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Voltage Reduction ???
- Thread starter mudshark
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- Joined
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Wow so many posts and so little information.
Solar panels always put out DC.
There are easy ways to convert voltage. It all depends on the current that these are expected to handle. As the current amount goes up then the cost for the larger semiconductors goes up. Yes, if you were in electronics you could build something but why reinvent the wheel?
In battery charging off of solar there is a device known as a charge controller. The smart charge controllers track sun output and maximize charge characteristics of the battery or bank of batteries you have. They take in a series strung higher voltage and through a digital switch arrangement convert the higher voltage to higher current. Same kind of idea as what happens on the power line pole. High voltage goes in and lower voltage but higher current comes out. The solar panels if attached directly to a battery will need a blocking diode to keep them from discharging the battery at night. The Charge controller way is what I would use. There are different ones you can get and they can be programmed for the batter bank voltage you use. 6 V is like golf cart batteries.
The use of higher voltage in solar even though it is DC is the same reason they use it in AC power line systems. Smaller wire size needed and less I squared R loss. With parallel panels the wire size would be thicker and thus more costly. The use of AGM battteries is also a plus rather than just some low grade types that will fail anyway.
Solar panels always put out DC.
There are easy ways to convert voltage. It all depends on the current that these are expected to handle. As the current amount goes up then the cost for the larger semiconductors goes up. Yes, if you were in electronics you could build something but why reinvent the wheel?
In battery charging off of solar there is a device known as a charge controller. The smart charge controllers track sun output and maximize charge characteristics of the battery or bank of batteries you have. They take in a series strung higher voltage and through a digital switch arrangement convert the higher voltage to higher current. Same kind of idea as what happens on the power line pole. High voltage goes in and lower voltage but higher current comes out. The solar panels if attached directly to a battery will need a blocking diode to keep them from discharging the battery at night. The Charge controller way is what I would use. There are different ones you can get and they can be programmed for the batter bank voltage you use. 6 V is like golf cart batteries.
The use of higher voltage in solar even though it is DC is the same reason they use it in AC power line systems. Smaller wire size needed and less I squared R loss. With parallel panels the wire size would be thicker and thus more costly. The use of AGM battteries is also a plus rather than just some low grade types that will fail anyway.
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First off there are 6v/12v trickle chargers, generally marketed for motorcycle batteries.
BUT this doesn't address the major failure mode for batteries that sit for long periods of time - sulphation.
There seem to be two types of circuits they use
a. fast high voltage pulses of limited energy that are enough of a voltage that it passes the threshold for the sulphate poisoning
b. pulses again, of a lower voltage BUT having a 3 megahertz (approx) frequency that hits the resonance of the sulphate molecule and busts it up.
There are things called solargizers (look it up and read their marketing material) that are connected TO the battery and their aim is not to top off the battery, but rather prevent sulphation - with a secondary effect of maintaining the state of charge.
I would point at some products - but I don't know if you are trying to do this on the cheap.
I am in a similar situation - I have 12v sump pump back up batteries that either go flat just when they are needed, or on the float maintainer / charger end up sulphated and unable to deliver when needed. Thus i need to come up with the right mix for the system.I am still researching it, and some added urgency has intruded since I discovered two marine deep cycle batteries in my Dad's basement. THEY if not terminally sulphated or dead will be the basis of the system.
If those two batteries are useless, I am going to get an Optima spiral cell marine deep cycle battery, and one heck of an expensive charger, maintainer and anti-sulphation pulser system. My car has an Optima spiral cell battery and it has lasted over TWICE (10 years and counting!!) as long as any other battery I have ever used in an automobile.
BUT this doesn't address the major failure mode for batteries that sit for long periods of time - sulphation.
There seem to be two types of circuits they use
a. fast high voltage pulses of limited energy that are enough of a voltage that it passes the threshold for the sulphate poisoning
b. pulses again, of a lower voltage BUT having a 3 megahertz (approx) frequency that hits the resonance of the sulphate molecule and busts it up.
There are things called solargizers (look it up and read their marketing material) that are connected TO the battery and their aim is not to top off the battery, but rather prevent sulphation - with a secondary effect of maintaining the state of charge.
I would point at some products - but I don't know if you are trying to do this on the cheap.
I am in a similar situation - I have 12v sump pump back up batteries that either go flat just when they are needed, or on the float maintainer / charger end up sulphated and unable to deliver when needed. Thus i need to come up with the right mix for the system.I am still researching it, and some added urgency has intruded since I discovered two marine deep cycle batteries in my Dad's basement. THEY if not terminally sulphated or dead will be the basis of the system.
If those two batteries are useless, I am going to get an Optima spiral cell marine deep cycle battery, and one heck of an expensive charger, maintainer and anti-sulphation pulser system. My car has an Optima spiral cell battery and it has lasted over TWICE (10 years and counting!!) as long as any other battery I have ever used in an automobile.
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The way to reduce voltage is through a regulator. The 12 to 35 V dc can be put into a LM7805 regulator- OK that gives out 5V but you want 6V so you put a couple of Silicon diodes in series with the ground path. so 5V plus 1.4 is 6.4 Vdc. Now if you want more than 1 to 1.2Amps. Then you need to start to build a Power transistor current amplifier. This is where heat sinks and TO-3 transistors get involved maybe a few in parallel.
There are adjustable regulators too like the LM317T. It gives the voltage regulation out but the higher power will be done by the power transistors.
Before you go off making the regulator you need to figure out the power and voltage input from the panel. The Amazon Panels are a joke and for low capacity projects.
Real solar panels are much larger and can deliver up to 320W peak.
http://sunelec.com/solar-panels
These are some of the real ones.
Keep in mind most cells give off only .5V dc ad can be up to 8 amps if the Mono 6x6" ones. So if you want to have 24Vdc out you will need 48 cells. Figure it out 48 cells at .5 foot square leaves you with 24 square feet required plus frame. So you might end up with a 4 foot by 6 foot panel.
24 V X 8A is just under 200W. Panels work best when at correct temperature and at a 90 degree angle to the sun.
I measured a battery drain once on a car that was sitting and it read 3 amps.
From what I saw in charge controllers on E bay I am not sure they would be best for car batteries as
the reference different battery chemistries. A linear regulator might be the way to go or a switcher will be more efficient.
As you can see this gets kind of involved.
There are adjustable regulators too like the LM317T. It gives the voltage regulation out but the higher power will be done by the power transistors.
Before you go off making the regulator you need to figure out the power and voltage input from the panel. The Amazon Panels are a joke and for low capacity projects.
Real solar panels are much larger and can deliver up to 320W peak.
http://sunelec.com/solar-panels
These are some of the real ones.
Keep in mind most cells give off only .5V dc ad can be up to 8 amps if the Mono 6x6" ones. So if you want to have 24Vdc out you will need 48 cells. Figure it out 48 cells at .5 foot square leaves you with 24 square feet required plus frame. So you might end up with a 4 foot by 6 foot panel.
24 V X 8A is just under 200W. Panels work best when at correct temperature and at a 90 degree angle to the sun.
I measured a battery drain once on a car that was sitting and it read 3 amps.
From what I saw in charge controllers on E bay I am not sure they would be best for car batteries as
the reference different battery chemistries. A linear regulator might be the way to go or a switcher will be more efficient.
As you can see this gets kind of involved.
You can simplify it easily by dropping the solar component. Remove it from the vehicle and put an easily obtainable battery maintainer on it.
I know people who are using the "cheap" Harbor Freight one. Right now it's $5.44 with a super coupon.
I'm using a Shumacher SC-1200A on my deep cycle marine battery.
If it's got to be solar, keep us informed about what you end up using/building.
I know people who are using the "cheap" Harbor Freight one. Right now it's $5.44 with a super coupon.
I'm using a Shumacher SC-1200A on my deep cycle marine battery.
If it's got to be solar, keep us informed about what you end up using/building.
Yes I will, only reason I'm thinking solar is the past couple years the pickup has spent the winters
parked out by the hay field bout a quarter mile from power, and on occasion I use it around the place.
Pain to pull the battery and replace it for occasional usage .... thot it might work for this purpose, dont know for sure yet
parked out by the hay field bout a quarter mile from power, and on occasion I use it around the place.
Pain to pull the battery and replace it for occasional usage .... thot it might work for this purpose, dont know for sure yet
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I have the perfect solution.
It's a switching regulator using with an adjustable under voltage lockout / threshold circuit, precise voltage regulation and current limiting or optional FOLDBACK current limiting.
FIXED COMPONENT ADJUSTMENTS ONLY.
All discrete components, easy to build. Reliable, stable, no maintenance required.
http://forums.phxaudiotape.com/show...g-Buck-Voltage-Converter-for-Battery-Charging
It's a switching regulator using with an adjustable under voltage lockout / threshold circuit, precise voltage regulation and current limiting or optional FOLDBACK current limiting.
FIXED COMPONENT ADJUSTMENTS ONLY.
All discrete components, easy to build. Reliable, stable, no maintenance required.
http://forums.phxaudiotape.com/show...g-Buck-Voltage-Converter-for-Battery-Charging
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Switchers are more efficient but harder to maintain. The Solar solution is not the idea one either. It will cost to implement and then be an attraction to thieves. I am sure a couple or 300 watt panels would keep the battery topped off but then additional battery maintenance is not a bad idea either.
Panels have to be maintained in the right position and free from dirt. They work in space but on land
there are other perils like wind, Dirt and people looking to get a hold of the panels. Which ever way you want to go. If the vehicle is always at the same place you could build a solar charging station like Tesla is doing across the northern states.
Panels have to be maintained in the right position and free from dirt. They work in space but on land
there are other perils like wind, Dirt and people looking to get a hold of the panels. Which ever way you want to go. If the vehicle is always at the same place you could build a solar charging station like Tesla is doing across the northern states.
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http://www.pulsetech.net/Assets/Misc/Our_technology_White_Paper.pdf
The 12v solargizer ($77) does NOT charge, the solar cells are providing only enough power to run the pulse module.
http://www.tstonramp.com/~rhinocharge/pulsesol.html
The pulsing COUNTERACTS the self discharge, and keeps the battery ready with whatever charge it started with.
It takes a DIFFERENT unit with additional solar cells (more wattage, ) to do a maintainer float charge type action.
(2 watt $225, 5 watt $315, 10 watt $599)
http://www.global-merchants.com/home/solargzr.htm
AND... get this: the float voltage VARIES by battery temperature. For a vehicle that is out of a controlled environment, this is important and MUST be included in the design.
My take on all this - The $77 solargizer , charge the bettery, park it, disconnect the battery to eliminate any drain from the vehicle, and install the solargizer - which I repeat will NOT charge the 6v battery any further.
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