Meriva keeps blowing bulbs

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So are you saying that the much greater voltage variation car bulbs are subject to does not require them to be constructed completely differently? Because I can assure you that they are, and if you research it you will see how.

Am I sure that mains-voltage lamps have an in-built fuse? Yep:

Omission of that fuse in cheap imported filament lamps is one of the reasons for nuisance tripping of circuit protection upon filament failure.

No I'm not; I'm telling you that a badly-written inaccurate article picked at random from Google's results proves nothing either way.

(Re-reads thread): No, I can't see were the OP said he used cheap bulbs. Care to remind me?

ECB?

The filament 'arcing' is *not* what causes the circuit protective device to operate. Read further down the article where the writer is corrected. Essentially, it's caused by pieces of blown filament shorting across the filament supports.

No it isn't. It's purpose is to protect the *circuit*, not necessarily the lamp.

The vehicle is less than 9 years old.

My last car that I had from new I kept until it was 10 years old with 100k on it. Total bulb failure in that time was 1 brake light.

My present car was purchased at six years old; it is now twelve years old. Total bulb failure in my ownership is two high-level brake light bulbs.

The OP is having to replace bulbs almost every week. That does not suggest 'dodgy bulbs' as the cause to me.

Chris

With what providence? The OP has stated that he has replaced the bulbs several times but with what?

Which says that OEM bulbs are better built to last. Back to unknown quality cheapo bulbs

What do you think happens with cheapo dodgy bulbs? The OP would be best off IMHO starting off by replacing the bulbs with Osrams or Philips and see if they still blow. (Assuming the voltage is indeed solid)

Oh it will. With the alternator turned hard on I've seen over 16 volts.

When things settle down on both my cars - ie battery pretty well fully charged - they both read 13.8v. Which is theoretically correct.

. Almost every week, something is going. When they've blown, they've usua lly gone that silvery-black colour, too. Is it going to be the voltage reg ulator, which is the only thing I can think of? Is there any way of testin g it? Will the voltage present at, say, the battery terminals be higher th an usual, which I think is something like 14 volts?

Finally got to the bottom of it. It was the cable that links the lights in the rear hatch to the main car body. It had popped out of the protective rubber conduit, and rubbed on the body. Should have been the first place I looked, really, because I'd seen it before on something else.

Am I missing something? I can see why this might keep blowing the fuse on those circuits, not why it should cause front bulbs to blow. Are you suggesting that the voltage dip on that circuit causes the alternator and/or regulator to increase the output voltage to try to compensate?

How would that blow bulbs?

repeated flashing on and off?

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Maybe, but the OP mentioned that front and rear bulbs were blowing, and I can't see how the broken wire in the rear would affect the front bulbs.

Chris

ear. Almost every week, something is going. When they've blown, they've u sually gone that silvery-black colour, too. Is it going to be the voltage regulator, which is the only thing I can think of? Is there any way of tes ting it? Will the voltage present at, say, the battery terminals be higher than usual, which I think is something like 14 volts?

s in the rear hatch to the main car body. It had popped out of the protect ive rubber conduit, and rubbed on the body. Should have been the first pla ce I looked, really, because I'd seen it before on something else.

I forgot to mention that on this occasion the bulbs were okay, but the fuse had blown. Sister assumed the bulbs had gone because they'd been replaced so often. I also don't understand how it would affect the front ones. I suppose only time will tell if the long-term problem is still there. The c ar has been a bit of a dog. Bought very cheaply from a private seller who fancied himself as a dealer. She couldn't resist the price but has regrett ed it since.

Explanation given above in other sub-thread.

Doesn't actually seem to make much difference with car bulbs. Otherwise the flashers would be a problem. ;-)

Indicator bulbs do that but don't blow any faster than other bulbs

Ah, now we get somewhere. I bet you don't have the old bulbs that you accused of being blown?

Sister assumed the bulbs had gone because they'd been replaced so often. I also don't understand how it would affect the front ones. I suppose only time will tell if the long-term problem is still there. The car has been a bit of a dog. Bought very cheaply from a private seller who fancied himself as a dealer. She couldn't resist the price but has regretted it since.

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rear. Almost every week, something is going. When they've blown, they've usually gone that silvery-black colour, too. Is it going to be the voltag e regulator, which is the only thing I can think of? Is there any way of t esting it? Will the voltage present at, say, the battery terminals be high er than usual, which I think is something like 14 volts?

hts in the rear hatch to the main car body. It had popped out of the prote ctive rubber conduit, and rubbed on the body. Should have been the first p lace I looked, really, because I'd seen it before on something else.

fuse had blown.

No, but they were replaced, and the replacements worked. And they did tend to have that silvery blackened glass appearance, so I didn't question that they were blown. Normally, I'd have a look at the filament, to see if it wa s just the case that the contact point needed cleaning, which I find is nea rly always the case.