Adding "Cap" to avoid lights "dancing/flickering"

[trekerboy]

I've built my AS's electrical system from the ground-up when we renovated it over the last two years. We've been full time in it for about 5 months now and it really bugs me that when we're playing the stereo the LED flights "dance/flicker" to the beat of the music. I'm considering adding a capacitor to avoid this scenario.

My current electrical system can be diagrammed like this:



Thinking of adding the capacitor like this:



As you can see, I have the capacitor between the battery bank and the whole 12v system, instead of just between the battery bank and the stereo.
Is adding a capacitor in this configuration a bad idea for some reason?

I searched the forum and Google alike and haven't found much in terms of people adding capacitors to their RV electrical systems like this. Am I the only one getting this "dance/flicker" when playing the music loudly?

[rmkrum]

Better to have a close look at the tightness of your 12 volt connections. Both grounds and hot sides. Sounds like something is loose.

The battery acts like a really huge capacitor if the wiring is solidly connected. Another capacitor really won't do much.


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[Lumatic]

Sounds very 60s. I'm no electrician but think I remember someone who added a diode to the circuit

[alano]

A capacitor across the battery wouldn't do anything. You'll never find a practical capacitor with sufficient capacity and with low enough internal resistance to compete with your batteries. Like the other comments I would check all your connections, particularly the ones feeding your LED lights as a first step.

[HiJoeSilver]

If your led's are flickering to the heavy beat them you've probably got a loose wire somewhere getting rattled loose by the bass.

How many watts is your stereo. Do you have a converter on feeding the 12v system.

[SuperTrouper]

Back in the day, we used to pay good money to get a light organ that flickered to the music at Radio Shack! I agree that it sounds like a loose connection somewhere to me. Does your coach have dimmers for the lights?

https://www.youtube.com/watch?v=e4lmiYTVZFU

[m.hony]

Adding a capacitor works in car stereo to keep the headlights from dimming with the beat of the music.
A larger AGM battery also helps in car stereo.
A second dedicated battery also helps in car stereo.
My Pathfinder has an AGM battery and a cap for the powerful aftermarket custom stereo.
My Tundra has an AGM battery for the powerful aftermarket stereo.
I think all motorcycles have AGM batteries. I have a powerful aftermarket stereo on the bike, too.
Anyway, the lights dim with the bass less than they used to in my vehicles now due to these upgrades.

[Jekerrville]

Led lighting is very particular to current. The voltage can vary a bit without much issue. But if the current is starved the intensity of the light will start to fade and flicker.

Unlike filament type blubs that require bridge circuit (AC powered) to dim, leds use a current pump to change intensity.

So, when Mr. Base woofer calls for lots of current to blast out "Stairway to Heaven" the AS lead acid battery does not have the rise time to supply the current fast enough and the led lights dont have the steady current supply and they flicker.

A couple of fat daddy electrolitic capacitors in series to the power leads of the base amp will supply the current needs and the leds will never see the current drop .

Also, by placing the caps on the power lead into the amp, the AS AC to DC converter circuits wont get upset. A 100 meg ohm resistor tween output of caps and ground will "bleed" down the caps after a long period so a potential (voltage) will not be floating around to cause the trailer power converter to become upset and fry.

Capacitors are not batteries. They are charge pumps. They store charge and release it quickly when needed. Batteries are not really designed to give a blast of power quickly. That is part of the reason why letting batteries get below a certain level then calling for lot of current makes them puck their little guts.

VataBoom!

[ijustlee]

A cap is what they use in cars so would probably work. Be aware that if you need to charge a big cap from 0 Volts they can draw a tremendous amount of current since they have no internal resistance and blow fuses. You might need to have some way to pre-charge the cap if it loses it's charge for some reason like storing the trailer.

[DavidsonOverlander]

Originally Posted by rmkrum

Better to have a close look at the tightness of your 12 volt connections. Both grounds and hot sides. Sounds like something is loose.

I had a problem with LED lights flickering when the pump ran. It turned out to be a loose a connection. The connections all looked good, but I replaced the wires to the pump just to be sure and the flickering stopped.

[trekerboy]

Originally Posted by Jekerrville

Led lighting is very particular to current. The voltage can vary a bit without much issue. But if the current is starved the intensity of the light will start to fade and flicker.

Unlike filament type blubs that require bridge circuit (AC powered) to dim, leds use a current pump to change intensity.

So, when Mr. Base woofer calls for lots of current to blast out "Stairway to Heaven" the AS lead acid battery does not have the rise time to supply the current fast enough and the led lights dont have the steady current supply and they flicker.

A couple of fat daddy electrolitic capacitors in series to the power leads of the base amp will supply the current needs and the leds will never see the current drop .

Also, by placing the caps on the power lead into the amp, the AS AC to DC converter circuits wont get upset. A 100 meg ohm resistor tween output of caps and ground will "bleed" down the caps after a long period so a potential (voltage) will not be floating around to cause the trailer power converter to become upset and fry.

Capacitors are not batteries. They are charge pumps. They store charge and release it quickly when needed. Batteries are not really designed to give a blast of power quickly. That is part of the reason why letting batteries get below a certain level then calling for lot of current makes them puck their little guts.

VataBoom!

Thank you for this thorough overview!

My goal in putting the cap right at the 12v panel was to handle the quick demands for power not only from the stereo but also to other high draw appliances (like the water pump). The water pump flicker I can live with (only happens when we start using the pump, which isn't that often) but the stereo induced flicker is something I'd like to fix. Sounds like a cap at the positive lead to the stereo is my best bet.

[trekerboy]

Originally Posted by SuperTrouper

Does your coach have dimmers for the lights?

Yes, it does, for 4 of the 6 switches controlling LED lights anyway. The ones that seem to flicker the worst are the ones NOT on the dimmers.

[Jammer]

Originally Posted by trekerboy

Is adding a capacitor in this configuration a bad idea for some reason?

Nope, although you can add it anywhere between the battery and the loads, as long as you keep the leads short on the capacitor.

I searched the forum and Google alike and haven't found much in terms of people adding capacitors to their RV electrical systems like this. Am I the only one getting this "dance/flicker" when playing the music loudly?

Maybe.

As suggested upthread, you should check to make sure that all the electrical connections are clean, bright, and tight. You would also want to be sure that there's enough electrolyte in the battery.

The next thing to ponder is the internal resistance of the battery. Batteries have a low internal resistance when new, and it gradually increases with age and use. The higher it is, the more of a voltage change there is when the current changes.

If your battery is older you might try replacing it first. That may very well clear up the problem.

If you do go with a cap, sizing and charge/drain concerns are the same as for car audio:

http://www.crutchfield.com/S-AQpcJHW...itors/faq.html

The car audio industry has caps for sale that look cool and have suitable mounting means and terminals, or you can buy one from an electronics place and put those things together yourself.

[m.hony]

The one in my Pathfinder looks very similar to the one pictured on Crutchfield, but it is blue and very old, like from the year 2000.
I don't guess they can change much except the color or graphics.