999zip999 said:
It says 15 amp max. does that mean I can't use 3 HP 660 12 volt 40 amp power supply in series ? Or through resistors . Or and ?
Plus a fan.
I think I see what you are asking, But lots of potential for wrong reply as I believe maybe a typo had crept in.
1; A 40 amp supply? Is that one of these server PSU's ? 4 amp maybe?
2: But for now assuming 40 amps corrrect. If a supply is rated at 40 amps, does not mean that it will pump out 40 amps regardless, just than it
can supply 40amps if asked to. ( Unless it says 12volt 40 Amp Constant Current......but in this case very very unlikely.)
3: Stringing these PSU's in series if 40 amp and 12 volt, Why ? one will be more than enough to drive that board.
But if they are 4 amps supplies, then yes you coudl string them together to give 4 ampsat 36 volt. Butbe careful that the outputs of each are fully isolated from input. So get a multi meter in resistance/ continuity range and check for continuity between the negative output and the input wires/ ground wire. If there is a circuit between output negative and input / ground, then no, you cant just series them, not without out working on them. You would hsve to open the supply up and modify it so output is isolated. Otherwise the second supply will short circuit the first supply to ground the instant you power them on.
BUT...If they are 40 amp supplies, then you won't need to series them. One will be enough. The 12 volt and 40 amp is 480 W. The module I linked to is 400 W, so a single 40 amp PSU is plenty. 12 volt in will allow that board to give up to 80 volt out.
But..... If those supplies, as I suspect , are really 4 amps, then 3 in series will be fine, as long as my point (3 above, ) is noted, and output of each isolated from input side of PSU. But three in series still won't give the power to run the board to its full capacity. Three of them will be 36 volts at 4 amps, so 144 watt.
But saying all that, it all becomes a bit bulky using three x 4 amp supplies Just try and find a PSU with greater power output. One single unti marked with a wattage of 400watt or greater, with an output voltage below your final battery voltage
This unit is a boost convertor , , only increases output. So of you ran one from 3 12 volt supplies in series, that is 36 volt, so I'd say output of the board would not be able to go below 36 volt.
If you have to start combining multiple PSU's to run this, then it no longer is a great idea in my thoughs, as other solutions then become more convienent. Like a ready build BMS battery charger.
I'd considered this unit more as a bike mounted 'grab a boost' charge device. This, the CC/CV part woudl be built on to the bike, then you just carry /leave at work /borrow any spare PSU for a quick improptu charge where needed.
The general public get nervous when they see our LiPo battery packs, or big bulky chargers with wires and sparks. But plug your bike into a little black box that looks like something they see everyday poweing their phone/printer/pc monitor etc, and no one blinks an eye. I can see three of them from where I am typing this.
I had no envisaged usign this as a hig current charge controller..it only outputs 10 amps after all.
I'd see it pared up with a small 65-100 watt wall wart type PSU to give an amp or so charge top up while at work or similar. With max voltage set well below pack max. So for my 20series 83v HoC pack I'd set thsi to about 79-80 volts to give a 1 amp top up charge.
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