Power supplies like the DroK
- Thread starter e67
- Start date
adamantium
Solar Enthusiast
- Joined
- Jul 17, 2022
- Messages
- 172
What are you talking about? Do you need an 120VAC to 12-48VDC converter?
adamantium
Solar Enthusiast
- Joined
- Jul 17, 2022
- Messages
- 172
Still not clear on what you are looking for. Are you looking for a bench power supply with precise continuous voltage and current adjustments, or are you just looking for an internal AC to DC power supply with fixed outputs between 12 and 48VDC? What is your price range? How many amps does it need to supply?
A DROK power supply that matches your basic description could mean anything.
Like this:
That type of power supply is very inexpensive and all of them are no name Chinese brands.
What is it for and why are you asking on a DIY solar forum? Are you trying to use it as a charger, LED driver, CCTV camera, testing electronics, what?
Can't really help you without a better understanding of what you need. Surely you can just search Amazon for '48V AC to DC power supply'.
Bench Power Supply Basics
www.tek.com
E36200 Series Autoranging Power Supply
The E36200 series single and dual output autoranging power supply can power devices that typically require higher output power with larger watt ratings.
www.keysight.com
adamantium
Solar Enthusiast
- Joined
- Jul 17, 2022
- Messages
- 172
I see, you want to build what Will built.
In his latest version of the milk crate backup power system he used the Drok 10A variable voltage constant current power supply. Its the one I linked to above. He says he likes that model the best. If you read the reviews, most seem to like it. However there have been some reported problems with the labels for the terminals and some component failures. Just like any other brand. For the price its a good power supply.
For the purpose of charging, all you need is any variable voltage power supply that can go up to 14.6VDC (12V LiFePO4 battery). So you don't need anything with a higher voltage than that. That means you can look for 24, 36, and 48 VDC power supplies. Drok sells a 20A 24VDC version of the same thing that Will used that would charge your battery twice as fast at the same price.
You can also use these alternatives:
Amazon.com: IMAYCC 110V AC to 48V DC Converter Max 480W 10A,0-48V Adjustable Power Supply with LED Display,Variable Switch Transformer Regulated 5V 10V 12V 24V 48V Buck Converter for CCTV Computer Lab. : Electronics
Amazon.com: IMAYCC 110V AC to 48V DC Converter Max 480W 10A,0-48V Adjustable Power Supply with LED Display,Variable Switch Transformer Regulated 5V 10V 12V 24V 48V Buck Converter for CCTV Computer Lab. : Electronics
www.amazon.com
There is no guarantee any of these power supplies are going to be better than the Drok. I would just buy the 24VDC@20A Drok. If you go any more expensive than $40 on one of these power supplies, you would be better-off buying a 12V LiFePO4 battery charger. A charger will be constant current and then constant voltage, whereas the Drok will just be constant voltage. The charger may also turn off automatically when done and won't be accidentally adjustable to a voltage greater than the battery can be charged at. You are better off with the charger not the power supply.
For example:
You can also get some good 14.6VDC LiFePO4 chargers on Aliexpress.
Vigo
Solar Addict
I've had maybe 4 of the chinese meanwell knockoff style power supplies so far.
I currently have a 0-24v 20a and a 0-48v 10a that work and that i'm keeping. Have one that i've blown up and repaired multiple times but is now a parts donor, and one i sent back because it wouldn't do what i wanted... Both the adjustable ones i have will go all the way down to 0 as far as what's on the screen, but i haven't verified their actual output with a meter other than in the voltage ranges I actually use them at. If you are trying to use them for something like that be SURE to verify the actual output voltage with a meter and don't trust the screen. Also put them somewhere where NOTHING will touch them because any slight contact to the potentiometer knob at all is going to ruin your experiment. But, from what i remember about turning the knobs all the way to 0v, it should work..
Also regarding bad reviews, the main patterns i've picked up have to do with running them at max load, and trying to adjust them to voltages they aren't specifically listed to hit. For example, i've had a '12v' power supply be able to adjust to ~17.5, and another one not able to go above 12.3. Well, they both do 12v which is what they SAY they will do, so if i don't like it i should probably buy something that actually states in its product description that it can do what i want it to, right? In my opinion if you are trying to reach any voltage between the common denominations (12, 24, 48., 60 etc) you should buy a zero-to-whatever adjustable model where 'whatever' is the next size up. So if you're trying to hit 14.6, it would be safer to buy a 0-24 model than a 'fixed' 12v model and adjust the pot, because it may or may not get you there.
As far as running them at max current, again kinda depends how you're doing it but it would still be safer to stay under the current rating for longevity. How you're doing it as in, are you orienting it in a way that convection flow is fighting the internal fan? Is it shoved up against something interfering with the cooling flow? Are you 'shorting it' to circuits that instantly take it to max current repeatedly, or are you hooking up at a lower current and then adjusting pot til current hits max, etc. Some things are harder on it than others. With an adjustable 0-to-whatever model you can just lower the voltage, make connections, and then ramp it up. Unfortunately when hooking it up to a lithium cell you can't really do that because you don't know the voltage you're setting it to until the battery rises to that voltage, so you'd have to measure it open circuit, turn it off, hook it up, turn it on, and then measure what the current is doing. Some of them are sold with current adjustments but most aren't so it's a decent likelihood that into a discharged lithium cell it's just going to sit at its max current until voltage rises near the setpoint. If you're just using them for balance charging then the voltage delta might be small enough that you're not running it at max current all that often. I've had one run at max current 8+ hrs a day for weeks and not break, so i'm not saying dont hit max current, but if you're switching a max-current circuit on/off repeatedly or doing max current and letting the power supply overheat, don't be surprised if it fails quickly.
I currently have a 0-24v 20a and a 0-48v 10a that work and that i'm keeping. Have one that i've blown up and repaired multiple times but is now a parts donor, and one i sent back because it wouldn't do what i wanted... Both the adjustable ones i have will go all the way down to 0 as far as what's on the screen, but i haven't verified their actual output with a meter other than in the voltage ranges I actually use them at. If you are trying to use them for something like that be SURE to verify the actual output voltage with a meter and don't trust the screen. Also put them somewhere where NOTHING will touch them because any slight contact to the potentiometer knob at all is going to ruin your experiment. But, from what i remember about turning the knobs all the way to 0v, it should work..
Also regarding bad reviews, the main patterns i've picked up have to do with running them at max load, and trying to adjust them to voltages they aren't specifically listed to hit. For example, i've had a '12v' power supply be able to adjust to ~17.5, and another one not able to go above 12.3. Well, they both do 12v which is what they SAY they will do, so if i don't like it i should probably buy something that actually states in its product description that it can do what i want it to, right? In my opinion if you are trying to reach any voltage between the common denominations (12, 24, 48., 60 etc) you should buy a zero-to-whatever adjustable model where 'whatever' is the next size up. So if you're trying to hit 14.6, it would be safer to buy a 0-24 model than a 'fixed' 12v model and adjust the pot, because it may or may not get you there.
As far as running them at max current, again kinda depends how you're doing it but it would still be safer to stay under the current rating for longevity. How you're doing it as in, are you orienting it in a way that convection flow is fighting the internal fan? Is it shoved up against something interfering with the cooling flow? Are you 'shorting it' to circuits that instantly take it to max current repeatedly, or are you hooking up at a lower current and then adjusting pot til current hits max, etc. Some things are harder on it than others. With an adjustable 0-to-whatever model you can just lower the voltage, make connections, and then ramp it up. Unfortunately when hooking it up to a lithium cell you can't really do that because you don't know the voltage you're setting it to until the battery rises to that voltage, so you'd have to measure it open circuit, turn it off, hook it up, turn it on, and then measure what the current is doing. Some of them are sold with current adjustments but most aren't so it's a decent likelihood that into a discharged lithium cell it's just going to sit at its max current until voltage rises near the setpoint. If you're just using them for balance charging then the voltage delta might be small enough that you're not running it at max current all that often. I've had one run at max current 8+ hrs a day for weeks and not break, so i'm not saying dont hit max current, but if you're switching a max-current circuit on/off repeatedly or doing max current and letting the power supply overheat, don't be surprised if it fails quickly.
adamantium
Solar Enthusiast
- Joined
- Jul 17, 2022
- Messages
- 172
What do you mean by 2.6v? The battery Will used if I remember correctly was a 12 LiFePO4 battery. That is 14.6V max. Individual LiFePO4 cells run at 3.65V each. So I don't know what you are talking about. But if for some reason you have some cells at 2.6V then yes it is supposed to support 0-24V or 0-48V depending on which power supply you are talking about. I don't have one though so I have no idea how good they are for your purpose. To help you better you need to provide more information about what you have or want to have. There are too many things on the table, and I can't see what you are pointing at.
Again, if you are trying to do battery charging, especially individual cell charging, and you don't have experience with all of this, you are much better off getting a single cell charger or a 12V LiFePO4 cell charger for your battery. Otherwise we need to discuss all the details about what you are trying to accomplish, rather than answer a question here or two without any context.
A charger will be constant current and then constant voltage, whereas the Drok will just be constant voltage. Can you explain this please?
What about this Victron?
adamantium
Solar Enthusiast
- Joined
- Jul 17, 2022
- Messages
- 172
Sure. Chargers for LiFePO4 batteries are designed to go through two phases while charging. They push a constant amount of current at the beginning because the cell is low on charge and wants to drink it up. That means that they basically generate enough voltage to maintain the same current for the first part of the charging process. Then when the voltage reaches the maximum they maintain a constant voltage on the cell until it finishes its charge. This means that as the cell finishes up the current flow decreases. That is the way batteries work. The can accept a lot of current at the beginning but then it slows down as they fill up.
With a constant voltage charger you are pushing a constant voltage on the cell from the beginning. That means you really don't have control over the amount of the current being pushed into the cell. If the cell is too small, you may be pushing too much current into it. Pushing too much may significantly reduce the life of the cell. Using a constant current charger ensures that you are only pushing into it what you have set the charger to, and that usually means that it charges at a lower voltage at the beginning and takes longer.
So what you need to know is what your battery cells charge rate is (typically referred to in units of C). A C is the capacity of the cell, so a 1C charge rate means you can charge it at the same current rate as its rating. A 1/2 or 1/3C rating means you can only charge it at 1/2 or 1/3 of its rating. So a cell rated at 40Ah with a 1C charge rating means you can charge it a maximum of 40A. You can control this with a charger that throttles the current rate automatically by watching how much current is flowing. Some charges have a fix current rate and others are variable. Even some cheap power supplies are like this. Drok sells another version of its power supply that allows you to control both the current and the voltage, and it works like a charger. Its price is about the same as a fixed rate charger.
Simple power supplies only charge with a fixed voltage or only allow you to adjust the voltage not the current. Those mentioned earlier in this thread are variable voltage power supplies, meaning you can control the voltage but not the current. They are not chargers, they are power supplies. To control the current you would need to add a current meter and only start the charger at a current rating your cells can accept by lowering the voltage to whatever is needed for that current. Over time you would have to continue increasing the voltage manually until you reached the maximum voltage of the cell.
With a constant voltage charger you are pushing a constant voltage on the cell from the beginning. That means you really don't have control over the amount of the current being pushed into the cell. If the cell is too small, you may be pushing too much current into it. Pushing too much may significantly reduce the life of the cell. Using a constant current charger ensures that you are only pushing into it what you have set the charger to, and that usually means that it charges at a lower voltage at the beginning and takes longer.
So what you need to know is what your battery cells charge rate is (typically referred to in units of C). A C is the capacity of the cell, so a 1C charge rate means you can charge it at the same current rate as its rating. A 1/2 or 1/3C rating means you can only charge it at 1/2 or 1/3 of its rating. So a cell rated at 40Ah with a 1C charge rating means you can charge it a maximum of 40A. You can control this with a charger that throttles the current rate automatically by watching how much current is flowing. Some charges have a fix current rate and others are variable. Even some cheap power supplies are like this. Drok sells another version of its power supply that allows you to control both the current and the voltage, and it works like a charger. Its price is about the same as a fixed rate charger.
Simple power supplies only charge with a fixed voltage or only allow you to adjust the voltage not the current. Those mentioned earlier in this thread are variable voltage power supplies, meaning you can control the voltage but not the current. They are not chargers, they are power supplies. To control the current you would need to add a current meter and only start the charger at a current rating your cells can accept by lowering the voltage to whatever is needed for that current. Over time you would have to continue increasing the voltage manually until you reached the maximum voltage of the cell.
adamantium
Solar Enthusiast
- Joined
- Jul 17, 2022
- Messages
- 172
I just realized that in the quote above where I said variable voltage constant current power supply, is confusing. What I should have said is variable voltage and fixed current. The power supply from Drok does not let you adjust the current during charge. The current will be at the maximum the power supply can deliver at the voltage you select. A charger with constant current will adjust the voltage automatically to ensure a constant current. If you battery accepts a charge current greater than the charger, then you don't need to worry about this, since the charger or power supply cannot push more current than the cells can accept.
adamantium
Solar Enthusiast
- Joined
- Jul 17, 2022
- Messages
- 172
I don't know anything about it. It says it has 7 stages. Nothing needs 7 stages. Like I said all you need are 2 stages. Everything else is a gimmick or related to after the charge is over. That is usually for trying to revive dead lead acid batteries for example or maintaining a float charge after charging. Its an awfully expensive charger for a 12V battery, and is only 15 amps. Sounds like a trickle charger for a boat to me. You can probably use it for other things as long as it supports the right voltages.
After watching the video its sounds like it has two modes: one for lead acid and one for lithium ion whatever they mean by that. It may or may not suited for LiFePO4 batteries. The price range for LiFePO4 12V chargers is around $60 for 30-40A and down in the $40 range for cheap 10-20A chargers off aliexpress. I personally don't care if my battery charger has Bluetooth. I want a dedicated charger for the battery I am charging that has as high a current rating as my battery. The smallest batteries for storage are at least able to charge at 40A, and most accept 250A or higher. Especially in a 12V configuration. A 12V 15A charger will take days to weeks to charge anything large. It sounds to me like that charger is for trickle charging one lead acid battery. The size and its specs indicates this. If that is what you need then great. Better deals at harbor freight or anywhere else.
Thanks for the breakdown. Wish Will would have explained this in video because it is hard to grasp for beginners. I returned the Drok and will get a charger at some point. Im in a van and there no free AC outlets so not important. But I did use it to charge my Jackery 1000 for back up, I got Drok up to about 13 volts, maybe 14, could not get 14.4 but I got 200 watts, 50 more from using Jackery charger. Now using 600 watt invertor to charge Jackery.
What size battery / brand charger you have. I have a 100 amp hour. A car battery shop I go to wont charge lifepo4 battery, do you why?
Thanks for your answers.
adamantium
Solar Enthusiast
- Joined
- Jul 17, 2022
- Messages
- 172
If we are talking about the little stuff, I have several chargers, inverters, and batteries. I have a 300Ah 48V, 60Ah 12V, 20Ah 48V, and other batteries. I have several 1S, 4S, 8S, and 16S LiFePO4 chargers. Most of the stuff I have is from China. I don't have a little portable like your Jackery. I build that stuff myself out of the parts I have.
A car battery shop won't charge a LiFePO4 battery because they probably don't have a charger for that chemistry and don't want to be blamed for damaging the battery. Car batteries are lead acid not lithium, and there are many varieties of lithium batteries with different voltages and charging rates. LiFePO4 is just one type. Also if the charger pushes more current than the battery can accept, then it will destroy the battery. However LiFePO4 batteries can be charged with lead acid chargers as long as the battery can be charged at the rate the charger supplies. They just aren't able to get up to 14.6V. A lead acid battery charger usually charges up to around 13.8V. If you have a battery with a high enough charging rate, then a lead acid charger will work okay. For example a charger that charges at 20A can charge a battery that has a charge rate of 20A or more. You need to know what you battery charge rate is and what the charger's chare rate is as I mentioned up above in the prior messages.
Also if you are charging a 12V LiFePO4 battery, you need a BMS. The cells can get out of balance without a BMS, and you can end up over charging or over discharging some of the cells. You can charge the cells individually with a 1S (3.65V) charger if you don't have a BMS, but it is better to just charge all of them at the same time with a 4S (14.6V) charger. You can get a list of many LiFePO4 chargers with varying capacities by going to Aliexpress.
For example:
1S (3.65V):https://www.aliexpress.com/item/225...00029447909257!sea&curPageLogUid=EsBiO4olVM7c
4S (14.6V):https://www.aliexpress.com/item/225...dd!64985166477!sea&curPageLogUid=rAyjoWgPnT0B
A car battery shop won't charge a LiFePO4 battery because they probably don't have a charger for that chemistry and don't want to be blamed for damaging the battery. Car batteries are lead acid not lithium, and there are many varieties of lithium batteries with different voltages and charging rates. LiFePO4 is just one type. Also if the charger pushes more current than the battery can accept, then it will destroy the battery. However LiFePO4 batteries can be charged with lead acid chargers as long as the battery can be charged at the rate the charger supplies. They just aren't able to get up to 14.6V. A lead acid battery charger usually charges up to around 13.8V. If you have a battery with a high enough charging rate, then a lead acid charger will work okay. For example a charger that charges at 20A can charge a battery that has a charge rate of 20A or more. You need to know what you battery charge rate is and what the charger's chare rate is as I mentioned up above in the prior messages.
Also if you are charging a 12V LiFePO4 battery, you need a BMS. The cells can get out of balance without a BMS, and you can end up over charging or over discharging some of the cells. You can charge the cells individually with a 1S (3.65V) charger if you don't have a BMS, but it is better to just charge all of them at the same time with a 4S (14.6V) charger. You can get a list of many LiFePO4 chargers with varying capacities by going to Aliexpress.
For example:
1S (3.65V):https://www.aliexpress.com/item/225...00029447909257!sea&curPageLogUid=EsBiO4olVM7c
4S (14.6V):https://www.aliexpress.com/item/225...dd!64985166477!sea&curPageLogUid=rAyjoWgPnT0B
Ampster
Renewable Energy Hobbyist
I haven't had any issues using a Meanwell power supply with one of those Drok boost/Buck converters to charge some of my hobby packs of Nissan Leaf modules. Depending how I configure them the Nissan module packs can have unusual voltages. One pack is 32 volts to power a wood chipper.
Similar threads
