Custom battery / smaller for less miles

[paul2978]

Hi


I have a peddle assisted motor one of the older kits that sits on the side of the rear gears. I believe its a 48V1000W. My main issue is that the battery pack is so dam heavy. its massive! and weighs down the bike a lot. My now journey is only 3 miles to work but I still want to use the peddle assist function as there are few traffic lights and my knees aren’t the greatest and I go home at lunch.


My question is – can I get a smaller battery pack for just a few miles usage each day. Im happy to charge it each night. 6-8 miles in total. Is this something I can build myself could someone direct me to sites that sell these? Or where I can work out the smallest battery pack for the 48v/1000w.


Many thanks in Adavnce


Paul

 

[Alan Quay]

Its not quite as simple as that.

Batteries are rated in Amp-Hours, which is a measure of capacity. Like a car fuel tank, the bigger it is the farther you can go between refills.

That's as far as the analogy goes though.

A Battery has a maximum current output. This relates to how big it is, and its 'C' rating. the C rating is usually around 1-2, meaning that a 10Ah battery can supply a maximum of 20A. If you want more current, you have to up the Ah Rating, or get a higher C rating.

In order to pump enough current to supply your 1000w Motor (I'd guess around 30A or more) then you need a big battery.

That said, if you present battery is made of lead then you could get a big improvement in weight by going to lithium.

 

[Deleted member 4366]

There's loads of batteries on Aliexpress. Take your pick. Lunar Electric Bikes sell a tiny 52v battery, which they call the mighty cube.

 

[anotherkiwi]

Tiny correction d8veh: lunacycle.com

 

[paul2978]

This is what I currently have - i now see its just a 24v. Oh my god it weighs a ton. Do you know if I can replace it with something like this. I'm happy to adjust the connections.

http://www.ebay.co.uk/itm/24v10-4ah-electric-bicycle-zhenlong-lithium-battery-for-Prophete-e-bike-Charger-/221879446605?hash=item33a90bac4d:g:FQoAAOSwbYZXa1xd

 

[Deleted member 4366]

Show your complete bike. There might be better replacement battery options.

In principle, you can use any 24v battery as long as can find a way of fixing it to your bike and you know how to wire it to your controller. The battery needs to be able to deliver about 15 amps continuous and 20 amps max. 25 amps max would be better. The one in your Ebay link might be a lttle light on power.

 

[paul2978]

Its about 4-5 years old the setup. It still works like new. Just need a smaller battery to lug about!

 

[Deleted member 4366]

https://www.aliexpress.com/item/24V-10AH-lithium-battery-super-power-electric-bike-battery-29-4V-lithium-ion-battery-pack-charger/32734228464.html?spm=2114.01010208.3.240.4MZa4i&ws_ab_test=searchweb201556_0,searchweb201602_3_10057_10065_10056_10068_10037_10055_10054_10069_301_10059_10033_10058_418_10073_10017_10071_10070_10060_10061_10052_10062_10053_10050_10051,searchweb201603_2&btsid=52d45b82-f2af-46c6-a6c5-3b31b17c56e8

https://www.aliexpress.com/item/24V-10AH-Rear-rack-Lithium-Battery-Aluminum-alloy-Battery-Pack-29-4V-Electric-bicycle-Scooter-E/32705830090.html?spm=2114.01010208.3.2.AVlnVP&ws_ab_test=searchweb201556_0,searchweb201602_3_10057_10065_10056_10068_10037_10055_10054_10069_301_10059_10033_10058_418_10073_10017_10071_10070_10060_10061_10052_10062_10053_10050_10051,searchweb201603_2&btsid=a616259d-7eb9-4be8-9890-c3d3d73c80a2

https://www.aliexpress.com/item/24V-12AH-Rechargeable-Li-ion-Electric-Bicycle-Bottle-kettle-Battery-with-15A-BMS-29-4V/32376146736.html?spm=2114.01010208.3.64.OQaeuV&ws_ab_test=searchweb201556_0,searchweb201602_3_10057_10065_10056_10068_10037_10055_10054_10069_301_10059_10033_10058_418_10073_10017_10071_10070_10060_10061_10052_10062_10053_10050_10051,searchweb201603_2&btsid=c496cea8-1f9a-4b62-bb5c-2a7a23943414

Have a look through these:

https://www.aliexpress.com/wholesale?minPrice=&maxPrice=180&isBigSale=n&isFreeShip=y&isFavorite=n&isRtl=n&isLocalReturn=n&isMobileExclusive=n&shipFromCountry=&shipCompanies=&SearchText=24v+lithium++battery&CatId=0&g=y&initiative_id=SB_20160919075709&needQuery=n