Where This Build Guide Comes From
Every step in this article comes from one source video — Parker The Basshead's DIY Lithium! 64AH for Under $400!! Car Audio Battery, watched more than 87,000 times by car audio builders. In it, Parker builds a 64Ah lithium bank from Headway cells, packages it in a proper battery box, adds an active balancer, and lands at a total cost of roughly $400 — a fraction of the price of a comparable ready-made lithium battery. If you would rather watch the build before reading the breakdown, the video is right here:
Car audio is one of the most demanding 12V loads a battery can face — bass hits can pull hundreds of amps in short bursts, and a stock AGM battery sags hard under that load. A lithium bank holds voltage far better, which is why serious installers move to lithium. The build below is the honest, first-time version of that upgrade: the reasoning, the parts, the wiring and the mistakes avoided.
Why Headway Cells for This Build
The video opens by comparing the three lithium options car audio builders actually use: CMax, Yinlong LTO, and Headway. Each has a real trade-off, and Parker's reasoning is worth following because it is exactly how you should pick a chemistry for a first bank.
CMax cells are cheap and popular, but they need to be compressed a specific way; if the cells are not held under the right pressure, they expand and die. For a first build that is a hidden failure mode. Yinlong LTO cells are the safest option — you can drill into them and they will not catch fire, and they last essentially forever — but they cost more and, crucially, need to be charged above 15 volts. That extra charging voltage can upset the regular electronics of a car, and LTO cells cannot be paired with an AGM battery in the same bank.
Headway cells hit the middle ground: cheap, well-tested, hard to ignite, and with a resting voltage close to 13 volts — which means they run happily alongside AGM batteries and charge from the stock car charging system. For a first-time lithium builder that compatibility is the deciding factor, and it is why the video builds with Headway 38120 cells.
Parts List and Total Cost
The video is unusually transparent about money, and the final tally is the headline: about $384 for a 64Ah bank, plus another $15-20 in wire, terminals and hardware you probably already have. Here is exactly where the money went:
32 Headway cells at $9.50 each — $320 shipped, including two spare cells bought in case any arrived damaged. Each cell is 3.2V nominal, and 32 cells at roughly 64Ah advertised capacity is the heart of the bank. Active balancer — $10. Battery box from AliExpress — $55 (two were ordered for $110, since a second bank is planned). Plus wire, M10 bolts, washers and lock washers from the spares bin.
To put that in perspective, the video notes that a comparable ready-made lithium battery — the Limitless 45Ah — runs around $1,100. This build delivers more capacity for roughly a third of the price, at the cost of a Saturday afternoon of work.
Cell Voltage and the 4S Series Layout
Headway 38120 cells are 3.2V each. To get above 12V, four cells are wired in series — a 4S bank at 12.8V. Thirty-two cells divide into eight groups of four: in the video, the bank is arranged with groups connected positive-negative, split through a plate, in the alternating series pattern that is standard for a multi-cell pack.
Before assembly, every cell was tested individually and all read above 3V — a small but essential habit. The video also shows the build starting with all cells paralleled for a while so they balance with each other before the series connections go on, which reduces the risk of a big current rush between cells at different states of charge.
Building the Bank: Series Wiring Step by Step
The assembly is straightforward if you follow the layout. The bank uses a positive-negative, positive-negative pattern with a plate in the middle and a crossover connection to reach the full 12.8V. Two runs of 0 gauge wire go from the terminals to the battery — probably overkill, but in car audio, overkill is the right direction.
The positive posts get longer bolts so there is room for a regular washer and a lock washer. A strip of tape is placed under the posts so the terminals cannot rub through the protective coating on the cells and ground out against the case. The video's tip: use lock washers or Loctite on the posts — vibration will loosen a plain bolt, and a loose high-current connection is a fire risk.
Why a Battery Box Instead of an Open Bank
Most DIY lithium banks in car audio are bare cells strapped together, but this build goes a different way: a real battery box from AliExpress, about $50 shipped, that is the perfect size for 32 cells. The box has padding on the bottom, keeps the cells protected, and gives the install a stock, commercial-grade look.
The safety argument is the strong one: no exposed cells, less chance of a strap or tool shorting across terminals, and a clean package that can even be sold to someone else. Cardboard spacers go between the cells so they cannot rub through their wrappers under vibration. It is not the flashiest look, but as Parker says, this system is about performing, not looks.
The Active Balancer: What It Does and Why You Need It
A 4S bank has four groups of cells, and no two groups are ever at exactly the same state of charge. Over time, small differences grow, and one group gets overworked while the others coast. The active balancer fixes this by pulling current from higher groups and pushing it into lower ones, keeping every group at the same level.
The balancer in the video costs about $10 and has five wires: red to the first positive, then the second, third and fourth positives, and black to the negative. If the bank is out of balance, little lights on the unit light up as it shifts amps between groups. It does not add capacity — it protects the life and performance of the cells you already paid for, which is why it is worth the ten dollars.
Wiring, Terminal Care and Final Voltage
With the balancer in place and the cells in the box, the main positive and negative posts are bolted down with M10 hardware. The finished bank reads 12.87V — right in the expected range for a 4S lithium bank at rest. The whole thing weighs about 30 pounds, which is the same size as a standard car audio battery but dramatically lighter than most AGM units in the same footprint.
The video also points out the practical details: use flexible wire or the box becomes very hard to close, and leave a little slack in the high-current runs so nothing is under tension. The bank should be good for 5,000-6,000 watts, and possibly 7,000-8,000 with a strong alternator and good charging.
Running Lithium Alongside Your AGM Battery
One of the reasons Headway was chosen is that it plays well with the rest of the car. Because the resting voltage sits close to 13V, this bank can run alongside the existing AGM battery and charge from the stock alternator without a separate charger or DC-DC converter — something the LTO chemistry cannot do without extra equipment.
That same compatibility question is central to any 12V lithium upgrade, whether it is a car audio bank, a marine setup, an RV or a golf cart: will the charging system in the vehicle actually charge the new chemistry safely? If the answer is yes, the upgrade is mostly labor. If not, you need a BMS or charge controller that speaks the right voltage profile — the kind of detail we walk customers through every day when they spec a custom lithium pack for a specific vehicle and load.
Safety Notes for a First-Time Build
Three safety points come out of this build and its comment section. First, use lock washers or Loctite on every post — vibration is the enemy of a high-current connection. Second, insulate everything that can rub: tape under the posts, cardboard between cells, and padding in the box, because a short across a lithium bank is a serious event. Third, verify every cell before assembly and balance the groups before first use.
The same discipline scales to bigger systems. When a manufacturer like us builds a pack, every cell is matched, every weld is tested, and the BMS protects against overcharge, over-discharge and overcurrent before the pack ever ships. That is the difference between a weekend DIY build — which can be totally safe with care — and a production pack engineered for years of service.
If you are not hunting for a consumer brand but need the battery itself — a custom LiFePO4 pack at a specific voltage and capacity, an OEM or ODM project, or wholesale supply for your own power station line — that is 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 will 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 replies quoted where they exist and our practical answers where the thread went unanswered. Thanks-only comments were left out on purpose; these are the ones with real information in them.
Source video: Parker The Basshead — "DIY Lithium! 64AH for Under $400!! Car Audio Battery" (youtube.com/watch?v=YEtrtGF7hOA). Comment excerpts are quoted verbatim from the video's top comments; creator replies are quoted where they exist, and unanswered threads carry Dajiu Energy's own answers. Part numbers, voltages and costs are transcribed from the video's build.