100W high beams in '98 V70

Discussion in 'Volvo V70' started by Jeffrey C Honig, May 28, 2005.

  1. I just installed some 100W H7 high-beam bulbs in my '98 V70. I'm a
    bit concerned about the current capacity of the wires. Has anyone had
    any problems doing this?


    Jeffrey C Honig, May 28, 2005
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  2. Jeffrey C Honig

    Bingo Guest

    A while back I had a '93 850 T5 estate - lovely car. Now replaced with a
    2000 V70 T5

    I had a load of problems with the headlights - the beam alignment was poor,
    they failed fairly quickly, and I had TERRIBLE trouble getting the retaining
    clips back on after I replaced the bulbs.

    One day, I took the headlight out to see what was wrong.

    The alloy bulb holder had very clearly become warped - the new bulbs
    wouldn't sit down flat, and the clips would not clip.
    I bought 2 new ones from the main dealer (luckily they didn't make me buy
    whole headlight assemblies) and everything worked again.

    I ASSUME a previous owner had used 100w bulbs.

    So beware - it may not be the wiring or fuses that give you the problems!

    Bingo, May 28, 2005
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  3. That was my concern - that the sockets or mounting would suffer. 10 AWG wire
    should handle the current okay and it is pretty standard for headlight
    wiring, but the socket contacts and any plastic near the lamps are usually

    High currents are the most common reason for connector contacts to fail.
    They start with a chicken/egg situation - it's hard to say whether heat
    comes first or the contact tension is too low. Anyway, one leads to the
    other, and so on until the contacts get hot enough to oxidize. The whole
    thing heads south in a hurry from there.

    Michael Pardee, May 28, 2005
  4. I would consider heavy duty harnesses, somehere on the net someone offered
    them, maybe IPD.
    Jeff Lesperance, May 30, 2005
  5. Jeffrey C Honig

    Andy Coles Guest

    A while back the lighting guru Daniel Stern would be giving you a rollocking
    by now for using overrated bulbs. Here is his sight.

    I have run 100/90w bulbs in a 740 and also a 760 but never gone beyond the
    standard 6/55w H7's as I believed the reflectors were polycarbonate and
    might be damaged if they got too hot. On both the 740 & 760 I did not have
    a problem.

    Whatever you do make SURE that the 3 contacts to the bulb are crimped really
    tight or you will get heat at the connection block due to resistance. This
    will also most likely cause a voltage drop and you could end up with an
    effec tive lower light output that using orig bulbs.

    Assuming you are ok with potential damage to the reflector - and if it
    already getting dull then I suppose you have little to loose - and you are
    hell bent on using the 100 W bulbs do be sure to check that the lighting
    relay will take the current.

    I have noticed that the 100w bulbs have a tendency to blacken quicker than
    regular 60/55w bulbs so you may have to change a bit more often. I always
    keep a spare with me in the glove box.

    Andy Coles, Aug 24, 2005
  6. Jeffrey C Honig

    Andy Coles Guest

    Andy Coles, Aug 24, 2005
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