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A 4S DIY battery kit for pack builders: case, smart BMS and the full accessory set for 100Ah-class prismatic LiFePO4 cells — supplied as a kit, assembled by you, branded by you.
A Kit, Specified Like a Component — Not a Finished Battery
This page is for assemblers, RV and marine outfitters, and distributors who build their own 12.8V packs: you source the cells, we coordinate the case, BMS and hardware around them. Four 3.2V prismatic cells in series give a nominal 12.8V pack; at 100Ah that is about 1.28 kWh — the classic drop-in size for RV, marine and portable power. What this kit is not is a finished battery: no cells are inside unless you order the tier that includes them, and nothing on this page should be read as a ready-to-install product.
The kit is supplied in three tiers. The market uses loose words like “complete kit” for all three, so we define each tier by what is physically in the box:
| Tier | What is in the box | What you supply |
|---|---|---|
| 1 — Case-only kit | Case plus accessory set: series busbars, sampling board or balance harness, insulation set, main terminals, protection hardware, fasteners | Your cells and your own BMS |
| 2 — Case + BMS kit (standard offer) | Everything in Tier 1, plus a fitted 4S smart BMS. This is the configuration meant when a listing says “Battery Case + BMS + Accessories (Cells Not Included)” | Your cells |
| 3 — Complete kit with cells | Everything in Tier 2, plus 4 matched Grade A cells of the model confirmed in your order | Assembly only |
If you only need the protection board itself, see our standalone smart BMS boards. If you would rather not assemble at all, the same capacity exists as a finished product in our 12V 100Ah deep-cycle LiFePO4 battery.
First Decision: Which 100Ah Cell Format?
Every other model in this kit series is built around one shared cell footprint. This one is not — and any seller who skips this point is setting you up for a case your cells do not fit. “100Ah-class” prismatic cells come in two incompatible format families:
| Format family | Representative cells | Cell size, L × T × H (mm) | What 4 cells look like |
|---|---|---|---|
| Family A — tall and slim | EVE LF105 (105Ah) | 130.3 × 36.35 × 200.5 (incl. terminals); terminal centres 67 mm apart | A row ≈145 mm thick standing 200.5 mm tall — a tall, narrow block |
| Family B — low and wide | EVE LF100LA (100Ah) | 160.0 × 50.1 × 118.5 (incl. terminals); terminal centres 97 mm apart | A row ≈200 mm thick but only 118.5 mm tall — a low, wide block |
| Family B — low and wide | CATL 100Ah | 160.8 × 49.9 × 118.8 | Same low, wide block geometry as LF100LA |
| Family B — low and wide | Lishen 102Ah | 160.0 × 49.9 × 115.5 (dealer-published data) | Same low, wide block geometry |
The two families need different cases, different busbar drilling (the terminal spacing alone differs by 30 mm), and different compression layouts. A Family A case cannot take Family B cells, and the reverse is equally true. So the buying sequence on this page runs the other way round from the rest of the series: name your cell model first — or measure the cells you already hold — and the case is matched to that format. If a quotation for a 12V 100Ah prismatic kit never asks which cells you are fitting, the case in it is a guess.
If you have not bought cells yet, let the installation decide: measure the space the finished pack must occupy. A tall, narrow compartment points to Family A; a low, wide one to Family B. If you are still choosing, our guide on choosing LiFePO4 cells for pack assembly covers the selection logic, and both formats sit in the cell range on our cell wholesale page.
Reference Standard Configuration
The table below is the reference build most buyers start from. On this model, read the Basis column carefully: the 100Ah prismatic kit is the least standardised format in the series, and this page marks plainly what is fixed, what is a published market reference, and what is confirmed per order — instead of printing a full spec table the market itself does not support.
| Item | Reference configuration | Basis |
|---|---|---|
| Pack format | 4S (4 × 3.2V cells), 12.8V nominal; ≈1.28 kWh at 100Ah, ≈1.34 kWh with 105Ah cells | Fixed by the kit design |
| Cell format | Family A (EVE LF105) or Family B (LF100LA class) — chosen before the case; the two are not interchangeable | Buyer decision, confirmed in writing |
| Case format | Sealed ABS waterproof case, or steel case | Option — see matrix below |
| Case size | Confirmed per order against your cell format. One published market reference exists for a sealed prismatic-cell case in this class: 250 × 173 × 245 mm (Luyuan ABS waterproof case, rated for 12V 80–105Ah prismatic builds) | Market reference, single published source — your case drawing is confirmed per order |
| BMS (Tier 2/3) | 4S smart BMS, 100A or 200A continuous class, Bluetooth monitoring | Brand family and model confirmed per order |
| Main protection | Fuse or circuit breaker in the main path | Rating varies by maker at this format — confirmed per configuration |
| Display | Optional add-on module at 4S; not a standard fit on this format | Option, confirmed per kit |
| Main terminals | P+ / P− terminal pair | Confirmed per configuration |
One honest note on why this page confirms more than it prints: dedicated cases for prismatic 100Ah cells are a niche corner of the market. The big case makers publish full ranges for 280Ah-class kits and almost nothing standardised here — one sealed-case reference is the only firm number we can cite, and steel cases in this class are produced to order rather than catalogued. A page that lists ten precise dimensions for this format is copying someone, or inventing them.
Configuration Options — Nothing Is Locked
| Dimension | Options | Notes |
|---|---|---|
| Supply tier | Case-only / Case + BMS / Case + BMS + cells | See tier table above |
| Cell format | Family A (tall/slim) / Family B (low/wide) | Decided first — it drives the case, busbars and layout |
| Case format | Sealed ABS waterproof case; steel case; custom dimensions for volume programmes | Custom sizes are an OEM item, confirmed per project |
| Cells fitted (Tier 3) | EVE LF105 / EVE LF100LA / CATL 100Ah / Lishen 102Ah | Must match the case format; terminal form confirmed against the physical batch — it is not published for every model |
| BMS family | JK (active balancing, Bluetooth built in) / JBD (passive balancing, Bluetooth module included) / Daly (classic passive or active-balance lines) | Category options — the brand and model in your kit are confirmed in writing per order, never assumed |
| BMS continuous current | 100A / 200A class | The mainstream classes at this capacity — size from your inverter and load profile, not from the cell label |
| Balancing | Active 1A or 2A, or passive balancing depending on BMS family | At 100Ah, passive balancing is adequate for most builds; active earns its cost on high-cycle use |
| Communication | Bluetooth app monitoring; RS485 as an optional module on some families | CAN is a custom item at 4S, not a standard feature — state it in the enquiry if you need it |
| Display | Add-on display module (2.5–4.3 inch class by family) / none | All three BMS families treat the display as a separate module at this format |
| Heating pads | Optional add-on | Not standard fit. Add them if the pack will charge below 0 °C; this is separate from BMS low-temperature charge protection |
| OEM appearance | Case colour, your logo and labels, rating plate, manual and packaging | See the OEM / ODM section |
What Is in the Accessory Set
- 3 copper series busbars — a 4S pack needs one link per cell junction, i.e. series count minus one; drilled for your cell format’s terminal spacing (67 mm or 97 mm centres)
- BMS connection busbar set — the main-path links between cell block, BMS and terminals (a separate set from the series links; count follows the board and case)
- Sampling board, or a balance-wire harness — the two market forms of the same job: routing the 5 sense taps (B0–B4) to the BMS in order
- P+ / P− main terminals
- Main-path fuse or circuit breaker — rating confirmed per configuration; makers at this format do not converge on one spec
- Insulation set — epoxy / fibre sheets between cells and case, EVA pads between cells
- Fastener pack — terminal bolts, case and lid screws
- Display module, if optioned
Exact counts of insulation pieces and fasteners follow the bill of materials of the case in your order and are listed in the order confirmation — makers vary these counts widely, and we would rather confirm ours in writing than copy a competitor’s packing list.
Assembly: Four Cells Into a Working 12.8V Pack
- Verify the format before anything is unpacked. Measure your cells — length, thickness, height, and the distance between terminal centres (67 mm on Family A, 97 mm on Family B) — and check them against the case drawing in your order. This five-minute check is the one this format punishes you for skipping.
- Check the cells before anything is bolted. Compare resting voltage and internal resistance across all 4 cells, and bring them to a common state of charge. A spread you ignore here becomes the imbalance you chase for the life of the pack.
- Insulate first. Epoxy or fibre sheets between the cell block and the case, separators between cells. A steel case and prismatic cell cans must never rely on the cell’s own film alone; on the sealed ABS case, confirm the internal layout leaves the insulation set in place.
- Set the single row of 4 under even compression. The block is ≈145 mm thick and tall on Family A, ≈200 mm thick and low on Family B — the end plates and strap follow the format. Fit them snugly and evenly; torque values come from the cell maker’s manual for your exact cell model, and there is no universal number.
- Land the sampling connections before the power path. Fit the sampling board or balance harness from B0 upward and verify all 5 taps read in sequence before any busbar carries current.
- Bolt the series busbars in order — 3 links, polarity checked twice. Work cell 1 negative to cell 2 positive and onward, checking polarity at every step with a meter, not by eye.
- Wire the BMS main path and protection. B− to the first cell’s negative, P− out to the load terminal, fuse or breaker in the main line, then the P+ terminal. Confirm the BMS wakes and reads all 4 cell voltages before the lid goes on.
- Supervise the first full cycle, then close up and record the build. Watch per-cell voltages on the app through the first charge, and note the cell batch, BMS model and settings on the build sheet — that record is what makes warranty discussions and repeat orders simple.
A necessary word on who should do this: a 12.8V 100Ah pack stores about 1.3 kWh and can deliver very high fault currents for its size. Assembly belongs with trained technicians using insulated tools. If your operation does not have them, buy the finished battery instead — it is the honest recommendation, and the finished range starts with our 12V 100Ah deep-cycle battery and the wider 12V LiFePO4 battery series.
Where a 1.3 kWh DIY Pack Earns Its Keep
- Drop-in lead-acid replacement under your own label — the 12V 100Ah size is the standard swap for a pair of lead-acid blocks, and local assemblers build it under their own brand for the replacement market
- RV and caravan power — outfitters fitting house batteries to their own layout and service model; see our RV battery page
- Marine auxiliary power — trolling motors, onboard electronics and small-boat house banks; see our marine battery page
- Off-grid and portable systems — cabins, field equipment and small solar kits where the pack is assembled and serviced locally; see our off-grid energy storage page
OEM / ODM: Your Brand, Your Specification
The kit format exists for buyers who sell under their own name. OEM options cover case colour, logo and rating labels, manuals and packaging; configuration options cover the BMS family and current class, the display, and — on Tier 3 — the cell model and format the kit is built around. For volume programmes, case dimensions can be produced to a project specification rather than taken from the standard range.
Our role in that process is coordination: requirements are confirmed in a written specification, matched against manufacturing partners’ production, and the agreed checkpoints and documents are handled on the export side. The specification confirmed in your order document is what binds the shipment — not this web page, which is why every variable item above is marked “confirmed per order”. Start from our OEM & ODM coordination page or the OEM / ODM RFQ checklist if you want the full document list.
What to Send Us for a Quotation
- Cell model — or your cell measurements — the exact cells you will fit; if the model is unknown, length × thickness × height plus the terminal centre distance identifies the format
- Tier — case-only, case + BMS, or complete with cells
- BMS current class and your load or inverter — so continuous current is sized against the real discharge profile
- Case format — sealed waterproof or steel, and any dimensional constraint of the compartment the pack must fit
- Quantity and destination — a sample kit for evaluation, or your expected regular volume, plus the destination port
One logistics advantage worth planning around: Tiers 1 and 2 contain no cells, so they ship as general cargo — no lithium-battery dangerous-goods freight. Many buyers ship kits by standard freight and source cells on a separate, optimised route; Tier 3 ships as regulated lithium cargo like any cell shipment. Exact packing dimensions and weights for your configuration are stated in the quotation.
Related reading before you enquire: the BMS selection guide for sizing the board, and the full 12V range on the 12V LiFePO4 battery page.
Frequently Asked Questions
I already hold 100Ah cells — will this kit fit them?
Only if the case in your order is matched to their format family — that is the whole point of this page. Send the cell model, or measure the cells: an EVE LF105 (Family A) stands 200.5 mm tall with terminals 67 mm apart, while an LF100LA-class cell (Family B) is 118.5 mm tall with terminals 97 mm apart. With the model or those four measurements, the match is confirmed in writing before anything ships.
Can I mix LF105 and LF100LA cells in one pack?
No. Mechanically they cannot share a case or busbar set — different footprints, different heights, different terminal spacing. Electrically it would be poor practice anyway: cells in one series string should be the same model, capacity and batch class, or the weakest cell sets the behaviour of the whole pack.
Why is there no single case size printed on this page?
Because there is no honest single number to print. Cases follow the cell format, and for prismatic 100Ah kits the market publishes almost nothing standardised — one sealed waterproof case (250 × 173 × 245 mm) is the only firm reference we can cite, and steel cases in this class are produced to order. Your case drawing, with its measurement basis, is fixed in the order confirmation instead.
Do I have to buy the BMS from you?
No. Tier 1 is case-only precisely for buyers with their own BMS platform. What we would ask is which board you plan to fit: the case’s BMS mounting position and protection hardware are arranged around a board class, and it is cheaper to confirm that fit on paper than to discover it on the bench.
Which BMS brand will my kit have?
The one confirmed in your order — deliberately. JK, JBD and Daly class boards are all in the option set, with different balancing types, current classes and communication options, and the right choice depends on your load profile and price point. Rather than printing a brand here and substituting later, the brand, model and settings are written into the order specification.
Is a display or heating included?
Neither is a standard fit at this format. Displays are add-on modules on all three BMS families here, and heating pads are an optional add-on, confirmed per order — we say so plainly because some listings imply otherwise. Add heating if the finished pack will be charged below 0 °C; it is a different thing from the BMS’s low-temperature charge cut-off, which is a protection setting on the board itself.
The DIY Kit Series
This page is the 12.8V 100Ah model in an eight-model DIY kit series: 12.8V 100Ah / 280Ah / 314Ah (4S), 25.6V 280Ah / 314Ah (8S), and 51.2V 100Ah / 280Ah / 314Ah (16S). Each model gets its own page because the cases, cell families and assembly details genuinely differ — the 100Ah models work to a different, dual-format cell system from the shared 280/314Ah footprint used by the rest of the series. The other seven models in the series: the 12.8V 280Ah DIY kit, the 12.8V 314Ah DIY kit, the 25.6V 280Ah DIY kit, the 25.6V 314Ah DIY kit, the 51.2V 100Ah DIY kit, the 51.2V 280Ah DIY kit and the 51.2V 314Ah DIY kit. The full product range is on Products.
Request a quotation for this kit: Start a DIY-Kit-12V100 inquiry · WhatsApp: +86 159 8945 0735
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