Hmm. Very odd. My ballast is the same, except it says (1)F32T8 and the diagram shows one lamp. Do the lamps appear to be at the correct color temperature and brightness when lit?

Well if it was one F32T8 and it was running two F17T8s it would be the same thing when they're in series...
So you still have the ballast from that cheapo wrap light? Maybe you could do some crazy EOL tortures like some of us do...
And that ballast might run one F40T12 or F34T12 just fine...my bathroom light (a Lithiona 2xF32T8 wrap light) is currently running F34T12s and seems fine...the lamps don't even seem to striate/flicker all that much, in fact the only time I saw them do that was when the came in from the unheated garage and were installed...since then they've been fine.

no i junked the ballas too. The leads on these are only a couple inches long and i think splicing ballast leads in fluorescent fixtures wooks very tackey not to mention i'd have to go buy some thin solid wire lol.

BTW, if this uses 0.9A, doesn't that mean it's using 108W?

Yeah, not too efficent
But I've seen even my fair share of really lossy, inefficent ballasts too...if I had that ballast and a KILL-A-WATT meter I'd be curious to see the wattage and power factor myself...

I highly doubt it really uses 108w . I'm guessing that ballast has a horrible power factor, maybe like 0.5 or less. Most real ballasts have a power factor of 0.9 or better.

I probably would have saved the ballast leads though, the short ones can be used as jumpers or shunts for instant start ballasts.

the red lead was charred. i'm guessing the amperage is wrong too lol.

Andy, you can calculate the actual wattage of your ballasts (or any appliance) by multiplying the voltage and amperage together. My 40W GE 0.5 amp ballast draws 60W. (remember the one in my preheat shop light?) The late 40s GE ballast that was in the light from my grandpa's shop draws 0.85 amps so 102 watts just to power a 40W T12. That's more than most two lamp rapid start ballasts! The replacement ballast for the fixture is rated at 0.6A, so it consumes 72 watts for a 40W T12 lamp. So older ballasts really do use more power than one would think, but that extra power consumption just tells you it'll last longer lol.

Why longer with more power consumption? Is it just a coincidence?
BTW a .8 amp full power HPF rapid start ballast like in our old fixtures draws 96 watts apparently...80w for two 40w lamps and 16w for losses...not terrible but not wonderfully efficent either. I don't know about other ballasts; I'll have to look and calculate...and might post the results...

What do you mean by your first question?

I mean is there a reason ballasts last longer if they're less efficient or is it just a coincidence/typical case of vintage products being better quality than comparable products currently marketed?

oh that was just a joke lol. I meant that older ballasts seem to last longer and it happens to be that older ballasts also tend to have higher ballast losses than newer ones too. It's probably coincidence, but maybe companies had once sacrificed efficency for longer life?

Oh when calculating the power of non resistive loads you have to take in to account the power factor or your calculation will be wrong. You have to multiply the result you get from volts * amps (VA) by the PF to get the correct power. Usually NPF/LPF ballasts have a PF of 0.50 and HPF has a PF of 0.90 or better. You can probably find the exact power factor on the spec sheets.

so volts X amps X power factor gets the correct wattage? So if a 120V 0.5A ballast has a 0.9PF, it's actual wattage is 54 watts?