dyno tests of the eRAM

[mark kibort <mkibort@xxxxxxxxxxxxxx>]

Message text written by Land Shark
>(a bunch of stuff about the ERAM)
>>>>>>>>REPLY to Land Shark reguarding dyno test.

 Mark if you want real numbers.. go buy a wattmeter
 and place it in circuit with your ERAM.

 Then record the power drain.. DURING a test
>>>>>>>>>yes, this is what we did. A fluke meter was installed to measure=

start up amperage
and running amperage.   as a surprise, the startup amperage was lower  as=

the spoolup time =

being greatly reduced due to the air already moving passed the fan.   30
amps , almost dead on.

 Then get back to us... the results, I'm sure are
 going to surprize you!
>>>>>>>>>>only surprise was the above.
 In both tests, you can't really determine the
 drain, as the eRAM will drink power from the =

 battery until the battery is below XX.X volts
 at which time the alternator charges and only
 THEN does it require the power from the engine!
If I remember the car electrical system correctly, (correct me if Im wron=
g)
but doesnt the =

alternator act on voltage drop from the battery, so that under high curre=
nt
loads, the alternator kicks in =

to keep the voltage at or close to 12.5 or 13 volts? =

Anyway we used a very small battery that was installed in the 911.  =

voltage drop was big when tested without the car running
as it was only a 100 amp hour battery.   Our runs were right after one
another with no Idle time but on the 4rd and 5th run, they were carbon
copies of the 3rd , albiet that the on time of the fan is only about 15
seconds.  On the race track that gives you acceleration from 60 to 120 mp=
h =

a couple of times in one lap over 2 min period, for 10 laps.  On my video=
s,
i have a LED light that goes on when the fans are on( WOT)
on a typical lap at laguna or sears point, even a fast track like
Thunderhill , or buttonwillow, it is only on for 20 to 35 seconds  total =
a
lap

.

 Ditto on the separate battery test.

 If you start thinking of current as "water" and
 a battery as a full city water tank, you'll get the
 picture.

 I've come to the conclusion that while you mean no
 harm, you simply don't get how a cars charging =

 system works.. the battery acts like a big "capacitor"
 in the system and you can take HUGE drains for a few
 seconds without feeling them "now" .. you only feel
 them when the charge occurs
>>>>>>>>>>>>This is what I posted .  Remember about my  post regarding
the batter taking on the high current drains and the alternator just slow=
ly
putting
the current back in at  lower current draw times or (lower voltage times)=


 (I guess this makes a battery like a credit card ;)

 The other way to do it is to use a batteryless car,
 but that would be VERY BAD with all the electronics
 which havent been hardened.. so a wattmeter is the
 way to go!
>>>>>>>>>>>>>as a note,  on small batteries of 11 amp hour =

or so , the voltage drop under a 30 amp load went down to 10.5 volts
on a 2 amp hour nicad pack, it went down to 9.5 for the same nominal
voltage.
obviously, the lead acid battery  can handle the current draw better. =

under an alternator,
the voltage didnt drop that much, hence the .5 to .75 hp drop on the dyno=
.

thanks for your reply
Mark

 Jim

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