Solar Charge Controller as Battery Charger only

[burraak]

Thank you everyone for taking your time in explaining the details and saving me from doing a blind shot ... really appreciate that ........

[inetdog]

So how do I know which power supply is made as current source and which one as voltage source? How do I recognize it ? because this info is something new to me I'm not an electronics expert Can you please explain this thing a little bit more ?
A power supply with 14 amp current output is suppose to be a good power supply to charge a 135AHr battery, Voltage in Meanwell 25V can be reduced to 19V and PWM will further decrease it around 14.4V therefore theoretically I was thinking of it as a perfect match

Very simple: Look for a power supply that has both a current limit adjustment AND a voltage adjustment. The current limit will protect the supply and the CC and will let the voltage go down when the current setting is reached. When the battery stops drawing high current (later stages of charging) the voltage limit will protect the battery from overcharging.

Some power supplies have a fixed (non-adustable) current limit which is there to protect the supply. If you hit that limit the voltage may drop to zero and require a manual reset.

[jflorey2]

Just got this question after reading your comment i.e Meanwell 24V 350W 14amp can also be adjusted around 19V (and current limit can also be reduced by changing R33) And in combination with PWM solar charge controller those voltages would be further reduced around 15V so Why it is OK to directly attach Meanwell to battery but not through PWM controller?

A good question. The big issues with doing it as you describe (24V supply into PWM charge controller) are 1) the nature of the load (slamming on-off) and 2) the inaccuracy of the current limit.

PWM controllers are either on or off - full load or none. That is a worst-case application for switchmode power supplies, since it forces rapid excursions from zero to full power at the point that the PWM controller starts to limit. Better power supply manufacturers test for this condition, but Meanwell is about as cheap as they come - so I wouldn't be surprised if they omit it,

Current limits on these supplies are not that accurate. I think they actually spec 105 to 135% (check your data sheet) but I've found that they can be anywhere from 100% to 140%, in one case over 150%. (Usually not an issue - the current limit is not intended to regulate current, just to protect the supply in the event of an overload or short circuit.) Thus you might see more than 20 amps from your system in current limit, and your charge controller will have to switch this.

As I mentioned, it might work. If you are going to try this, the first thing I would try is getting a good active load and setting the output to constant voltage, 13 volts. Connect the supply. If the output stays up at 13 volts and the current is reasonable (i.e. 17 amps or something) then the second issue has been addressed. Then connect the charge controller between the two devices and slowly ramp the voltage up. At some point the PWM will start opening to limit the charge. Watch the output of the supply - if it's varying between ~14 and 19 volts, and the current is ramping up and down without big glitches or overshoots - and the supply is obviously not in distress* - then the first issue has been addressed.

Or just get a charger.

(* - distress defined as blown fuses, overheating, arcing, whining or clicking, or error indications.)

[Mike90250]

most power supplies are voltage sources. You can get a current limiting PS but not many are made, and they will cost $$

[burraak]

It's just a power supply. You can use them as cheap chargers. For example, a 600 watt 48 volt supply can be dialed back to 42 volts and used to charge 36 volt electric bicycle batteries, and a 15 volt supply can easily be set to 13.8 volts and make a very cheap lead acid battery charger/maintainer. It will NOT do multi step charging, so is not suitable for lead acid applications that are cycled often. But to maintain the various lead-acid batteries I have for my job it works OK.

One of the reasons that Meanwell supplies seem to work well is that the small/medium supplies will run in current limit - in other words, they don't just shut down on overcurrent, they limit the current and continue operating. This isn't how they are designed to run, which is why it's critical to ensure that they have plenty of cooling and also why it's critical to drop the voltage on the output. If a 600 watt supply is run at 48 volts 12.5 amps it will generally work OK; that is what it is designed to do. If the same supply is run into current limit at 14 amps it is now running at 672 watts, which is outside its thermal rating. By dropping the voltage to 42 volts the supply is now running at 588 watts at a current limit of 14 amps.

(Needless to say a dedicated lead-acid charger would be far better.)

Just got this question after reading your comment i.e Meanwell 24V 350W 14amp can also be adjusted around 19V (and current limit can also be reduced by changing R33) And in combination with PWM solar charge controller those voltages would be further reduced around 15V so Why it is OK to directly attach Meanwell to battery but not through PWM controller?

[jflorey2]

Is the mean well power supply, also a charger?

Let me reiterate that it is MUCH better to buy a dedicated charger than to use a power supply, or even a power supply + charge controller.

if it is why not just charge two 12 volt batteries in series?

You need ~28 volts to charge two 12 volt batteries in series, not 24. That's why you need a 15 volt capable supply to charge a 12 volt battery.

[burraak]

Not going to work and you will destroy your Meanwell power supply. Your PWM controller is made to operate from a current source. You Power Supply is a Voltage Source. You are going to let the Magic Smoke Out of the Meanwell, and quite likely the PWM controller.

So my advice is go for it. You will learn a lesson, and you will not like it one bit.

If you have a AC power source, there is no reason to use 3-Stage Charging. All you need is a Float Charge of 13.6 to 13.8 volts. All 3-stage doe sis make the job quicker. Catch is for Solar it does not work because there still are not enough hours in a day to complete.. If you want as fast as possible you still use a Float Charger set to 14.4 to 15 volts and terminate when current tapers to .03C.

What you can do if you have electronic design experience is make a Shunt Regulator using something like a TI LM7812 and a 15-amp MOSFET to step down the Meanwall to a usable voltage. Replace D1 with a 2.4 volt Zener diode to raise the voltage from 12 to 13.8 volts.

So how do I know which power supply is made as current source and which one as voltage source? How do I recognize it ? because this info is something new to me I'm not an electronics expert Can you please explain this thing a little bit more ?
A power supply with 14 amp current output is suppose to be a good power supply to charge a 135AHr battery, Voltage in Meanwell 25V can be reduced to 19V and PWM will further decrease it around 14.4V therefore theoretically I was thinking of it as a perfect match

[jflorey2]

Is the mean well power supply, also a charger? if it is why not just charge two 12 volt batteries in series? If it's just a power supply, not sure what to do with that.

It's just a power supply. You can use them as cheap chargers. For example, a 600 watt 48 volt supply can be dialed back to 42 volts and used to charge 36 volt electric bicycle batteries, and a 15 volt supply can easily be set to 13.8 volts and make a very cheap lead acid battery charger/maintainer. It will NOT do multi step charging, so is not suitable for lead acid applications that are cycled often. But to maintain the various lead-acid batteries I have for my job it works OK.

One of the reasons that Meanwell supplies seem to work well is that the small/medium supplies will run in current limit - in other words, they don't just shut down on overcurrent, they limit the current and continue operating. This isn't how they are designed to run, which is why it's critical to ensure that they have plenty of cooling and also why it's critical to drop the voltage on the output. If a 600 watt supply is run at 48 volts 12.5 amps it will generally work OK; that is what it is designed to do. If the same supply is run into current limit at 14 amps it is now running at 672 watts, which is outside its thermal rating. By dropping the voltage to 42 volts the supply is now running at 588 watts at a current limit of 14 amps.

(Needless to say a dedicated lead-acid charger would be far better.)

[Sunking]

I only have 24V Meanwell 350W 14amp supply , The PWM change controller LS2024B which I have provide automatic 3 stage charging (and voltage can be set by user) that is why i want to use it

Not going to work and you will destroy your Meanwell power supply. Your PWM controller is made to operate from a current source. You Power Supply is a Voltage Source. You are going to let the Magic Smoke Out of the Meanwell, and quite likely the PWM controller.

So my advice is go for it. You will learn a lesson, and you will not like it one bit.

If you have a AC power source, there is no reason to use 3-Stage Charging. All you need is a Float Charge of 13.6 to 13.8 volts. All 3-stage doe sis make the job quicker. Catch is for Solar it does not work because there still are not enough hours in a day to complete.. If you want as fast as possible you still use a Float Charger set to 14.4 to 15 volts and terminate when current tapers to .03C.

What you can do if you have electronic design experience is make a Shunt Regulator using something like a TI LM7812 and a 15-amp MOSFET to step down the Meanwall to a usable voltage. Replace D1 with a 2.4 volt Zener diode to raise the voltage from 12 to 13.8 volts.

[burraak]

Is the mean well power supply, also a charger? if it is why not just charge two 12 volt batteries in series? If it's just a power supply, not sure what to do with that.

I think what separates a Power supply from a charger is functions like cutoff voltage, charging stages etc and I don't see anything like that in Meanwell Power supply specs .... However Meanwell does manufacture chargers but those are diffrent items

[Logan005]

Is the mean well power supply, also a charger? if it is why not just charge two 12 volt batteries in series? If it's just a power supply, not sure what to do with that.

[burraak]

And a new 15V 23A Meanwell 350W supply is about $40. That is a better choice.

Not a great idea. 14 amps is its rated power. Meanwells typically hit current limit between 10% and 40% above that. So not only will you be overloading your supply, you may be overloading your charge controller. It might work depending on tolerances and margins.

But it sounds like you are going to do it anyway because it's cheap, so go for it. Do it on a concrete floor so that if it blows you don't risk a fire. Odds of a fire are low; most likely it will just smoke a bit if that. Then if/when it blows, buy the other Meanwell.

thank you so much this is exactly the info I was looking for i.e the risks involved.... No I'm not going to do it ...... thank you again

[jflorey2]

I only have 24V Meanwell 350W 14amp supply

And a new 15V 23A Meanwell 350W supply is about $40. That is a better choice.

I already have equipment in hand I just want to confirm if it is OK to connect 24V 350W 14amp power supply to a 20amp Solar charge controller .

Not a great idea. 14 amps is its rated power. Meanwells typically hit current limit between 10% and 40% above that. So not only will you be overloading your supply, you may be overloading your charge controller. It might work depending on tolerances and margins.

But it sounds like you are going to do it anyway because it's cheap, so go for it. Do it on a concrete floor so that if it blows you don't risk a fire. Odds of a fire are low; most likely it will just smoke a bit if that. Then if/when it blows, buy the other Meanwell.

[Logan005]

Most smart battery charger donot come with user configurable parameters,My PWM LS2024B has 3 stage charging and voltage can be set by user that is what I like. And pls note my 20amp solar charge controller LS2024B is PWM not MPPT
and one reason why I'm asking for the solution is because I already have equipment in hand I just want to confirm if it is OK to connect 24V 350W 14amp power supply to a 20amp Solar charge controller .

go ahead and give it a shot then. But before you do, go to e-bay and order the transistor and the cap that are on the end stage of your PS, they will likely both blow, or at least they did in mine.

[burraak]

Get a proper smart battery charger. You can not feed an MPPT CC with a basic power supply. I have tried and had to repair my power supply. I love the Samlex line of power supplies. I have a 24 volt 15 amp unit that handles my constant loads and maintains my deep cells flawlessly. $200

Most smart battery charger donot come with user configurable parameters,My PWM LS2024B has 3 stage charging and voltage can be set by user that is what I like. And pls note my 20amp solar charge controller LS2024B is PWM not MPPT
and one reason why I'm asking for the solution is because I already have equipment in hand I just want to confirm if it is OK to connect 24V 350W 14amp power supply to a 20amp Solar charge controller .