The lightest conversion with smallest battery

[logicped]

I converted a mid range hybrid a couple of years back with a Cyclotricity rear wheel kit and 36v/11aH rack battery. The bike runs fine, but is just about unusable when the battery is dead as it's simply too heavy. All the weight at the back isn't good either. Just found out that the rack battery and the rear wheel weighs a hefty10kg (probably not including the rack itself)

I am about to convert a decent light hybrid and want the lightest solution with smallest amount of assist possible (10-15 miles or so). I see the https://www.cytronex.com/ front hub setup and small battery coming in at 3.6kg which is significantly lighter, but over £1000 for the conversion. Are there any similar products but slightly cheaper? Happy to have a front wheel drive or mid drive.

I see this company at approx £700, but not available to buy yet. https://www.lightest.bike/SHOP/Lightest-250W-kit-with-battery-presales-p221067532

Thanks

 

[Bikes4two]

• Just by way of comparison, I have a TSDZ2 250w, 36v which ways in around 3Kg and a 10Ah bottle battery, also around 3Kg
• I have seen 36v 7Ah bottle batteries around so undoubtedly lighter but I don't know by how much.

 

[Nealh]

If you want lightest with little or no assist that rides almost as good as unpowered then the Bafang G370 1.7kg front hub, fits that bill to a tee. Also there is the 1.44kg akm 75sx.
A small 10s2p mini bottle battery with inner controller in the base 2kg.
Price is approx. half that the cytronex is.

8Fun Bafang G370 36V250W Front Hub Motor 1.7kg [Bafang G370] - $175.75 : Zen Cart!, The Art of E-commerce

Zen Cart! 8Fun Bafang G370 36V250W Front Hub Motor 1.7kg [Bafang G370] - ★★★★★ 8Fun Bafang G370 36V250W Front Hub Motor 1.7kg Specification: 1. Voltage: 36V. 2. Brake type: V-Brake,Disc brake 3. Connector: Waterproof Hall sensor and sensorless compatible connector. 5. Fork size: 100mm...

www.topbikekit.com

1.44kg AKM-75SX 36V250W EBike Front Driving Hub Motor 20/32/36 holes [AKM-75SX 36V250W Front Motor] - $99.75 : Zen Cart!, The Art of E-commerce

Zen Cart! 1.44kg AKM-75SX 36V250W EBike Front Driving Hub Motor 20/32/36 holes [AKM-75SX 36V250W Front Motor] - ★★★★★ 1.44kg AKM-75SX 36V250W EBike Front Driving Hub Motor Specification: 1. Voltage: 36V. 2. Brake type: V-brake, disc brake and disc brake are compatible. 3. Connector: Waterproof...

www.topbikekit.com

10S2P HT-1 36V7AH Bottle Mini Battery Panasonic NCR18650GA Cells + KT Inner Controller [HT-1 Battery 36V7AH] - $137.75 : Zen Cart!, The Art of E-commerce

Zen Cart! 10S2P HT-1 36V7AH Bottle Mini Battery Panasonic NCR18650GA Cells + KT Inner Controller [HT-1 Battery 36V7AH] - ★★★★★ Bottle Mini Battery 36V7AH 10S2P Panasonic NCR18650GA Cells + KT inner controller SPECIFICATION: 1-Normal voltage:36V 2-Capacity:7AH Panasonic NCR18650GA 3.5AH cells...

www.topbikekit.com

10S2P HT-2 Mini Bottle Battery 36V10AH Samsung 21700-50E Cells+ KT Inner Controller [HT-2 Battery 36V10AH] - $170.05 : Zen Cart!, The Art of E-commerce

Zen Cart! 10S2P HT-2 Mini Bottle Battery 36V10AH Samsung 21700-50E Cells+ KT Inner Controller [HT-2 Battery 36V10AH] - ★★★★★ HT-2 Mini Bottle Battery 36V10AH 10S2P Samsung 21700-50E Cells+ KT Inner Controller SPECIFICATION: 1-Normal voltage:36V 2-Capacity:10AH Samsung 21700-50E cells 3-Cells...

www.topbikekit.com

 

[Nealh]

My G370 is used often to tow a trailer, the max I have pulled is +125kg just the once. Normally anything from 20kg - 90kg.

 

[mr_ed]

i have a bbshd with a 17.5ah battery so my tank weighs 25kgs!

I fancy building another with one of the 1.75kg bafang hubs and using batteries from a standard power tool, Bosch/MAkita, 36v 5ah.

but to be fair it wouldnt make enough difference to be worth the effort/expense. once on the move I don’t notice the weight, its only lifting it out of the garage!

 

[AndyBike]

I see muddyfox is doing a single speed ebike weighing 18.something kg for £550 with an internal battery. That looks ranged to about 15 or so miles, more if its a flat area, no wind and you weigh 8 stone.

https://www.evanscycles.com/brand/muddyfox/electric-avenue-hybrid-bike-700516#colcode=70051611

 

[StuartsProjects]

I fancy building another with one of the 1.75kg bafang hubs and using batteries from a standard power tool, Bosch/MAkita, 36v 5ah.

Seen the batteries, but are there effective & secure battery holders ?

 

[mr_ed]

Seen the batteries, but are there effective & secure battery holders ?

Im sure something could be made from a charger cradle, stick it in a small frame bag.

 

[Nealh]

One can buy tool battery outlet bases to wire in parallel or series such as the example below.
18V Li-ion Battery Adapter DIY Wire Cable Connect Output Tool For Makita / Bosch | eBay

 

[StuartsProjects]

One can but tool battery outlet bases to wire in parallel or series such as the example below.
18V Li-ion Battery Adapter DIY Wire Cable Connect Output Tool For Makita / Bosch | eBay

Are they available for the 36V batteries ?

 

[Nealh]

If a 36v tool battery uses the same footprint as an 18v and the actual pack itself is just taller holding twice the cells, then the same adapter would work.
Other wise a good option is to series a pair for 36v, the cheapest option may be is to buy the Parkside batteries from lidl 20v and buy Parkside 3D printed adapters from ebay.
It all depends on how well the adapter retains the battery as a fixture.

 

[Nealh]

This is from a few years ago approx. 6, Blair's e cruiser was on ES and a very nice bespoke tool battery bike.
Blair’s E-Cruiser, using DeWalt cordless tool battery packs | ELECTRICBIKE.COM

 

[StuartsProjects]

If a 36v tool battery uses the same footprint as an 18v and the actual pack itself is just taller holding twice the cells, then the same adapter would work.

Interesting.

I was thinking a Brompton conversion, one of the tool batteries could be placed on the top tube by the saddle. Would not impact the fold so much, although the saddle might not go down so low.

Small battery maybe, but enough for most Brompton trips which tend to be short.

 

[Nealh]

Tony Lee aka Woosh 3D'd a tool battery base to use on his Brompton I believe for a lightweight option.

 

[Kwozzymodo]

My Specialized hybrid with 700c wheels and hydraulic disc brakes weighs in at 8.5 kg without the electrics and a single chainring conversion.
I’ve added a rear hub motor and 36v 7ah bottle battery. That brings the weight up to just over 12.5kg

I can do around 20 miles on a full charge of the battery.

 

[Woosh]

Tony Lee aka Woosh 3D'd a tool battery base to use on his Brompton I believe for a lightweight option.

This is my Brompton with Bosch tool battery:

The battery is lockable:

I suppose you can open the battery case and fit something else like 21700-5000mAH cells for more distance but then, if you make your own battery, just as well fit it inside the controller bag. The only thing is the bag is not lockable like the fitting on the luggage block. I also like a low CoG.
The Cute Q70 motor weighs 1.2kgs.

 

[Bonzo Banana]

If a 36v tool battery uses the same footprint as an 18v and the actual pack itself is just taller holding twice the cells, then the same adapter would work.
Other wise a good option is to series a pair for 36v, the cheapest option may be is to buy the Parkside batteries from lidl 20v and buy Parkside 3D printed adapters from ebay.
It all depends on how well the adapter retains the battery as a fixture.

I've seen some Parkside battery packs stated as 20V which I realise a lot of companies do when they are actually 18V packs but what annoyed me about them is they claimed 80Wh capacity on the pack 20Vx4Ah when clearly they were not a real capacity of 80Wh. 18Vx4Ah is 72Wh. No idea on how good the cells are fitted to these though. Is there a known cheap battery pack that uses good cells?

 

[StuartsProjects]

The battery is lockable:

Very nice.

Where did you get the bracket part that has the lock on it, the Brompton block bit ?

 

[mr_ed]

My Specialized hybrid with 700c wheels and hydraulic disc brakes weighs in at 8.5 kg without the electrics and a single chainring conversion.
I’ve added a rear hub motor and 36v 7ah bottle battery. That brings the weight up to just over 12.5kg

I can do around 20 miles on a full charge of the battery.

that sounds nice!