Peter's custom bikes

[DasDouble]

Some idiot drivers think they are racers and overtake a line of cars in my lane, from the front. Do they think there is enough room beside a cyclist or are they blind and don't even notice the cyclist at all? What can you do when a car is coming from the front in your lane, endangering your life instead of his own? Choose the roadside potholes, because the other option is a head-on collision.
The result of the fall is here, and I was lucky. Some bruises on my back and side also. And I'm very angry. The guy did not even stop, disappeared in a second!
Similar situations happen way too frequently here, I will buy a camera just to record and share them.

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(edit: sorry for the disgusting photos. At least it is a reminder that bikes are not always good for health.)

Oh boy.. Im sorry for you. Its just like a motorbike driver. You always have to think that everyone wants to kill you. If you think really in such a way, you will be concentrated lol^^ Just two days ago, I had a close call with a scooter:

I drove with my Bosch Pedelec (25 km/h) to school. I overtook two boys on their bicycle. One of them looked at my Bike because of the sound, it is making while driving. I looked to him back because I was a bit enoyed of all these people looking at a 17 years old boy with a Pedelec (I have to drive every day 44 Kilometers to school) - and while looking enoyed back to him, I didn´t reallize that a scooter was coming directly from the front. I the last millisecond, I was able to kick around the hanlebars. A half of a second later, I would have crashed directly in the scooter. My fault.

-Always concentrate and expect the unexpected ^^

-Elias

[peters]

FS bike status after 7 years of moderate use (1500..2000km/year).
Still using the original 1400Wh headway lifepo4 batteries that I usually discharge to 30-40%, but I wanted to check its condition so I went to fully discharge it. I took a trip to an abandoned air defence missile base from the cold war era that is on a peak (Pilis) in the nearby mountains 30km away from my apartment in Budapest. Today it's a public hiking area.

Path towards the peak:

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Old military road to the base:

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Missiles were parked under these concrete shelters, now entrance to the site, and there are a few similar ones:

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Central bunkers on the plateau for vehicles and command post:

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View from the roof of the same bunkers, the circular tower on the left is now a viewpoint. Feels like on dragonstone :

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View from the trail down:

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The pack in its new state was a little above 15Ah, and now it is only 14. At high power mode the BMS disconnected at 13.5Ah, then I could drive 0.5Ah more at low power (<1500W). I expected better because the cells were charged only ~350 times, never overcharged or overdischarged, but maybe the capacitance degraded also with age.
At home I checked the cells, 2 of them were fully discharged, 2 others were close to it, and the others were also at very low level, so there are not only 1-2 significantly weaker cells.
3 of the cells have higher self discharge than the others, so the balancing at 350mA always takes 1 hour after 1 week of rest.

The battery->BMS balance wire connectors with tinned contacts have some resistance due to oxidation that must be cleaned sometimes, because the contact resistance with the shunt (when connected) is a voltage divider and then the voltage measured by the BMS is not the same as the cell voltage. Then the cell balancing does not work exactly as expected. The connectors should be changed to gold plated ones.
There were no other issues with the circuits, I use the same BMS, display and controller (my old designs) since 2013-14.

Planning to build a new pack with 18650-s or 21700-s with twice the capacitance in the same size and weight that should be capable of >10kW.

[peters]

Inside the frame since 2013-14, already a bit obsolete:

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[Stealth_Chopper]

Peter, that's one nice long lived custom eBike you created, great story and images.
Mike

[DasDouble]

Lol, just saw this post from 6 years ago.. Oh baby, crazy how much has changed since then. Built two EV's, started my engineering study, met the greatest person on planet earth and improved my grammar in english a bit^^ See ya all in 6 years again, I guess (Maybe until then I'll be married and have kids?? If yes, dont call them Kevin future me! lul)

Some idiot drivers think they are racers and overtake a line of cars in my lane, from the front. Do they think there is enough room beside a cyclist or are they blind and don't even notice the cyclist at all? What can you do when a car is coming from the front in your lane, endangering your life instead of his own? Choose the roadside potholes, because the other option is a head-on collision.
The result of the fall is here, and I was lucky. Some bruises on my back and side also. And I'm very angry. The guy did not even stop, disappeared in a second!
Similar situations happen way too frequently here, I will buy a camera just to record and share them.

DSCN7301.JPG
DSCN7302.JPG

(edit: sorry for the disgusting photos. At least it is a reminder that bikes are not always good for health.)

Oh boy.. Im sorry for you. Its just like a motorbike driver. You always have to think that everyone wants to kill you. If you think really in such a way, you will be concentrated lol^^ Just two days ago, I had a close call with a scooter:

I drove with my Bosch Pedelec (25 km/h) to school. I overtook two boys on their bicycle. One of them looked at my Bike because of the sound, it is making while driving. I looked to him back because I was a bit enoyed of all these people looking at a 17 years old boy with a Pedelec (I have to drive every day 44 Kilometers to school) - and while looking enoyed back to him, I didn´t reallize that a scooter was coming directly from the front. I the last millisecond, I was able to kick around the hanlebars. A half of a second later, I would have crashed directly in the scooter. My fault.

-Always concentrate and expect the unexpected ^^

-Elias

[peters]

I made a fix for my BMS connector oxidation problem mentioned above (May 07 2021) without replacing the connectors, but with a firmware modification that I thought to present briefly.
Now when a cell voltage is at the top, the shunt (or bleed) resistor is switched with a 50% PWM signal, and the voltage is measured twice in every PWM cycle: the unloaded cell voltage is measured when the shunt is off, and this value is used for controlling the outputs (charge enable and the shunt for the cell). The voltage is also measured when the shunt is on, and the difference of the two voltages is used to detect the condition of the connector. When the diff is above 0.1V (corresponds to ~0.3ohm contact resistance at 350mA), it is signaled on a LED and it can be regarded as an error indicating that the connectors should be cleaned. The status could be also sent on a bus to the display, but in my case the BMS is not connected to the display.

This works for half a year already without problem, the pack was charged 25-30 times and the balancing works more reliably and faster than before, even when the contacts are not clean and the diff is more than 0.1V.
With better connectors the contact resistance issue is surely less likely to happen, but this firmware feature improves the fault tolerance because it can detect the failure when the cable+connector resistance from the battery to the BMS is unacceptably high for any reason.

The photo shows one block of this old DIY BMS with the connector on the top with the gray oxide on the contacts (there are 4 identical blocks on the PCB, each for up to 8 cells; the SO8 IC-s are opamps configured as subtracting amplifiers to measure the cell voltages, the other two chips are optocouplers for isolated communication with the other blocks. Atmel uC, regulator and transistors that switch the shunts are on the other side).

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