Guidance on options for 36V ~250Wh battery

[DarkerSide]

Hi folks

Specc-ing a conversion of my current commuter into an ebike, using the Tongsheng 250W TSDZ2. Could do with some hive-mind thoughts on battery options...

It's a 40km round commute with about 450m of climbing. On a test ebike with Shimano Steps, I was consistently using about 200Wh from the battery. I want to keep the battery as small/light as possible (the bike already weighs a tonne...), so I'm thinking about 250Wh would be a reasonable compromise. Needs to be downtube mounted.

Initial plan was a small bottle-battery (handy bonus - if I needed additional capacity for something, I could just buy a second and swap them over as needed during a ride). However, I'll be unplugging it daily to charge in the office, and I'm a little concerned about the waterproofing/fatigue on the battery/motor connection, even with a decent connector. Am I safer buying something with a battery "mount plate" so I can heat-shrink wrap the mount-motor connection, and then relying on the battery-mount connection being a bit more robust for repeated plug/unplugging?

Commute is all-weathers in central Scotland, so we do rain well...

Cheers

Rob

 

[KirstinS]

May I suggest you read this. Although I have no personal experience the hive mind suggests that 36v isn't the way to go here

TSDZ2 36 V AND 48V NIGHT AND DAY

I now have tried both versions in the same bike [ it started out with a bbs01 must have to much spare time ] the 36v250 watt legal version with a 17.5ah battery with sanyo ga cells and the 48v legal with a cheap no name battery 13ah the following observations 1 The 48v is the one to go for...

www.pedelecs.co.uk

 

[Andy-Mat]

Hi folks

Specc-ing a conversion of my current commuter into an ebike, using the Tongsheng 250W TSDZ2. Could do with some hive-mind thoughts on battery options...

It's a 40km round commute with about 450m of climbing. On a test ebike with Shimano Steps, I was consistently using about 200Wh from the battery. I want to keep the battery as small/light as possible (the bike already weighs a tonne...), so I'm thinking about 250Wh would be a reasonable compromise. Needs to be downtube mounted.

Initial plan was a small bottle-battery (handy bonus - if I needed additional capacity for something, I could just buy a second and swap them over as needed during a ride). However, I'll be unplugging it daily to charge in the office, and I'm a little concerned about the waterproofing/fatigue on the battery/motor connection, even with a decent connector. Am I safer buying something with a battery "mount plate" so I can heat-shrink wrap the mount-motor connection, and then relying on the battery-mount connection being a bit more robust for repeated plug/unplugging?

Commute is all-weathers in central Scotland, so we do rain well...

Cheers

Rob

As batteries age, they generally lose a bit of capacity, this is due to many things that are difficult to quantify accurately, but it will rely on temperature, weight of rider, weight of bike, quality of cells, quality of charger, speed of charging and and and....
So may I suggest that you buy a quality battery, sized to be around 20%+ more range than you need each day! So even when capacity drops, it still does what you want....
That you have a cheap 24 hour timer, that allows the battery to be fully charged, but cuts off the mains as close as possible to the end of charge! Experience will let you know "when"...
I myself use a cheap electro-mechanical 24 hour charger, wiring inside modified so that when it cuts the power (to the charger), it also cuts the power to the tiny motor inside the timer, so stopping it from switching on again 24 hours later!
I have been told here that there are some quality expensive chargers, that handle this far better than the cheaper ones, but I have no personal experience with them. It is certainly possible and they are probably far cheaper than a new battery!
Leaving a battery on a cheap charger, and assuming the charge has stopped just because the LED is green, will eventually damage the battery, though some here do not believe that!
A quality battery, carefully looked after, should give 5 years + service.
Let us know how you get on.
Andy

 

[DarkerSide]

Thanks Kirstin, that's good to know. For some reason I thought the 48V only came in 350W (ie not UK legal), so glad someone's pointed that out). And thanks Andy for charger advice.

Just to come back to my original question; for repeated battery disconnection and with a main concern on waterproofing, am I better with a battery cradle/mount, or does it not really matter?

Cheers

 

[KirstinS]

Thanks Kirstin, that's good to know. For some reason I thought the 48V only came in 350W (ie not UK legal), so glad someone's pointed that out). And thanks Andy for charger advice.

Just to come back to my original question; for repeated battery disconnection and with a main concern on waterproofing, am I better with a battery cradle/mount, or does it not really matter?

Cheers

Im an all year round commuter, hailong (or HL) downtube mounts are very good. Maybe have to clean the contacts every couple of thousand miles or re-bend the pins. Tbh it's likely to be least of your worries. I've had no issues

Woosh sell the 48v legal version with good support (if it fits your bike)

 

[DarkerSide]

Humbly reporting back in. Ta da:

Not quite finished yet (the hydraulic brakes I bought were a European kit, so I need to switch the levers over), but managed a test lap successfully. Post on the build is here.

Thanks for the guidance above!