I paid about $2.2k including tax to have Schwinn Hybrid bike converted to eBike in May 2020. Battery pack weight was about 9lb and motor was about 8lb vs the bike weight about 23lb (Aluminum body).
With a throttle only max speed 28mph on flat road. I used it mostly for weekend rides 10 miles round trip 800 to 1000ft elevation gain. Battery was 48V 25A rated 13Ah with USB outlet. I used the USB just once for my phone in 15 months. After riding about 150 miles on inital charge it showed about 25% battery after I used an average of 10% pedal power assist which is 2.5A and 48V or 120W. I barely compensated for the extra weight and did not really use Pedal Assist to make biking easier. I used max pedal assist or throttle only when I was riding 2 to 4 miles round trip tennis courts about 2 to 3 times a month depending on weather.
Suddenly the battery died and will not charge. Green light indicated that battery was fully charged. I took it to the same place which did conversion. They asked for $435 for the battery. Their labor rate is $90 per hr. So I assume that they would have charged me 525 plus tax about $570 but warranty on the battery was only 1 yr even though "expected lifetime" is 5yrs.
I contacted 5 local bike shops. 3 do not service eBikes. 1 did not respond and 1 said they if I buy the battery, they could install for $50 to $100.
I looked and found a 10Ah battery without USB Hailong battery plate, without USB $270 including delivery on eBay. A light USB battery pack I have will do the job for the rare case. For my usecase a larger battery was only more weight. This one was about 2lb lighter and range is still probably lot more than I need. Manufacturer's instructions interestingly suggested that I charge the battery fully and discharge it 3 to 5 times initially to make sure that I get max capacity. I guess I have to use the throttle or max pedal assist just to drain the battery. The instructions also called for not exposing the battery to over 113F or below freezing temp which may happen anywhere in the US in a garage. They suggest bringing the battery inside on such extreme days. They also suggested that I charge it to at least 60 to 80% once in 3 months regardless of use.
All I needed was a hex wrench and a heat gun or hair dryer and a 1/2 inch heat shrink wrap for $2.50 at Harbor Freight. I just removed the old battery by unlocking it with the key, cut off the old shrink wrap and disconnected the plus and minus Anderson connectors, removed the battery plate with hex wrench and installed the new plate, slid the shrink wrap over the power cable, connected power and used heat gun (also $10 at Harbor Freight but any hair dryer would do the job). In 5 min $272.50 I was back in business.
A friend of mine bought a brand name eBike and he too had to have the batery replaced. Luckily for him it was under warranty but otherwise brand name ebikes with propreitary battery would probably cost a lot more.
I looked at the instructions in the manual of the battery. Chinese manufacturer. I asked a friend of mine who is in the business of building solar and battery backup solutions if it is worth paying a 50 to 60% premium for battery buit using 18650 cells by Panasonic, LG or Samsung. He told me that premium is not worth it because the warranty is still 1year even with those and the premium is not worth it because they by no means last 50 to 60% longer. Tesla uses CATL Chinese cells in many of their cars.
Is it worth replacing the a dead cell? It takes about 30min perhaps to open the battery pack and check each of the parallel cells. 10Ah battery I bought is made up of 13 3.7V cells in series to add up to 48V, 2.5Ah each 4 cells in parallel 10.5Ah. I would have to open it and check 13 of the parallel cells to determine how many are bad. Then the entire parallel set of 4 have to be removed and replaced with cells of the same voltage as the rest. Even then I would have a mix of old and new. A professional service would charge about $200 to do this. Still warranty would not get extended. DIY requires investing $60 in a low cost spot welder, $10 for nickel strips, $12 minimum for 4 cells retail price and 2 hrs total labor perhaps. So spending $82 vs $272.50 for a new battery pack 1 yr warranty and 5min of my time was easy decision.
I looked at many videos on youtube on eBike DIY including how to replace the battery, install the motor, sensors for speed, gear change, throttle. You could buy a kit for about $1100 with parts and tools including tax and shipping vs $2.2k I paid to convert my bike. I think it takes max 4hrs to do it. There are lots of videos on youtube. If you are a DIY person, give it a shot. I told my friends that if they or their friends want to convert their bikes to electric or replace battery, I can help at no cost as a community service.
Hope this helps someone save time and money. Happy riding!
