12VDC Solar to 1.2VDC Regulator?

CCinPA

Member
Location
Central PA USA
I have a requirement to connect a 12VDC Solar-panel to a 1.5VDC device. Since the 12-volts may fluctuate, I need some sort of regulator? If so, what type?
 

iceworm

Curmudgeon still using printed IEEE Color Books
Location
North of the 65 parallel
Occupation
EE (Field - as little design as possible)
What is the current requirement at 1.5V?
What is the tolerance on the 1.5V?
edit to add: What is the tolerance on the 12V?
Does the 1.5V require isolation from the 12V?
Can you build your own circuit board and mount in a box?
Or, are you required to buy a commercial product?​

Is lack of listing going to be an issue?

If the current is small, tolerance is <.1V, no isolation required, you can build you own, and lack of listing is not an issue, the solution is four parts if you count the heatsink, <$20.
If you have to buy a commercial product, isolation required, <.05V tolerance, probably still no listing, maybe a recognized component, you are in the $X00 range.
 
Last edited:
What is the current requirement at 1.5V?
What is the tolerance on the 1.5V?
edit to add: What is the tolerance on the 12V?
Does the 1.5V require isolation from the 12V?
Can you build your own circuit board and mount in a box?
Or, are you required to buy a commercial product?​

Is lack of listing going to be an issue?

If the current is small, tolerance is <.1V, no isolation required, you can build you own, and lack of listing is not an issue, the solution is four parts if you count the heatsink, <$20.
If you have to buy a commercial product, isolation required, <.05V tolerance, probably still no listing, maybe a recognized component, you are in the $X00 range.
Agree more details needed. If low current required, a simply IC linear voltage regulator for 5 bucks (plus a heatsink) would do it.

A "12 volt" solar panel will typically be ~17 V open circuit.

Try googling something like "dc-dc buck converter" or maybe "adjustable dc-dc converter" to find a plug and play unit.
 

synchro

Senior Member
Location
Chicago, IL
Occupation
EE
Also, what is the requirement on ripple or noise on the 1.5V output. For example, if it's for lighting it would be relatively tolerant to noise. But an audio application would not be.
 

iceworm

Curmudgeon still using printed IEEE Color Books
Location
North of the 65 parallel
Occupation
EE (Field - as little design as possible)
now that we have thoroughly intimidated you with specs, just make some guesses.

What you are asking for is not real common. I have not heard of anything COTS. Here is a possible solution.

vicor regulator evaluation board from mouser
https://www.mouser.com/Search/Refine?Keyword=pi3421 ~$60

I have always liked vicor - they make pretty good stuff.

This particular chip is not isolated.
If you need isolated, vicor makes an isolated dc-dc converter to feed the regulator. You will have to make your own board. Shouldn't be to tough, 2 pins in - 2 pins out. ~$200

For commercial systems, a problem will be replacement parts. You will have to document really well.
 

winnie

Senior Member
It looks like you are trying to link https://www.amazon.com/DROK-90010-Waterproof-DC-Buck-Converter-Voltage-Regulator-8-22V-to-1-15V-5V-12V-3A-Adjustable-Output-Power-Supply-Transformer/dp/B00C0KL1OM

That is the basic concept for what you want. A 'voltage regulator' is a device that somehow adjusts its operation to maintain a somewhat constant output voltage while its input voltage (and output current) fluctuates.

With that said, the devil is in the details of the actual operation, and thus the specifications that you were asked for. The details that you don't even know to ask about are the reason that this is not a DIY forum, however for 12V to 1.5V I don't think anyone will fuss. This particular device might be perfect, or might be wrong 6 different ways from Sunday. This particular device is almost certainly not UL listed, is made for relatively high current, and consumes a significant amount of power to function.

-Jon
 

iceworm

Curmudgeon still using printed IEEE Color Books
Location
North of the 65 parallel
Occupation
EE (Field - as little design as possible)
CC you did great. - way better than anything I found
just go to their website and check the specs. See if it matches what you need
 

iceworm

Curmudgeon still using printed IEEE Color Books
Location
North of the 65 parallel
Occupation
EE (Field - as little design as possible)
I don't know what Gar has in mind, however try these for starters:
  • 24V solar cell charging a 12V battery. Do you need some kind of a charge controller, so the battery doesn't boil out?
  • Conversion efficiencies. The solar panel is 1.5W, the ornament is 1W. If the solar pumps 1.5Watt-hours into the battery, you get less than 1.5WH out of the battery. I don't know what the efficiency of the 12V - 1.5V converter. However, I'm pretty sure that 1 watt in will give you less than 1 watt out. How many hours of load operation per day are you planning? Do you have enough power to keep the battery charged?
  • What do you have in mind for a battery voltage cutoff? Letting SLA batteries go completely flat tends to degade the battery.
You might look through Instructables. They have a lot of stuff. Something might be similar.

Just some random thoughts
 

CCinPA

Member
Location
Central PA USA
I don't know what Gar has in mind, however try these for starters:
  • 24V solar cell charging a 12V battery. Do you need some kind of a charge controller, so the battery doesn't boil out?
  • Conversion efficiencies. The solar panel is 1.5W, the ornament is 1W. If the solar pumps 1.5Watt-hours into the battery, you get less than 1.5WH out of the battery. I don't know what the efficiency of the 12V - 1.5V converter. However, I'm pretty sure that 1 watt in will give you less than 1 watt out. How many hours of load operation per day are you planning? Do you have enough power to keep the battery charged?
  • What do you have in mind for a battery voltage cutoff? Letting SLA batteries go completely flat tends to degade the battery.
You might look through Instructables. They have a lot of stuff. Something might be similar.

Just some random thoughts
As I ponder all this great information... Is it really true that a24v into a 12v will "boil" the 12v? Then taking this one-step-at-a-time... Would replacing the 12v rechargeable with a 24v rechargeable be a step in the right direction?
 

iceworm

Curmudgeon still using printed IEEE Color Books
Location
North of the 65 parallel
Occupation
EE (Field - as little design as possible)
Don't know.
Batteries generally require a charge controller.
Unless the power source id not sufficient to charge the battery. Which might be your case. If you are charging all day,running all night, the energy budget looks pretty close.

You really need to do some of the research
For example, did you ever get a copy of the converter specs?
 

gar

Senior Member
190826-0643 EDT

CCinPA:

From your first post, a 1.5 V device.

What is the device? How far from the 1.5 V power source to the 1.5 V device? Is there just one and only one device at one location? If many devices, then how are they distributed in space? How much peak current does the device require, and all devices? What is the average steady state current to the device, or devices? Why such a low voltage device?

The specifications you provided were insufficient.

What is your electrical background?

.
 

winnie

Senior Member
As I ponder all this great information... Is it really true that a24v into a 12v will "boil" the 12v? Then taking this one-step-at-a-time... Would replacing the 12v rechargeable with a 24v rechargeable be a step in the right direction?
Another way to read this question is 'what happens to the batter when it gets overcharged'? The answer depends upon the battery chemistry. For example, if you overcharge a lithium ion battery, then you can get metallic lithium to plate out...you don't boil the battery but you might ignite it. When you overcharge NiMH then you get electrolysis of water to Hydrogen and Oxygen...NiMH cells are designed with bit of catalyst, so for low rates of overcharge the H2 and O2 simply recombine to make water and heat. At high rates: yes, you boil the battery. Some types of Lead Acid battery will do the same; others will vent flammable gas.

If you carefully match the source to the battery then you won't have a problem. But if you don't want to use a small solar panel on a relatively large battery, then you need a charge controller.

-Jon
 
Another way to read this question is 'what happens to the batter when it gets overcharged'? The answer depends upon the battery chemistry. For example, if you overcharge a lithium ion battery, then you can get metallic lithium to plate out...you don't boil the battery but you might ignite it. When you overcharge NiMH then you get electrolysis of water to Hydrogen and Oxygen...NiMH cells are designed with bit of catalyst, so for low rates of overcharge the H2 and O2 simply recombine to make water and heat. At high rates: yes, you boil the battery. Some types of Lead Acid battery will do the same; others will vent flammable gas.

If you carefully match the source to the battery then you won't have a problem. But if you don't want to use a small solar panel on a relatively large battery, then you need a charge controller.

-Jon
To continue with Jon's post, for flooded lead acid batteries, if the charge rate is below a certain percentage of battery amp hour rating, then you don't need a charge controller since the charger will never overcharge the battery. I dont remember the figure, you can probably Google it easily. Think of those motorcycle trickle chargers that you just leave on continuously. They put out about an amp. You can get a small simple chsrge controller from a place that sells solor/off grod equipment like backwoods solar.com.
 
Top