Simply,..a BIG Battery install,..1989
#46
Rennlist Member
Thread Starter
Good discusion guys. I have wondered if the overvolt protection relay from a Benz could be integrated into a DME relay position. Right off, the OVP relay has round pins, not the spade type. OK, one could fasion an "adapter" if all outputs are compatible. Loren, you have a Benz overvolt relay lying around?
there are red top ones, black top ones, and maybe green. They were superscesions of each other IIRC and compatible with back dating within the benz products. The latest version (red top IIRC) is the latest. For "Benz", I mean all 201, 202, 107, 124, 126, 129, and others share the same part.
The OVP relay is the one with a fuse on top under a clear flip top cover. Some may have actually had 2 fuses.
there are red top ones, black top ones, and maybe green. They were superscesions of each other IIRC and compatible with back dating within the benz products. The latest version (red top IIRC) is the latest. For "Benz", I mean all 201, 202, 107, 124, 126, 129, and others share the same part.
The OVP relay is the one with a fuse on top under a clear flip top cover. Some may have actually had 2 fuses.
I'd like to see these protection relays that you're mentioning Bird.
Best,
Doyle
#47
Rennlist Member
Thread Starter
Best,
Doyle
#48
I haddah Google dat
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^ Me too!! I'd buy one, but I don't consider myself capable of making one.
And was I being inconsiderate? I know how much Loren HATES Pelican Parts and Radio Shack both.
And was I being inconsiderate? I know how much Loren HATES Pelican Parts and Radio Shack both.
#49
"Loren, you have a Benz overvolt relay lying around?"
Yes, but it did its job, i.e. it's done. My customer assumed he had
a bad M/B ECM, but his charger 'cooked' the relay.
The M/B over-protection relay is a 'passive' device in that it blows
the fuse once over-voltage occurs. The ideal circuit would shut-down
the DME relay at a set voltage (16-18 volts) and restore the voltage
once the voltage was below the setting.
The circuit could be easily placed in the existing DME relay.
Yes, but it did its job, i.e. it's done. My customer assumed he had
a bad M/B ECM, but his charger 'cooked' the relay.
The M/B over-protection relay is a 'passive' device in that it blows
the fuse once over-voltage occurs. The ideal circuit would shut-down
the DME relay at a set voltage (16-18 volts) and restore the voltage
once the voltage was below the setting.
The circuit could be easily placed in the existing DME relay.
#51
Race Car
Thanks Loren. That does clarify a bit. The rule was that if the fuse was blown, the relay was done. Some thought the fuse could be replaced. Try here, about 2/3 down the page, red top relay(aluminum casing). click on the image and you will see the pins, and their outputs. The circuits (85,30,15 etc) are the same for Porsche as benz. I would love to see a plug and play for such a device in a Porsche.
http://www.europartsdirect.com/epc-items.asp
http://www.europartsdirect.com/epc-items.asp
#52
"The circuits (85,30,15 etc) are the same for Porsche as benz."
The problem is that the DME relay has a fuel pump control part
of it, i.e. part A - power to ECM, part B - power to fuel pump.
I'll come up with a circuit and try to fit it into a DME relay.
The problem is that the DME relay has a fuel pump control part
of it, i.e. part A - power to ECM, part B - power to fuel pump.
I'll come up with a circuit and try to fit it into a DME relay.
#54
Here's the circuitry added inside the stock 911 3.2 DME relay to protect the
DME ECM from an over-voltaging alternator:
DME ECM from an over-voltaging alternator:
Last edited by Lorenfb; 01-26-2011 at 02:08 AM.
#57
I haddah Google dat
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Absolutely. I was thinking a new thread with tags would make a better breadcrumb trail on Google for someone who was specifically looking to avoid a dme overvolt condition.
#58
"I move to make a new thread with ^ that diagram. Is there a second?"
Do it! It's for you guys to use to protect your electrical system.
"Nice,..very similar to:::::::"
That's correct, i.e. The BASIC functionality is the same, the defrost unit turns 'on'
a relay and the DME relay mod turns 'off' a relay. The defrost circuit is over-designed
by someone who had an interest in selling components to the defrost relay manufacturer,
Hella, and thus could have been simplified.
Remember:
1. The defrost unit - turns 'on' the center heat element with a cabin switch thru a relay
and the upper/lower elements are turned 'on' thru a second relay when the battery voltage
goes above a set point.
2. The DME relay mod - functions as a normal DME relay (powers the DME pins 18/35
and powers the fuel pump via the ECM pin 20) but then shuts-off if the battery voltage
exceeds 18 volts.
Do it! It's for you guys to use to protect your electrical system.
"Nice,..very similar to:::::::"
That's correct, i.e. The BASIC functionality is the same, the defrost unit turns 'on'
a relay and the DME relay mod turns 'off' a relay. The defrost circuit is over-designed
by someone who had an interest in selling components to the defrost relay manufacturer,
Hella, and thus could have been simplified.
Remember:
1. The defrost unit - turns 'on' the center heat element with a cabin switch thru a relay
and the upper/lower elements are turned 'on' thru a second relay when the battery voltage
goes above a set point.
2. The DME relay mod - functions as a normal DME relay (powers the DME pins 18/35
and powers the fuel pump via the ECM pin 20) but then shuts-off if the battery voltage
exceeds 18 volts.
Last edited by Lorenfb; 01-26-2011 at 10:06 PM.
#60
Rennlist Member
Thread Starter
And thanks to Rusnak for the thread suggestion! Never thought my battery thread would end up with an overvoltage protect theme....I learned a lot on this one!!!
You are (and always have been) a big help to me Loren.
Best,
Doyle
You are (and always have been) a big help to me Loren.
Best,
Doyle