My Lithium Battery Pack Project

[Enginenumber]

My Lithium Battery Pack Project
Well, before I go too far, I will say I had very limited experience in electrical, lithium batteries and so forth. This took about 3-4 months of reading watching videos, following forums, advice off some electrical buddies, people experienced in Lithium batteries , set ups, and so forth to complete it.
Even today, I struggle to use a multi meter properly, so it was a challenging effort, to learn about this stuff. One of the reasons I didn’t buy a complete unit ready to go , I travel into remote areas and need to understand the battery and systems associated with it , so if there are issues , hopefully I can rectify them myself. Some resellers of the generic made units couldn’t tell me what components were used or brand of battery cells inside either.
I had 3 attempts to draw what I thought was a wiring diagram for the whole thing, as it was starting to look like a spaghetti load of wiring, I didn’t quite understand. Apparently my diagram and electrical symbols and wiring were not recognised by people with electrical certifications either, ha ha. Had a few amendments there!
I had previously run a 100ah agm and 80w solar panel for a number of years ,running fridge and other 12v devices. This is all in a express van, solar is the only charging source for the battery, which lasted 6 + yrs.
I choose 4/ 3.2v 160ah Winston cells, into 12v 160ah battery with top balancing of individual cells prior to assembly .The terminals were protected with a few layers of electrical tape during assembly, as everyone had warned me not to touch anything on the terminals with metal objects.( was quite nervous during assembly) The cells were clamped together with 3/16 threaded rod, 4 each side into 3mm aluminium plate each end. Another 4 threaded rods were used vertically also into Ali plate and large washers.
Conductive carbon grease was added to inter-links , bolts and terminals.

Bolting cells together.jpg

I then fabricated a plywood box for the battery with a 60mm void in the end of the box for Anderson plugs, wiring, gauge, etc. The battery was as big as I could fit behind the passenger seat, the seat needs to pivot back for engine access, so the battery box was hinged so it pivoted back with the seat.

Two 100kg straps fitted and adjusted so when the seat goes down into position, the straps tension and hold the front edge of the battery box secure and prevent movement. 2 piece slide off hinges used for quick battery removal, and locking tab on hinges.
I wanted to run a 2000w inverter, I had to fabricate a circuit that would run about 200amp draw in the box. I included 3 smaller 50amp Anderson plugs with resettable breakers, cig plug and 2 usb charge ports, also a larger Anderson plug in the base of the box for the inverter to plug in to. Isolator switch fitted on positive battery cable. 2 Terminal fuses were used with 200amp fuses, terminal fuse blocks were turned on edge for added strength. (Only really needed one fuse) I used off cuts of Copper bus bar , cut down to suit, as battery terminals.
Solar panels were increased to 240w all up 6/40w panels, Victron MPPT 15/75 controller used, as this was compact, solid, and adjustable parameters. Victron BMV 700 was also fitted into the void in the side of the battery box to control low voltage cut off , monitoring and so forth. All the power draw goes through the shunt , the regulator was wired between the battery and isolator , so if the cut off triggers or I switch off the isolator, it will still accept charge into the battery.
After lots of research on switching/relays, solenoids , high power draw was a concern when switched on, also room in the box was an issue, I settled with 2/ 100 amp solid state relays in parallel with low power draw, relays were wired to switch together, through the BMV 700 relay. The solid state relays were mounted on a folded 3mm aluminium bracket that would keep the relays off the ply just in case of potential heat issues in the circuit when the inverter was on, the aluminium bracket would also act as a added heat sink, heat sink grease apply to backs of relays as well. The small switching wires were fused as well, and placed into some of that small flexi conduit.
Most of the fixed items in the box void were bolted directly through the ply end panel, not screwed to prevent coming loose with vibration. This will make it easier to work on if required, as it all comes off in one piece. There is also an opening in the base of the void to allow some airflow around.

fitting in ply box.jpg

After assembly I took the pack to an Auto sparky buddy, just to double check what I had done, got the thumbs up there. Full of confidence, I placed the battery outside away from anything where a fire or explosion could occur! I then stood back and hit the switch, nothing happened, it all worked, surprisingly..
I then had a 3mm polycarbonate clear cover made for the top of the battery.
Trying to work out all the settings on the regular and gauge was a challenge. I have it going ok, just may need some fine tuning on settings. The relays cut out and switch back on when discharged to set voltage and soc cut outs, so that’s good. I have run a 1000w sandwich toaster through a 2000w inverter and everything works ok, no heat there either , plugged a 4 slice toaster in for a laugh, drawing 163 amps, pretty funny stuff for me.
I now have no flat battery issues anymore, and realised I should have done something like this years ago. May have missed a few things out, but this was most of the important stuff I did. I have an individual cell voltage monitor to put on the battery yet, just having a break from it all atm.
The 160ah is a bit overkill for my vehicle , I am sure 100ah would of done the job. I can now park in the shade for extended periods and not have to be too concerned. It was certainly the long way round DYI, however I have a very basic understanding of it now and learnt something, well hopefully.
One happy Camper now!

More Pics to come

Regards,
Engine number

[BillieBlue]

Well done enginenumber ,now you can go anywhere .

[Enginenumber]

I also wrapped it in carpet to somewhat make it look like a part of the furniture.

End of battery box.jpg

Finished battery.jpg

High Volt sticker.jpg

Regards,
Enginenumber

[BillieBlue]

Looks very professional enginenumber ,just like a bought one ,only better

[Noggins]

What was the total cost of the whole job ?
I'm looking at doing something similar but demountable to fit up for home useage as well when the van is just sitting around between trips.( x portable 300W -2x150- solar panels will be fitted on the house roof in near future )

My thoughts are why have all that capacity and just use it for short periods when the house supply cost is getting past ridiculous and I can use it on a daily basis.

Ron

[BruceS]

Lovely job!!
I wish I could finish my projects with such a good appearance!!
I couldn't see any cell level monitoring involved? Maybe it isn't needed?

[BernieQ2]

Bruce mateee if you would let Wendy upstairs yours would look that good as well .
Nice job engine number bloke .
Bernie .

[native pepper]

Excellent job, no one should look at my projects, unless you want eye strain. I'm one of those that if it works, that's it and my wiring looks like swiss cheese spaghetti, wrapped in mouldy old tape.

My cell containers are made from aluminium from old roadside signs that the local council dispose of. For fitting out of the bus, used second hand materials and the pine framing was reclaimed from the local transfer station and so bent, the rooms tend to looked warped and the ply lining is also second hand. Even made the swivel seats myself from discarded car seats, you could call it the junk yard bus.

Always admire those that have the patience and time to make their things look really cool. I just slap things together so they work and that's it and supposed to be a builder by trade.

[Enginenumber]

Yes,
was a lot of work ,research and money. I didnt go with cell monitoring , some people reccommend it , some dont , some swear by monitoring , others dont think it is worth it on 12v type smaller packs.
For me it was more complication and wires , maybe more stuff to go wrong and confusion for me, as I still cant work out the electricity stuff to well. The big battery packs need it I think, as it is hard to sometimes find a bad cell. I wont comment to much about it all , as its not my area of expertise.

Battery in Van complete.JPG

Battery tilting.jpg

The cost for the battery cells ,box, wiring, components , etc over $2000 in materials alone. ( all new stuff )
This was a custom built one off item , the hours of work and experimental stuff was the big thing you cant see !!

testing on trolley.jpg

This is a photo of where I was almost completely lost and wondered what the hell I was doing, ha ha.

Been going a couple of months now , I just need to sort out some settings on the Victron Blue Solar Regulator and get it to charge properly , and that will be it, hopefully.

Funny, the last words of one of the guys where I got the cells from ,( I showed him what I had done) When I questioned how long are they going to last , 10 yrs you think? He replied very quickly with , those cells will outlast your vehicle, your driving!! Thought that was pretty funny and I think he might be right.

Why did I do it?

Well I have been through 5 cranking batteries over the years,also the 100ah agm(30kg) , carrying that inside charging it , swapping things around, parking in shade ,solar panels,regulators, more flat batteries,lots of camping ,(frequent fridge browser ), getting pretty peed off ,and basically needed something better suited, that be run down below 50% without shorting the life of the battery.

Thanks for the comments, makes me feel like it was worth it.

Regards,
Enginenumber

[native pepper]

You shouldn't have any problems with your setup, all you have to do is keep them balanced and the pack within the range of 14v and 12v, then all will be well. You can buy a cell equaliser on ebay pretty cheap and it will keep your cells so close together, you won't notice it and they draw very little power. I have one on a 120ah portable pack and the cells are always balanced, also have them on my house and bus packs.