I don't think the market needs fast charging. Schwinn tried that with their lithium titanate batteries. They struggled to sell their bikes. In the end, they had to reduce the price of their bikes by 50%. Those batteries could be charged in 5 minutes and have a nearly infinite life. I have a couple if anybody wants to come and get them.

 

Instead, you should concentrate on specific energy. People want light-weight batteries with around 500 Wh.

 

Hi d8veh,

 

Yeah we have heard if the Toshiba SCiB cells, they are great for niche applications, their two main downfalls are the price (titanate is very expensive) and very low cell voltage meaning they are very heavy; I believe the pack was 24v @ 4Ah so very heavy.

 

You said you have a couple avalible, do you have the battery packs themselves or the whole bike? We are based in birmingham so not too far.

 

It would be interesting to see what chargers were used on these packs.

It would be interesting to see what chargers were used on these packs.

 

i have just the batteries and chargers now. The chargers are massive. I think they're something like 8 amps, but the battery has two huge terminals for some sort of fast charger. The terminals look good for about 50 amps. They go directly to the cell-pack, by-passing the BMS. The BMS is very sophisticated. Unfortunately, it has a sleep mode and nobody knows how to wake them up, so anybody that bought one of these bikes and left in in the garage for a few months cannot use it anymore. You can find them on Ebay for next to nothing, swap the battery and controller for normal 36v ones, and you get a really nice electric bike for about £500.

I am not denying that at all, the reason I started this thread was to focus on what we could add to our system to make it work for the community, such as the 30minute 500Wh version, not to talk about the viability of our tech as we know it works.

 

One of the biggest discussions we have been having is the formfactor of the battery casing, most of the products being sold have been focused on the bottle frame style design and there are several options:

 

• Bottle frame style
  
• 'in tube' battery
  
• Panier battery pack
  
• hub battery
  

All of these have their pro's and cons, but the two that have been front running are the bottle style or the in tube, the in tube has a big advantage of harder to be stolen but the frame is a more universal design.

 

What are your experiences and issues with what is on the market at the moment?

 

I run a Bosch system with a battery on the rear rack . It is a reasonable compromise. The battery can be removed or charged in situ .

My comments as a consumer .

1. Battery built into frame a designers delight but would be a nightmare for many users . The mains would need to be adjacent to the bike, and this may probably not suit if the bike is is stored in a shed. Also the bike will be heavier for transport say by bike rack.

2. Battery in the hub. This has a certain elegance from a designers viewpoint but would be even worse than option 1 . Not only does the bike need to be close to the charging point but it is at a lower level therefore more bending over by the user. Also any weight in the rotating part the wheel has an additional effect on effective bike weight. The weight is effectively doubled ... The actual weight of the battery. + The moment of inertia by a quirk of maths equals this weight .

3. Bottle types a good location but maybe limited in capacity?

I don't think the market needs fast charging. Schwinn tried that with their lithium titanate batteries. They struggled to sell their bikes. In the end, they had to reduce the price of their bikes by 50%. Those batteries could be charged in 5 minutes and have a nearly infinite life. I have a couple if anybody wants to come and get them.

 

Instead, you should concentrate on specific energy. People want light-weight batteries with around 500 Wh.

 

 

I could see a value in having a charger of weight 0.5 kg capable of giving 80% charge to a 400 to 500 whr battery in under 30 minutes. It would enable the tourist break off for a coffee or lunch and then proceed for double the distance.

1. Battery built into frame a designers delight but would be a nightmare for many users . The mains would need to be adjacent to the bike, and this may probably not suit if the bike is is stored in a shed. Also the bike will be heavier for transport say by bike rack.

 

Two very important points,

i store the bike in a shed and a detachable battery means i can also transport and lift the bike on a car rack less the battery

Our system could likely do a full recharge on a 500Wh pack in 30 minutes. That may suit you?

 

A 500 watt battery that would charge in 30 mins would definitely coax me into parting with a few quid.

Hi OP

 

Since the information provided by yourself has been a little sparse, excuse my question if it is not relevant.

 

Is your charging topology applicable to other cell types, or just your own proprietary packs? I (and many others into high power setups) run a multi kW pack and would definitely be interested in a high power (2kW+), high density, high efficiency, compact charger/supply.

Edited January 27, 20179 yr by danielrlee

Hi OP

 

Since the information provided by yourself has been a little sparse, excuse my question if it is not relevant.

 

Is your charging topology applicable to other cell types, or just your own proprietary packs? I (and many others into high power setups) run a multi kW pack and would definitely be interested in a high power (2kW+), high density, high efficiency, compact charger/supply.

Can I add the thought of batterypacks for domestic photovoltaic cells - currently they run at about £7000-8000 for a 7KwH battery pack for a 4Kw photovoltaic cell installation

A 500 watt battery that would charge in 30 mins would definitely coax me into parting with a few quid.

 

 

Glad to hear :-)

Hi OP

 

Since the information provided by yourself has been a little sparse, excuse my question if it is not relevant.

 

Is your charging topology applicable to other cell types, or just your own proprietary packs? I (and many others into high power setups) run a multi kW pack and would definitely be interested in a high power (2kW+), high density, high efficiency, compact charger/supply.

 

At the moment we are only working with certain cells (so we can get something out in months not years) but we have tested it with Lead acid and other lithium chemistry.

 

Our target at the moment is a 1.2kW 'ish' charger as this is compatible with mains outlets (have to take into account potentially bad house wiring)

Can I add the thought of batterypacks for domestic photovoltaic cells - currently they run at about £7000-8000 for a 7KwH battery pack for a 4Kw photovoltaic cell installation

 

We are working in this area also.

Update!

 

I wanted to give you all an update on our progress and what we are expecting to achieve in the next 12 months before launch.

 

We have sized up 3 battery packs for a 48 volt system, a 132wh pack (for scooters), a 264wh pack for Ebikes and a 396wh pack for extended range.

 

One of the main advantages of running at 48 volt (well 57.6v when fully charged) is the efficiency is higher in the whole system, we are running several % higher efficiency on the motors, >88% efficiency on the charger and our test bench is running beyond expectations.

 

We have several versions of our charger running now but in a very 'dirty prototype' stage and have received grant funding to develop the system to a fully running system (mainly the battery management and analysis system).

 

We have estimates for our charging speed that are pretty much on par with what we estimated:

 

 

• We have a 900 watt charger estimate with our 48v system looking like it will be 20 amp output (20 amp @ 57.6v)
  
• Our 132wh pack <10 minute to charge to 100%
  
• Our 264wh pack <20 minute to charge to 100%
   
  
• Our 396wh pack <30 minute to charge to 100%
  

We think that the pricing will be just below the cost of the Bosch system for equivalent battery sizes but with fast charging, as we are using the highest quality components to keep the efficiency high and not cheap components and parts that we have witnessed with most of the Chinese charger versions.

 

Let me know if you have any questions so far.

 

Thanks!

Did you check whether a 48v battery is allowed under EN 15194? The standard says "up to 48v". Some test houses interpret that as 48v max, so they don't allow 48v batteries that can go up to 57.6v.

 

264WH is not enough for an Ebike. You need a minimum of 400Wh - ideally 500Wh.

Did you check whether a 48v battery is allowed under EN 15194? The standard says "up to 48v". Some test houses interpret that as 48v max, so they don't allow 48v batteries that can go up to 57.6v.

 

264WH is not enough for an Ebike. You need a minimum of 400Wh - ideally 500Wh.

 

We have been working with systems up to 60v for some time now, the CE and UL standard for high voltage is >60v DC so as long as you work below this during charging then you are fine. This applies the same for the EN 15194 standards as far as we have experienced.

 

Regarding the higher capacity packs, yes we can go higher, we should be able to charge a 450wh pack in under 30 minutes, the problem you have is then diminishing returns on the size of the pack in Wh vs the miles range. Once you go beyond 400wh packs you will see a large drop off due to the weight of the system.

 

We have been focusing more in efficiency gains and high quality and efficiency BMS systems to maximise the potential of the power already in the pack.

 

Thanks,

This applies the same for the EN 15194 standards as far as we have experienced.

You had better check that. If I was your boss, those words wouldn't fill me with confidence that you know the answer.

You had better check that. If I was your boss, those words wouldn't fill me with confidence that you know the answer.

 

inunell is the boss.

inunell is the boss.

You had better check that. If I was your boss, those words wouldn't fill me with confidence that you know the answer.

 

We know the answer so don't worry about that :-)

Inunell,

 

do you intend to integrate your charger into docking stations?

Inunell,

 

do you intend to integrate your charger into docking stations?

 

 

We have not really focused on size and implementation at the moment, we are currently working about 9cm x 9cm x 30cm size of the chargers, so they can be either separate or built into a docking station. If they are in docking stations they can also be easily paralleled up for more power output.

 

The three things we are focusing on with our architecture is, lowest price per watt, efficiency and reduction in bill of materials.

 

 

Thanks,

whenever I asked a manufacturer for charger in their docking stations, they stop talking to me and yet, you can't have a public shared e-bike without charging and docking stations. I must add that there are a couple of French systems for that.

whenever I asked a manufacturer for charger in their docking stations, they stop talking to me and yet, you can't have a public shared e-bike without charging and docking stations. I must add that there are a couple of French systems for that.

 

Yep completely agree that you need docking stations for hire schemes and that is what we are focusing on for our own hire scheme. The only reason I can see why they may stop talking to you once you say that is they probably see limited number of sales for more effort. Silly really.

We know the answer so don't worry about that

What is the answer then? Many people would like to know. Does your battery comply with EN 15194 or not?

What is the answer then? Many people would like to know. Does your battery comply with EN 15194 or not?

 

 

All of this is in early prototype stage so we have not certified it yet (we are focusing on the charger) but yes it will be EN 15194 when we finish.

Here is another question: Bottle rack mount or pannier mount, which is the most popular? We are designing for bottle mount but have scope to have two versions if demand is there.