Lead-acid to lithium conversion:is it cheaper per kilometre? Split the four costs and find out
The method first, the conclusion second. Cost per kilometre is not "what the battery costs" divided by "how far it goes" — it is four components added together:
① Depreciation = capital outlay ÷ (cycle count × effective distance per cycle);
② Electricity = consumption per km (Wh/km) ÷ 1000 × local tariff;
③ Maintenance = annual maintenance events × cost per event ÷ annual distance;
④ Downtime = annual lost operating days × daily revenue ÷ annual distance.
Only the first is tied to the battery itself; the other three are set by your tariff, your roads and your fleet availability. This page publishes no currency amount — put your local lead-acid price, tariff, daily distance and daily revenue into those four formulas and the answer arrives on its own. If you would rather not do it by hand, use the conversion payback calculator: enter daily distance, fuel price, electricity price and total conversion outlay.
verifiedThis page gives the method and the basis, not amounts. Substitute your own local lead-acid price, tariff, daily distance and daily revenue — the result differs so much between markets that we do not publish an "average saving".
Service-life bases: fix the denominator before you divide
The numerator is money and the denominator is distance. Get the denominator wrong and the conclusion is wrong. At the same nominal capacity the two chemistries are not in the same league on either dimension — cycles or effective distance per cycle — so the gap in lifetime distance is far wider than the gap in purchase price.
| Basis | Lead-acid (same nominal capacity) | LiFePO4 (same nominal capacity) | Effect on cost per km |
|---|---|---|---|
| Cycle life | 300 – 500 cycles | 3,500 cycles @1C to ≥80% SOH | Denominator differs by about 7 – 10x |
| Usable depth of discharge | 50–60%, held back to protect life | 88–90% recommended | Effective distance per cycle differs by about 1.7x |
| Distance per cycle | Limited by the usable capacity above | About 1.7x the same-label lead-acid set | The two denominator effects compound |
| Equivalent service years (one cycle a day) | About 1 – 1.4 years | About 7 – 9 years | Replacement frequency sets how fast depreciation spreads |
| Maintenance | Watering, terminal cleaning, periodic equalising | Essentially maintenance-free, BMS-managed | Feeds component ③ |
| Fleet availability basis | About 70% for cheap graded / workshop packs | 99.2% annual availability for automotive A-grade | Feeds component ④ |
Availability and cycle-life figures come from the comparison table in the cycle life and SOH whitepaper; usable capacity and consumption come from the capacity and range engineering guide. Note that the service years above assume one full cycle a day — a double-shift fleet running two cycles a day reaches the end of a lead-acid set far sooner.
Specification notice:The figures above are engineering reference values. They may differ with production batch, configuration and actual duty cycle, and the percentages for life, efficiency, availability and coverage are engineering estimates and bench references. Contact us for the detailed specification sheet.
The four components of cost per kilometre, and how to compute each
All four methods are written out with the currency positions left as variables. Enter your own local numbers — do not infer your own account from somebody else’s tariff and somebody else’s daily distance.
- 01savings
Depreciation: outlay ÷ (cycle count × effective distance per cycle)
The numerator is not just the pack: it also includes controller and instrument adaptation, battery bay rework and mounting brackets, the charger (a CC-CV unit is mandatory for lithium) and installation labour.
Numerator: pack + adaptation + bay rework + charger + labour
The denominator is cycle count multiplied by genuine effective distance per cycle — effective, meaning the lead-acid 50–60% usable capacity is discounted first and then converted at passenger consumption of 55–68 Wh/km (heavy cargo 95–125 Wh/km).
This is the only component strongly tied to chemistry, and the one most often miscomputed: comparing purchase prices alone is comparing numerators only. - 02bolt
Electricity: consumption per km ÷ 1000 × local tariff
Take consumption from typical figures: passenger rickshaw 55–68 Wh/km, heavy cargo 95–125 Wh/km. On unpaved or overloaded duty the rolling-resistance coefficient (an engineering assumption) rises from 0.015 to 0.035 and consumption per kilometre increases by nearly half, so use the top of the band for your route, not the bottom.
Includes ≥94.5% charge conversion efficiency
Include charging losses: our chargers deliver a combined conversion efficiency of ≥94.5%, so the meter reads a little more than the pack actually stores.
The tariff is local, and the gap between a night off-peak rate and a daytime peak rate often moves cost per kilometre more than battery depreciation does. - 03build
Maintenance: annual events × cost per event ÷ annual distance
Lead-acid needs watering, terminal cleaning, periodic equalising and remedial work when cold weather cuts capacity. LiFePO4 is essentially maintenance-free, with the BMS managing balancing and protection.
Lead-acid has consumables and labour; lithium is near zero
The method: take the maintenance events actually incurred in a year × (labour + consumables and travel), then divide by annual distance. If the driver does the work, still cost the labour time consumed, otherwise the true lead-acid cost is understated. - 04schedule
Downtime: lost days × daily revenue ÷ annual distance
The component most often left out, and frequently the decisive one. The availability gap is the loss: on our own basis, automotive A-grade packs run at 99.2% annual availability while cheap graded or workshop-assembled packs sit near 70%.
Converted from the availability gap; double it for double shifts
The method: annual lost operating days × daily revenue, divided by annual distance to spread it across each kilometre. For a double-shift passenger fleet, a lost day costs two shifts, which makes this component grow very fast.
Honest answer: the cases where staying on lead-acid is the better call
Converting is not the right answer for every fleet. In the four-part method above the numerator (capital outlay) is clearly higher for lithium, and it only thins out when the denominator (lifetime distance) is large enough. So the test is simple: how many kilometres your vehicle actually covers a year, and whether lithium supply and service can reach you.
Where lead-acid, or staying on it, is the better call
Do not convert just to be modern- cancelVery low daily distanceShort shuttles covering only 20–30 km a day: the denominator is too small for the depreciation advantage to spread, and a lead-acid set lasts long enough anyway
- cancelNo local lithium supply or serviceIf the destination market has no lithium repair capability and no parts channel, one fault stops the whole pack and the downtime cost eats every saving
- cancelThe vehicle is near end of lifeWith only a year or two left in the frame, motor or controller, the outlay cannot spread over enough distance — better to run it out
- cancelYou plan to sell soonThe benefit needs 6–8 months or more of continuous operation to repay, and it is hard to recover in a second-hand price
- cancelLocal lead-acid is very cheap and easy to swapWhere lead-acid pricing and replacement convenience are exceptionally favourable in your market, the short-run arithmetic genuinely favours it
Where conversion wins almost every time
The denominator is large enough, and three of the four components improve at once- check_circleMore than 80 km a dayThe denominator is large enough for depreciation to spread, and it removes a midday top-up from the schedule
- check_circleDouble-shift operationThe pack is fully used twice a day, exhausting lead-acid cycle life quickly and multiplying lithium’s replacement-frequency advantage
- check_circleHigh cost of downtimeWhen a lost peak day costs two shifts of revenue, the gap between 99.2% and 70% availability becomes the deciding factor
- check_circlePassenger dutyAbout 160 kg lighter at equal capacity converts directly into seat margin — a benefit lead-acid simply cannot provide
- check_circleSwapping or fleet-management plansLithium supports quick-release structures and CAN 2.0B, so it can join a swap network or a fleet platform; lead-acid cannot
Five questions on conversion and cost per kilometre
So which is cheaper per kilometre — lead-acid or lithium?expand_more
Why can I not simply compare the price of a lead-acid set with the price of a lithium pack?expand_more
Cycle-life figures get overstated — how do I verify one?expand_more
Lithium is hard to buy and harder to service in my country. Is converting still worth it?expand_more
If I only change the battery and keep the vehicle, how does the arithmetic work?expand_more
Send your duty cycle and we will model it on the same four components
Give us destination port, normal payload or occupancy, daily distance and motor rating, and we will return capacity selection, the conversion outlay structure and FOB / CIF pricing, with the shipping document list attached. This page publishes no amounts and issues no quote divorced from your parameters.
- Selection advice and conversion outlay structure within 24 hours on working days
- Sample packs can prove the real daily distance and consumption before you commit to a container
- Fleet size, routes and energy data are strictly confidential; NDA available first
Specification notice:The figures above are engineering reference values. They may differ with production batch, configuration and actual duty cycle, and the percentages for life, efficiency, availability and coverage are engineering estimates and bench references. Contact us for the detailed specification sheet.