Upgrading ebike battery pack


New member
Local time
11:55 PM
Jun 21, 2018
I've now had a few months experience with my bike and now need to upgrade. Firstly, my flooded lead acid battery is showing it's limitations. The range is very limited as the power drops off rapidly after about half an hour. After this it's ok on the flat but useless on hills. I need to source a new battery pack, probably LiPo4, and I wonder if there is a supplier in the UK as postage costs add 50% to the costs if imported.

Also I will probably need a more powerful motor than the current 200W (if it is indeed that much) as it struggles to push my 16 stone bulk around. Anyone out there with any ideas as to how I can improve my current machine?
Flooded lead acid batteries are for starting gas engines. They deliver high amps for short periods of time which is needed to turn over the engine. They are not designed for ebike applications. You need deep cycle or sealed lead acid batteries.

Deep cycle batteries are used in battery banks for off grid power and are usually too big for a bicycle. An electric car ok.

SLAs are used in uninterrupted power supplies and are smaller than a motorcycle battery of the same amp hour.

The plates in a flooded battery are thinner and more surface area is exposed to the electrolyte thus deliver high current quickly. Sealed and flooded batteries have much thicker plates so less electrolyte is exposed, thus are able to deliver a current over a longer time frame.

Flooded batteries are charged to 13volts deep cycle and sealed lead acid batteries are charged to 14.4volts