An e-rickshaw is a business, and the battery set is its fuel tank and its largest running cost. Most e-rickshaw owners in Delhi NCR replace the set about once a year, and a set that fails at eight months instead of twelve can erase a month of earnings. The good news is that the main causes of early failure are not mysterious. They come down to how the batteries are charged, how deeply they are drained, whether they are kept topped up with water, and how hard the vehicle is worked. This guide covers each of these in practical terms.
How the set works, and why one weak battery matters
An e-rickshaw typically runs on four 12 volt batteries connected in series, which gives a 48 volt system. In a series string the voltage adds up, while the capacity in Ah stays the same as one battery. The current flows through every battery in turn, so the string behaves like a chain. If one battery has lost capacity, it is the first to run empty during a long day, and when it runs empty, the whole vehicle slows down or stops, even if the other three still have energy in them.
This has two consequences. First, you must think of the set as a single system, not as four independent batteries. Second, the weakest battery is also the one that gets the most abuse, because the charger pushes the same current through all four, and a weak battery reaches full voltage sooner or hits trouble sooner than the healthy ones. A single bad battery can drag down the life of the other three. That is why checking each battery separately, rather than looking only at the overall pack, is valuable.
Charging discipline
Charging habits are the largest single factor in battery life, and they are free to fix.
- Charge fully, every night. Lead-acid batteries last longest when they return to full charge regularly. A set that is routinely charged for only two or three hours between shifts develops sulfation on the plates and loses capacity. Let the charger complete its cycle until it switches to its finishing mode.
- Use a charger made for the set. The charger must suit a 48 volt lead-acid string. A very cheap or damaged charger that overcharges will boil water out of the cells, heat the batteries and shorten their life. One that undercharges leaves the set perpetually short of full.
- Let hot batteries cool before charging. Batteries are warm after a long run. If you can, give them a short rest and avoid putting a fast charge into very hot batteries.
- Do not top up with short, frequent charges as a habit. Occasional opportunity charging is fine, but a pattern of running a set low and repeatedly giving it a quick boost works the batteries harder than one full overnight charge.
- Charge in a ventilated place. Charging releases hydrogen gas. Do not charge in a closed room where people sleep, and keep sparks and flames away from the charging area.
- Check the plug, socket and cables. A loose or burnt plug reduces charging current and can start a fire. Repair it, do not tolerate it.
Depth of discharge: do not run the set to empty
Depth of discharge is how much of the stored energy you use before recharging. For lead-acid batteries, the deeper the discharge, the fewer the cycles you get from the set. Using half the capacity each day is much gentler than using nearly all of it. You cannot fully control this in a commercial vehicle, but you can avoid the worst cases.
- If the vehicle starts to feel weak on slopes or flyovers, or the speed drops, do not push for one more trip. A battery drained to exhaustion is damaged every time.
- Plan routes and shifts so that the vehicle returns to charge before the batteries are completely flat. If the route regularly takes the set to its limit, the set may be undersized for the work, and a higher-capacity set is a better investment than replacing a smaller one early.
- Never leave a discharged set standing for days. A flat battery sulfates quickly. Charge it as soon as you can after a heavy day.
In cold weather, the same set gives a shorter range, because batteries deliver less when they are cold. Do not mistake the winter drop for a failing set; compare like with like.
Topping up water
Most e-rickshaw batteries are flooded tubular batteries with caps. They are cycled hard and charged often, and they lose water as they do. Water level is probably the most neglected maintenance item on the vehicle.
- Check the level regularly. Because of the heavy use, a weekly or fortnightly look is a sensible habit, and a more frequent look in summer.
- Use distilled or battery-grade water only. Never use tap water, and never add acid.
- Top up after charging, so that the rising level during charging does not push electrolyte out. Fill to the level mark and no higher.
- Wipe the tops of the batteries dry and clean. Spilt electrolyte and dust form a damp film that lets current leak across the top of the battery, and it corrodes terminals and the tray.
If one battery uses much more water than its neighbours, it is probably failing, overheating or taking more of the charging voltage than it should. That is a warning to test it. Our general guide to water topping and terminal care goes through the same steps in more detail and applies equally here.
Load: passengers, goods and slopes
The motor draws more current when the vehicle carries more weight, climbs a gradient or starts from a standstill. High current means more heat inside the batteries and a faster drain. Regularly overloading the vehicle beyond its rated passenger or goods capacity shortens battery life and also stresses the motor and controller. Smooth starts and steady speeds use less energy than repeated hard acceleration. Tyre pressure matters too: under-inflated tyres increase rolling resistance and use more power for the same distance.
Keep an eye on added loads. Extra lights, a loud sound system or a mobile charging point wired directly to the battery drain the set when the vehicle is not running and can leave it low before the day has started.
Terminals, cables and tight connections
An e-rickshaw draws heavy current, and loose or corroded connections generate heat. Check every terminal and connecting strap when you check the water. Look for crust, discoloured or melted clamps and cables that move when pushed. Clean corrosion off, tighten each clamp firmly, and coat the finished connection with petroleum jelly or terminal grease. Replace any cable with damaged insulation. A poor connection on one battery can make the controller misread the pack and can cause voltage drops that reduce range.
How to spot the weak battery in the set
With a multimeter, measure each battery separately after the set has been fully charged and rested for a few hours with the vehicle switched off. A fully charged and rested 12 volt battery reads around 12.6 to 12.8 volts. A battery that reads clearly lower than its neighbours, or one whose voltage drops much faster than the others when the vehicle is running, is the weak link. A workshop with a battery tester can check the capacity under load, which tells you more than a voltage reading alone.
If one battery is failing and the others are still sound, replacing only that battery can be tempting. It rarely works well. A new battery has higher capacity and lower resistance than the old three, so it is charged and discharged differently, and the set ends up unbalanced. In most cases the better choice is to replace the whole set together. If the set is only a few months old and just one battery has failed, check the warranty first and speak to the seller before you buy anything; our guide to how battery warranty works in India explains what to ask. Commercial use sometimes has different warranty terms from private use, so read the card.
Storage and idle time
If the vehicle will not run for a week or more, charge the set fully before parking it, and charge it again every few weeks while it stands. Disconnect any accessory that draws current. Keep the vehicle under cover, and keep the battery tops dry.
Choosing a replacement set
When the set has come to the end of its life, replace it with a set of the same type and capacity that the vehicle was designed for, unless your routes have outgrown it. Always buy all four at the same time, from the same batch if possible. You can compare options in our e-rickshaw batteries range, which is sold as a full set of four with delivery across Delhi NCR. Your old set has scrap value, so ask about exchange when you buy, and you can read how trade-ins are valued on our page about selling an old battery.
