have an internal structure than would appreciate being mounted anything but up. These might be fine, but if the bottom battery is literally carrying the weight of the top one it could potentially be an issue over time. Again, it just depends on what's in there and if they truly secured it. Prismatic vs pouch vs cylindrical all have different packing styles. Another consideration is where they place the temp sensors and if those locations are sensitive to orientation. On the topic of heat you are probably also going to get some internal temp differences due to the stacking. If that causes any concern I'm not sure. It would be something to look at if you are in a warm climate and use that inverter to run an induction cooker.

I like that those batteries have the wired communication links. I'd like to see more batteries with that functionality in addition to bluetooth. Ultimately, I'd like to see a standard communication protocol across brands, but that's unlikely. It's serial using an RJ connector.

Love that you used good fuses and not flaky breakers that a lot of people seem to be using.

I might have missed it, but how are you covering it with panels?
 

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Discussion Starter · #3 ·
Looks solid. I know this kind of thing takes a long time to plan and then assemble.

The only thing that came to mind when I looked at this was I wasn't excited about stacking the batteries on their side. For the most part in theory Lifepo4 batteries can be mounted in any orientation based on the general cell type not having sloshing liquid etc. I don't know much about these specific batteries and their internal structure, but I've opened several Lifepo4 batteries and have seen the insides. Not many of them appeared to have an internal structure than would appreciate being mounted anything but up. These might be fine, but if the bottom battery is literally carrying the weight of the top one it could potentially be an issue over time. Again, it just depends on what's in there and if they truly secured it. Prismatic vs pouch vs cylindrical all have different packing styles. Another consideration is where they place the temp sensors and if those locations are sensitive to orientation. On the topic of heat you are probably also going to get some internal temp differences due to the stacking. If that causes any concern I'm not sure. It would be something to look at if you are in a warm climate and use that inverter to run an induction cooker.

I like that those batteries have the wired communication links. I'd like to see more batteries with that functionality in addition to bluetooth. Ultimately, I'd like to see a standard communication protocol across brands, but that's unlikely. It's serial using an RJ connector.

Love that you used good fuses and not flaky breakers that a lot of people seem to be using.

I might have missed it, but how are you covering it with panels?
Thanks @pounce I used the fastest acting fuses I could find (midi/ami), with the exception of the ANL 100A that covers the positive from the factory auxiliary. I had one of those flaky Amazon audio online breakers under the seat pedestal to keep it close to the battery. Turns out AYBC specifies you can fuse the battery anywhere within 72 inches of the battery, do I took the opportunity to get rid of the breaker.

The panels are plywood on the top and sides stained grey to match my bed rack. The front facing the sliding door is cut from an extra Con-pearl factory side panel I had. It's ugly but it'll do. I'll post a pic later

Last and most importantly, I confirmed the battery orientation with Renogy -- these are pouch cells. As far as weight bearing, the cases showed no sign of flex (batteries are only 26# each), so I was more concerned with bouncing. I may regret this, but I decided to use a small amount of VHB tape between the batteries to make sure they wouldn't bounce against each other or shift in relation to each other. I was concerned about the terminals getting torqued by the 2/0 cable if there was a shift. So, long story short, I am fairly confident the battery orientation is okay. I have been monitoring battery temperature with Renogy's app, and haven't seen any variation yet. Frankly, the self heating batteries are likely overkill because I don't imagine ever letting the van interior get below freezing in a charging situation. Renogy is a bit cautious and kicks on the self heating function at something like 41 degrees F.

The comm links are used by the BMS's to balance the cells, as well as to control charging from the comm linked DC-DC/MPPT.
 

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I'd consider aluminum for the sides. Vents on bottom and top to help with convection flow. Aluminum would help with passive heat transfer. Wood is insulating. Maybe it doesn't matter if you intend to have active fans.
 

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Discussion Starter · #5 · (Edited)
I'd consider aluminum for the sides. Vents on bottom and top to help with convection flow. Aluminum would help with passive heat transfer. Wood is insulating. Maybe it doesn't matter if you intend to have active fans.
Aluminum is a good idea. I used wood and plastic, as I mentioned, pics below. I was worried about heat with my previous set up, but I never had an issue. I've "burned in" the new inverter running an 1800 watt heat gun for 5 minutes, and the inverter fans didn't even come on. I then ran the ICECO off of AC through the inverter for a couple of days. No issue. I doubt I'll have enough battery capacity to ever run the inverter long enough for any heat issues. BTW, heat is another reason why I put the DC-DC on top of the rack -- it has a big heat sink on it.


Finished product. Note the missing M6's on the lower pedestal cover, which I'm waiting on. The exposed red 4 AWG is behind the plastic cover -- there is conduit up to that point.
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Power box side that faces forward towards driver's seat.

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Selfie of the rear-facing inverter panel. Note it is a 20A circuit.


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Set up with driver's seat swiveled to the rear. Those hanging wires are the seat control module I toasted.

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Discussion Starter · #7 ·
Cool. Do you have shore power?
Not real shore power. I have a DC power supply wired to simulate solar. Because my panels have a quick disconnect in the form of an Anderson connector, I can disconnect the "real" solar and plug in the DC power supply to produce DC current. That avoids the need for a diode to protect the solar panels because they are never connected when shore power is on.

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I have Southwire (Home Depot) non-metallic conduit from the power box to the driver's rear of the van, exiting at the rounded rectangular opening of the angled rear corner at floor level. Here's the conduit:

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I fished a Southwire (Home Depot) sheathed round 12/3 12 AWG stranded cable through, and have a 15 foot coil with a waterproof plug at the corner. It fits nicely through the door seal as does the 10 gauge solar cable.
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It powers the Mean Well. I added a lighted rocker toggle to turn off the shore power from inside the van.

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The Renogy DC-DC/MPPT has some significant limitations on the solar side, namely a 25 volt maximum input voltage, so the Mean Well is set at 23.+ volts and I get about 20 amps of faux solar. You have to parallel any typical 100 watt panels, and that boosts wire gauge requirements. So I know my set up it won't power the inverter continuously, and in that sense I definitely do not have shore power. But I've done OK at foggy, rainy Oregon campgrounds!

The Renogy DC-DC/MPPT is also limited, significantly for those who want to solar up top with no disconnect. When solar is on and the Renogy MPPT is working, regardless of how much solar, the alternator input is limited to 1/2 the rating of the DC-DC. So the 50A DC-DC/MPPT I installed would produce only 25A of the alternator if solar were connected full time, even if solar is producing, say, just a couple of amps. As I said, because of my portable solar setup, it's not a problem for me.

As you noted, the planning and research that goes into these projects, including SketchUp and corrugated plastic mock-ups, is enormous. But instead of paying $6k to an installer, I did it for less than 1/2 of that (including about 15 to 20% "overbuying" to avoid delay and more shipping charges if I underbought.

I suppose a Goal Aero or Bluetti could do the same for less, but I think my version meets the @pounce "set it and forget it" test. I chose to install a 3-way switch so I could draw amps off the factory auxiliary battery as an emergency backup (won't handle the inverter), as well as a main cut-off between the factory auxiliary battery and the inventoried the project plus an enormous amount of my time. But I don't need to touch the switches, ever, if I don't want to. Even the possible double connect of a solar panel and shore power without a diode should be a problem because the open-circuit voltage of the panels is 24.3 volts, which is higher than the Mean Well voltage.
 

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Discussion Starter · #8 ·
One thing leads to another. So far induction seems feasible for solo coffee and breakfast before drives of 30 minutes or more, or with ample sun for the 2 100A panels I have.


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YouTube and Amazon's finest. Silent with cast iron. I need a small saucepan. I've heard the tri-ply pans can scream:

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Here it is about 2:30 into the 4:58 boil (see bubbles on the bottom) of 1 quart room temp water. At full power it was pulling 79.68 amps. With all my futzing, I used about 10 amps to boil a quart.

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@focus805 Your second revision power box looks awesome! Must have taken a lot of planning, and I love how organized and serviceable everything seems to be. The height of the box also seems like a perfect height to prop up your legs when the chair is swiveled around. Is the lower "platform" in the front of the box just to cover the larger wires and avoid tripping on them?

I have the same cook top but haven't used it very much. Just tested it to make sure it works with my Bluetti (yes I cheated a bit by not designing my own power box). Kudos to you. May the power be with you.
 

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Discussion Starter · #10 ·
@focus805 Your second revision power box looks awesome! Must have taken a lot of planning, and I love how organized and serviceable everything seems to be. The height of the box also seems like a perfect height to prop up your legs when the chair is swiveled around. Is the lower "platform" in the front of the box just to cover the larger wires and avoid tripping on them?

I have the same cook top but haven't used it very much. Just tested it to make sure it works with my Bluetti (yes I cheated a bit by not designing my own power box). Kudos to you. May the power be with you.
Thank you kindly. Yes on the lower platform -- I used the 3030 aluminum extrusion to make a path for the 3 - 4 AWG cables (2 negatives to handle the 200 amps. The cables are in conduit under the

I am a little shy about having cookware and liquids on the box until I get the edge of the top sealed against the interior side panel, so my feet will likely spend a fair amount of time resting there!

Having done the job twice now, I'd say more power to you going with a portable like the Bluetti. ;) The only significant downside I can think of is charging time off of a standard 12v plug (cig lighter). I like the notion of being able to bring the box inside if needed.
 
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