Running one electric three-wheeler is a battery problem. Running forty is a scheduling problem that happens to involve batteries.
The decisions that matter at fleet scale are not the ones that matter for a single vehicle. Nobody optimising a fleet cares much about the last ten kilometres of range; they care about how many vehicle-hours they lose to charging, how many spare packs they have to hold, and what happens on the day the depot loses power for six hours. This piece is about those decisions.
The metric that should govern everything
Single-vehicle owners think in cost per kilometre. Fleets should think in cost per available vehicle-hour, because at fleet scale the binding constraint is almost never range — it is how many vehicles are on the road when demand is highest.
Consider two configurations for a forty-vehicle e-rickshaw fleet.
| Smaller packs, cheaper | Larger packs, dearer | |
|---|---|---|
| Pack | 60.8V 80Ah | 60.8V 120Ah |
| Range per charge | ~97 km | ~146 km |
| Cost per pack | ₹52,000 | ₹74,000 |
| Fleet battery capital | ₹20.8 lakh | ₹29.6 lakh |
| Vehicles needing a mid-shift charge on a 120 km day | All 40 | None |
| Charging points needed | 40 overnight + day capacity | 40 overnight |
| Depot handling per day | 40 mid-shift moves | None |
The cheaper option saves ₹8.8 lakh in capital and then costs it back in day charging infrastructure, labour to move vehicles, and the vehicle-hours lost while they sit. On a fleet doing long days, the larger pack is usually the cheaper decision, and it is invisible if you compare only the quotes.
Size packs so the longest normal day needs one charge, not two. The point at which a fleet needs mid-shift charging is the point at which it needs a whole second layer of infrastructure and process, and that step change costs far more than the extra amp-hours would have.
Standardise ruthlessly
The single highest-return decision in fleet battery management is to run one voltage, one pack format and one charger type across every vehicle you can.
Mixed fleets accumulate expensive failure modes. A driver plugs a 19S pack into a 58 V charger and it never fills; a 16S pack meets a 69 V charger and the BMS disconnects, or does not. Spares must be held in every variant, so you hold more of them. Every mechanic must know which pack goes in which vehicle. Fault diagnosis becomes guesswork because no two vehicles are comparable.
Standardisation is worth accepting a compromise for. A single 60 V 100 Ah specification that is slightly generous for the short routes and slightly tight for the long ones will outperform a perfectly optimised mixed fleet, because everything downstream gets simpler. If two variants are genuinely unavoidable — passenger vehicles and loaders, say — make them visibly different and colour-code the connectors.
Depot charging: size for current, not energy
Depot electrical capacity is the constraint most fleets discover late, usually when the last few chargers start tripping the incomer.
Forty vehicles each drawing 22 A DC at around 69 V is roughly 61 kW of DC output. At about 90% charger efficiency and a power factor around 0.95, that is somewhere near 71 kVA of AC demand if everything charges at once — before lighting, workshop equipment or anything else on the site.
Three ways to manage this:
Stagger the start times
The cheapest fix. Vehicles return over two or three hours anyway; plugging them in as they arrive rather than all at 9 pm flattens the peak considerably at no cost.
Exploit the taper
A charger draws full current only during the constant-current phase and tapers over the last 45–60 minutes. Across forty vehicles started at intervals, average demand is well below the theoretical peak — but only if you have measured it rather than assumed it.
Charge overnight on purpose
Where commercial tariffs vary by time of day, shifting load into cheaper hours can be worth real money across a fleet. It also usually coincides with when the vehicles are standing anyway.
Whatever you do, size the depot cabling and protection for the real simultaneous load with margin. Undersized depot wiring heats, drops voltage, makes every charger derate, and eventually fails somewhere inconvenient.
Swap or charge?
Battery swapping gets discussed constantly and suits fewer operations than its advocates suggest.
| Charge in place | Swap packs | |
|---|---|---|
| Capital | One pack per vehicle | 1.3–1.5 packs per vehicle |
| Vehicle downtime | 4–6 hours | Minutes |
| Labour | Plug in and leave | Handling, tracking, lifting |
| Pack design | Fixed mounting, sealed | Quick-release, durable connectors, handles |
| Wear point | Little | Connectors — every swap is a mating cycle |
| Suits | Fleets with a real overnight window | Vehicles that must run near-continuously |
Swapping earns its extra capital only when vehicle utilisation is genuinely the constraint — two shifts a day, or a delivery operation where a vehicle standing still is lost revenue. For a fleet that parks from 10 pm to 6 am, swapping adds cost and handling for a benefit nobody uses.
Note the wear point too. A swappable pack’s connectors see a mating cycle every swap, and connector degradation is a leading cause of failure in swap fleets. If you go this route, specify connectors rated far above your working current and inspect them on a schedule.
Opportunity charging, and the trap in it
Between the two sits opportunity charging: topping up during natural standing time rather than treating charging as a separate activity.
A cargo three-wheeler stands 20–40 minutes per load being filled and emptied. At 0.3C that recovers 10–20% of pack capacity per stop, using time that was already lost. Across a working day this can add several trips without extending anyone’s hours. It is the closest thing to free capacity a fleet can find.
Passive cell balancing only happens during the constant-voltage taper at the top of a full charge. A fleet that lives on opportunity charging and never completes a charge will drift out of balance across every pack simultaneously, losing usable capacity fleet-wide over a few months. Schedule one full charge to completion per pack per week — and make sure it is not unplugged when the current starts tapering, because that is exactly the part that matters.
This is the most common systemic mistake we see in fleets that have otherwise done everything right. It presents as every vehicle gradually losing range at the same rate, which naturally gets blamed on the batteries.
Instrument the fleet
At forty vehicles you cannot manage batteries by asking drivers how the range is. You need data, and a BMS with a communication interface is what provides it.
What is worth tracking per pack:
- Cycle count — the real measure of consumption, and the basis for predicting replacement.
- Capacity against rating — measured periodically, this is the only honest health metric.
- Cell voltage spread at full charge — the earliest warning of imbalance, months before range loss is noticeable.
- Temperature extremes — identifies vehicles parked badly or packs mounted without ventilation.
- Over-current and protection events — often points at a driver or a route rather than a battery.
The highest-value item is cell voltage spread. A pack whose cells are drifting is recoverable if caught; the same pack six months later, with one cell having done far more work than the rest, often is not. Our BMS guide covers what to specify to get this data at all.
Drivers determine battery life more than batteries do
Give forty identical packs to forty drivers on similar routes and after two years they will not be in similar condition. The spread is routinely 15–20% in remaining capacity, and it is almost entirely behavioural.
Four habits account for most of it, and all four are trainable.
Where the vehicle is parked
The single largest factor, and the one drivers have most control over. A vehicle parked in direct afternoon sun runs a pack 10–15 °C hotter than one in shade, and calendar ageing roughly doubles for every 10 °C above about 30. Over two years, shade versus sun is a substantial difference in remaining capacity, and it costs nothing.
Plugging in immediately after a hard run
Charging adds heat to a pack that is already hot. Twenty minutes of standing before plugging in costs nothing and avoids compounding thermal stress at the worst moment.
Running the pack flat habitually
Repeatedly discharging to the BMS cut-off is hard on the cells and hard on the BMS, which was designed as a backstop rather than a routine switch. Drivers who plan their day to finish with 15–20% remaining will get noticeably more life from the same pack.
Unplugging when the charge “looks done”
The constant-voltage taper at the end of a charge is when cell balancing happens. A driver who unplugs as soon as the current starts falling — because the indicator is showing nearly full and they want to get home — is preventing the BMS from doing its job. Repeated across a fleet, this is the most common cause of fleet-wide capacity loss.
Park in shade. Wait twenty minutes before plugging in after a long run. Do not run it to zero. Leave it plugged in until the charger says it has finished, not until it looks nearly finished. Four sentences, and they are worth more than most specification decisions.
Instrumentation makes this manageable rather than aspirational. A BMS that logs temperature extremes will identify which vehicles are being parked badly, and protection events will identify which drivers are running packs to the floor. That turns a general instruction into a specific conversation with the two or three people who need it.
Plan replacement before it plans you
A fleet bought in one go will need replacing in one go, and that is a large cheque arriving at an unhelpful moment.
If you are buying forty packs, consider phasing them — twenty now, twenty in six months. It costs a little in procurement efficiency and spreads the replacement cliff permanently. If the fleet is already uniform, start setting aside a replacement provision from year one rather than discovering the need in year five.
Track cycle count rather than calendar age. Packs on different routes wear at genuinely different rates, and a fleet-wide replacement based on purchase date will scrap good packs alongside worn ones. Rotating vehicles between demanding and easy routes evens the wear, and costs nothing but scheduling.
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The checklist
- Size packs so the longest normal day needs one charge, not two.
- Standardise voltage, pack format and charger across as much of the fleet as possible.
- Size depot supply for real simultaneous current, and stagger plug-in times.
- Choose swapping only if vehicle utilisation is genuinely the constraint.
- Use opportunity charging where standing time exists — but schedule a weekly full charge.
- Instrument every pack, and watch cell voltage spread above everything else.
- Phase purchases so replacement does not arrive all at once.
- Rotate vehicles between hard and easy routes to even out wear.
One more, which belongs on every fleet checklist and is almost always missing: decide now what happens to the packs at the end. Forty batteries reaching end-of-life together is a disposal problem with a compliance dimension, and batteries leaving your premises through an undocumented scrap channel are still your batteries in a regulatory sense. Agreeing a take-back route with your supplier at the point of purchase costs nothing and removes a problem that is genuinely awkward to solve retrospectively — our piece on Li-ion recycling in India covers how the routes work.
Most of these cost nothing to implement and are far harder to retrofit than to plan. If you are building a fleet from scratch, or trying to work out why a mature one is losing range across the board, send us the details — it is a conversation we have often.