David's 2001 Civic EV (80-100 mile range; 65+ MPH; 8 second 0-60)

[Daox]

Originally Posted by Cobb

Its very easy for me to make a 5 mile trip and end up driving 150 miles. Id have to return home and trade vehicles if I had purchased a leaf or some ev like vehicle. I guess that is where the volt comes in?

Yep, or the PHEV Prius, or C-Max Energi, or the soon to be PHEV Accord or Fusion Energi... Thankfully the choices are growing.

I am leaving then on the trunk deck. This car is going to be my all year round car, including nasty winters so I want the batteries sealed from the elements.

Ah, I'm guessing you don't have a welder where you could just make a box and weld it into the chassis where the gas tank or spare tire well was.

[TheSGC]

Originally Posted by Daox

Ah, I'm guessing you don't have a welder where you could just make a box and weld it into the chassis where the gas tank or spare tire well was.

I really thought about that, and I was about to but the cross frame is right in the way. I am also putting some insulation and airflow in the trunk to keep the batteries are a decent temperature all year round.

[TheSGC]

Today I got the power cables finished and the battery installed.


Next I have to install the circuit breaker, then it's battery time! I am aiming for a Friday afternoon test drive, depending on how fast the batteries charge once I install them.

I still have to integrate the tachometer and design the circuits to run the A/C motor and heater system. I haven't looked out how the Honda electronic temperature controls work, so that's another project.

[Daox]

Have you balanced your batteries yet?

[TheSGC]

Originally Posted by Daox

Have you balanced your batteries yet?

Not yet, I am still deciding how to do it. My original plan was to just hook them up in series and let the MiniBMS do it's job. Right now they are within 0.004v, usually 0.002v from each other. I'm going to read through the MiniBMS manual and see what it says I should do.

I could use a bench power supply to charge them in series, but that would take days, if not weeks to charge.

[Daox]

You really need to balance before using them in the car. .004V at rest turns into 1V difference at the far end of the charge/discharge curve quite fast. If they aren't balanced you'll start toasting cells. I've delt with it already in my PHEV kit on my Prius where my discharge rates are nowhere near what yours are.

[adamj12b]

David,

You can just wire them all in parallel and connect a CV power supply dialed in to what voltage you want and let it go for probably a day. Once the current tapers, to a specific value, you should be all set.

This is how I eventually plan to do my cells.....eventually....

-Adam

[Daox]

As long as you know how your setup works and you have provisions to protect the cells from overcharge and overdischarge you'll be fine. Its not like lead acid where you can just plunk them in and go.

[TheSGC]

I think I am going to hook everything up and charge up the batteries with the MiniBMS active to it will shutdown the charger if a cell hits 3.6v. I am charging to 3.5v/cell so that gives me some room and if I need to balance more I will.

My problem is I only have a 3A power supply so that would take 169 days to top off! What I may end up doing is installing everything, charging up and if HVC becomes a problem, then balance with the batteries mostly charged.

[Daox]

What do you have to detect low state of charge? What about if a single cell goes low?