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buck converter

792 views 8 replies 5 participants last post by  wmdcrowder 
#1 ·
anybody using buck converters rather than the expensive charge controllers , seems that if you load the system with a large battery bank it should work well .
 
#4 ·
Batteries charge in three or four distinct stages based on how much charge it starts with ( or without ) and the batteries temp. A charge controller takes in feed back on the batteries condition and state of charge and temp and provides the optimum charge rate. Some now even convert extra volts into extra amps and they stop charging when the battery is fully charged of if the charger detects a problem with the battery.

Doesn't look like a Buck converter ( I assume British name for a transformer from the looks of things ) does any of those things just steps the voltage up or down. Changing the voltage changes the amps to keep ohm's law balanced .. no auto cut off and a lithium battery is a dangerous combination.. charging a wet cell with no controls could boil off your water and ruin the battery.. and in either case, how would you know when your battery was charged?

the example provided in the link is working with very low voltage and low amperage.

You don't say what kind of voltage or amperages you intend to work with ... I have parts of my system that for safeties sake needs about a 1"diameter copper wire that costs a couple bucks a foot and in a system problem may have to handle 400 amps without exploding into flame ..

You can do it with a simple transformer.. you will lose an incredible amount of power due to the inefficiencies advanced circuitry is NOT monitoring, handling, or fine tuning, and you will have to personally be continually testing the batteries state of charge to know when to stop the charging.

I use a rather complex charge controller system that is driven by computer to allow for some customization and the integration of using grid power to back up the solar panels and turn on and off the standby generator if both grid and solar is lost... this means my batteries ( about $3000 worth) will never get ruined from mischarging or running them down too far regardless of what happens.
 
#5 ·
There are two types of transformers - buck and boost [although there are combinations of both]

A "buck" transformer takes in higher voltage (line) and reduces it to a lower voltage (load).

A "boost" transformer takes in a lower voltage (line) and increases to a higher voltage (load). [most common]

These changes in voltage are directly related to how the transformer is wound and where the load-side taps are made in these windings.

One shot, you should be advised that the charge controllers used on solar setups also monitor the spikes and valleys of the voltage input of the array due to differences in available light and smooths the sine wave to the battery charger. These spikes and valleys will cause batteries to over-heat if the voltage is not controlled.
 
#6 ·
really thinking about using toyota batteries and a small harbor freight solar panel to power a remote building most likely will buy the controller but all the chinese panels put out is a trickle charge of about 45 watts on a good day thinking a led light on all the time could maintain the level if the battery bank was bigger than needed .
 
#7 ·
One shot.. everything in a solar system comes in different sizes.. you can get Chinese solar panels in every size you can get US made panels.. controllers come in different sizes... and batteries come , not only in different sizes, but in different chemistries and constructions. using the wrong type or construction of batteries can get real expensive because what works for starting a car.. doesn't last very long when used as part of a solar system and will need frequent replacing.

Why don't you just tell us exactly what you are trying to do... maybe folks here can save you a lot of money and aggravation

If you just need an LED light on 24 hours you can just get a $10 LED lantern and power it with rechargeable batteries that you recharge in your home by plugging the battery rechargers into a wall socket ? cost $20-$30 bucks all up.
 
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