There are certain things that I would like to do, but due to not having a powerful power supply, cannot. My projects are often very limited by the power supplies I have lying around. You don't really find anything above 100 or 200 watts. I cannot really invest a huge amount of money and get a LBPS that serves my needs. And if I want something to be portable, I can maybe use a power bank for charging a phone, or some standard batteries, but nothing more powerful. And the capacity is often pretty low too.
So to be able to make more power hungry projects portable, and have access to very large amounts of power, getting a medium sized SLAB (sealed lead acid battery) seems worthwhile. The voltage may not be the most precise, and it would need to be recharged a lot. But typically you can get at least a few 10s of amps and 100s of watts out of it. I found this one on ebay that is 12V 18AH and can, allegedly, supply 10KW. I am highly skeptical of this, as that would be almost 1 kA! But maybe it is the peak power, pulsed for a small fraction of the second. Maybe there is a datasheet or something that states the actual continuous discharge.
https://www.ebay.com/itm/Mighty-Max...877461?hash=item2cb8f8d9d5:g:xzcAAOSwjDZYga3K
So do people think I could continuously discharge it at 100-200 amps? I would be happy with around 70-100 amps max for discharge. But I want a decent headroom (maxheadroom lol) so that I do not shorten the lifespan and have other issues. If people think there is no way I could actually continuously and safely discharge it at those currents, then some suggestions for other batteries would be great. I want at least 10 AH and 12V, and it should be under $40.
And once I have a decent SLAB, I still need a way to charge it. I looked around and the chargers are insanely expensive (a 10A one is almost $100)! So a DIY approach would probably be more effective. I do not want it to take more than a few hours to charge it from almost completely depleted to almost 100%. Less time is obviously ideal. I have heard some stuff on what is needed to charge it properly but do not know too much. I have just heard that you need a voltage higher than the nominal voltage and constant current for certain parts is ideal. I am considering getting this CC/CV buck converter and this SMPS. Then I can figure out the ideal voltages and currents later.
https://www.ebay.com/itm/24V-DC-15A...622296?hash=item3d65f5f298:g:xFQAAOSwrjZbA2xn
https://www.amazon.com/Aideepen-Con...stant+current+constant+voltage+buck+converter
Would that work to charge them quickly and properly? And what does everyone recommend for voltages and currents here? I want optimal lifetime.
Also I try to avoid mains whenever possible. But given that almost all the power supplies require you to wire the mains yourself, I guess I will have to. But where would I get a mains cord for it, and what is the best way to avoid shorts and exposed wires here? Is heatshrink or something else required to ensure safety? Those screw terminals, especially with how close together they are, are making me nervous. I understand electrical safety and take all the necessary precautions, but do not really have any experience wiring mains.
I also need to have short circuit and over-discharge protection. I plan to be careful, but accidents do happen. And I am not going to be constantly measuring the voltage. So for overcurrent protection a fuse probably makes the most sense, as opposed to some sort of high current switch and shunt/hall. I want a fuse that can handle a few seconds of a little bit over the maximum current, or high inrush currents, but will blow if it is over by a little for more than a few seconds or by a lot for more than a fraction of a second. Or if there is some other resettable commercial option that is economical that would be nice. But I have heard that fuses are notorious for allowing overcurrent close to the max for many minutes. So what ratings do I look for in a fuse? What products do people suggest here?
For overdischarge, I plan to have a mosfet that turns an active buzzer with resistor on when the voltage is low enough. It should only consume a few 10s of mAs, and alert me to disconnect and start charging it. I will make sure to not leave it unattended. Is this a terrible idea, or will it be good enough for my purposes?
Then once I have all the equipment there is still the issue of the high current wiring. From what I have heard, screw terminals and think metal bars are commonly used for those types of connections, as opposed to soldering. Welding is more common if it needs to be permanent (like in a welding power supply). I do not really have the stuff to weld so I guess I will have to use other connectors. If someone could recommend some sort of pack that includes a lot of terminals and stuff, that would be great. Flexible welding wire seems like the best option here but I do not really know where to get it. Suggestions there would also be great.
So to be able to make more power hungry projects portable, and have access to very large amounts of power, getting a medium sized SLAB (sealed lead acid battery) seems worthwhile. The voltage may not be the most precise, and it would need to be recharged a lot. But typically you can get at least a few 10s of amps and 100s of watts out of it. I found this one on ebay that is 12V 18AH and can, allegedly, supply 10KW. I am highly skeptical of this, as that would be almost 1 kA! But maybe it is the peak power, pulsed for a small fraction of the second. Maybe there is a datasheet or something that states the actual continuous discharge.
https://www.ebay.com/itm/Mighty-Max...877461?hash=item2cb8f8d9d5:g:xzcAAOSwjDZYga3K
So do people think I could continuously discharge it at 100-200 amps? I would be happy with around 70-100 amps max for discharge. But I want a decent headroom (maxheadroom lol) so that I do not shorten the lifespan and have other issues. If people think there is no way I could actually continuously and safely discharge it at those currents, then some suggestions for other batteries would be great. I want at least 10 AH and 12V, and it should be under $40.
And once I have a decent SLAB, I still need a way to charge it. I looked around and the chargers are insanely expensive (a 10A one is almost $100)! So a DIY approach would probably be more effective. I do not want it to take more than a few hours to charge it from almost completely depleted to almost 100%. Less time is obviously ideal. I have heard some stuff on what is needed to charge it properly but do not know too much. I have just heard that you need a voltage higher than the nominal voltage and constant current for certain parts is ideal. I am considering getting this CC/CV buck converter and this SMPS. Then I can figure out the ideal voltages and currents later.
https://www.ebay.com/itm/24V-DC-15A...622296?hash=item3d65f5f298:g:xFQAAOSwrjZbA2xn
https://www.amazon.com/Aideepen-Con...stant+current+constant+voltage+buck+converter
Would that work to charge them quickly and properly? And what does everyone recommend for voltages and currents here? I want optimal lifetime.
Also I try to avoid mains whenever possible. But given that almost all the power supplies require you to wire the mains yourself, I guess I will have to. But where would I get a mains cord for it, and what is the best way to avoid shorts and exposed wires here? Is heatshrink or something else required to ensure safety? Those screw terminals, especially with how close together they are, are making me nervous. I understand electrical safety and take all the necessary precautions, but do not really have any experience wiring mains.
I also need to have short circuit and over-discharge protection. I plan to be careful, but accidents do happen. And I am not going to be constantly measuring the voltage. So for overcurrent protection a fuse probably makes the most sense, as opposed to some sort of high current switch and shunt/hall. I want a fuse that can handle a few seconds of a little bit over the maximum current, or high inrush currents, but will blow if it is over by a little for more than a few seconds or by a lot for more than a fraction of a second. Or if there is some other resettable commercial option that is economical that would be nice. But I have heard that fuses are notorious for allowing overcurrent close to the max for many minutes. So what ratings do I look for in a fuse? What products do people suggest here?
For overdischarge, I plan to have a mosfet that turns an active buzzer with resistor on when the voltage is low enough. It should only consume a few 10s of mAs, and alert me to disconnect and start charging it. I will make sure to not leave it unattended. Is this a terrible idea, or will it be good enough for my purposes?
Then once I have all the equipment there is still the issue of the high current wiring. From what I have heard, screw terminals and think metal bars are commonly used for those types of connections, as opposed to soldering. Welding is more common if it needs to be permanent (like in a welding power supply). I do not really have the stuff to weld so I guess I will have to use other connectors. If someone could recommend some sort of pack that includes a lot of terminals and stuff, that would be great. Flexible welding wire seems like the best option here but I do not really know where to get it. Suggestions there would also be great.