Adjust voltage of IC GOGOGO 71.4V/5A charger
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eee291
100 kW
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flippy
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find the datasheet on the chip next to the big 100v cap.
compare the example layouts of the datasheet with the charger and find the voltage divider resistors that control the voltage and replace it with a trim pot. then you have a charger you can set to any voltage.
compare the example layouts of the datasheet with the charger and find the voltage divider resistors that control the voltage and replace it with a trim pot. then you have a charger you can set to any voltage.
Thanks, I will try. I have some basic knowledge of electronics.
If the conversion is possible, it will be an extremely cheap option for charging 48-100 volts
For example, I now need 24 Lifepo4 x 3.55V = 85.2 V
The price of a 5A charger is $ 26.
The price of a 8A charger is $ 45.
If the conversion is possible, it will be an extremely cheap option for charging 48-100 volts
For example, I now need 24 Lifepo4 x 3.55V = 85.2 V
The price of a 5A charger is $ 26.
The price of a 8A charger is $ 45.
Any?flippy said:
Wouldn't that be limited to a pretty narrow range around the intended nominal?
Obviously there are pricey adjustable units like Grin Satiator or lab PSUs, but if these cheap one-voltage units could be converted to similar functionality that would be fantastic!
flippy
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range is within reason. once you go out the nominal range of the transformer the efficiency takes a nosedive. the same happens to the saturator and friends. its inherent to the design of switchmode power supplies. in linear (lab) supplies you will hear clicking of relays if you change the voltage as it switches to different transformer taps to get into the proper range.
the cheap luna style chargers that come from aliexpress can be set to a huge range if you upgrade the capacitor to 100V and dial down the current to stay within the watt limit of the charger. they are cheap enough to not care.
that chip is a comparator. try finding the main control IC, it might be on the bottom on some boards.
the cheap luna style chargers that come from aliexpress can be set to a huge range if you upgrade the capacitor to 100V and dial down the current to stay within the watt limit of the charger. they are cheap enough to not care.
that chip is a comparator. try finding the main control IC, it might be on the bottom on some boards.
flippy
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john61ct said:
such huge powers in such a low voltage range requires dedicated supplies. getting a 1000W supply that can run from 2~10+V is "cost prohibitive" to say the least.
i have used a few HRP-600 3.3V models to charge large LFP cells individually so there was no need for balancing. they have the perfect votage range and can deliver huge amounts of amps.
if you are planning to get some big amps going then you need a supply with a dedicated range.
especially on the low ranges it really makes a difference. beyond 70 volts or so the relative difference becomes smaller so the supply can handle the efficiency loss better.
I do not need higher than 5V, could even settle for 3-5, just including LTO would be nice.
If not direct rectifier going that low, I'm thinking go with a 48V buss, the DCDC buck converters down to 5V are cheap as chips per 10-20A output, just makes for a bit of a project.
If not direct rectifier going that low, I'm thinking go with a 48V buss, the DCDC buck converters down to 5V are cheap as chips per 10-20A output, just makes for a bit of a project.
flippy
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those buck converts wont sustain those loads for long, i have tried. they are actually only 5A or so. the mosfets an diodes are just too crappy and you burn the board if you push more. replacing them takes time and money so just buying a single high power mean well will yield a more positive experience.
a HRP-300 3.3 does 2.8~3.8V at 100+ amps so perfect for LFP and LTO but ouside the range for single cell lipo.
a HRP-300 3.3 does 2.8~3.8V at 100+ amps so perfect for LFP and LTO but ouside the range for single cell lipo.
Another approach with promise, tap into the USB type-C PD spec, let a small cell / pack plug into any decent charger, it requests what it wants.
25-35W is doable with OTS cheap components, but haven't yet seen a "spoofer" can request infinite-variable voltage, so far 5V 9V and 12V presets only.
https://youtu.be/G8Tfdbmb7L8
25-35W is doable with OTS cheap components, but haven't yet seen a "spoofer" can request infinite-variable voltage, so far 5V 9V and 12V presets only.
https://youtu.be/G8Tfdbmb7L8
Just suggestion
I use power supply from an old PC to charge a hobby LIPO battery packs . They can be found today even practically free of charge … A few years ago we were replacing the computers in the company and gathered a few more 250 - 300 W of these blocks …
Just requires a super simple modification
I do not have a lot of time this week, but I'm going to continue with the topic.
The circuit diagram is very simple. There are not other chips except these. The circuit diagram is very similar to a conventional swiching power supply or dc/dc converter. Operational amplifiers turn off the device when it reaches the target voltage. This is done via the opt-in TM817 as feedback. One of amplifiers controls the fan and LEDs, the other feedback
or something like thatI apologize for my English
Here I started to specify the electrical circuit.
The output voltage should be regulated by this chip UTC3845D. Unfortunately, It is totally unknown for me.
... DC-to-DC fixed-frequency current-mode control schemes, with a minimum number of external components.…
The output voltage should be regulated by this chip UTC3845D. Unfortunately, It is totally unknown for me.
... DC-to-DC fixed-frequency current-mode control schemes, with a minimum number of external components.…
flippy
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check the datasheet. those 2 comparators are your target. they feed yes/no into the regulator chip. one is for current the other is for voltage.jelev_k said:Here I started to specify the electrical circuit.
The output voltage should be regulated by this chip UTC3845D. Unfortunately, It is totally unknown for me.
... DC-to-DC fixed-frequency current-mode control schemes, with a minimum number of external components.…
those comparators have a resistor network/divider to set their trigger point, those resistors need to be changed on the voltage side.
john61ct said:
problem is those dont do CC as far as i can see.
I never understood that concept, at least for battery charging.
AFAIK, CC happens naturally, isn't even a function of the source's power regulation,
as long as C-rate is low and the battery depleted.
Soon as the HVC setpoint is reached, charging terminates, isolates from the 48V buss.
If there never is any CV charging going on, how can you say it isn't CC?
AFAIK, CC happens naturally, isn't even a function of the source's power regulation,
as long as C-rate is low and the battery depleted.
Soon as the HVC setpoint is reached, charging terminates, isolates from the 48V buss.
If there never is any CV charging going on, how can you say it isn't CC?
eee291
100 kW
john61ct said:
That is incorrect. Most power supplies don't have CC because they are designed to have a load attached that is within the Power spec of the PSU, if the current is exceeded it will shut down. A CC PSU will lower the output voltage in order to keep the current to whatever it was set to.
So if you connect a 12V Battery that is fully discharged (~10V) into a 12V PSU you will get a over-current Showdown condition real fast.
The best thing you can do at that point is to get a boost converter and set it to a value that won't trip the PSU over-current protection.
The PSU must be capable of non-hiccup-mode current regulation. most PSUs are not---they tend to be the type that just shutdown if they can't hold a constant voltage. Some recover once the load is removed, some don't until completely power-cycled.john61ct said:
Chargers (and LED PSUs, and adjustable V/C lab PSUs) are specifically designed to hold a constant current (whatever the max current is set to), for the given load.
The current will of course taper off as the voltage goes up enough so that along with teh circuit resistance it won't allow full current anymore.
And the voltage will rise until it reaches the limit set in the PSU/charger, and the current reduces to whatever tiny amount is allowed by the votage differnece between PSU and battery and the circuit resistance.
