I would just like to state, feel free to PM a notification if you post on this thread and its been quiet for a month or so or its likely I won't notice it for weeks(if your lucky). I don't browse the forum much at all especially this section. Tho I do visit the site pretty much daily and use the chat quite often.
I used a 23watt ballast to light a 14 watt normal output T5 which is a 21" bulb. It has been running 11 hours daily for a few months now with no issues. Same bulbs same ballasts. The ballasts inside CFLs can very quite a bit, so that could be a factor as well. In my original post, if memory best serves me both the ballasts shown there are of similar wattages. When I was originally experimenting with these ballasts I typed this on another forum:
"This post is already long enough but I would like to add that the Westinghouse ballasts initially seem better then GE, Feit electric, and sylvania. Overall they are pretty similar. GE and Feit electric seem pretty much identical(Feit being the one in the first post). Sylvania and westinghouse both have a resistor in one of the power leads(inside the white sleeve). Westinghouse is the only one that had 2 capacitors,which together had a higher rating then the same wattage Feit ballast. They were also the only ones who bothered to insulate the wires from the ballast to the bulb. Funny as its also the cheapest. The 23 watt 4 pack cost me about $7 at fleetfarm."
I would also like to point out that despite what I said in my first post about overpowering with these ballasts. From my experiences I no longer believe this is true. I have a kill-o-watt meter and my fixture uses two 23 watt ballasts to power two 14 watt bulbs. Over all the power consumption is only 29-30 watts. Tho the light is plenty for the tank it is running on. This does highly suggest these ballasts can't overpower a bulb.
@ MoneyMitch, the whole point of this is to use non-specific ballasts as T5 ballasts are silly over priced
@ romanlutsk I really recommend ring wire terminals for attaching the wires to the bulbs as I did in the original post. You need the blue 16-14 gauge ones. Its like $1 for over a dozen at any hardware store. For the most part they fit the pins very snugly, a few need squished a tiny bit with a pliers. For T5s you do need to strip the plastic coating off one of the terminals as their isn't enough room. Only do one and I would wrap it with electrical tape. They also work very slick for power compact fixtures. I bought a used square-pin fixture once. A current satellite that did work very nicely for 5-6 years before ballast failure. For some silly reason they have square and straight pin bulbs, with the square ones being more expensive(and much smaller selection). The cheapest solution was cutting off the socket and using a couple cents worth of wire terminals. It ran just fine this way for 4-5 years.