E-Bike for Coast to Coast ride

Peter.Bridge

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So my sister (55yo) is doing an organised coast to coast e-bike ride in June (mixture of roads and off road). She currently has a 12 year old plus KTM Macina with rim brakes , hub gears and a Bosch Classic+ mid motor and a PowerPack 400 Frame battery that she uses for commuting to work.

So each day of the 3 day ride they do around 50 miles and the first day there is 4500 ft of ascent (slightly less on subsequent days). She recently did a 15 mile ride in the North York Moors (with 1600 ft of ascent) with her friend which took them 2 hours 24 minutes and the battery was down to 2 green lights (out of 4). So she will definitely need another battery. I suspect, if she is down to 2 green lights, it is around 1/3 battery left (she charged it up before I could get there with my meter !) She weighs around 85 kg. She has constant problems with the hub gears especially going up hills, trying to change down.

So I got to thinking

1) Could get another PowerPack 400 battery (around £300) and then charge both batteries overnight on her trip
2) Do these early Bosch motors have locked canbus batteries , if not, possibly replace with a "generic" 36V 20 or 25 Ah battery with branded cells ?
for options 1) and 2) the rim brakes are sub optimal and the hub gears need adjusting (don't know how) and she won't be able to use it while I'm fiddling with it
3) Instead of a new battery, could put the money towards buying a bike off facebook marketplace and I'll convert - possibly a 48V controller/motor and 20Ah battery
4) If answer to 3) is yes, Hub or mid drive ? Just a little worried at the average speed they were going and the amount of hills, that the hub motor might not be at its most efficient. Thinking 48V Bafang G020 or AKM-128 for hub drive or TSDZ8 for mid drive
 

matthewslack

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Nov 26, 2021
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I suspect CANBus for all Bosch batteries. The big change fairly recently was the smart system. Others know more than me...

Simplest is a second, compatible Bosch battery. Also two chargers, preferably 4A not 2A. Great for charging on the road. 8A combined charge rate means an hour's lunchtime charge makes a real difference. This is my winter configuration, and it allows unlimited multi day range subject to friendly cafes and pubs. Never been a problem for me to find. I swap between batteries as needed so that I arrive at a charging stop with roughly equal charge states, so always utilising both chargers.

Separate issue: for touring, check you are happy with gears. My setup was transformed by replacing 9 speed 11-36 with 11 speed 11-51. All hills are now possible!

There is another way, like I use on my Shimano CANBus bike to make my solar work, but there is a small element of risk. Unlikely to hurt anything, but I have not tried to fool a Bosch!

The extra battery is a generic, as big as you like or need. The combination is done using the 'two big diodes' approach.

Negative wires from both batteries are directly linked. Positive from each battery goes to the input side of a diode. The outputs of both diodes are joined, and go to the motor as normal. So you have to cut the positive wire from Bosch battery to motor and insert a diode.

The effect is the bike does not know anything has changed, and it does not care where it's electrons are coming from. Both batteries discharge roughly in step and the diodes prevent any back charging.

The Bosch battery is required for turning the bike on, so must never be allowed to get flat. Startup for my Shimano system is with the extra battery disconnected: turn on as normal, wait for self test etc, then plug in the generic battery.

With my Shimano, there is no problem if the bike turns off because I'm stopped for a while. Just disconnect the generic battery, restart in the normal way. This is a nervous event first time!

Controlled power off is disconnect generic first, then turn off in normal way.

I have pictures, later, but also search 'solar trailer build' and ignore the solar panels and charge controllers.

Test before you go...!

Edit: didn't see the hub gears bit, that is a potential issue as (gearing) range may be restricted. Smaller chain wheel might help.

Hub motor, like my original gears, limits route choices because there is a hill steepness that is just 'no'. I had to avoid all OS map 'chevrons' in my first season with 11-36 cassette.
 
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Nealh

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The early Bosch systems stiil used some comms (battery/controller ) but not 100% sure if the systems were fully CANbus , but it is probably safe to say that a generic battery would not be compatible to use.
 
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matthewslack

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The moment the range issue is mastered, a new world of freedom opens up!

I met a couple doing the coast to coast back in September, he, analogue, her, 500Wh Bosch stepthru, managing on one battery and a lunchtime charge.

Hilly area north of Skiddaw I think. Their final day, hadn't had any troubles.
 
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sjpt

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From the £300 or so you mention you may have already seen that Merlin have good prices.
In the rack version the 500 battery is hardly any more expensive than the 400,
though I see now that in the frame battery there is a huge difference.
 
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saneagle

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You can't use a generic battery as a Bosch replacement due to comms, but you can wire one in parallel to the Bosch one, which means splicing the two wires into the two main power wires from the battery to the motor. It's probably a good idea to add some protection diodes so that you don’t have to worry about matching voltages when you switch on.
 
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Peter.Bridge

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I've been having a look on Facebook marketplace and Gumtree and there are quite a lot of Trek Marlin 5s and 6s extra small (my sister is just under 5', her current KTM Macina (size small) is too big for her - I'm 1' 5" taller than her !)


61887

They have hydraulic disk brakes, Altus 2* 8 or 9 speed gears and coil forks, 27.5" wheels. Largest cog on the chain set is 42 teeth. Obviously no room on the downtube for the battery, but they do have pannier rack attachment points. Thinking possibly 48v 18.2Ah rack battery and TSDZ8 mid drive . Any thoughts ? Am I right ruling out a TSDZ2 ? @Az. I know you've done some Tongsheng conversions

Maybe tight with chainstay to go from 42t to 44

markup_1000008649.jpg
 
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Az.

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I've been having a look on Facebook marketplace and Gumtree and there are quite a lot of Trek Marlin 5s and 6s extra small (my sister is just under 5', her current KTM Macina (size small) is too big for her - I'm 1' 5" taller than her !)


View attachment 61887

@Az. I know you've done some Tongsheng conversions
I wouldn't convert this Trek. Chainstay might be a big problem. Also as you mentioned no room on downtube. It is an mtb. How and where your sister is riding? Battery on rear rack and mtb is not a good idea.
 
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Az.

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I am reading thread form the beginning now. 3 day coast to coast ride. Nice.

This one?


They take everything with them on bikes or car will carry luggage?

I love TSDZ8. Can't recommend it enough, but it is a heavy beast.
 

Peter.Bridge

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I am reading thread form the beginning now. 3 day coast to coast ride. Nice.

This one?


They take everything with them on bikes or car will carry luggage?

I love TSDZ8. Can't recommend it enough, but it is a heavy beast.
This is the itinerary

 

Peter.Bridge

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I wouldn't convert this Trek. Chainstay might be a big problem. Also as you mentioned no room on downtube. It is an mtb. How and where your sister is riding? Battery on rear rack and mtb is not a good idea.
Yeah, on road and off road but on tracks, bridal paths, not serious mtb - they say can be done on gravel bikes and hybrids
 

Peter.Bridge

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So ideally, yes, would be able to mount battery on downtube. Found an extra small 2020 specialized rockhopper expert x2 (29er) locally for £150 with uprated air forks and dropper post. Just asked for the internal dimensions of the frame triangle to see what battery I could fit



Chainstay possibly looks ok ?
 
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Az.

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Looks maybe doable. Worth trying, but in my opinion you are looking in wrong direction. Avoid 29inch wheels. 27.5 - maybe. Ideally 26inch.

The smaller the wheel the bigger the frame triangle (usually) or step through maybe?
 
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Peter.Bridge

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Looks maybe doable. Worth trying, but in my opinion you are looking in wrong direction. Avoid 29inch wheels. 27.5 - maybe. Ideally 26inch.

The smaller the wheel the bigger the frame triangle (usually) or step through maybe?
OK I've printed out cardboard templates of Hailong Max, Hailong Plus and Hailong G70 (which does a 48v 17.5Ah version) and the TSDZ8 bottom bracket template. I'll see if I can find any XS frames that fit !

Incidentally, has the flaw in the TSDZ8 been fixed where level 1 and 2 would only give assistance if you were really supplying a lot of pedal effort ?
 

soundwave

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Peter.Bridge

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any bosch batt from 2014 is can bus and gen 2 gen 1 had no can bus.
Thanks @soundwave it's this one


I guess that is no canbus ? I'm intrigued to know if I could just use any battery or if there is some sort of rudimentary communication between battery and controller
 

soundwave

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no as far as i can remember but is the bike worth it ?

guy in my sig can tell you for sure but with the gen 2 bms if you cut power it bricks the bms.

can you get a voltage reading of it as with can bus the bms wont turn on the cells so all i get is the 5v can bus voltage.

if the batt has just pos and neg inside it has no comms but the bms could be uart like bafang so if thats the case will need another bms and case.
 
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Az.

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Incidentally, has the flaw in the TSDZ8 been fixed where level 1 and 2 would only give assistance if you were really supplying a lot of pedal effort ?
I heard Tongsheng released new firmware and addressed this issue. To upload software by yourself you would need a special cable which is quite expensive.
My TSDZ8 is quite old now (pre update I think). Level 1 is hard, level 2 is very easy. I guess you can make things better just by going into menu and by increasing power level. This should improve power delivery on level 1... I think. I never tried as I have no need for that. It is easier to press a button and change level from 1 to 2 if needed.
I heard Woosh update firmware before shipping, so best to ask Andy. If you want legal TSDZ8, you must buy it from Woosh anyway. Don't forget to ask for a friends and family discount for forum members.

I am happy for your sister. I am sure she will have a great time.
 
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Peter.Bridge

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So using the TSDZ8 template looks like it will fit an old XS Gary Fisher (disc braked !) hardtail MTB she has in her garage. The frame triangle is quite small - any suggestions for downtube batteries ? The coast to coast ride has mechanics, support etc, so I was thinking maybe get 2 * 48V 10AH batteries and she can swap half way each day. I notice there are "side opening" batteries, where you slide the battery sideways off the battery mount.