Front battery is out...
Sunday, January 10, 2016
Wednesday, September 2, 2015
New Batteries!
The game of Tetris begins again... I have acquired 456 Enerdel CE175-360 batteries, which I am so far planning to install in a 76S 6P pack. This will mean a jump from 170V to ~310V fully charged. With the current pack, full load (1000A!) would result in ~30V of IR drop across the bus bars, current sense shunt, fuse, and the cells themselves, so really no more than ~130kW of output power. This new pack will see much lower max current (maybe 600A?), and at 6P will be much lower impedance (0.7mOhm > 0.45mOhm) so hopefully much less IR drop (less heat) and guaranteed full power across the pack capacity range. 40kW more power, with a weight reduction would be noticeable!
These batteries are much higher density so the pack can be arranged for better overall weight distribution in the car. It should result in ~50/50 weight distribution. The green box in the diagram below is a placeholder for a Toyota MGR unit to hopefully add an extra 50kW peak motor with regen to the rear wheels.
A Visio drawing of the old vs new pack arrangement is shown below.
The game of Tetris begins again... I have acquired 456 Enerdel CE175-360 batteries, which I am so far planning to install in a 76S 6P pack. This will mean a jump from 170V to ~310V fully charged. With the current pack, full load (1000A!) would result in ~30V of IR drop across the bus bars, current sense shunt, fuse, and the cells themselves, so really no more than ~130kW of output power. This new pack will see much lower max current (maybe 600A?), and at 6P will be much lower impedance (0.7mOhm > 0.45mOhm) so hopefully much less IR drop (less heat) and guaranteed full power across the pack capacity range. 40kW more power, with a weight reduction would be noticeable!
These batteries are much higher density so the pack can be arranged for better overall weight distribution in the car. It should result in ~50/50 weight distribution. The green box in the diagram below is a placeholder for a Toyota MGR unit to hopefully add an extra 50kW peak motor with regen to the rear wheels.
A Visio drawing of the old vs new pack arrangement is shown below.
Friday, July 3, 2015
Updates...
When I inspected the motor controller water cooling lines at the conyroller inlet and outlet, I found they were dry, so no cooling at all!
Today I rerouted the entire motor controller cooling circuit, adding a reservoir just higher than the controller.
While I was in there in also changed my home made vacuum reservoir to a more compact and lightweight commercial unit.
When I inspected the motor controller water cooling lines at the conyroller inlet and outlet, I found they were dry, so no cooling at all!
Today I rerouted the entire motor controller cooling circuit, adding a reservoir just higher than the controller.
While I was in there in also changed my home made vacuum reservoir to a more compact and lightweight commercial unit.
Wednesday, July 1, 2015
Sunday, June 28, 2015
First track event completed!
It didn't perform as well as I'd hoped. The car handled great, but it was the first time this drive train has been used in anger, and so there was bound to be some teething problems...
I found that the Soliton1 motor controller was limiting the max current after only a couple of laps. It was down to as low as 300A or so at full throttle! That meant a long slow crawl up the hill towards the corkscrew... Argh! When I returned to the paddock I found that the coolant lines from the heat exchanger were cold, while the controller was hot. The pump was running, so I must have air in the system. I suspected the routing of the hoses and the lack of a reservoir at the highest point was not going to work well, but I didn't think it wouldn't work at all! Anyway, I've ordered an OBX 1 1/4 quart universal coolant expansion tank, and I'll re route all the lines a bit better.
Another thing that happened was that the vacuum pump pressure switch has stopped working. I guess it just couldn't take the heat. So, I'm taking this opportunity to replace the vacuum pump with a Hella UP30 and a nicer vacuum reservoir, along with a new PSF109S 81-330 pressure switch.
All in all, it was a really fun event, and it was fun to chat with other early adopters.
It didn't perform as well as I'd hoped. The car handled great, but it was the first time this drive train has been used in anger, and so there was bound to be some teething problems...
I found that the Soliton1 motor controller was limiting the max current after only a couple of laps. It was down to as low as 300A or so at full throttle! That meant a long slow crawl up the hill towards the corkscrew... Argh! When I returned to the paddock I found that the coolant lines from the heat exchanger were cold, while the controller was hot. The pump was running, so I must have air in the system. I suspected the routing of the hoses and the lack of a reservoir at the highest point was not going to work well, but I didn't think it wouldn't work at all! Anyway, I've ordered an OBX 1 1/4 quart universal coolant expansion tank, and I'll re route all the lines a bit better.
Another thing that happened was that the vacuum pump pressure switch has stopped working. I guess it just couldn't take the heat. So, I'm taking this opportunity to replace the vacuum pump with a Hella UP30 and a nicer vacuum reservoir, along with a new PSF109S 81-330 pressure switch.
All in all, it was a really fun event, and it was fun to chat with other early adopters.
Saturday, June 20, 2015
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