Help us build a better Ebike battery

[soundwave]

http://www.bga-reworking.co.uk/insat-li-nmc-ebike-battery-10ah-24v-36v-48v.html

the dealer price for a 500w bosch battery from magura is £480 and rrp £700

tho any batt you make will not work on a bosch gen 2 bike.

 

[lnunell]

During the warmer months, I tend to ride twice a day. Unfortunately, it's a six hour wait to charge up for the second ride, so yes, fast charging would be good for me.

That sounds great, what is the pack that you are suing at the moment?

 

[Fordulike]

That sounds great, what is the pack that you are suing at the moment?

48v 11.6Ah, using Samsung 29E cells. 2amp charger.

 

[lnunell]

48v 11.6Ah, using Samsung 29E cells. 2amp charger.

Is it an OEM pack or did you build it yourself?

 

[Fordulike]

Is it an OEM pack or did you build it yourself?

OEM from Eclipse Bikes. This one in fact.

http://www.eclipsebikes.com/116ah-lithium-frame-battery-samsung-cells-p-1105.html

 

[craiggor]

I use 36v 4ah 144 wh lawn mower batteries,Xiongda 2 speed motor for hill climbing. I put 2 in parallel because they sag a bit to much when only using one.I bought them because they where cheap £34 each with a charger on offer at B&Q. I bought 6.I like the idea of small wh batteries because you don't need to carry 600wh when you only need 150wh/300wh to get where you are going. Will your motor be hub or crank drive ?

 

[shemozzle999]

Hi all,

I am new to the ebike scene, but my company has started to develop an Ebike battery that can be fully charged in under 15 minutes and will be charged safer than traditional charging (our IP). We are looking to have this tech mainly sold to bike hire schemes (boris bikes) that will be used significantly but we see a market to sell to consumers also. We already have our technology in industrial applications and in single cell products but we are now pushing our technology towards Ebikes..

This is not a advertisement or marketing effort so we will not be saying what business we work for; but we are looking for current owners of ebikes to help us out with what really matters to you as owners. We are about 6 months away from full working 150 and 300Wh battery packs that can charge to 100% in under 15 minutes, below are the specification we are looking to achieving.

• 48 volt
• 32 cells in the pack with 2 in Parallel and 16 in series layout.
• The pack will be approximately 60% of the weight of the lead acid cells, saving weight.
• 15 minute charging to 100%
• 150 & 300Wh Pack
• 1500-2000 cycles (0-100% DOD)
• Total weight = 3Kg.
• Estimated range: 31 Mile (pedal assist).

We estimate that we will be able to retail the battery packs price wise to both Shimano and Bosch, we also know that our packs will last longer and be more durable. So 15 minute charging and longer life are the pros, but we will be seeing a slightly heavier pack and a larger charger to be able to power this kit.

Can you let me know what you would expect from this kit? What you miss on the current ebike batteries and motors? Desired features? What you think of the specs we have put above, and do you even care about 15 minute charging?

We want to really push the design and development to be ready this year but we feel contributions from the community will be a great addition to creating a great product.

Thanks,

Leigh.

Biggest problem with ebike batteries is the BMS requires power to monitor the battery which depends on one bank of cells powering it. When not in use the draws current which unbalances the pack.

If you use a multi mixed pin d type connector to connect the battery to the charger you could remove the BMS from the battery and put it in the charger, the battery would only need fuse protection as the ebike controller monitors voltage and current levels.

http://pedelecs.co.uk/forum/threads/batteries-in-aircraft-cabin-baggage.23762/#post-298954

The battery d type connector could also carry all the cell balance leads to the controller for bespoke controllers.

For easier dealer servicing use these weldless cell connectors:

http://www.akbattery.com/

 

[lnunell]

I use 36v 4ah 144 wh lawn mower batteries,Xiongda 2 speed motor for hill climbing. I put 2 in parallel because they sag a bit to much when only using one.I bought them because they where cheap £34 each with a charger on offer at B&Q. I bought 6.I like the idea of small wh batteries because you don't need to carry 600wh when you only need 150wh/300wh to get where you are going. Will your motor be hub or crank drive ?

We are looking at crank drive at the moment as our primary focus is on the battery pack. The main issue with hub motors is the excess strain on the rotor can cause huge headaches warranty wise.

 

[lnunell]

Biggest problem with ebike batteries is the BMS requires power to monitor the battery which depends on one bank of cells powering it. When not in use the draws current which unbalances the pack.

If you use a multi mixed pin d type connector to connect the battery to the charger you could remove the BMS from the battery and put it in the charger, the battery would only need fuse protection as the ebike controller monitors voltage and current levels.

http://pedelecs.co.uk/forum/threads/batteries-in-aircraft-cabin-baggage.23762/#post-298954

The battery d type connector could also carry all the cell balance leads to the controller for bespoke controllers.

For easier dealer servicing use these weldless cell connectors:

http://www.akbattery.com/

Yes, we have been debating whether to keep the BMS in the charger unit or the battery itself; it was our decision to keep the BMS in the pack, the reason was that our BMS is an active system with nA quiescent (standby) consumption. So it is fairly sophisticated and we estimate that it would take 10 years (ish) on a self to discharge fully.

 

[lnunell]

Biggest problem with ebike batteries is the BMS requires power to monitor the battery which depends on one bank of cells powering it. When not in use the draws current which unbalances the pack.

If you use a multi mixed pin d type connector to connect the battery to the charger you could remove the BMS from the battery and put it in the charger, the battery would only need fuse protection as the ebike controller monitors voltage and current levels.

http://pedelecs.co.uk/forum/threads/batteries-in-aircraft-cabin-baggage.23762/#post-298954

The battery d type connector could also carry all the cell balance leads to the controller for bespoke controllers.

For easier dealer servicing use these weldless cell connectors:

http://www.akbattery.com/

However I do really like the idea of being able to physically disconnect the pack from the BMS, for transport.

 

[anotherkiwi]

16 Ah (20 Ah nominative) of 37 V LiPo, no BMS, charges in about an hour with 2 x 250 W chargers behind a 540 W power supply or a 12 V car battery. Slightly over 79 km range on a bad day depending on the direction of the wind, the number of glasses of red wine... +88 km on a good day.

An hour is a good enough charging time for leisure users and commuters - lunch break means 2 charges a day are easily done.

 

[lnunell]

16 Ah (20 Ah nominative) of 37 V LiPo, no BMS, charges in about an hour with 2 x 250 W chargers behind a 540 W power supply or a 12 V car battery. Slightly over 79 km range on a bad day depending on the direction of the wind, the number of glasses of red wine... +88 km on a good day.

An hour is a good enough charging time for leisure users and commuters - lunch break means 2 charges a day are easily done.

The problem you have with LiPo and no BMS is it is very dangerous for the average consumer and there is really no way a company could sell this as a unit.

I like the range and charge time you mentioned though, we can always develop a cheaper 1 hour charger for our unit.

 

[Crockers]

Are we looking at a British company here, manufacturing batteries and motors in the UK or will it all be farmed out to the Far East. .?

 

[lnunell]

Are we looking at a British company here, manufacturing batteries and motors in the UK or will it all be farmed out to the Far East. .?

We are a UK company, we are working with a couple of other companies to design, test and mass produce in the UK. Components and cells will be made in outside the UK however (as these are the only factories). These would be for the EU and US market.

We will be aiming to produce our cheaper units for cycle hire abroad depending on the buyer.

 

[shemozzle999]

However I do really like the idea of being able to physically disconnect the pack from the BMS, for transport.

Whatever you decide I would check out the latest developments on the proposals for new regulations on EU standardization for electric vehicle charging.

Check out this site:

http://extraenergy.org/main.php?language=en&category=extraenergy&subcateg=&id=88293

 

[shemozzle999]

I think the market was influence by the Chinese following the laptop model where they sell a cheap charger and have the BMS in the laptop but I prefer the powertool and lipo market where the battery is just a battery and the charger is intelligent.

 

[Woosh]

I think 0.1C-0.2C chargers are perfectly adequate for e-bikes.
2A chargers don't even need a fan.
I can see benefit of fast charging on bikes for rental but why do you want to carry 30% extra weight on your own bike using LFP cells? and pay for a special 500W or 1.2Kw charger?

 

[lnunell]

I think the market was influence by the Chinese following the laptop model where they sell a cheap charger and have the BMS in the laptop but I prefer the powertool and lipo market where the battery is just a battery and the charger is intelligent.

The thing is that alot of people think that the BMS is solely used for protection and balancing during charging; where actually you need the BMS on the pack during discharge to communicate with the controller and increasingly to shuttle power during use.

The question I think is now not should you have a BMS on the pack but how much do you spend on the BMS. There are some BMS's that are down right dangerous that are being advertised, most of the vehicle industry has switched to active balancing. The challenge is making it cheap enough that it is feasible.

 

[lnunell]

I think 0.1C-0.2C chargers are perfectly adequate for e-bikes.
2A chargers don't even need a fan.
I can see benefit of fast charging on bikes for rental but why do you want to carry 30% extra weight on your own bike using LFP cells so you can watch your special 600W charger at lunch hour?

That either 30% extra weight or 30% less Wh would get you a pack tat charges in 15 minutes (I know not for everyone) but would also last 3 times as long as traditional Li-ion and Li-Po packs. Some pack last less than 18 months with regular use, so having 1500-2000 cycles is a very big pro.

We are also looking to start a buy back scheme for used packs so at the end of life you can reclaim the value depending on the degradation in the cells.

 

[soundwave]

why not build some 10kw tesla style power walls id be interested in them if they were cheap enough.

got 3kw of panels on my roof