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Discussion Starter · #1 ·
I installed landing lights into GT turn signal housings. 35amp stock alternator can't handle the additional 2x100w lighting load when combined w/headlights. Alternator also visually appears to struggle a bit in combined run of headlights and modest peaks of stereo/amp/CDchanger (BeastieBoys lay down a bigger hurt on dash lights than Johnny Cash ;) ).

So, I need more juice... but how much? Future GT plans don't include much more DC consumption... but some growing room would be good.

80 bucks can get my Bosch alt rebuilt to 55amps... and it drops right back in.

80 bucks can also get 63amps (or more) of GM alt w/misc. brackets... rids of the external regulator... just sucks a couple extra modification hours from my non-Opel life.

I'm at an impasse... do I really need more than 55amps? :confused: Can someone advise (or direct me towards an existing list or formula) ballparking my current component draw/requirements -
-like:
Headlight brights
wiper motor high
fan high
a lump sum of misc stock GT relays, coil & bulbs
2 100w flood bulbs
a bridged 400w-peak mofset amp
a 40w deck
a cd changer
...& "maybes" for down the road...
convert to electronic ignition?
electric radiator fan?
a capacitor for the stereo amp?

Thanks!
-Dan
 

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some #'s

1 watt = 1 Volt * 1 Amp

Headlight brights
-legal limit is 60 watts each- @10A for the pair

wiper motor high
[email protected]

fan high
[email protected]

a lump sum of misc stock GT relays, coil & bulbs
[email protected] is probably a good # for everything

2 100w flood bulbs
-just over 8A each, though they are notoriously inefficient, so maybe more

a bridged 400w-peak mofset amp
-surprisingly, probably 12-20A tops

a 40w deck
-6-8A typically

a cd changer
-1/4A

...& "maybes" for down the road...
convert to electronic ignition?
-might actually lower the load slightly, shouldn't increase it any unless you go with a "hotter" coil

electric radiator fan?
[email protected]

a capacitor for the stereo amp?
-Doesn't add anything, just helps keep the "bump" in the stereo from "bumping" the lights


Aside from the fabrication time, the GM alternator is one of the best bang-for-the-buck upgrades you can do to the Opel, in my opinion. Once done, a failed one onle costs $35 to replace, but if there are issues with the Opel one you're out the same $100 again.

I should start fabing-up the required brackets for the GM alternator myself to sell. What do you suppose a set of brackets would be worth to make the swap into a 20 min chore? Hmmmm....
 

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If the 35 watt alternator was adequate before you added the 100 Watt lights and you don't have any intention of adding any additional high wattage accessories, you will need an additional 17 amps. (200W / 12 volts) That brings your total to 52 amps. The efficiency of the lights doesn't affect the required current. 100 watts is 100 watts. a low efficiency lamp just doesn't put out as much light (candle power) for the same wattage as a high efficiency lamp.
 

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Stephen, from one of my GM books for the V-6 mod, there was a statement on alternators that described the alternators as having the case halves riveted together were of low amperage output, the ones that were bolted together were 100 amps and higher. This is with the basic one wire output, kinda that I'm putting in the GT. It has the standard one wire output to the battery connection at the solenoid and a second plug with a single wire that would go to the lite in the ammeter, for sensing voltage. BTW this alternator is for the 95/96 V-6 Camaro, and may be a prime candidate for the Opel replacement, because of the connection for the sensing voltage. JMTCW.
 

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Discussion Starter · #5 ·
oldopelguy said:
Aside from the fabrication time, the GM alternator is one of the best bang-for-the-buck upgrades you can do to the Opel, in my opinion. Once done, a failed one onle costs $35 to replace, but if there are issues with the Opel one you're out the same $100 again.

I should start fabing-up the required brackets for the GM alternator myself to sell. What do you suppose a set of brackets would be worth to make the swap into a 20 min chore? Hmmmm....
Awesome fast reply(s)... thanks!

I'm definately now on board with you on GM alt upgrade opinion. And since dmcbrass took the pain out of addition for me (thanks :D ), I see that a 55amp Bosch isn't a very strong option for growing room. Man, 35amp w/stock equip. was cutting it close!

Prefabed GM/Opel conversion bracket worth? Serious or not, I like these kind of hypothetical questions! Well, past car projects have forced me to qualify my car-hobby labor/value vs. painting the house to my wife... I break even at only 8 bucks an hour (acquiring tools and supplies do factor in to this figure)... but the low figure LOST the argument for me. My free time is worth about $5/hour (I'd wait in line for you at that rate) ... but if my wife was giving me crap, I'd have to charge $10! So, FWIW, to me: one-time-shot cost on SB Chevy brackets is $25, plus 2 hours modification labor (what I'd bill myself + what I'd make standing in line [with wife] = $18/hour) at $36. I guess if you could supply bolt-up brackets below the $60 mark, I personally would feel like I got a steal!

Thanks Again!
-Dan
 
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