MR16 bulbs

[Packhorse]

Been looking for a high colour temp bulb but the supply seems a bit limited.

I want a spot bulb of 10deg or so, 12volt, 20-35watt, 4000k+.
Is there such a bulb? The only 4000k+ bulbs I can find here are 38 deg flood.
What spec bulbs do you guys use?

I use a 14.4volt 5amp/hour battery with a Mag light head.

 

[patdivelight]

Hi

Solux and Whitestar have a narrow spot ( 10 or 12°) in 20 and 35Watt. (colourtemp 4700K)
Do you think a 5Amp batterypack will be ok for a 35Watt bulb?
What batteries are you using? I am thinking of building a 5Amp pack with Cyclon sla 2Volts buth I'm not shure if 5Amp is ok?

 

[Parrothead_Diver]

Using a 35W bulb at 14.4V with a 5AmpH battery should give you about a 2 hour burn time. A 20W bulb at the same voltage should yeild about 3.5 hours.

 

[Packhorse]

Mmm. not to sure about that.

35w/12v = 2.9 amp so that should give you 100 min of burn time
Increasing the voltage by 20% increases current consumption by about 20%
So a 35w bulb (rated at 12v) running on a 5ah 14.4 volt battery will last about 80 min.
Also the Ah or mAh ratings are based on a longer burn time eg .5amp for 10 hours as opposed to 5amp for 1 hour. This will reduce burn time.

OK according to Ohms law a 35w 12 v bulb has a reistance of 4.114 ohms so the same bulb driven at 14.4 volt = 50 watt and 3.5 amp current draw.
Also note that your voltage will be higher on a full charge and drop as the battery goes flat. This will differ between SLA & Nicads etc. So the wattage will be even higher and burn time even lower.

I find a 20w (@12 volt) bulb is bright enough and give enough for 2 dives or even 3.

 

[Packhorse]

Neith solux or whitestar seem to be avaliable here in NZ

 

[patdivelight]

Neith solux or whitestar seem to be avaliable here in NZ

I'm about to order some bulbs myself (in a few weeks). Do you want me to order some more en send them over to you?

Solux: 35Watt in 10, 17, 24 or 36° Colortemp 4700K. Price is 15.95 Euros/piece.
Whitestar: 35 Watt in 10, 24 or 36° Colortemp 5300K. Price is 25.30 Euros/piece
Solux I order in Holland, Whitestar in Germany. There will be a small shipping kost to Belgium but as I need several bulbs the shipping cost should be only about 1 euro a piece or something.

I don't know the shipping cost from Belgium to NZ, but I can ask that at the post office...

 

[Packhorse]

Thanks for the offer. Wow they are expencive. I pay about $9 NZ (4.50 Euro) for my current bulbs or $10 for a pack of 5 50watt 36deg. But I supose you pay for quality.
I can get 20 or 50 watt 36deg 4200K for $15.
I might have a further look around the lighting outlets here and if I cant find any I wil tank you up on that offer.

Thanks