Where This Guide Comes From
Every number in this guide comes from one source video — Will Prowse's 32kWh LiFePO4 battery build, watched more than 431,000 times on DIY Solar Power with Will Prowse. In it he takes sixteen 628Ah prismatic lithium iron phosphate cells, bolts them into a factory busbar frame, wires a BMS, runs a full 0.2C capacity test that scored 107% of rated capacity, and then turns the finished pack into a mobile EV charger. If you prefer to watch the build before reading the breakdown, the video is embedded below:
The build answers a question almost every home battery owner asks once they price out a ready-made 32kWh server rack: can you assemble the same capacity yourself, in a weekend, and save the markup? The video shows the honest answer — yes, in about 90 minutes of assembly, if you buy matched prismatic cells and keep your expectations realistic about lifting and installation. Below is the full breakdown, with every measurement taken from the on-camera build.
Why Build a 32kWh LiFePO4 Battery at All?
The video starts with a statement that frames the whole project: 32 kilowatt hours of storage, lithium iron phosphate cells, and a pack that weighs over 600 lb. The size immediately tells you what this battery is for — it is not a portable power station you carry by hand. It is a stationary energy bank, designed to live on a pallet and be moved with a pallet jack, and to absorb or deliver serious amounts of power for hours at a time.
Why would anyone build that instead of buying it? The short answer is cost and control. A ready-made 32kWh server rack or home battery at this capacity carries a retail premium for its enclosure, certification and brand. When you assemble the same chemistry yourself from cells and a busbar frame, you pay for the raw energy storage and the protection electronics, and you get to pick the exact voltage, capacity and form factor that your inverter and rack accept. That is the same calculation behind many of the packs we discuss in our buying guides, and the same reason a growing number of off-grid owners size their own banks.
The Cells: 628Ah Prismatic LiFePO4 and the Pack Math
The heart of the build is sixteen prismatic LiFePO4 cells rated at 628 amp hours each. Prismatic cells are the flat, aluminum-cased format used inside most modern home storage batteries — they pack more energy per volume than cylindrical 18650s and they are far easier to bolt into a rigid frame. Each cell in the video is marked at 2009.6 watt hours; divide that by the 3.2V nominal voltage and you get the 628 amp hour rating printed on the case.
The pack math is worth doing out loud. Sixteen cells in a 16S configuration give 51.2V nominal (16 × 3.2V). At 628Ah, that is 51.2 × 628 = 32.15 kWh of nameplate storage — hence the 32kWh in the title. The cells are connected positive to negative in series with busbars, and in this kit the busbars come with captive screws, which the creator notes is a major improvement over older kits where you had to place and hold loose hardware while tightening. For anyone sizing a bank, the same arithmetic applies: volts × amp hours = watt hours, and your inverter's input voltage range decides how many cells you put in series.
Assembly: 90 Minutes From Box to Charging
The assembly itself is almost anticlimactic after the size of the cells. Sixteen cells are dropped into a pre-built frame, the series busbars are bolted down, the positive lead is connected, and the pack shows voltage. The creator is honest that this one was easy to assemble — a factory-made frame and captive screws turn a build that looks intimidating into a mechanical job with a socket wrench. Total time: about 90 minutes, which is the title claim and it holds up on camera.
The lesson for a first-time builder is that cell quality and frame quality decide how easy a large pack is to assemble. Matched cells with consistent voltage and a frame that holds them rigidly make the difference between a two-hour project and a two-day fight. If you are sourcing cells for a build of your own, ask for matched voltage and capacity data before you buy — it is the cheapest insurance against a pack that fights you at every connection.
BMS Setup and the App Configuration
Once the pack is charged, the video shows the BMS setup that every battery of this type needs. The BMS is a 16S unit with an app, and the critical step is telling it the pack's capacity so its state-of-charge calculation is correct. In the video the password is the factory default — either 1234 or 123456, depending on the firmware — and the creator stresses that you always have to configure this on every one of these batteries, every single time, because a BMS that does not know the pack's real capacity will misreport state of charge and can cut off early or allow unexpected discharge depths.
The practical takeaway: a BMS is only as good as its configuration. Capacity, cell count, over-voltage and under-voltage limits are the settings that matter, and they should match the specific cells you installed, not the default screen values. Most 16S LiFePO4 BMS units ship with sensible defaults for cell voltages but wrong total capacity, and that single wrong number is behind most "my battery died at 40%" complaints on the forums.
The 0.2C Capacity Test: 107% of Rated
The most valuable part of the video for a buyer is the capacity test. To verify the pack really holds what it claims, the creator discharges it at 0.2C — for a 628Ah pack, that is roughly 117 to 125 amps — through a NEMA 14-50 outlet wired to an EV charger. Discharging through an EV charger is a clever way to create a big, controllable load: instead of dumping 6,000 watts into heat guns and heating up the shop, the energy goes into an electric vehicle and does useful work while the test runs.
The result: 672.91 amp hours pulled, against a 628 amp hour rating. That is 107% of rated capacity — a very healthy score that says the cells are fresh and well matched. It also shows why testing matters: a pack can look fine at rest and still come up short under load, and a 0.2C discharge with a calibrated shunt is the only way to know what you actually bought. The shunt in the video was reset before the test, and a ground-neutral bond had to be added to the temporary wiring before the EV charger would run — a small but real reminder that high-power temporary wiring needs the same grounding discipline as permanent installs.
Turning the Pack Into a Mobile EV Charger
After the test, the pack goes onto a heavy-duty cart and becomes a mobile EV charging station. The creator's shop cart, previously running on 14kWh, now carries the 32kWh pack, and an inverter and EV charger are wired to it. The numbers on camera: charging at 32 amps at 240 volts, pulling 152 amps from the battery, with headroom for 50 more amps. That is enough for a Model 3 to gain about 144 miles of range, or about 86.4 miles for a less efficient Model X — impressive numbers for a battery that lived on a pallet two days earlier.
The broader point is architectural: a 51.2V, 32kWh pack paired with a hybrid inverter and a level 2 charger is a complete system. It can be charged daily from a small off-grid solar array and discharge at level 2 charging rates, which makes it a realistic backbone for a cabin, workshop or emergency setup that needs EV charging plus house loads. The creator's honest caveat is that adding a hybrid inverter to a cart is not the best use of the hardware — for a stationary install he recommends a 12,000 XP or SRNE-style hybrid inverter instead.
Lifting, Moving and Handling Big Batteries Safely
The second half of the video is a safety lesson, and it is the part worth reading twice. Mid-project, the creator dropped a 100 lb server rack battery on his foot while moving it with a hand truck, and the injury — soft tissue damage, no fracture, but weeks of pain — is shown on camera. His point is blunt: a 100 lb battery did this, and this build is 600 lb. The engineering lesson is that a large battery is not heavy like a piece of furniture; it is heavy like a machine tool, with hard edges, live terminals and zero forgiveness if it tips.
The video also shows the equipment that makes large packs manageable: a real forklift for the channel, straps over the forks, and proper lifting points. The creator even bent the lifting lugs on the pack frame using an engine hoist, which is why he emphasizes lifting from higher up with a spreader bar rather than a short strap. For anyone planning a pack over roughly 300 lb, the practical rule is: have a plan for lifting before the pack arrives, use rated lifting gear, wear protective footwear, and never tilt a battery on a hand truck unless it is strapped down. That last mistake is exactly what caused the injury on camera.
What the Build Teaches About Scaling to Smaller Packs
Everything in this 32kWh build scales down cleanly to smaller DIY projects. The series math is identical at 4S or 8S; the BMS configuration discipline is the same at 12V or 48V; and the capacity test — even a simple one with a known load — is worth doing at every size, because it tells you whether the cells you received match the cells you paid for. The lifting lesson scales even harder: the smaller the pack, the more tempting it is to carry it casually, and the creator's injury is a reminder that even 100 lb can do serious damage.
For someone building their first LiFePO4 bank — say a 12V 100Ah pack for an RV or a 5kWh home backup — the same sequence applies: match the cells, bolt or weld the connections properly, configure the BMS with the real capacity, and test before trusting it. That first small pack teaches the whole skill set, and the confidence it builds is exactly what makes a 32kWh project feel like a weekend job instead of a mountain.
Final Thoughts: When a 32kWh DIY Battery Makes Sense
The video closes on a practical note: this battery is technically DIY, but it is not for everyone. If you have the lifting equipment, a stationary location and a real load — an EV to charge, a house to back up, a workshop to run — a 32kWh pack assembled from matched prismatic cells is an outstanding value. If your system has to move, or you do not have rated lifting gear, the smaller model or a ready-made unit is the smarter choice, and the creator says so plainly.
The deeper message is about honesty with yourself. A 600 lb battery is not a weekend impulse project — it is an engineering decision about weight, lifting, ventilation and wiring. Do the math, buy matched cells, configure the BMS, test the capacity, and respect the weight, and a DIY 32kWh bank can be the backbone of an off-grid system for a decade. Skip any one of those steps and the same pack becomes the most dangerous thing in your shop.
And if you would rather not hand-assemble a 32kWh pack at all — or you need the same capacity at a voltage and size that fits your inverter — that is exactly what we do. Dajiu Energy is a Chinese manufacturer building LiFePO4 batteries for RVs, homes, golf carts and portable applications since 2017. Our product range covers LiFePO4 drop-in replacement batteries, EV and golf cart batteries, wall-mounted home storage, portable power stations, commercial energy storage and battery swap cabinets — explore the full lineup in our product center, or browse more buying guides. Tell us your voltage, capacity and size, and we'll engineer the pack to hit it.
What Viewers Are Asking (Top Comments on the Video)
These are the most useful of the video's top comments, with the creator's own replies where they exist and our practical answers where they don't. Thanks-only comments were left out on purpose — these are the ones with actual information in them.
Source video: Will Prowse — "HUGE 32kWh LiFePO4 DIY Battery w/ 628Ah Cells! 90 Minute Build" (youtube.com/watch?v=vU7saFzCTA8). Comment excerpts are quoted verbatim; creator replies are shown in italics where present. Build figures are transcribed from the video's measurements.