Total Loss Power Supply

[whittlebeast]

Has anyone used one of these?

https://raceenergyperformance.com/products/tdc-30

I am installing a motor into a chassis that it was never intended to be mounted in and I am running out of room. This is a dedicated autocross car / race car. Does anyone have experience with these things? In my wiring setup, all power related to the Squirt comes thru on wire so install should be a breeze.

http://www.nbs-stl.com/CRX/Civic%20CRX%20Wiring.jpg

Andy

[DaveEFI]

Not sure it would help much as MS already compensates for varying battery voltage. I'd be inclined to use the space it takes to fit a bigger battery. You'll almost certainly get a shorter running time from your battery with this sort of device. And it's not a good idea to run any lead acid battery flat, as it shortens the life. Even with deep discharge types.

[dontz125]

Not sure why they're emphasizing the high-voltage needs of modern ECUs; any ECU that doesn't have voltage compensation for the spark and injectors AND a low drop-out regulator to feed the 5v processor is pretty poorly designed, IMHO. The coils should starve long before the ECU becomes an issue.

The only black box I can think of that might have a higher minimum voltage requirement is a DC-DC CDI, where it uses an inverter to boost the 12v up to 200-300 vdc to charge the firing cap. Even then, this shouldn't be an issue unless the engine is revving past what the box was originally designed for; the Ignitech DC-CDI-P2 Race units have problems with high-revving TZ and RS GP bikes, needing upwards of 14-15v to really wind out.

[jacky4566]

Sounds like an overpriced magic box. With a simple buck–boost converter you could have amps of current.

To be fair. The old Nissan ECUs, Like really old 70s analog kind, would melt if they were run on low voltage for extended periods of time (longer than cranking). Its actually really impressive they could build injector controllers without logic chips we have.

[whittlebeast]

I see no need to operate at more than 14 V as long as it is a stable 14 V. I have not come across a cheap way to do this. I bet I will have $300 in any reasonable option.

[jammy86]

I see no need to operate at more than 14 V as long as it is a stable 14 V. I have not come across a cheap way to do this. I bet I will have $300 in any reasonable option.

On race cars it is typical to run at 16V due to going light on the wiring harnesses and accepting that their will be more voltage drop across the harness than on a production car....


Just get a good AGM battery, run it total loss (no alt) and charge it between races if the car doesn't run for too long. Varta Silver Dynamic or Start/Stop or whatever they call it these days. Those things can take a beating and all "automotive" electronics should be fine down to 8V

[whittlebeast]

I wound up going to the *Race Energy device. A couple of reasons.

1) it was lighter than the alternator and related brackets.

2) I gives a rock steady voltage for critical devices. I was concerned with fuel pressure dropping as well as issues with injector dead time and coils charge time.

3) My car was an easy install as all critical engine related power was coming from one large wire

4) There simply was very little room in the engine compartment and replacing an alternator on a race weekend would be a nightmare if I could find one.

5) 250 psi cold cranking compression was killing my supply voltage to the squirt. This thing holds a rock solid 13.5 volts.

6) I got to get a very hot constant hot wire out of the engine compartment.

7) The road racers I know that have them, love them.

I like cool stuff. Time will tell.

Andy

[whittlebeast]

I forgot to mention that the alternator runs about 4 times the speed of the crank. The crank jumps from about 4000 RPM at most apexes to about 9000 RPM coming off every corner in about 3 sec. That works out to 16000 to 36000 and back about 10 times in every run. That can't be an insignificant drag on HP.

Andy

[prof315]

I forgot to mention that the alternator runs about 4 times the speed of the crank. The crank jumps from about 4000 RPM at most apexes to about 9000 RPM coming off every corner in about 3 sec. That works out to 16000 to 36000 and back about 10 times in every run. That can't be an insignificant drag on HP.

Andy

Only due to belt friction.... I had a friend who owned and ran a starter/alternator repair shop and a 200A diesel alternator only requires a 1HP motor to spin up to full load.

[DaveEFI]

746 watts per hp. 200 amp at 12v 2400 watts. Something doesn't add up.

How much power an alternator takes depends on the load on it. With a bit added on because nothing is 100% efficient.

[whittlebeast]

Spin an altinator up to 35000 rpm and the grab it with your hand to get it back down to 10000 rpm all in 2 sec and get back to me with the results. The angular momentum along is very significant. My old motor accelerates at 13500 rpm per sec on a throttle stab like on a down shift. That is about 50000 rpm per sec at the altinator.

Andy