Crit my auxiliary battery setup...
Hi Folks,

First post, and a long one. I'd like to showcase my battery box design and would appreciate it if you could possibly point out something I've missed (despite the obvious wood = fire hazard!!).

First, the setup:

1. I wanted something that would fit into my Paj nicely for those long camping trips. It would need to be removable as I sometimes don't get the opportunity to park my truck next to my tent, and I HATE walking for cold beer unless it's the zombie apocalypse or similar - I'm running an ARB 47l fridge.

2. My girlfriend needs to be online ALL THE TIME during working hours, and loadshedding has caused major strain. So, something easy to operate, portable again (seeing as she lives at her own place a lot of the time), and slightly aesthetic.

So, after much Googling I decided on the following:

CTEK D250S for the solar input option.
300W inverter for those 220V moments.
Solbian flexible 120W solar panel - light at around 2 kg, and pretty efficient.


After looking at all the bits for around 4 days, and playing with various layout I eventually settled on the following layout for the electronics:

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Everything is mounted on a single board, which is slotted into the battery box. The whole assembly can be removed if necessary with minimum effort (9 screws) and slid out.

I had to find a way to hook up the damn inverter which would push it up against the top plate firmly, and eventually came up with the idea of using cable ties, fed through custom made hooks on the top lid. It's not ideal, but seems to do the job - I didn't want to mess around with disassembling the inverter.

I also did not want to cut the CTEK sensor wire down, so I just coiled it and tagged it down.

Top view of the panel, quick test to check everything worked:

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I then tested it with the solar panel attached - the CTEK fired up and did it's job. I ran it on and off over a period of 4 days to check if there was any major heat given off by the CTEK, which I did not really expect, DC-DC being pretty efficient.

I also checked the inverter out, ran it at full load for 6 hours. Surprisingly, it runs pretty cool, and did not cut out after 4 hours as the manufacturer specs say. Bonus.


Onto the box. Here's the initial pic:

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I had to cut a slot for air inflow for the inverter (as it has it's own built-in fan). I also, just to be on the safe side, added another fan cutout in case things got hot during charging.

I also realised I would need some sort of way of checking the CTEK status in case of error, so I cut a window into the box front and closed it off with a bit of perspex.

Finally, put everything together:

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I still need to finish the lid and handle. Will probably have a little hinged lid over the panel. I cut out the section in front of the plugs so the lid can stay closed during any DC action. With the inverter running, however, the lid would need to be open to allow airflow through the inverter, so if there was any cable attached to the 220V socket, the lid would be forced to stay open.


I put in a 50A fuse from the +ve terminal which allows me to do current checks, besides being a fuse :-)

The fan I've connected up to a voltage level sensor (simple opamp circuit): if the voltage at the terminals goes over 13V, the fan switches on. I surmised that the most current would be drawn for charging when the alternator was running, so that would probably be the time when I would most likely need cooling of some sort.

The last thing I need to do is test it in my truck - I'm still trying to figure out how the hell to run a cable from the main battery to the boot through the bodywork. Any ideas here would be most appreciated!

Now that I've got this done, the next trick is to build my packing system around it, probably very similar to SimonB's setup, but will a few mods of my own.

So, any comments or suggestions? Anything I've forgotten?

Cheers!

EB.
Re: Crit my auxiliary battery setup...
Looking good. Where do we place orders! :-)
Thanks for sharing.

On my gen3 the cable from the front runs underneath the vehicle and then into the third seat stow bay through one of rhe rubber grommets. I have however heard of people running it from firewall through rubber just in front of passenger knees about, and then under carpet/sills to the back as well.

CATS
2009 Pajero 3.2 DiDc Lwb GLS (Gen4) - Casper (Starting to grow on me)
2001 Pajero 3.2 DiD Lwb GLS Manual (Gen3) - Snoopy (SOLD but not forgotten)
2008 Pajero 3.2 DiDc Lwb GLS Auto (Gen4) - Silvester (SOLD)
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Re: Crit my auxiliary battery setup...
Thanks for the reply, CATS!

Underneath the vehicle? Hm, a novel concept. I'll look into it. Far prefer inside, though I must admit, the outside option has sparked some thought.

Orders? Well, after all that I've seen <scratches beard and polishes bayonet> I suspect that after I quote most forum denizens will mutter into their beards and decline :D
Re: Crit my auxiliary battery setup...
It looks really nice and well planned.
Will you be placing it in the whole for the 3rd row of seats ?

Having the battery box portable helps allot and we use ours quite a bit in the house and in the nose cone of the trailer.

I would look at
1) cutting handles to assist when carrying it
2) Having a Hella and a normal cigarette lighter output

For the cable

I took My cable through the front grommet through the roof into the load bin

In the holder for the jack I split the cable into 2
1 x for the trailer that goes out via the grommet and
1 x coiled up to be used fo the dual battery inside the car

I took the grommet out and drilled 2 holes in it slightly smaller than the actual cable and then forced it through


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I then guided the cables back into the load bin and used a 24 spanner and a screw driver to get the grommet back into place.
The top went in as normal an I then used the spanner to put pressure on the rubber and used the screwdriver to push the rubber upwards until it popped back in.

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We did some slow water crossings since with now water entering
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Re: Crit my auxiliary battery setup...
Thanks for your response!

Regarding placement: I have sort of permanently removed my 3rd row of seats - while I like the fold-down-into-bed concept initially, I found that the 3rd row was just a hassle, really. I use my truck for a lot of carting stuff around, and they cut down seriously on carrying space.

My packing system will be designed to still use the bed concept (first level of shelves at right height to continue on from the folded down second row, with removable upper shelves).

I plan to situate the battery abutting the back of the second row of seats, with the fridge behind it, sort of. It'll be positioned in a space specially designed for it, with some sort of lockdown mechanism still to be designed.

I have two Hella outputs. I would have got a standard cig lighter as well, but no stock. No problem, I can always make up a converter, or get a cig lighter socket later - the dimensions are similar, should be an easy replacement job.

I intend putting a strong handle on it, I'm still deciding the way to go with that. Considering how to build one in without enlarging the overall profile too much ;)

You took your cable through the roof? That's a novel approach I had not considered - thanks for that, I'll look into it!

EB
GHM
Re: Crit my auxiliary battery setup...
I routed my cable through the firewall and under the carpet and door cover strips.
The earth i took of a bolt in the well for the third seat. Very quick and easy installation.Make sure you put a fuse on the positive next to the vehicle battery.
I made my box long and narrow to fit in the well for the third seat. Made a new wood cover with carpeting for the well. The wooden battery box supports the cover so I have full packing space at all times in the trunk area. For the solar panel I bought the large fishing rod holder suction cups from Midas and removed the rod holder section then bolted the solar panel to the suction cups. It works like a dream and I drive with my solar panel in place on the roof.
My box is removable and I also use it in my Triton and in the house when we have load shedding. My Triton I put the cable through the box section of the chassis.Also took the earth off a bolt at the rear.
Good luck
GHM
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