So I got myself a nice frame... That was last summer, so things are very slow here. However!
I finished my battery build yesterday, which is a big step forward. Incredibly I might hit the road this year (sad irony).
So about the battery. I decided to stick with "industrial" and certifiable voltage - 48V. For lithium-ion that would be 13 cells in series, however due to dimensional restrains and my own requirement to keep the cells in perfect current balance, the number of series cells had to be even and dividable by 3. So 12 cells and 45V it is. It is lower than 48V (which is not so good), however total end-of-charge voltage is 52.2V, which is within reach of any industrial 48V power supply (adjustable up to 10%, which is 52.8V).
Ok, so 12s it is. How many p? 27... Just because it was a maximum that would still fit. 324 cells in total. Cell model is LG D1, 10Wh per cell, so 3.4 kWh in total. These can give 1C long term and 2-2.5C peaks. 8.5kW peak is OK with me. By ES DIY folk standars, where system power is controller phase current times pack voltage, my system is "17kW". (lol)
Anyway 3.4kWh will probably give me up to 100km of range on city roads. And up to 350km on legal (25km/h) limit (if someone asks "how far can it go").
Total battery weight is around 16kg, which lands us on 212 Wh/kg. It is even more than Tesla's. And around 30-60% better than any LiPo's used today. Go figure.
In this battery I have used my own technology developed last year, which improves overall battery safety a lot. It's fuses. On each cell, 324 pcs. in total. The idea is to protect the battery from one failed cell: if cell fails and shorts out internally, it can manage this even on it's own, however it can not manage another 26 cells in parallel, pumping current in to it. In such case fuse blows and the cell simply disconnects from the pack, fire is avoided and I end up with 4% decrease in capacity... Which is not as bad as burned down home.
By the way I have commercialized this solution and can now offer a 90Ah "single cell" prismatic bolt-on packs for larger vehicles and stationary storage. PM if interested.
One side of the battery has this funny shape to perfectly meet with shape of frame, to avoid mechanical stress in construction on bad roads. Also every cell and all parts of the battery are glued together. I am just not going to "service" the battery. These cells have a fail rate of 1 per 100'000'000, so I am quite confident. And even if I lose one... Not worth the hassle.
Another feature is the BMS that will go with it. Note that it is still in prototype stage, however I expect a public release in a month or so. I am told it will be actually smaller than current prototype.
The BMS is fully programmable and supports 5-16 series cells. Current with onboard mosfets - up to 30 amps, however there will be a version with onboard 200 amp current sensor and control of external contactor. And there is a connector for external current sensor if you would like to go even higher, like 1000 amps maybe? With this BMS, I don't see why not.
It has several programmable multi-purpose input-outputs: fan, heater, temp sensors (2), buzzer, LED, contactor, charger relay, analog fuel gauge, etc. Also it has a functioning bootloader, so be prepared for easy and quick bugfixes and new features. On top of that, it has lifetime statistics (for warranty and information purposes), and event list for debugging. So you will know when, for example, charging finished and if it was full charge or early finished due to some (specified) reason (like AC loss, overtemperature, etc.). Also it has an excellent standby power consumption - just microamps when in standby (not charging, not discharging). So no more dead batteries after winter's storage.
And bluetooth! Apparently a bluetooth (BLE V4) addon module is coming up as well, which opens some additional possibilities. In picture below, android app is shown. It is a very nicely designed and easy to read interface, especially very bright and crisp on samsung's OLED display. That is just a quick teaser, I can not tell a lot more yet. I guess supplier will jump in and share more details. Probably you are wondering when and how much. Well, I'd guess 1-2 months and around 100€.
No photos of full bike yet, as I still have a lot of lines on TODO list, like motor, controller, lights, 12V system, onboard charger, etc.
I finished my battery build yesterday, which is a big step forward. Incredibly I might hit the road this year (sad irony).
So about the battery. I decided to stick with "industrial" and certifiable voltage - 48V. For lithium-ion that would be 13 cells in series, however due to dimensional restrains and my own requirement to keep the cells in perfect current balance, the number of series cells had to be even and dividable by 3. So 12 cells and 45V it is. It is lower than 48V (which is not so good), however total end-of-charge voltage is 52.2V, which is within reach of any industrial 48V power supply (adjustable up to 10%, which is 52.8V).
Ok, so 12s it is. How many p? 27... Just because it was a maximum that would still fit. 324 cells in total. Cell model is LG D1, 10Wh per cell, so 3.4 kWh in total. These can give 1C long term and 2-2.5C peaks. 8.5kW peak is OK with me. By ES DIY folk standars, where system power is controller phase current times pack voltage, my system is "17kW". (lol)
Anyway 3.4kWh will probably give me up to 100km of range on city roads. And up to 350km on legal (25km/h) limit (if someone asks "how far can it go").
Total battery weight is around 16kg, which lands us on 212 Wh/kg. It is even more than Tesla's. And around 30-60% better than any LiPo's used today. Go figure.
In this battery I have used my own technology developed last year, which improves overall battery safety a lot. It's fuses. On each cell, 324 pcs. in total. The idea is to protect the battery from one failed cell: if cell fails and shorts out internally, it can manage this even on it's own, however it can not manage another 26 cells in parallel, pumping current in to it. In such case fuse blows and the cell simply disconnects from the pack, fire is avoided and I end up with 4% decrease in capacity... Which is not as bad as burned down home.
By the way I have commercialized this solution and can now offer a 90Ah "single cell" prismatic bolt-on packs for larger vehicles and stationary storage. PM if interested.
One side of the battery has this funny shape to perfectly meet with shape of frame, to avoid mechanical stress in construction on bad roads. Also every cell and all parts of the battery are glued together. I am just not going to "service" the battery. These cells have a fail rate of 1 per 100'000'000, so I am quite confident. And even if I lose one... Not worth the hassle.
Another feature is the BMS that will go with it. Note that it is still in prototype stage, however I expect a public release in a month or so. I am told it will be actually smaller than current prototype.
The BMS is fully programmable and supports 5-16 series cells. Current with onboard mosfets - up to 30 amps, however there will be a version with onboard 200 amp current sensor and control of external contactor. And there is a connector for external current sensor if you would like to go even higher, like 1000 amps maybe? With this BMS, I don't see why not.
It has several programmable multi-purpose input-outputs: fan, heater, temp sensors (2), buzzer, LED, contactor, charger relay, analog fuel gauge, etc. Also it has a functioning bootloader, so be prepared for easy and quick bugfixes and new features. On top of that, it has lifetime statistics (for warranty and information purposes), and event list for debugging. So you will know when, for example, charging finished and if it was full charge or early finished due to some (specified) reason (like AC loss, overtemperature, etc.). Also it has an excellent standby power consumption - just microamps when in standby (not charging, not discharging). So no more dead batteries after winter's storage.
And bluetooth! Apparently a bluetooth (BLE V4) addon module is coming up as well, which opens some additional possibilities. In picture below, android app is shown. It is a very nicely designed and easy to read interface, especially very bright and crisp on samsung's OLED display. That is just a quick teaser, I can not tell a lot more yet. I guess supplier will jump in and share more details. Probably you are wondering when and how much. Well, I'd guess 1-2 months and around 100€.
No photos of full bike yet, as I still have a lot of lines on TODO list, like motor, controller, lights, 12V system, onboard charger, etc.
