A tale of 5 ballasts

[Shcrews]

so how long is the average life span for a 600w or 1000w cap? i'm sure i have some that are at least 2 or 3 years old

 

[simon]

so how long is the average life span for a 600w or 1000w cap? i'm sure i have some that are at least 2 or 3 years old

Good question. From now on, I'll be changing mine every 2 years. At least that's the plan. I'll be monitoring the light intensity and change them sooner, if needed. I've also started writing the cap change dates on the ballasts with a black marker. Figured, it would made for an easy log.

I still want to take some pics of the process. Probably this weekend.

Simon

 

[simon]

Just went to Ebay and had a look at light meters. One can be had for as little as $20! Damn, that's inexpensive. There's no reason not to own one.

This is the one I have, but there are quite a few options in its price range:

http://cgi.ebay.com/NEW-Digital-LCD...emQQptZLH_DefaultDomain_0?hash=item2c5327cc1b

Simon

 

[SmokinErb]

Quick question, I didn't even finish reading the thread, so it could have already been addressed...

But don't the caps often hold a current/charge even after they've been shut off? Sounds like a shock risk if you're not too careful.

 

[simon]

But don't the caps often hold a current/charge even after they've been shut off? Sounds like a shock risk if you're not too careful.

Yes, the cap does store a charge. Essentially, one has 2 options:

1. Let the ballast sit for an extended period (8-10 hours) and the cap will discharge over that time.

2. When removing the old cap, cutting the 2 wires and not worrying about it. Typically, a cap is discharged by touching its wires to each other. It would be pointless to do so at this point, as one can simply toss the thing in the garbage. The wiring is shielded. One would have to make a hell of an effort to make contact. You'll see what I mean when the pics are up.

Simon

 

[simon]

Updated first post with install pics.

Simon

 

[SupraSPL]

*...The capacitance value will affect lamp performance of Constant Wattage ballasts in ways that cannot be determined by the ohmmeter method.

* The capacitor in a reactor or high reactance ballast circuits will only affect the ballast power factor and not ballast operation. Capacitor failure in these circuits will cause line supply current changes possibly causing circuit breakers to activate or fixture fuse failures.

So if I understand the situation correctly, magnetic ballasts can operate without capacitors, but their power factor will be very low (.5 pf like my 70w HPS). So we add capacitors to bring the pf up and when they malfunction (which is common?) the lamp output suffers?

If that is all correct, I assume this makes a stronger case for digital ballasts?

 

[FireFly22]

It seems as though some of the stores around here don't want to let you in on the fact that the cap. needs replacement. I went to get a new dryfilm cap for my 400 and the guy was gona charge me 50$ then he told me that a new kit was 85$. I hate being wastful but I think these guys are out to sell us all new gear. Still hunting for a good price cap.

 

[simon]

It seems as though some of the stores around here don't want to let you in on the fact that the cap. needs replacement. I went to get a new dryfilm cap for my 400 and the guy was gona charge me 50$ then he told me that a new kit was 85$. I hate being wastful but I think these guys are out to sell us all new gear. Still hunting for a good price cap.

You probably didn't see the link posted earlier. 400HPS caps for ~$13:

http://atlaslightingsupply.com/cap_ignitor.html

I'll update the first post.

Simon

 

[Buffalo Brown]

http://atlaslightingsupply.com/cap_ignitor.html

trying to get one online...the cart says a price of 154.80 for one 400w hps cap.

 

[FireFly22]

Weir eh! Its the decimal point shits on that site for the cap only, I tried to order a ballast and it showed the correct amount. Sorry this is off topic but has anyone ordered from this site before? And 69$ shipping to here? My bad, they will only ship me a box of 10.

 

[grow nerd]

Excellent thread. Didn't know this about caps.

 

[Cheeb]

Good thread..important thing thats never mentioned anywhere.

Was blown away when we replaced a CAP in a friends ballast. Was notibly more intense with the new CAP..


Anyone changing a cap - make sure the uF rating on the new cap and old cap are the same. There are different types of caps out there.


.

 

[LolaGal]

Krunch: Ask the SSystems dude, or tell me if you know, or simon, anybody.

How long does it generally take for the capacitors to need changing? 4 years? 5 Years?

 

[hippie_lettuce]

Free's SunSystem (250w) had to have its capacitor changed after a couple of years (after a few times of having the light go completely out, or flickering...and at first we thought we had a faulty timer, but bought a new timer and HPS was still not working correctly), and luckily it was within warranty so the capacitor was replaced for free.

 

[simon]

Krunch: Ask the SSystems dude, or tell me if you know, or simon, anybody.

How long does it generally take for the capacitors to need changing? 4 years? 5 Years?

I really don't know. From now on, I'll be testing and possibly replacing the caps every 2-3 years. Since coming across this issue and fixing the problem, my garden is a whole different animal. Never again.

Simon

 

[SKUNK420]

So if I understand the situation correctly, magnetic ballasts can operate without capacitors, but their power factor will be very low (.5 pf like my 70w HPS). So we add capacitors to bring the pf up and when they malfunction (which is common?) the lamp output suffers?

If that is all correct, I assume this makes a stronger case for digital ballasts?

not exactly. Magnetic HID ballasts have very few parts when compared to digital ones. Kinda like car engines EFI vs. Carbs or the current problem: throttle cables or computer controlled throttle plates. Anybody who knows about car knows what I mean or if you own a Toyota or hell almost all new cars.
There pros and cons to all things.

 

[Avenger]

So if I understand the situation correctly, magnetic ballasts can operate without capacitors, but their power factor will be very low (.5 pf like my 70w HPS). So we add capacitors to bring the pf up and when they malfunction (which is common?) the lamp output suffers?

If that is all correct, I assume this makes a stronger case for digital ballasts?

There are several different magnetic ballast circuits. Some do require a capacitor for lamp operation and some do not require a capacitor for lamp operation.

The ballasts that do not require a capacitor for lamp operation, for example a Reactor circuit or a High reactance circuit can have a capacitor added to improve the power factor. but this capacitor does nothing for lamp operation.

The ballasts that do require a capacitor for lamp operation, for example Constant Wattage Autotransformers, have a capacitor in the circuit to improve power factor and also to help regulate the current the lamp is allowed to draw. So if the capacitor in a CWA ballast fails, it will affect lamp operation.

Capacitors can fail in several ways. They can fail open, shorted, or they can lose capacitance.
An open capacitor will not let the lamp operate at all.
A shorted capacitor will probably allow the lamp to draw excessive current and cause premature failure.
A capacitor that has a lower capacitance than what the ballast is designed for will underdrive the lamp resulting in lower lamp output. This is what Simon experienced. Heat is the number one killer of capacitors. Excessive heat will cause the dielectric material to breakdown, causing the capacitance to change and ultimately causing the capacitor to fail open.


Digital ballasts are full of capacitors, electrolytic capacitors that are extremely sensitive to heat.

 

[simon]

Thanks, Avenger, for adding to the thread.

With the comments above in mind, perhaps there are ways to make the caps last longer. I'm thinking of something as simple as a PC fan installed inside the enclosure to draw the air through.

Simon

 

[Enevold]

What a great thread!!!

I have some ballasts that came in metal cases with a handle on top. Very handy for moving them, but they really build up the heat and degrade the components. If anyone else has this kind, take the covers off!!!