Trying to get a replacement battery in the Philippines for our Pedelec
In 2014 I bought a conversion kit for converting a bicycle into a Pedelec, which according to German traffic regulations is an electric bicycle with 25km/h max. speed and pedal assist only, and had it shipped to the Philippines. I used my wife’s old bicycle which she was not using anymore as the basis and converted into “Electra“. My daughter and myself used it occasionally, but not a lot. Four years later, the battery was dead. After opening up the casing it turned out that three cells were visibly broken.
I tried to contact the vendor of the conversion kit, who did not exist anymore and ended up writing to the German company that had assembled the batteries. They responded saying that it is a very old model and that there is no stock left. A year passed by with Electra without power. Then I bought three 18650 cells in a shop in Quirino in Manila, but I did not trust them, and besides, I did not have a spot welder usually used to connect the cells. More months passed, then I learned in February 2021 from a friend that there is a shop in Manila, Energia Box, that makes battery packs for Trottibikes. I asked for the price for a battery equivalent to the broken one and was informed that they could make one, originally they quoted me 11,500 PHP for 36V, 13Ah, 10S, 5P, total discharge rating 50A, BMS rating at 35 Ampere. They use Liiokala M26 cells with a discharge rating of 10A/cell. Supposedly they use Dali BMS. That would be US$ 240, with no trouble of import, shipping as dangerous goods etc. So I ordered a pack, to be fitted inside the original battery box. Due to the limited space in the box they could only fit a 10S, 3P configuration and the price got reduced to PHP 9,500 or about slightly under US$ 200.
A few days later I could pick op the new battery in Manila. They arranged the cells differently, so the box did not close anymore and there was a 4mm gap between the top and bottom housing shells. Anyway, I used a lot of silicone and the battery worked. For three charges. Then it went dead very quickly even when fully charged. More months passed, I was too busy to go back to the company and complain. in 2022 I then decided to open up the custom made battery to be able to measure voltages of each block and to inspect the cells. The first surprise was that the BMS was not Dali, some after market prodcut with no brand name printed on it. Second was that one block basically had zero voltage. It would not accept current when connected directly to a power supply, so the cells being in battery nirwana.
Now I have to get into battery building, I thought, and ordered three more cells from them, which arrived in the mail two days later. Again, no spot welder, so the repair project ended on the shelf again. When in Germany in 2022 I then decided to invest in a spot welder. It went into the Balikbayan Box, so again three more months before I could do something meaningful.
In the meantime I changed the simple no-name BMS to a Smart BMS from Dali. It can connect with Bluetooth to the mobile phone and give you the voltages of each individual cell block, something I thought might be useful for monitoring the health of he cells, rather than doing guess work on what might be wrong. I then finally changed the broken cells, turned out that two cell blocks needed changing, not just one.