Converting auto electrical into domestic

[beepstar]

Hi

I have a front end off a crashed motorbike that I have decided to turn into a light for my garage. The piece has 2X 12v 55w bulbs. Please advise on what transformer I would need to power it up. Is it as simple as 240v- 12v *a?

Thanks

 

[tazz]

W/V=A....therfore... 110/12=9.16A, so nearest size 12v dc power supply would be 10A....quiet a big sod so possible din rail 10A switch mode.....but both are expensive, £120 + and not worth the outlay

 

[beepstar]

Crikey £120!!!
Thanks for the info Tazz, it definitely isn't worth the outlay. There I was thinking I could just use an old phone charger or something...

 

[ImpededLoop]

Or a 12V lighting transformer (or two transformers) as you'd use for 12V downlights.

 

[amlu]

old car battery charger you may have laying around should do the job too....

 

[davesparks]

It could be interesting to try using a battery charger!

I don't know about commercial chargers but alm of the charging circuits I have built have been of the constant current variety, so you might get a lamp that barely glows, or maybe blows instantly.

 

[DPG]

No problem this one - get LED replacement bulbs fitted to it and then you can use a much lower rated, and therefore cheaper, powers supply. Plus no high current rated switches will be needed. Daz

 

[davesparks]

Just use downlight transformers, either 2x 55W or a 115W one

 

[DPG]

I'd still stick LED bulbs in - save a fortune on electricity and it will run cooler. Daz

 

[Robotstar5]

Have a look for a 10A CB (radio) power supply? bound to be a few used cheap ones on Fleabay.

 

[Lucien Nunes]

But ensure that it is the continuous rating. Some units are rated at only 50% duty cycle as you never transmit continuously and receiving takes much less power. I'd fit LEDs or use lighting transformers.

old car battery charger you may have laying around should do the job too....

This used to be sort-of possible in the days that domestic chargers used to be a transformer and rectifier with enough resistance to limit the current. My first battery charger gave IIRC 17V off-load dropping to 11V at 5A, and would power a headlamp OK. But modern ones very often won't give any output until they see a battery of at least a few volts connected, and then start a program of varying current and voltage limits to charge the battery as fast as possible without damage. My favourite brand of 12V charger goes up to 16V briefly at the end of the equalise stage, so not good for halogen lamps!

 

[DPG]

That Lucien knows his stuff. BUT just put LEDs in for chuffs sake. No offence Lucien Daz

 

[Welchyboy1]

110va 12v lighting transformer, about £12

 

[Engineer54]

I think it's going to be just a little more involved that just changing a halogen lamp for an LED lamp on this motorbike front end!! Think about it!! lol!!

 

[DPG]

I think it's going to be just a little more involved that just changing a halogen lamp for an LED lamp on this motorbike front end!! Think about it!! lol!!

Why? LED versions of automotive halogen bulbs are commonly available. Direct replacements. Lol etc !!!