ElectricMotorcycleForum.com
Makes And Models => Zero Motorcycles Forum | 2013+ => Topic started by: ms_smart on August 22, 2021, 04:18:07 PM
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I had a longer day trip (582km) in warm weather condition (30 degree celsius) partly on German Autobahn, partly on country roads. The first charging stop went well with full charging speed. I than drove Autobahn with 130 km/h. The second stop the charger started with full speed, but throttled down after ten minutes to 6 kW. It was getting worse at the third and fourth charging stop, where it throttled down to 3.8 kW. After a while it went up to 5 KW. The last stop was back to full speed since the weather cooled down and I dropped speed to 110 kmh. In total I lost 50 minutes (full day) on charging compared to "normal" behavior and the ride took 10 hours 45 minutes instead of calculated 10 hours.
Have you seen something similar? Is this expected behavior? At least in Germany 30 deg celsius and 130 kmh on Autobahn is nothing uncommon in summer time....
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That seems normal on a battery that is air cooled. 130kph is probably up to 10-15kW constant power, close to 1C, this is heating up the battery. Charging at 12kW is also close to 1C, again heating the battery. The BMS is protecting the battery by not charging at full power. There's not much that can be done: running a bit slower like you did, charging slower and keeping the bike as much as possible in the shadow or inside a cool place.
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Ow interesting. I haven't ridden my SRF like this before but now I definitely want to try it. The only times mine throttled so far was because of cold weather (like freezing cold).
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https://www.electricmotorcycleforum.com/boards/index.php?topic=11345.0 is reporting something similar, though 2 times at the same charging station (reduced charging to 6kW at temperatures at or above 30C).
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Are you running on FW19? Because that seems to have some improvements for high charge rate at high pack temperatures.
Improvements for charge rate tapering at high charge rate and at high pack temperatures
Also it would be great if you can keep track of your pack temperatures too on the dashboard. Might help to know if you need to go easier on the throttle to reduce high charge/discharge.
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I think the best answers to this will be found if you can monitor the temperatures of the bike components, specifically the battery. I mean, we're all thinking it and some people are saying it, but I'd like to confirm with some data, please.
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I am on FW 19. Attached is a screenshot. The temperature is the outside temp. It shows 40 deg Celsius although the outside temp was only 30 degrees. I assume, that the temp sensor catches heat from the battery. There was no fault or warning on the dashboard . This was the fourth charging stop on this day - and the worst in terms of charging speed. I have reduced speed after stop 2. This helped to increase charging speed at stop 3, but apparently things are heating up again although I was not above 110 kmh. charging data below is reported from my energy bill (Maingau).
Stop kWh time average charging speed (KW)
1 8.35 00:41:15 12.15
2 8.91 01:05:23 8.18
3 5.66 00:31:42 10.71
4 7.70 01:04:11 7.21
I looked up the article from enaef. For me it is unclear, if he saw the reduced charging speed from the beginning. In my case it always started with full speed (11.6 kW on DC) and than throttled down after some time.
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That 40C is the weather and I've seen that indeed creep up when charging fast so it's definitely influenced by the bikes components.
For the battery (and motor) you can change the dash quadrants to display that.
(https://i.ibb.co/drz6zxP/Screenshot-2021-08-24-at-16-24-00.png) (https://imgbb.com/)
That said I haven't checked how accurate these readings are and if they're easy to get from OBDII or serial.
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I looked up the article from enaef. For me it is unclear, if he saw the reduced charging speed from the beginning. In my case it always started with full speed (11.6 kW on DC) and than throttled down after some time.
Well, the reduced kW charging was both times from the beginning.
The temperature I gave also were for air, given at the dashboard, right at the beginning.
And yes, charging at high kW always raises the dashboard-air-temperature. In warm weather up to ~40 degrees Celsius.
I have changed the other dashboard-temperature from motor to battery just after coming back from the last ride.
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The temperature sensor the dash uses is in the exhaust from the 2 3kW chargers, so it won't remain accurate after you start charging. As others have mentioned, the battery temperature is the one used to limit charging rate, and its inside the monolith.