LED bulbs and resistors. Sir Liam?

Aidan_M_M

Some of the newer Motorhomes need resistors fitting on the dc positive supply to the lights, if you retrofit LED bulbs where there was halogens. In that case, aside from heat, is there any actual benefit?

niloc1951

Aidan_M_M wrote: »

Some of the newer Motorhomes need resistors fitting on the dc positive supply to the lights, if you retrofit LED bulbs where there was halogens. In that case, aside from heat, is there any actual benefit?

Are you talking about road lights or those in the accommodation.

I have fitted LED's to all my interior lights, they were a straight replacement, didn't need resistors fitted.

When you say newer motorhomes, from what year do you mean.

Why?

Are they bloody stoopid load sensing things like modern indicators or someat?
Resistors create heat nil gain.

Aidan_M_M

niloc1951 wrote: »

Are you talking about road lights or those in the accommodation.


When you say newer motorhomes, from what year do you mean.

Interior lamps , in my own field it is in some factory builds , with Schaudt EBL electrics , from about 2005.
I have retro fitted the LEDs myself to loads , with no issue.

Sir Liamalot wrote: »

Why?

Are they bloody stoopid load sensing things like modern indicators or someat?
Resistors create heat nil gain.

Dunno Liam , it seemed odd to me too , a resistor + LED is surely as power hungry as a Halogen? IIRC , without the resistor fitted , the lights had a tendency to flicker sometimes . It was on a circular I got from Schaudt once.

Hrmm need more data T.

There's no good reason an interior bulb would flicker powered by non-dimmed DC. I'd expect it's a bodge solution for something.

Are these inverter powered?

Depends on the configuration of the resistor. If it's used to current or voltage limit it'll use less power. If it's used to simulate an incandescent load it'll use same.

Aidan_M_M

No, stock Dc 12v Liam. Unless it's something to do with when the AC charger is connected on EHU?

What value resistor did they recommend for which fixtures (ohms and watts)? Have you got a copy of the circular?

I've seen some rude boy's mini-PA systems cause pulsing but that's due to under wiring or too small batteries or both. DC doesn't oscillate, shouldn't be a problem.

Chargers are really sawtooth DC but the battery and charger filtering should buffer it, possible the charger has ripple which an incandescent would chew though without fuss (it'll be listed on the charger spec). I'd be tempted to try to replicate the symptoms and see if they're really necessary.

My laptop battery absorption causes a pulse on my strip lights but it's a low duty cycle PWM issue that resistors won't solve and it's in perfect timing to the load voltage drop.

Led flicker is usually due to under-loaded dimmers. The charger should be a steady enough voltage for most fixtures.

crabbypaddy

Could be an inline constant current supply if theyre using simple g4 replacements. Could also be that they want to prevent the use of regular bulbs so they can downrate the fuse. Or if the fittings are being replaced they may not be rated for the heat of a halogen.

Scenario is LEDs retrofitted to incandescents P, so they're stock fitted and designed for halogens.

I was thinking constant current but that would require them to spec. the LEDs you use, besides the leds will already have the appropriate resistors internally.

Aidan stick a DVM, on the battery while it's charging/load supply at full load and read AC volts for curiosity's sake.

hrrrmm.

Is it a parallel resistor to suppress transients from compressor fridges and water pumps and the like? I can imagine intermittent inductive loads creating issue.

crabbypaddy

Sir Liamalot wrote: »

hrrrmm.

Is it a parallel resistor to suppress transients from compressor fridges and water pumps and the like? I can imagine intermittent inductive loads creating issue.

Maybe its a parallel resistor because they've gone and put in blown bulb detection on the control panel like these newfangled can bus cars:pac:

Could be an inline filter to keep switching noise from these kind of efforts out of the radio / tv http://www.dhresource.com/albu_235118331_00-1.0x0/Wholes%202pcs/los%20G4%20MR16%20GX4%20GZ4%20G5.3%2012%20SMD%20LED%20Bulb%20Super%20Bright%20White%20Compatible%20AC%20and%20DC%2011-28V.jpg.

I'm sure Aidan_M_M will be along with photos to put us out of our misery :pac:

I love a good photo of a DVM in action.

o' course if you asked me to fix it


I'd say stick that Schaudt chocolate block teapot in the skip. Fit a TriStar hybrid system, some decent conductors and some real meters not calibrated by the manufacturer of the charger.
Then fit LEDs with a built in line filter, PWM dimming or voltage regulators. :pac: