The Going-Ons @ Pacific Electric Vehicles

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19 May, 2010

Quick Update — BMS For Sale

Filed under: Uncategorized — coryrc @ 5:51 pm

Hey all you DIYers, the Pacific EV BMS is for sale!

http://pacificev.com/ev_battery_management_system_bms.html

More coming soon. We’re hard at work developing new technology for EVs.

Seattle Electric Vehicle Conversions

9 February, 2010

The Sunbeam Alpine is Stripped Down

Filed under: Electric Vehicle Conversions,Sunbeam Alpine — coryrc @ 8:16 pm

Stripped Alpine Front

The transmission is out and off to our partner to build the adapter plate.

Back View of Stripped Alpine

Empty Engine CompartmentRear view of the SLI battery box and differential

Ewww, oil burner

Pacific Northwest Electric Vehicle Conversions

Our Web Store Is Open

Filed under: Battery Management — coryrc @ 6:48 pm

but not much for sale yet.

Pacific EV Shop

For now, we’re just selling a good power steering pump. We have a few extra, so act quickly!

We’ll  be adding our BMS to the page once it is in stock.

Seattle Electric Vehicle Conversions

14 January, 2010

Some Sunbeam Specifications

Filed under: Uncategorized — coryrc @ 5:41 pm

Our 1967 Sunbeam Alpine electric vehicle conversion will have:

  • 60 miles range with lightweight Lithium batteries
  • 130kW peak (hey, I don’t have to translate it to horsepower because it’s British!)
  • 150V battery system
  • Regenerative Braking
  • Electric Heating
  • More to come… we’re busy working on it!

If you interested in a similar or different electric vehicle conversion for yourself, please contact us to discuss your options!

Pacific Northwest Electric Vehicle Conversions

8 January, 2010

Why Voltage-based BMS Works

Filed under: Battery Management — coryrc @ 12:47 am

I had an e-mail exchange with a fellow I met at our local Seattle Electric Vehicle Association about my company’s battery management system, which prevents every cell from ever going above or below programmable setpoints.

Also, reader, please do not forget PEV offers electric vehicle consulting services for your own project.

I guess what I’m asking is, when a battery cell is in circuit, its voltage and the current going through it are interdependent.  Under heavy load, a cell’s voltage will sag, but remove the load, and the open cell voltage will jump back to a quiescent level.  At November’s SEVA meeting, Stephen Johnsen[sic] showed a video of dragging a TS cell’s voltage down to 0.5V under an 800 amp load for 20 seconds, but when when he switched the circuit OFF, the voltage jumped right back up to 3.2V.  If you had a BMS that was just looking at voltage, then I think 0.5V would have tripped alarms in anybody’s system, even though the cell wasn’t anywhere close to dead.

Ah, I see where you’re coming from, but there are several reasons why you don’t want nor need to do the above.
The reasons you don’t need to are
1. 800A loads the cell to 0.5V, but 150A might load the cell only down to 2.0V (I would need the cell size to give you a more exact number) The power increase is only 33%, while efficiency drops 75%.
2. Once you have an EV-sized pack, you don’t need more than 3C for very quick acceleration, so there is no need to go below safe voltage. (unless you have a very heavy vehicle w/ short range, but then you may as well use flooded LA)
The reasons you don’t want to are:
1. Probable cell damage — until shown otherwise, I’m going to assume drawing a cell below its recommended voltage damages it like NiMH and LA and unlike NiCd (which will take anything so long as you don’t reverse them)
2. Greatly reduced efficiency — drawing at that rate versus a 1C draw (@3.2V) requires 6.4 times more Ah used per kilowatt-hour delivered

No one has shown it is safe to take the cells below 2.0V, but there are multiple independent sources of test data showing if you never allow the cells to go above 4.25V nor below 2.0V at any time, they last 3000 cycles. I would not risk cutting the lifetime of $10000 batteries for a small increase in peak power, but I’m happy to help others do the testing on their dime :).  So, reader, if you wish to sponsor this test, e-mail me!

Seattle Electric Vehicle Conversions

24 December, 2009

More Alpine Pictures

Filed under: Electric Vehicle Conversions,Sunbeam Alpine — coryrc @ 11:28 am

I promised more pictures of the 1967 Sunbeam Alpine waiting to be converted. Enjoy!

Inside of the Alpine

Inside of the Alpine

Alpine's Engine

Alpine Engine

Alpine Trunk

Back of the Alpine

Seattle Electric Vehicle Conversions

15 December, 2009

A Sunbeam Alpine ready for teardown

Filed under: Electric Vehicle Conversions,Sunbeam Alpine — coryrc @ 2:08 pm

Our customer Roger desires a clean, fun electric vehicle with sporty performance and a highway range of 60 miles. He came to the right place! I’ll post pictures and information as the project progresses.

Pacific Northwest Electric Vehicle Conversions

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