Hella H4 Bulbs ? (1 Viewer)

[mallred]

My 80 bj42 came with Hella H4 headlights, I need a replacement bulb, the one that burnt out was 50/55 watt, In searching EBay I found a 50/100 watt bulbs for $14.99 each, should I go with these or stay with the 50/55 ? Am I correct in thinking that the first # is low beam and the second is high ?

Thansk Myrle

 

[Degnol]

Yes, you are correct. I have the 55/100s on a BMW and they are bright. But you can probably get the matching bulb at any autoparts store.



Ed

 

[Rice]

$15.00 is a little high and i'm not so sure I would do the 100W bulb without a wiring upgrade.

 

[Degnol]

$15.00 is a little high and i'm not so sure I would do the 100W bulb without a wiring upgrade.

Well, maybe a relay, but 100W divided by 12V = 8.5 amps x 2 =17 amps, not including, tail side and stop. Just don't use the brakes?

On my cruiser I have a 20 amp fuse (stock) for lights, so he should be OK, but as it is a BJ, I don't know, maybe a 24V bulb is more expensive? But that would also redice the amps to 4............................so I dunno?????


Ed

 

[Rocky_LC]

Ed -

If you are saying a BJ42 is a 24V system - then disregard all this. If his runs on 12 Volts then.....

The bulb is rated based on the supply voltage (which should be constant in his rig). So I don't think you can get away with buying a higher VOLTAGE bulb and get the same output power.

Follow my "back of the envelope" calculation....

2 electrical equations:

Power = VI (Voltage times Current)
Voltage = IR (Current times resistance)

for the 24V, 100 Watt bulb: Current = 100/24 = 4.25A
Therefore: Resistance of Bulb = 24/4.25 = 5.64 Ohms

When you go the other way with a 12 V Supply (on a 24V bulb):

Current = 12V / 5.64Ohms = 2.12 Amps
Power = 2.12 Amps * 12 Volts = 24 Watts



Correct me if I am wrong.

Rocky

 

[mallred]

Thanks guys, after thinking this over the 50/55 are just fine, they well out shine any light I have had in a cruiser and go further then I need with its speed. , BTW the 24 vlt bj40s have 12 vlt headlight systems as I just found out via the international Forum and a volt meter.

 

[honk]

Thanks guys, after thinking this over the 50/55 are just fine, they well out shine any light I have had in a cruiser and go further then I need with its speed. , BTW the 24 vlt bj40s have 12 vlt headlight systems as I just found out via the international Forum and a volt meter.

Your lights are 12 volt, but not all 24 volt cruisers have 12 volt lighting, in case someone out there relies on the above post. Every owner would do well to check his system with a voltmeter across a headlight connector, light switch on.

 

[mallred]

Your lights are 12 volt, but not all 24 volt cruisers have 12 volt lighting, in case someone out there relies on the above post. Every owner would do well to check his system with a voltmeter across a headlight connector, light switch on.

There seems like when I get to thinking I know something there is something else to learn, My education continues, Thanks

 

[Fourrunner]

You many want to consider replacing with a better lamp. Don't get me wrong, but hella's are nice, but you may want to check out Osram Silver Stars. Don't buy the Sylvana Silverstars, make sure it is the osram. These are supposed to rock. Will have a set in my truck soon. A little more money than hellas and Sylvana's but you get what you pay for.

 

[Rice]

You many want to consider replacing with a better lamp. Don't get me wrong, but hella's are nice, but you may want to check out Osram Silver Stars. Don't buy the Sylvana Silverstars, make sure it is the osram. These are supposed to rock. Will have a set in my truck soon. A little more money than hellas and Sylvana's but you get what you pay for.

Last longer, better light, or both? Where can you buy them? Thx

 

[Fourrunner]

Not sure how long they will last, most the sites I read said they lasted as long or longer than most they have tried (piaa, sylvanas, etc) Here is the place I bought mine from.

http://www.electricalconnection.com/other-lighting/bulb_euro-hl.htm

They are supposed to give off more lighting etc. Will let you know when I get them installed.

 

[Degnol]

Ed -

If you are saying a BJ42 is a 24V system - then disregard all this. If his runs on 12 Volts then.....

The bulb is rated based on the supply voltage (which should be constant in his rig). So I don't think you can get away with buying a higher VOLTAGE bulb and get the same output power.

Follow my "back of the envelope" calculation....

2 electrical equations:

Power = VI (Voltage times Current)
Voltage = IR (Current times resistance)

for the 24V, 100 Watt bulb: Current = 100/24 = 4.25A
Therefore: Resistance of Bulb = 24/4.25 = 5.64 Ohms

When you go the other way with a 12 V Supply (on a 24V bulb):

Current = 12V / 5.64Ohms = 2.12 Amps
Power = 2.12 Amps * 12 Volts = 24 Watts



Correct me if I am wrong.

Rocky

Rocky, sounds like you are well versed in some sort of EE-speak, so I will defer to you. But Bj's are at least in some part 24V. My point being that if you double the voltage, you "halve" the amperage. It works that way in AC, but maybe not in DC. Dunno.

As far as the fuseblock is concerned, amps is the shiz AFAIK. I am a big believer in relays, and that seems like the thing to do if you increase the current draw in a circuit, as in when I installed the HEI, I put in a 30A relay.

All my calculations were based on a 12V bulb in a 12V circuit or a 24V bulb in a 24V circuit. Not a 24V bulb in a 12V circuit.
Hope this clarifies my pitiful attempt at a solution!

Ed

 

[honk]

Rocky, sounds like you are well versed in some sort of EE-speak, so I will defer to you. But Bj's are at least in some part 24V. My point being that if you double the voltage, you "halve" the amperage. It works that way in AC, but maybe not in AC. Dunno.

As far as the fuseblock is concerned, amps is the shiz AFAIK. I am a big believer in relays, and that seems like the thing to do if you increase the current draw in a circuit, as in when I installed the HEI, I put in a 30A relay.

All my calculations were based on a 12V bulb in a 12V circuit or a 24V bulb in a 24V circuit. Not a 24V bulb in a 12V circuit.
Hope this clarifies my pitiful attempt at a solution!

Ed

Not at all pitiful, Ed, even though you said "AC' twice when you meant to say both 'DC and 'AC' once each , and I agree with your practice of adding a relayed supply to high current systems.

There is a voltage drop due to resistance in any length of wire. It is higher the thinner the wire. To supply headlights, particularly high draw headlights, and in your case an HEI system with battery voltage through large gauge wire from a relay activated by the OEM wiring is a sure way to supply full battery voltage to those systems.

Wire deteriorates over time. It's insulation breaks down into inefficiency, and corrosion or simple oxidation increases it's resistance, both thus lowering the voltage it may deliver. Resistance also makes heat which can eventually melt whatever insulation the wire may have and result in shorted circuitry anywhere in a vehicle. Stock wiring may continue to operate stock systems for a long time, but it is often insuffient to supply newer more powerful sytems such as those we use in upgrading vehicles.

Your (and my) relays offer a good solution. They also lessen the chance of an overheated wire element resulting in a vehicle fire or 'smokeout' of melted insulation.

 

[Degnol]

Not at all pitiful, Ed, even though you said "AC' twice when you meant to say both 'DC and 'AC' once each

There, I fixed it. Drinking and typing. Never should have taken that correspondence course.


Ed

 

[handcannon]

Couple of questions,I've never dealt with these new replaceable bulbs before. What is the difference between the H4 and H7 bulbs? Where do you find the part that replaces the sealed beam unit so that you can use these bulbs. By the way, headlight relays (and other relays) are in my future plans.