Advice choosing mid-drive for a Kona Ute cargo bike

[Pedropete]

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UPDATE: FWIW and on the off chance anyone's interested, I went with the torque-sensing 48v TDSZ2 unit and 17.5Ah 48v LG-celled Hairon pack from PSWPower. The cells in these packs are confirmed as being decent quality 3500mAh M1Js, so pretty good value.

Also, if buying from a seller like PSWPower who lists in USD and offers Paypal, don't let Paypal force you into paying in GBP and accepting their ripoff exchange-rates. Instead, in the Paypal confirmation window, click on the text link next to the price and choose to pay in USD and use your confirmed debit or credit card to pay. Ideally use Mastercard as their rate is massively better than Paypal's. I saved around £35 over Paypal's rate by doing this. Obviously you'll want to pay off the balance so the interest doesn't eat up any savings you've made.

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Morning all,

Was fortunate to bag a mk2 Kona Ute for a good price last weekend and now need to convert it to a mid-drive daily runabout & load-lugger and weekend family fun-wagon.

I'd be very grateful for people's experiences of mid-drive conversions, especially on long-tail cargo bikes.

It will be covering between 10-30 miles a day with occasional family weekend trips of 20-50 miles, moving me (95kg), child and their seat (15kg + more every day) and between 5-30kg of shopping, camping gear or other assorted gubbins on some reasonably hilly routes. I'll probably use it for local work meetings too when they start happening again.

I'm a strong cyclist without assistance and not interested in silly top speeds, especially on a loaded bike with a passenger and a relatively flexy frame. I'm far more interested in hill-climbing ability with a load, reliability, durability and range, and being able to do the school/shopping run without needing a shower afterwards. Don't want much, do I.

Narrowed it down to the 48v TDSZ2, the BBS01b-ETM (an undercover BBS02 ?), or just a straight 48v BBS02.

On batteries, I'm thinking the bigger the better (17Ah+) with the best quality cells I can find. I'm aware that the ideal is to keep the pack charged to 90% and to not discharge below 10-15% in order to prolong usable lifespan, so a bigger pack will help me stay in that range.

I'm also aware that the TDSZ2 can offer a better chain-line out of the box, whereas the Bafang may need an aftermarket chainring and possibly even cranks to deal with chainline and Q-offset.

Any particular pitfalls to look out for, or recommendations for suppliers?

Was looking at PSWPower for the TDSZ2 and quite curious about the quality of their 48v LG-celled 17.5Ah pack.

Many thanks in advance,

Pete.

 

[CXRAndy]

If you buy a open firmware model kit, then you have the ability to tweak all sorts of settings.
https://www.eco-ebike.com/collectio...ttle-and-e-brakes-36v-48v-52v-10-18a-250-750w

I bought mine from Electrfy bike, but the other listed is also recommended. T
his link has lots of good information
https://github.com/OpenSource-EBike-firmware/TSDZ2_wiki/wiki#Features_and_configurations

I'd go for the temp sensor too, to protect the motor from overheating with sustained power on climbs. The TSDZ2 has a sacrificial plastic blue gear which can shred gears if you launch hard with a big gear. It can be replaced with a brass gear which is noisier. The custom firmware has been altered to reduce launch current, so this will help.

The battery, I would go for 52V, it lessens the current for same power (Power=Watts x Amps). Other than that they're a doddle to install.

I did my wife's shopper with a custom firmware model last year 52V battery. Works very well and easily does 40 miles with a 90% charged battery.

 

[Pedropete]

If you buy a open firmware model kit, then you have the ability to tweak all sorts of settings.
https://www.eco-ebike.com/collectio...ttle-and-e-brakes-36v-48v-52v-10-18a-250-750w

I bought mine from Electrfy bike, but the other listed is also recommended. T
his link has lots of good information
https://github.com/OpenSource-EBike-firmware/TSDZ2_wiki/wiki#Features_and_configurations

I'd go for the temp sensor too, to protect the motor from overheating with sustained power on climbs. The TSDZ2 has a sacrificial plastic blue gear which can shred gears if you launch hard with a big gear. It can be replaced with a brass gear which is noisier. The custom firmware has been altered to reduce launch current, so this will help.

The battery, I would go for 52V, it lessens the current for same power (Power=Watts x Amps). Other than that they're a doddle to install.

I did my wife's shopper with a custom firmware model last year 52V battery. Works very well and easily does 40 miles with a 90% charged battery.

Thanks @CXRAndy . Impressed by the level of configuration offered by Eco-ebike but I put my order in at PSWPower last Friday so too late to change it and at £600 all-in I'm happy with the deal, especially with the cells specified for the pack. I went with the throttled version though so I'd have the extra channel spare when it comes to custom firmware.

Good advice on the firmware, thanks. Having swotted up over on Endless-Sphere I was planning to do this as I like the idea of dialling back the acceleration and keen to avoid lunching the gears on climbs or hill starts, especially when loaded up. I also like that Eco-Ebikes are running 850c units for their firmware instead of the LCD3s most people have used so far; the 850c looks like it should be an easier interface to work with.

Regarding the blue gear, as you say, it seems a lot of people miss the point of them being deliberately sacrificial. Not unlike people swapping solid DMFs into diesel drivetrains without consideration for the knock-on consequences.