How can they give you 7km per charge when some of us can get that from our 20ah 48v batteries? Here's someone with actual practical experience. He got about 100 meters.
Would fast charging make much difference?
- Thread starter AntonyC
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I will have a solution for you in a few months. I have been working on it for a while, but health issues and other projects have slowed progress. I gave a few clues a few months back, but I don't want to give full details until it's finished. In the meantime, get a bigger battery.
I thought that was pretty good!
How long is a piece of string?
Its a BBSHD running at 52v, so it has the potential to run at over 1000W. I like that it is over-engineered for my use, although perhaps a bit heavier than is necessary. I've capped the current at 20A rather than the stock 28 (if I recall correctly). It's done 2500 miles with nothing other than a little grease...even the chain hasn't stretched!
On a short trip (20 miles or so) I'll tend to run at about 400W. For a long trip, I'll stick at about 200W and use the gears more and accept a slower speed on ascents. Last week I got 85 miles out of it doing this and still had 19% on the battery. The 52V BBSHD does behave a little unpredictably when the battery is running low... the controller can only sense the current voltage (whereas the BMS knows exactly how many Ahs have been consumed) and so as the voltage sags when you draw power then the motor controller thinks the battery is flat and starts to limit the power and intermittently cut it. So I've found if you run it below about 46V then it gets annoying.
I think 50 miles is pretty good! The bike weighs 25Kgs and I'm 75Kgs (well 80) and routes are fairly hilly.
EV's batteries have different chemistry compared to most of e-bibke batteries. The latest Lithium iron Phosphate from CATL (they called it the Shengshin battery) can be charged at 4C until 100% full. Your e-bike battery would normally be charged between 0.2C and 0.4C.
When you charge a battery, higher temperature makes the Lithium more mobile and thus increases the charging current. If you don't monitor the battery's temperature, you can have a runaway positive feedback loop, like the Larsen effect through an amplified microphone. Your battery will smoke in seconds. Ordinary batteries and chargers don't talk to one another so stay away from fast chargers.
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You didn't answer the question. Do you pedal?
I think extra battery is the solution you are looking for. I have seen a nice rack to carry two spare batteries somewhere, but I can't find it now.
Yes, I do pedal. I don't have a throttle fitted to my bike. I can show you a graph of heart-rate over the 85 miles?
Extra battery is one solution, but if you could charge a significant amount whilst stopped for lunch then you wouldn't need to be carrying that extra weight/expense. Say you wanted to go away for a week, wild-camping and doing 100 miles a day. I'm very happy to stop for lunch for an hour and find a pub in the evening etc!
Yes. I know Tesla's have to precondition (heat up) their battery before fast charging... I'm not sure if this is done electrically or if they circulate fluid through the battery to provide heating/cooling. We wouldn't want that complexity on an e-bike.
I suspect my requirements aren't that fast... I can get a 10A charger off-the shelf, which would give me about 40 miles per hour of charge; that's perfectly adequate. So its more about having a network of publicly available chargers that can be relied upon!
I should read up on my BMS but I suspect the documentation is all in Chinese... it may be pointless feeding 10A to my battery as the BMS may just shutdown or throttle it. I guess this is a major cause of the ebike fires we have; deliveroo riders trying to fast-charge with dodgy chargers.
I looked at the Zap Map earlier this morning and the listed 3 pin plugs in areas that I'm familiar with looked a bit questionable. Only one in my town and from what I could see it was someones house. Being able to piggyback on the EV charger network would be great and I'd be happy to pay the same rates per hour for tying up a charger as they do.
I've got a BBS02 with 48V 20Ah battery - it came with a 4A charger. I wonder how much it varies by motor. In theory the torque sensored motors would detect when you are not pedalling as hard and not add as much assistance but I'm not sure it really makes that much difference. I wonder if you tested the BBSHD, BBS02, BBS01 TSDZ2 and TSDZ8 over the same circuit with the same rider.
This post said up to 30% more range on TSDZ2 than BBS01 : https://www.pedelecs.co.uk/forum/threads/tsdz2-or-bbs02b.33783/
Here it said the BBSHD was slightly more efficent than the BBS02 https://endless-sphere.com/sphere/threads/2019-motor-simulator-mid-drives-and-other-updates.100461/post-1470112
To be honest I'm always surprised how high the battery voltage is when I come back for a ride on my BBS02
I suspect the differences are pretty small
That's a decent distance ! I think I would need to be reasonably careful with my 20Ah battery to do that range
Every time I have asked in cafes they've been fine charging the battery - if you had a 4A charger that would get a decent amount of charge in 1 hour ?
Indeed... I wouldn't take that chance if the battery wasn't rated for it.... I'm not saying my current battery is. I'm saying ideally, in future, I can buy an ebike that has a connector on it that would allow me to recharge it in any EV charger... I might look to see what my battery is rated for.... the 2A charger was supplied by EM3EV with the battery...maybe thats their maximum recommendation.
(I keep my bike battery in an ammo case, charge it in there, via the BMS, with the charger on a timer plug, in an out-building, with a linked heat alarm to the smoke alarms in the house, and make sure I only do it when I'm in, and I bought a top-quality EM3EV battery).... so I'm suitably cautious!!
if the BMS talks to the charger then fast charging at 10A is very doable.
I have a pair of these lithium titanate batteries that were clearly designed for fast charging. Those two massive contacts, where it says + and -, go direct to the cell-pack, not through the BMS. No system or instructions were provided for fast charging. Lithium titanate can be charged up to 10C, so that's 50A for these packs or 5 mins from empty to full.
Schwinn Tailwind Battery Pack Teardown
Canonical source: http://syonyk.blogspot.com/2015/06/schwinn-tailwind-battery-pack-teardown.html Copied here, because
endless-sphere.com
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Given how little a charger weighs, making use of the extensive network of 13A power sockets is the easiest answer.
It becomes a relationship management issue then!
It becomes a relationship management issue then!
I just found this adapter on Aliexpress:
www.aliexpress.com
AFAICT, it should let you power any device with a UK plug (BS1363) using a public Type 2 EV charger.
See 2nd product variation for UK compatible plug.
So, who's going to be the first to try it out?....
Portable 220V Type 2 Male Plug to Schuko Socket EV Charging Adapter For EV Charger EV Connector - AliExpress 34
Smarter Shopping, Better Living! Aliexpress.com
www.aliexpress.com
See 2nd product variation for UK compatible plug.
So, who's going to be the first to try it out?....
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Wow.... I had no idea such things existed. I've looked at EM3EV and they provide up-to 6A chargers.I just found this adapter on Aliexpress:
AFAICT, it should let you power any device with a UK plug (BS1363) using a public Type 2 EV charger.Portable 220V Type 2 Male Plug to Schuko Socket EV Charging Adapter For EV Charger EV Connector - AliExpress 34
Smarter Shopping, Better Living! Aliexpress.com
See 2nd product variation for UK compatible plug.
So with these two things then I could go a long way to achieving my objective.
Approximately 33% charge in an hour whilst eating lunch...
I'd guess if the car charger is charging by the KW rather than by time then it'll cost pennies too.
These adapters have been around for a while butI still don't know of anyone using one on a bike battery.
A potential problem is that the public chargers and
EVs need to "handshake" before the charge will proceed, raising the question of whether the bike items will be recognised.
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If you scroll down to the feedback on the product listing, you can see a number of individuals using it to successfully charge their ebikes. I think the 'handshake' you mention is just a constant voltage present on the 'CP' pin, dictated by a specific value resistor contained within the adapter (not 100% sure about this though).
It's far more than that. The handshake has to agree the maximum charge rate, essential when some public chargers can deliver uk to 375 kW rate these days but most e-cars can only accept far less. 50kW in my 2018 Nissan Leaf, 22 kW in the case of earlier Renault Zoe's. And then the charge rate phases down as the battery fills, drastically dropping once at around 80% of charge.
What the public chargers will make of EAPC components I've no idea. It's maybe worked ok until now since the great majority of public chargers are very limited anyway, the largest proportion of them mainly in car parks and supermarkets being slow, operating at 3kW maximum.
And of course the question of the reaction when an e-car driver turns up to find the only charger occupied by a bicycle.
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