I have this automotive bulb 12V 75/75CP P45t , its in candle power not watt , so can it be loaded to 150 watt photovoltaic panel ?
i have read on google that cp can't be converted to watt , do you think 75 cp is close to 55 or 60 watt in withstanding ?

 

Hello,

In your post you stated p45t.
Here is one at ebay:
http://www.ebay.com/itm/12v-headlig...Parts_Accessories&hash=item58a72ead82&vxp=mtr

It is a 40/45 Watt lamp.

Bertus

 

the lamp you pointed to is for NARVA but my lamp is flosser , what is the relation between p45t and the power it can load.?

 

Hello,

The p45t is the size of the base.
The round bulb will be 40/45 Watt.
If it is a halogen ( H4 ) bulb it will be 60/55 Watt.
See this page for more info:
http://www.donsbulbs.com/cgi-bin/r/b.pl/625545-12v-60|55w-p45t-h4~flosser.html

Bertus

 

no it isn't halogen , here is my lamp http://flosser.com/commerce/products/asymmetrische-lampen/12v-7575cp-p45t/

 

Hello,

Here is a page about the candle power:
http://www.donsbulbs.com/cgi-bin/r/d.pl/cp.html

Bertus

 

It looks like it might also be 75 watts, so the panel probably won't be able to get it going because the cold resistance will be very low.

 

It looks like it might also be 75 watts, so the panel probably won't be able to get it going because the cold resistance will be very low.

He could have built the electronic load I designed for him and done his experiment three times by now.

 

He could have built the electronic load I designed for him and done his experiment three times by now.

There are always some people that don't want to do it, "my" way. When I start feeling irritated about it, I take a break from AAC because the real problem is that I feel over-invested. Sometimes that takes a few weeks.

Of course, you can choose whatever method or combination of methods you want. I only wish success for you.

 

thanks to MikeML ,I connected two bulbs in series as load to the panel and it works but it wasn't of full power , i measured volt and current and it give about 30 watt over every lamp . i don't know they could withstand more if the panel power increased.

 

Hello,

Here is a page about the candle power:
http://www.donsbulbs.com/cgi-bin/r/d.pl/cp.html

Bertus

it is written in this page that
"A 100 watt common incandescent bulb emits about 120 candlepower."
if i trusted this info , my lamp might have been around 62 watt .

 

It looks like it might also be 75 watts, so the panel probably won't be able to get it going because the cold resistance will be very low.

This came up on another thread a while back. I tested a 12v 50W bulb, and found the filament would light reliably from any current over about 40% of the normal running current, so the 12v 50W (4 amp) bulb would light from any current over approx 1.6 amps.

A couple of other 12v bulbs performed very similarly.

Although the cold resistance value of the element is very low, >=40% of rated current is enough to get the filament metal over the thermal runaway point where it starts to glow (and its resistance then jumps right up).

 

Yes, I think now about what the IV curve looks like and there is current to heat it up. Interesting.