LED driver, voltage smoothing

[GILow]

Hi all,

I’ve had great success using 12 volt LED strip lighting in the cabin. But the lights flicker with any kind of voltage variation.

Can anyone point me to a decent voltage smoothing solution? Each strip draws close to one amp, so I’d be looking for something that can handle that sort of current, or even a single device capable of four amps to run the whole cabin lighting circuit.

Happy to solder something up out of components if you think that’s the best approach.

Matt

[s/v Jedi]

Originally Posted by GILow

Hi all,

I’ve had great success using 12 volt LED strip lighting in the cabin. But the lights flicker with any kind of voltage variation.

Can anyone point me to a decent voltage smoothing solution? Each strip draws close to one amp, so I’d be looking for something that can handle that sort of current, or even a single device capable of four amps to run the whole cabin lighting circuit.

Happy to solder something up out of components if you think that’s the best approach.

Matt

I bought and tested these: https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1
but while converting some lights I skipped installing them and try without first. The nice thing is that you can set a fixed “dimming” point to reduce intensity to preference.

[xxxxx]

A bit more info and a precise power usage would help.

You mention just under 1 amp each string, or about 4 amps for the entire cabin. If that's an estimation it might make a difference in your options.

As a start point, I'd recommend a few cheap 12v 3A voltage regulators. You could mount them on a board, but I'd probably just dead-bug solder it together and call it a day.

LM1085IT-12 would work. They're about $2 each if I recall correctly. If you need more power, there's a 5A variety: LM1084-12, but I'd sooner use two 3A regulators (one per side of the cabin?) than a single 5A to cover the entire thing.

Maybe one regulator per LED string. Not sure how your lights are wired up. Are they all in series? That might mean you're forced to use a single 5A regulator.

The concern is heat more than capacity. You may need a small heatsink if you use a single unit, but if you spread it you might get away with not using one.

YMMV. You'll have to experiment.

[s/v Jedi]

Originally Posted by xxxxx

A bit more info and a precise power usage would help.

You mention just under 1 amp each string, or about 4 amps for the entire cabin. If that's an estimation it might make a difference in your options.

As a start point, I'd recommend a few cheap 12v 3A voltage regulators. You could mount them on a board, but I'd probably just dead-bug solder it together and call it a day.

LM1085IT-12 would work. They're about $2 each if I recall correctly. If you need more power, there's a 5A variety: LM1084-12, but I'd sooner use two 3A regulators (one per side of the cabin?) than a single 5A to cover the entire thing.

Maybe one regulator per LED string. Not sure how your lights are wired up. Are they all in series? That might mean you're forced to use a single 5A regulator.

The concern is heat more than capacity. You may need a small heatsink if you use a single unit, but if you spread it you might get away with not using one.

YMMV. You'll have to experiment.

No, a normal regulator won’t work to stabilize 12V to 12V. You can make a stable 9V with it, not higher. You really need a switching buck/boost design DC-DC converter. Saves a lot of energy as well, instead of converting it to heat.

[xxxxx]

Originally Posted by s/v Jedi

No, a normal regulator won’t work to stabilize 12V to 12V. You can make a stable 9V with it, not higher. You really need a switching buck/boost design DC-DC converter. Saves a lot of energy as well, instead of converting it to heat.

You're right. Forgot to take into account the dropout voltage.

OP, what is the input rating for your LED strips? Often for "12v" devices it'll be 9v-14v, or something similar.

In which case, you can still use the same series LM1085 but use the LM1085-ADJ instead of the LM1085-12. You can then adjust it to 9, 10, or possibly even 11v as you like. This'll depend on how low you let your battery bank go.

Or, just use a 10v regulator (L78S10CV) or a 9v regulator (L78S09CV).

[s/v Jedi]

LED strips are 12.0V

I don’t know why the effort to do it wrong when the converters I linked are just $5 and work perfectly?

[xxxxx]

Originally Posted by s/v Jedi

I don’t know why the effort to do it wrong when the converters I linked are just $5 and work perfectly?

"Happy to solder something up out of components..."

To me it sounds like the OP might like to try things him/herfself and learn something new.

It's not "wrong" at all, but it might not be your preferred solution, and that's totally fine.

We don't know enough about the OPs setup to say either way which is right or wrong. For all we know, the problem might be undersized wiring and corresponding voltage drop.

[s/v Jedi]

Originally Posted by xxxxx

"Happy to solder something up out of components..."

To me it sounds like the OP might like to try things him/herfself and learn something new.

It's not "wrong" at all, but it might not be your preferred solution, and that's totally fine.

Okay. So you know that 12.0V is needed and that you can not make that from a 12V DC boat system using a linear regulator. So how are you going to solder a DC-DC converter together? Best you can hope for is copying the little module, buy those components and spend at least 5 times as much money, then without pcb make a reliable supply?

[s/v Jedi]

OP: if you don’t like tinkering then these are better: I recommend to use two so as not to overload one.
https://www.amazon.com/dp/B06Y5JHZG2...v_ov_lig_dp_it

[xxxxx]

Originally Posted by s/v Jedi

Okay. So you know that 12.0V is needed and that you can not make that from a 12V DC boat system using a linear regulator. So how are you going to solder a DC-DC converter together? Best you can hope for is copying the little module, buy those components and spend at least 5 times as much money, then without pcb make a reliable supply?

You are clearly way smarter than I am, and I have no idea what I'm talking about. You're right. Your way is the best way. Heck, it's the only way. Turns out these were not the droids I was looking for.

[Bill O]

Originally Posted by GILow

Hi all,

I’ve had great success using 12 volt LED strip lighting in the cabin. But the lights flicker with any kind of voltage variation.

Can anyone point me to a decent voltage smoothing solution? Each strip draws close to one amp, so I’d be looking for something that can handle that sort of current, or even a single device capable of four amps to run the whole cabin lighting circuit.

Happy to solder something up out of components if you think that’s the best approach.

Matt

Matt,
We have many strings of 12v LED strip lights in our boat and really can't remember them ever flickering. We have dimmers on every set (4 or 6 amp depending on the string), so maybe that's the difference. Do you have a dimmer for each set?

Previously we had some 5V LEDs and used a buck down regulator. Unfortunately, while the lights were good, the regulator caused a significant amount RF noise.

Only reason I mention this is to check new regulators for RF interference before you purchase many of them.

[conachair]

Originally Posted by GILow

Hi all,

I’ve had great success using 12 volt LED strip lighting in the cabin. But the lights flicker with any kind of voltage variation.

Can anyone point me to a decent voltage smoothing solution? Each strip draws close to one amp, so I’d be looking for something that can handle that sort of current, or even a single device capable of four amps to run the whole cabin lighting circuit.

Happy to solder something up out of components if you think that’s the best approach.

Matt

A bit more info wqould be handy - is the strip wired direct to the 12v boat power of does it already have a regulator?
What sort of voltage variation & what is causing that?
Plenty buck/boost dc-dc converters on ebay these days that can set constant current or constant voltage.
Little point soldering much yourself anymore unless you really enjoy it or are in a rush, jlcpcb will make it for you cheaper than you can make something yourself
https://easyeda.com/
https://jlcpcb.com/

This doesn't work that well, fet is too small and gets a bit warm but would be easy to just put a header in and use a bigger fet.
https://easyeda.com/editor#id=|fc14a...71ce36cf79a37d

[Bycrick]

Your standard voltage-regulator ICs usually require that the INPUT voltage be 2-3 volts greater than the output voltage. However, there are readily available Low Dropout linear regulators that will work with only 0.2 volts differential. So, you will get 12 volts out with an input voltage down to 12.2 volts. Below that, and the output voltage will drop. IIRC, Micrel 28000 series regulators come in a 3 and 5 amp version at several fixed voltages and an adjustable version. About $3 plus a couple of capacitors. I pop-riveted mine to a small scrap of aluminum for a heat sink, which turned out not to be necessary at 1amp load.

[nelly]

Originally Posted by GILow

Hi all,

I’ve had great success using 12 volt LED strip lighting in the cabin. But the lights flicker with any kind of voltage variation.

Can anyone point me to a decent voltage smoothing solution? Each strip draws close to one amp, so I’d be looking for something that can handle that sort of current, or even a single device capable of four amps to run the whole cabin lighting circuit.

Happy to solder something up out of components if you think that’s the best approach.

Matt

By voltage variation do you mean when you run equipment such as a water pump?

I had this same issue. Was resolved by running 4awg (overkill but whatever) from the batters to the panel. Previously something like 12awg was used - way too small.

Issue is now gone!

[xxxxx]

Originally Posted by odonnellryan

By voltage variation do you mean when you run equipment such as a water pump?

I had this same issue. Was resolved by running 4awg (overkill but whatever) from the batters to the panel. Previously something like 12awg was used - way too small.

Issue is now gone!

Yep.

Originally Posted by Bycrick

Your standard voltage-regulator ICs usually require that the INPUT voltage be 2-3 volts greater than the output voltage. However, there are readily available Low Dropout linear regulators that will work with only 0.2 volts differential. So, you will get 12 volts out with an input voltage down to 12.2 volts. Below that, and the output voltage will drop. IIRC, Micrel 28000 series regulators come in a 3 and 5 amp version at several fixed voltages and an adjustable version. About $3 plus a couple of capacitors. I pop-riveted mine to a small scrap of aluminum for a heat sink, which turned out not to be necessary at 1amp load.

Yep

Originally Posted by Bill O

Matt,
We have many strings of 12v LED strip lights in our boat and really can't remember them ever flickering. We have dimmers on every set (4 or 6 amp depending on the string), so maybe that's the difference. Do you have a dimmer for each set?

Previously we had some 5V LEDs and used a buck down regulator. Unfortunately, while the lights were good, the regulator caused a significant amount RF noise.

Only reason I mention this is to check new regulators for RF interference before you purchase many of them.

Yep.


[QUOTE=conachair;3184935]A bit more info wqould be handy - is the strip wired direct to the 12v boat power of does it already have a regulator?
What sort of voltage variation & what is causing that? [QUOTE]


Yep.


Unfortunately we just don't know enough about the OPs set up to offer any one "best" solution.


I'm betting he's wired directly and seeing the drop as loads are applied. I still contend it'd be worth trying an 85-cent regulator and see if it solves his problems to his liking.