Hi Dennis.

Am only using 2 bulbs total. (I'm converting to round headlights)

Great points! I considered possible effects of higher wattage bulbs on
other drivers but didn't think of the wire from alt. to battery wire
and the potential over load to stock alternator.

In terms of effects on other drivers, maybe I'll "Watt down" on the
bulbs. Saw mention of 80/100 Watt bulbs on one of our vendor websites
so figured those would be OK.

Was planning on running a single #8 wire then split to two #12 but
will run two #10 wires as per this diagram Alistair kindly posted:

http://shufti.files.wordpress.com/2011/09/headlight-relay-light-circuit5.jpg

Great tip on carrying spare bulbs. Would do so anyhow. Speaking of
which, glad I had the sense to buy four of these H4 "Motorcycle"
headlights from BusDepot. Great deal. I have them on my '81 just with
stock wattage bulbs. ENORMOUS improvement over sealed beam!

Neil.

On Wed, Oct 24, 2012 at 7:09 PM, Dennis Haynes <d23haynes57@hotmail.com> wrote:

> Are you using "4" 100 watt lamps for the high beams? If so then you need 15
> amps not counting the in rush of starting cold bulbs. Yes check the
> resistance of a bulb at room temperature and use ohm's law to calculate the
> current. 14 gauge wiring for each set, 12 or even 10 gauge to battery. I use
> 20 amp circuits for each side. Don't forget to upgrade the wiring from
> alternator to the battery cable. Keep spare bulbs and sockets on hand for
> long trips. Melt downs and burned out filaments are common with the high
> wattage bulbs.  400 watts is about 33 amps out of the 90 max available from
> the alternator. High beams with AC or both heater fans and then the radiator
> fan can result in overloading the alternator. You may now need to consider
> power management while driving. Probably half the bulb upgrades I have done
> over the years have been pulled out. Also consider that while you may not
> get flashed by oncoming traffic you can be putting glare into vehicles you
> follow. Truckers can really get affected due to the high placement of their
> mirrors.
>
> Dennis
>
>
> -----Original Message-----
> From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of
> neil n
> Sent: Wednesday, October 24, 2012 6:33 PM
> To: vanagon@GERRY.VANAGON.COM
> Subject: Headlight Upgrade Double Check (fuses)

> Hi all.
>
> I'm installing H4 round headlights with 80/100 Watt bulbs.

> Will four 10 Amp fuses suffice for 80/100 Watt bulbs?

--
Neil n

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