Dharmawan Kusna Handoyo spends his workday in a 2-by-3-meter cubicle, soldering batteries. He has been building DIY battery packs since 2009, when he installed one in his own electric bike — but in the past few years, it has become his main source of income. He sells the packs for hundreds of dollars apiece, luring back customers with the promise of a longer-range battery capacity.
“I put a lot of attention on how the buyer will use the bike,” Handoyo told Rest of World. “I think carefully about where to place the battery to avoid scratching.”
Handoyo is part of a growing community of battery packers in Indonesia, driven by the frenetic growth of the e-bike market and the complete absence of battery regulations in the country. This has created an opportunity for shops that can cobble together replacement batteries, which often provide more range for less cost. These homemade battery packs come with real concerns over safety and reliability — but for many riders, it’s a risk worth taking.
Electric two-wheelers (known in Southeast Asia as E2Ws) have become more popular in Indonesia since 2023, when the country announced a subsidy of 7 million rupiah ($445) for new bikes built with a certain amount of local parts. A total of 62,000 e-bikes were registered in Indonesia as of September 2023, according to the Ministry of Transportation — nearly three times the registrations in the previous year. The country has not enforced any regulations around batteries manufactured at home or by small businesses, which has led to a thriving market for scrappy replacements. Local Facebook forums are littered with advertisements for local batteries, and a search for “lithium battery for E2W” on Indonesia’s e-commerce giant, Tokopedia, yields more than 700 results.
Hadi Wijaya replaced his bike’s original battery for one made by his friend. He told Rest of World the homemade battery is both cheaper and has a longer range. “I sold the original batteries for around 17 million rupiah ($1,081), then bought a custom-made battery for 13 million rupiah ($827),” said Wijaya. The homemade battery uses lithium polymer cells, and has a range of up to 150 kilometers (1 mile = 1.6 kilometers) in a single charge, whereas the original can only reach 100 kilometers. Wijaya has now teamed up with his friend to sell e-bike batteries. “I can tell you that most people I know who use Gesit [Indonesia’s e-bike brand] no longer use the brand’s original battery,” he said.
Manufacturing the batteries is delicate work, starting with the cylindrical battery cells. Packers often use 18650 lithium-ion cells — essentially a larger, rechargeable version of a standard flashlight battery. Cells can be bought directly from component companies like LG, Panasonic, and China’s EVE, and purchased from online marketplaces like Alibaba. There can be as many as 100 cells in a single pack, welded together with nickel strips and connected to the vehicle through a battery management system. Homemade battery packs are also bulkier than branded batteries, wrapped in bright blue heat-shrink tubing instead of the standard polycarbonate case.
Khairul Amin, based in Madura, East Java, has built battery packs since 2016. He aims to sell 10 batteries a month or more. The cheapest batteries in Amin’s shop cost 1.5 million rupiah ($95), but he has sold packs for as much as 35 million rupiah ($2,226) when a customer needed to power an entire car.
Online sellers on Facebook groups typically only state the voltage and amperage of batteries, but more complex factors like the discharge rate of individual cells could cause unexpected problems, according to Agus Purwanto, a chemistry lecturer at Sebelas Maret University. “Every battery has a rating: 1C, 2C, 3C, indicating the discharge rate of the battery,” he told Rest of World. If the underlying cells have different discharge rates, it could result in damage to the battery.
Ady Siswanto, owner of e-bike workshop Dyvolt in Jakarta, told Rest of World he takes care to match the internal resistance and capacity of the cells. “If the battery cells’ capacity isn’t uniform, the battery will have issues, like shutting off all of a sudden,” said Siswanto, who learned automotive mechanics at a local polytechnic before launching his battery pack business in 2017. Controls on overcharging and general defects are also serious concerns.
The chaotic nature of Indonesia’s e-bike industry means it’s difficult to find batteries that are officially certified by manufacturers. Complicating the issue further is that each e-bike maker has their own battery size and design, with no standards shared across companies. “There are possibly more than 20 battery sizes in the market right now,” Bowo Kusumo, CEO of Spora EV, told Rest of World. “That’s a big headache.”
As part of Indonesia’s efforts to standardize EV batteries, a consortium of state companies started the Indonesia Battery Corporation in 2021. One of its initiatives is launching its own battery-swap technology using the country’s nickel reserves. Backed by Hyundai and LG, the battery cell factory is geared to start construction this year.
But the flourishing online market of homemade batteries may pose a threat to battery-swap startups. More people making batteries creates demand for used battery cells, which are often scrapped from existing branded batteries that enter the secondary market, or stolen from public swapping stations. Already, prospective buyers are eyeing used batteries on Facebook forums.
“These home-based EV packers are a concern to the E2W industry,” Irwan Tjahaja, CEO of Swap Energi Indonesia, told Rest of World. “We need to make sure there is a safety procedure that packers follow — from design, packing to testing … Otherwise, accidents might happen.”