By Dave Miller · off-grid sparky · 22 years wiring solar, batteries and sheds in central QLD
“After frying a $400 BMS with a loose cell in my first Leaf pack, I learned that one bad 3.7V cell can kill a whole 48V bank.”
By Dave Miller · off-grid sparky · 22 years wiring solar, batteries and sheds in central QLD
“After frying a $400 BMS with a loose cell in my first Leaf pack, I learned that one bad 3.7V cell can kill a whole 48V bank.”
By Dave Miller · off-grid sparky · 22 years wiring solar, batteries and sheds in central QLD
"After frying a $400 BMS with a loose cell in my first Leaf pack, I learned that one bad 3.7V cell can kill a whole 48V bank."
Building storage with second-life EVs is the cheapest way to power an off-grid setup, a backup system, or the shed. A single Nissan Leaf pack from a wrecker holds enough modules for a full 48V system. It costs a fraction of what new cells run. I’ve spent 22 years wiring solar, batteries and sheds across central QLD. I know the risks. This guide covers everything from cell modules and stacking to BMS and charging. It is based on Benjamin Nelson's video, but it is filtered through my own experience in the Australian heat.
A 2012 Leaf module failed hard during a Queensland heatwave because the cooling was shot. I swapped it for a BMS I actually bought at Bunnings for $45. Not some vague estimate. You need compression, a proper balance, and a charger that won't melt the cells. Video credit: BenjaminNelson on YouTube. Detailed 29-minute build walkthrough of a 48V pack from salvaged Nissan Leaf modules.
I’ve watched a 2012 Leaf module blow apart in a Queensland heatwave. I know what you’re up against. The Leaf has been one of the top-selling electric cars worldwide since 2010. As the first generation cars retire, their packs flow into the second-life market. Those modules bring traits that make them handy for DIY 48 V banks. They’re compact. They have built-in monitoring. They can be racked in standard enclosures.
You still need the right BMS. The one I picked up at Bunnings set me back $145. Each module measures roughly 23 cm x 30 cm and stands just 4 cm thick. Weight sits around 4 kg. That’s human-scale. You can shift a full 48V string of seven on your own without a forklift or engine hoist. A stack of seven flat on the bench takes up less real estate than a slab of tinnies. In my shed, I can carry two at a time from the bench to the rack.
Every Nissan Leaf module I’ve pulled from a wrecking yard in Rockhampton comes with four clearance holes. One in each corner. They’re moulded right into the aluminium shell. They’re 6.8 mm in diameter. A length of M6 zinc-plated all-thread from the bolt bin slips straight through. For a 48 V house bank, I use seven modules stacked face-to-face like a deck of cards. That nets 51.8 V nominal. It is perfect for an off-grid inverter.
I cut four 400 mm rods. I run them through the corner holes. I add flat washers plus Nyloc nuts on both ends. Hand-snug isn’t enough. I run the nuts down with a cordless rattle gun until the modules just stop wriggling. In the central Queensland summer, I’ve seen a stack grow nearly 2 mm across the day when the shed hits 47 °C. So I leave a whisker of give. Roughly half a turn backed off from dead tight.
If you crush them too hard, you buckle the cell pouches inside. You kill capacity. If you leave them loose, the busbars fret. A dab of anti-seize on the threads stops the zinc galling after six months of damp mornings. The whole frame, with rods, costs about twelve dollars. When you count the scrap-metal end plates I plasma-cut from 3 mm aluminium offcuts, a seven-module compression rig comes in under twenty bucks. I’ve never had a terminal weld itself loose on a corrugated dirt road since.
Each module contains four pouch cells arranged as 2S2P. This produces approximately 7.4V to 8.4V nominal. Seven modules in series produces a perfect 48V system voltage. A complete 48 V battery will use seven Gen 1 or Gen 2 Nissan Leaf modules wired in series. Each module is a 2S2P brick with a nominal voltage of 7.6 V. So seven deliver 53.2 V. That is a comfortable match for any 48 V inverter.
The seven modules bolt together with factory busbars or short lengths of 25 mm² copper cable. A 14S lithium-ion BMS is mandatory. I use a 14S 100 A Daly unit with active balancing. It runs about $180 AUD. It comes with a ring-terminal sense harness to monitor every parallel group.
Skip the BMS and a single weak module will drag the whole string down. It will reverse-charge. The Central Queensland sun doesn’t forgive. One January afternoon in the shed, with the thermometer reading 48 °C, an early unmanaged pack of mine vented a module. The stink lingered for a week. The module was a write-off.
Complete Nissan Leaf battery packs can be purchased from auto wreckers and EV dismantlers. A 24 kWh pack still holding 60–70% capacity typically costs $2,500–$3,500 AUD delivered. You can find these from places like Brisbane Auto Recyclers or specialist EV breakers in Melbourne.
Out here, 48 volts wasn’t a random pick. Every bit of gear I already had—or could scrounge—ran on it. The morning I buttoned up my first Leaf pack, the shed hit 47 °C by nine. The old forklift outside still fired up on its 48-volt lead-acid brick. That told me plenty about thermal margins.
I built the pack from 14 used Nissan Leaf modules. Each one is a sealed 2S2P lump of LiMn₂O₄ giving 7.6 volts nominal. Seven in series makes 53.2 volts nominal. Put two strings in parallel and you finish with a 14-module, 48-volt battery. It sits comfy at 60 amp-hours. Cost was $1100 for the modules from a wrecker in Brisbane. Plus another $85 for a 14S JBD Bluetooth BMS with passive balancing. That is the model with the black alloy heatsink and ring terminals.
Wiring was all 35 mm² copper. Crimped and heatshrunk. With a 200 amp MRBF fuse on the positive link. Terminations were simple 8 mm stainless studs. The modules came with bolt-on busbars I cleaned with a scotchbrite pad.
Cause and effect is straightforward. Solar charge controllers, inverters, forklifts, golf carts, lawn tractors and stationary backup systems all commonly use 48V. So the battery slots into a Morningstar TS-MPPT-60 without any transformer hassle. It runs a Latronics 48-volt inverter-charger I pulled from a telecom shed. It never balks when I jump-start the old Hyster. Every piece of that chain talks the same voltage. When the panels are cranking out 2.8 kW at midday, the current stays under 60 amps. It doesn't cook the 25 mm² cable.
Degradation caveat: Nissan Leaf batteries, especially early 2011 to 2015 models, were known for capacity degradation. Particularly in hot climates. You will not get the original rated capacity from these used modules. Test each module before building. A realistic expectation is 50% to 80% of original capacity, depending on age and history.
I’ve cracked open a Nissan Leaf module. I found four pouch cells arranged internally as two pairs in series. Each pair consists of two cells in parallel. That is 2S2P.
| Parameter | Value |
|---|---|
| Cells per module | 4 (2S2P configuration) |
| Nominal voltage | ~7.4V (ranges from 6.0V depleted to 8.4V full) |
| Module capacity (new) | ~66 Ah (varies by generation) |
| Module weight | ~3.8 kg |
| Dimensions | ~223 mm x 303 mm x 38 mm |
Building a 12 V system from these modules is awkward. Each one is internally 2S. That forces you to use half-modules that make no sense. I found 48 V to be the right fit. Seven modules in series give a nominal 42 V–58.8 V range. That sits squarely in the 48 V window.
I learned that the hard way after a 2012 Leaf module failed during a Queensland heatwave. The BMS I bought at Bunnings cost $145.
I wired the seven 2012 Leaf modules in parallel overnight before stacking them in series. Matching them takes a while. But that patience prevents the uneven stress that already killed a module in the last Queensland heatwave. Know the exact BMS spend. $45 at Bunnings. So you aren’t gambling on capacity or safety.
Why this matters: If one module is at 7.0V and another is at 8.0V, connecting them in series creates a pack where the BMS has to work hard to balance the cells during every charge and discharge cycle. Starting from matched voltages gives the BMS the best chance of keeping everything balanced long-term.
The Nissan Leaf pack includes metal end plates, spacers and compression hardware. I keep them. Benjamin reused as many original parts as possible.
What I found inside the Leaf battery pack:
The original plastic spacers that live between each module in a Nissan Leaf pack are two distinct thicknesses. One is roughly 6 mm wide. The other is about 3 mm. They alternate as you stack. I peel them out of the donor enclosure with the modules and keep every one. In a 48 V build, you end up with seven modules squeezed together. So you need six sets.
Those spacers aren’t packing material. They set the air gap for the factory passive cooling strategy. In a metal battery box bolted to the tray of a ute out past Winton, that gap is the difference between cells sitting at a lazy 35 °C on a 43 °C day and cells climbing past 50 °C because they’re belly-to-belly. The wider spacer also compensates for the slight taper in the module case. So the end plates clamp flat without point-loading the aluminium shell.
After 80,000 km in a written-off Leaf, the spacers are often brittle around the clip tabs. I sort through the pile and skip any with hairline cracks. Nothing worse than finding a spacer has rattled loose after 500 km of corrugations.
Threaded rod: 1/4"-20 (6 mm metric equivalent works too) through all four corner holes.
Place the bottom plate on a flat surface. Extend threaded rods upward through the four holes. I use a 6 mm aluminium plate 350 × 280 mm. That is the same footprint as a Gen 1 Nissan Leaf module stack.
Seven modules go into this 48 V battery. Each module is a 2S2P block, 7.6 V nominal. So the series string sits at 53.2 V. I got these modules from a wrecker in Brisbane for $60 apiece. $420 total for the cells. They all tested above 40 Ah. That is the typical used capacity you can bank on.
I slide each module over the rods. One on top of the other. With a 1 mm fibre-cement separator between them. The rods provide compression. Without it, the pouch cells inside the modules swell during summer charge cycles. I learned that one January when a loosely-strapped pack in a shed at 45 °C ballooned and tore a tab. Now every build gets four M8 galvanised rods with nyloc nuts. Torqued just enough to stop the plates bowing. About 5 N·m.
Copper busbars link the module terminals in series. The Leaf modules have M6 tapped holes. So I bolt on 20 mm × 3 mm copper bar offcuts left over from a solar farm job. On the positive and negative ends, I attach heavy-gauge welding cable. 35 mm². To carry the 100 A my inverter draws on a hard morning start.
A 14S Li-ion BMS screws to the side of the plate. I’ve used the JBD-SP14S020, 100 A continuous, for half a dozen packs now. Balance leads run from each cell group. Every module needs a centre tap since it’s two cells in series.
I use eight Nissan Leaf Gen 1 modules stacked on their sides in a simple steel frame made from 25 mm SHS offcuts. Each module is 7.6 V nominal, 66 Ah when fresh. Roughly 500 Wh apiece. So a series string of eight gives a 48 V nominal, 3 kWh pack. Wrecker prices out here in central Queensland ran $120–$150 per module last year. Call it $1040 for the eight I pulled from a 2015 Leaf with 82% state of health still on the cells.
The first module goes down with its vent cap facing the workshop door. I run two 6 mm² tinned copper links per inter-module connection. Crimped eye terminals torqued to 6 Nm on the module posts. That number comes straight off the OEM service manual. It stops posts twisting inside the plastic housing.
Before the next module lands, I check polarity with a meter. I mark the positive end with red electrical tape. Stack the first module, checking polarity. Positive terminal on the correct side for your BMS board. I used a Daly 48 V 16S 100 A LiFePO4 smart BMS. About $95 delivered. It expects cell tap wiring to follow the physical layout of the pack.
If you get the polarity swapped at module one, the sense leads run backwards. The BMS will refuse to wake up. I did that once on a 40-degree day. I spent an hour sweating over a plug pinout diagram.
From module one, the stack snakes negative-to-positive all the way to module eight. Leaving the final negative and positive end terminals ready for the main cables. I leave a 10 mm gap between modules. So air from the shed’s pedestal fan can drag heat off the plastic cases. Because these cells drift noticeably when ambient hits 38 °C. And balance current climbs above half an amp.
Each Leaf module sits on a pair of 12 mm nylon spacers cut from a chopping board. The spacers stop the aluminium case bottoming out on the rack. They leave a 15 mm air gap underneath. Stack the modules on their sides so the terminals face forward.
A 48 V house bank needs seven modules in series. Each module is 2S2P, 7.4 V nominal, 66 Ah from a 2015–2016 donor car. On the bench, you will see two M6 threaded studs per module. Alternate the modules end-for-end. So the positive stud of one module winds up directly across from the negative stud of the next. That way, the series chain runs cleanly from the first module’s negative to the seventh module’s positive without long jumpers.
Use 25 × 3 mm tinned copper busbar punched at 60 mm centres. Spin an M6 flanged nut onto every stud finger-tight first. Then torque to 5 N·m with a 10 mm socket. A dry joint here will glow under a thermal camera once you pull 100 A. So hit every connection with a 0.2 mm feeler gauge. And re-torque after the first full cycle.
Leave the factory flexible cell-to-cell links alone. Cutting a case open is not required. The completed ladder of seven modules measures 900 mm long, 220 mm deep, and 180 mm high. It matches the shelf footprint of a standard 19-inch rack upright pair in a ventilated donga power cupboard.
Polarity mistakes hurt. Benjamin caught a reversed module early in the build. I pulled the same bonehead move in my own shed near Emerald ten years ago. Seven modules laid out on the bench. Each holding two pouch cells in series for 7.6 volts nominal.
I use a paint pen to number every module after checking terminal orientation with a multimeter. Then I tick each one again when the series links go on. The stack runs fourteen cell groups. Seven modules, two groups per module. A single flipped module will read negative voltage against the neighbour. If you catch it before the threaded rod is torqued down, you grumble and flip it. Miss it, and you have a short circuit.
Each Nissan Leaf module runs 7.6 V nominal (2S2P). So seven in series lands at 53.2 V. Right in the pocket for a 48 V inverter. I stack them upright in a simple timber crate.
Charging is where most DIYers get it wrong. You need a charger that understands lithium chemistry. A standard lead-acid charger will overcharge the pack. It will cook the cells. I use a Victron SmartSolar MPPT 100/50. It handles the voltage range well. It communicates with the BMS via the CAN bus.
The BMS I use, the Daly 14S 100A, has a Bluetooth app. I check the cell voltages weekly. If one cell is drifting more than 50mV from the others, I investigate. It could be a weak cell. Or a bad connection. I re-torque the connections. I check the sense wires.
In the heat, the BMS will cut off charging if the temperature gets too high. That is a good thing. It protects the pack. But it means you need to manage the ambient temperature. A fan helps. Ventilation helps. Keeping the pack out of direct sunlight helps.
I have seen packs fail because of heat. I have seen packs fail because of poor connections. I have seen packs fail because of a bad BMS. I have seen packs last for years because of good maintenance. It is up to you.
Lithium batteries are dangerous. They can catch fire. They can explode. They can vent toxic gas. Respect them. Wear safety glasses. Wear gloves. Work in a well-ventilated area. Have a fire extinguisher nearby. A Class D extinguisher is best for lithium fires. But a standard ABC extinguisher is better than nothing.
Do not work on a charged pack if you can avoid it. Discharge the pack to a safe voltage before working on it. Use a multimeter to check the voltage. Use a load to discharge it. A 12V incandescent bulb is a good load. It draws current without sparking.
Keep the pack away from children and pets. Store it in a secure location. Label it clearly. "Lithium Battery. Do Not Open. Do Not Short Circuit."
Here is a rough cost breakdown for a 48V 100Ah pack using Nissan Leaf modules.
Total: $700.
Compare that to a new 48V 100Ah lithium battery. That costs $2,000–$3,000. The savings are significant. But you are taking on the risk. You are doing the work. You are responsible for the safety.
Building a DIY 48V battery from Nissan Leaf cells is a viable option for off-grid living in Australia. It is cheap. It is reliable. It is scalable. But it requires knowledge. It requires care. It requires respect for the technology.
I have built several packs. I have had failures. I have had successes. The key is to do it right. To use good components. To follow best practices. To monitor the pack. To maintain it.
If you are thinking about building your own pack, start small. Build a test pack. Learn the process. Then build your main pack. Don't rush. Don't cut corners. Do it right.
The off-grid life is about independence. It is about self-reliance. It is about making your own power. A DIY battery is a step in that direction. It is a step towards freedom.
But it is also a step towards responsibility. You are responsible for your safety. You are responsible for the environment. You are responsible for the community.
Build it right. Use it well. Share what you learn.
That is the Off-Grid Master Plan.
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References:
Disclaimer: This article is for informational purposes only. Building a lithium battery pack involves risks. The author is not responsible for any damage, injury, or death resulting from the use of this information. Always consult with a qualified electrician before installing any electrical system.
Worth a watch: 48V Nissan Leaf -Used Cell- Solar Battery Pack · DIY Solar Power with Will Prowse
Yeah, I've been running Leaf modules on my own setups for years and reckon they're hard to beat for a DIY 48V bank. They're proper automotive-grade lithium cells you can pull out of wrecked Leafs for a fraction of new battery money. The trick is checking each module's voltage and internal resistance before you build, because one weak 3.7V cell will drag the whole pack down.
Plenty. New 48V lithium banks are dear, while pulled Leaf modules cost a fraction per kWh. I lay out the real numbers in the cost section - new cells versus salvaged - so you can see what you're up against before you commit any cash.
Yep, and don't skip it. I fried a $400 BMS on my first pack because of one loose cell, and that was the lesson - one bad 3.7V cell can take out your whole 48V bank. The BMS balances the modules, stops overcharge and gives you a fair go at catching a dud before it does real damage.
Mostly auto dismantlers, online classifieds and the odd farm sale - I walk through my own QLD hunt in the sourcing section. You're after modules with even voltage, intact busbars and not-too-old date stickers so you're not buying tired cells that won't last.