2 175w MH's on a 400w ballast?

blakeoe · 09/26/2006, 08:17 PM

Can it be done? Is there a way to run two 175 watt halides on a 400 watt ballast? What about one 250 watt bulb on a 400 watt Ballast?

saveafish · 09/26/2006, 08:57 PM

ive heard about some putting a 250 on a 400 but you cant put 2 175 on a 400 it takes a lot of votage to fire them and i have heard of the exploding 6000deg glass and metal flying that is not a good thing

blakeoe · 09/26/2006, 10:12 PM

I have heard that both can be done. Seems like it may just be hear say (i hope not!!) Has anyone ever actually tried this? Maybe someone with electrician experience can help.

PaulErik · 09/26/2006, 11:18 PM

It wonâ€™t work. The reason is because the ballast is only providing voltage and current for one lamp operation. A 175 watt bulb has the same starting and ignition voltage requirement as a 400 watt bulb. It would take a higher open circuit voltage and current to get both bulbs to start in series. The bulbs will not work in parallel because the bulb with the least resistance will fire first and usually only one bulb stays lit.

PaulErik · 09/26/2006, 11:23 PM

You should always match ballasts with the proper lamp. It is highly recommended to match ANSI codes rather than just wattage because each ANSI specification varies electrically.

The ballast is what limits arc current to a metal halide bulb. If a 250-watt bulb (ANSI M58) was operated on a 400-watt (ANSI M59) ballast the lamp would be overdriven beyond manufacturers specification limits. An ANSI M58 lamp is designed to be operated at approximately 2.1 amps and an ANSI M59 ballast limits/provides approximately 3.2 amps.

cyberdude47 · 09/27/2006, 10:26 PM

As an electrician I agree 110% with paulerik DON'T TRY IT!

Avast Marine · 09/28/2006, 12:33 AM

PaulErik is someone you should defenitely listen to on this.

09/26/2006, 08:17 PM	#1
blakeoe Registered Member Join Date: Mar 2006 Location: New Orleans Posts: 370	2 175w MH's on a 400w ballast? Can it be done? Is there a way to run two 175 watt halides on a 400 watt ballast? What about one 250 watt bulb on a 400 watt Ballast? __________________ Somethings Fishy Around Here!! Current Tank Info: 72 gallon bow front

09/26/2006, 08:57 PM	#2
saveafish Registered Member Join Date: Sep 2006 Location: indiana Posts: 873	ive heard about some putting a 250 on a 400 but you cant put 2 175 on a 400 it takes a lot of votage to fire them and i have heard of the exploding 6000deg glass and metal flying that is not a good thing __________________ If it was'nt for the sea I could not see or sing ( Jimmy Buffet ) I like to glue animals to rocks and put disturbing amounts of electricity and saltwater next to each other Reefing is'nt how long you been in it. It is how deep you get in it. Current Tank Info: 400g display build, 300g sump, 75g ATO, 75g refug and a few more. Close to a 1000g. 200g mixing station.

09/26/2006, 10:12 PM	#3
blakeoe Registered Member Join Date: Mar 2006 Location: New Orleans Posts: 370	I have heard that both can be done. Seems like it may just be hear say (i hope not!!) Has anyone ever actually tried this? Maybe someone with electrician experience can help. __________________ Somethings Fishy Around Here!! Current Tank Info: 72 gallon bow front

09/28/2006, 12:33 AM	#7
Avast Marine RC Sponsor Join Date: Feb 2006 Location: Northern VA Posts: 2,446	PaulErik is someone you should defenitely listen to on this. __________________ Dan Don't rush art, you get bad art.

09/26/2006, 11:18 PM	#4
PaulErik Premium Member Join Date: Dec 2000 Location: North Charleston, SC Posts: 1,703	It wonâ€™t work. The reason is because the ballast is only providing voltage and current for one lamp operation. A 175 watt bulb has the same starting and ignition voltage requirement as a 400 watt bulb. It would take a higher open circuit voltage and current to get both bulbs to start in series. The bulbs will not work in parallel because the bulb with the least resistance will fire first and usually only one bulb stays lit.

09/26/2006, 11:23 PM	#5
PaulErik Premium Member Join Date: Dec 2000 Location: North Charleston, SC Posts: 1,703	You should always match ballasts with the proper lamp. It is highly recommended to match ANSI codes rather than just wattage because each ANSI specification varies electrically. The ballast is what limits arc current to a metal halide bulb. If a 250-watt bulb (ANSI M58) was operated on a 400-watt (ANSI M59) ballast the lamp would be overdriven beyond manufacturers specification limits. An ANSI M58 lamp is designed to be operated at approximately 2.1 amps and an ANSI M59 ballast limits/provides approximately 3.2 amps.

09/27/2006, 10:26 PM	#6
cyberdude47 Registered Member Join Date: Mar 2004 Location: BC, Canada Posts: 154	As an electrician I agree 110% with paulerik DON'T TRY IT!