I am wondering to what extent this infamous OVP relay is important or even necessary.
What I understand it does is that when it senses an overvoltage from the alternator/battery( could not come from any where else) it cuts off current to: ?(The main engine computer and possibly the ABS computer)
There is a transistor in the relay, that senses voltage and when it senses above a certain voltage it activates an electrical switch(relay) to cut off current. On the OVP relay, there is also a fuse that does the same thing, except that it does not reset like a relay when the condition disappear.
To me, it seems that the fuse should take care of dangerous overvoltages and that the relay itself could be done without. If the fuse keeps blowing, one should know to check the working of the alternator/battery. The OVP relay does not advise that it is engaging and does not alert you to overvoltages which are necessarily lower than what should blow the fuse. I have read somewhere that the sole reason for the ovp was to protect the engine computer (in itself that is good).
The fuse on the OVP relay seems to do that already. Intermittently cutting off current to the battery (like the OVP relay does) just insures that it does not charge correctly and does nothing to fix the alternator/battery problem that triggers the OVP relay. When the fuse blows, that is a clear message.
I am thinking of bypassing the relay with a switch and just making sure that the fuse is in the circuit. If the fuse blows, then I can replace it, then activate the relay function with the switch and drive on if possible. If the problem is very serious, the fuse will blow again(carry a supply), if the problem is not too serious, I will be able to drive on and repair the alternator/battery problem in a location of my choice.
Any comments on these thoughts?
Am I being an optimist or is my solution viable?
I would really appreciate your comments.
Jacques.

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J.R.

One thing a fuse won't sense is someone jumping a car battery with the jumper cables cross wired! You can permanently damage a lot of components that way!

That happened accidentally with my VW, with it's far from sophisticated wiring harness. I trashed a voltage regulator and a $1200 head unit that way!

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2009 ML350 (106K) - Family vehicle
2001 CLK430 Cabriolet (80K) - Wife's car
2005 BMW 645CI (138K) - My daily driver
2016 Mustang (32K) - Daughter's car

Ok, here is why you don't want to do that. In the event of an overvoltage situation, the relay removes the critical device from power. Assume that said devices can tolerate 15 volts just fine, but at 17 volts, will short out and fry. Yes, a fuse will blow from the over current. Trouble is, the over current comes from a massive current drain when the sensitive parts break down from the excessive voltage. So basically , if you just had a fuse and switch, the fuse is a "your electronics are fried" idiot light. The relay is in a race to try to prevent damaging voltage from reaching the electronics before they can fail. It is probably a close race as it is.

Lets use some logic. The only way you get overvoltage is if the voltage regulator quits working. A relay is a switch. I never heard of an overvoltage relay, if there is such a thing, it would work by opening the circuit to the component in question. Basically the same as a fuse, more like a circuit breaker because I assume it could be reset.

And current is DRAWN by a device, not fed to it.

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MB-less