Re: Tried to burn up my battery pack, car, and garage today

["Joe Smalley" <joes@worldfront.com>]

I have a gizmo I built several years ago for just this type of situation. It
is an SCR with a trigger circuit that turns the SCR on when the battery
voltage is below a setpoint. It was designed to handle 20 amps coming out of
a charger such as yours. When I built it, I wired it with only 14 gauge wire
so it won't handle 20 amps as is. If you are interested, I can post the
schematic or take it to Woodburn for you.

Joe Smalley
Rural Kitsap County WA
Fiesta 48 volts
NEDRA 48 volt street conversion record holder
joes@worldfront.com


----- Original Message -----
From: "John Bryan" <jbryan4@mindspring.com>
To: <ev@listproc.sjsu.edu>
Sent: Tuesday, July 30, 2002 3:22 PM
Subject: Tried to burn up my battery pack, car, and garage today


>
> I guess it had to happen sometime. Whenever a human is
> involved you know that things will eventually go wrong. I got
> home from the store around noon and decided to juice up my
> car quickly with my Badass-Boy Charger. It's similar to a
> Bad Boy Charger, only it runs on 220 and has the ability to
> take out my car's pack. The car was only down 8.5 Ah, so I
> planned on only leaving it plugged in for about 20 minutes
> and then letting the onboard system take it from there. I
> checked the E-meter and saw 18 amps flowing into the 192 Volt
> pack before I left and basically didn't come back.
>
> This pack is made up of 16 Optima YellowTops that
> are 6 years old this September. They have powered my trusted
> daily ride for the last 5 years. The problem today is that I
> was really tired from getting awaken all night by exploding
> powerline transformers. My stupid alarm clock can't handle
> the noise, so I got up and reset it at 2:30 and again at
> around 5. So I was really tired when I sat down and started
> having lunch - already having forgotten all about the car.
>
> After I finished eating I sat down in a really
> comfortable chair and started reading a fine book. Meanwhile,
> my battery pack was heading for record voltages as it continued
> rapidly charging even after becoming completely filled. As the
> batteries eventually started into full thermal runaway, I closed
> the book, set it down, and settled into a nice peaceful and
> restful sleep. I woke up a couple of times, only to go right back
> to my badly needed slumber. Suddenly, I cracked my eyes barely open,
> then I...remembered. I felt my eyes go wide like saucers and I just
> literally flew out of the chair and ran from the house.
>
> On my way to the garage, I came to the Badass Boy Charger
> about halfway between the house and the garage. After yanking
> the plug and holding the cord that led to the garage, I wondered
> what I would find at the other end. The car had been on charge
> for 2 hours and I fully expected to find a terrible mess and a
> ruined pack. I was amazed to find that although the batteries
> were all very hot, not a single one of them had vented. I'm sure
> they were extremely close though. I started sniffing around to
> see if I could detect any telltale aromas, but all that I could
> smell was clean, hot, yellow plastic. They were around 110 deg.
>
> As they cooled down I kept an eye on them and put them
> on float with the onboard system holding each module at 13.8 Volts.
> I have the feeling they are going to live! If anything they seem
> to be even better than before, judging from the extremely long
> off times that I'm seeing with the chargers. Times that I haven't
> seen for a couple of years or so. I consider myself very lucky
> and feel that I came just as close to that line as I could without
> stepping over it. It'll be interesting to see how the pack performs
> on its next run. The solution to this is obviously an automatic
> shutoff, another of those things getting higher and higher on my
> list of things to do.
>
> Seeya,
> John
>