TheBloke Posted June 30, 2015 Author Report Share Posted June 30, 2015 Hi guysMy DNA 200 arrived this morning. Very exciting. Or it would be if I had anything to wire it to My battery and wires turn up tomorrow.I am an absolute novice at mod making so I want to keep this as simple as possible. It will be a desk installation, probably not even in a box. I just want it up and running for testing and experimentation. As soon as I can buy a professional mod with the chip in, I will (I tried to order the Opus 200 but Opus won't ship outside the US )So although I bought a 3s battery pack, I'm wondering if a power supply might be even easier. No worrying about balance plugs and I'll never have to re-charge it. I've seen the FAQ talking about the issue with the balance charger port when using a power supply - needing to fool it with 3 resistors. But it also says I can probably just disable cell monitoring in EScribe? So my question is, will that work and is that all there is to it? Buy a 12V / 25A / 300W power supply (like this one, photo below), wire positive and negative up to the battery inputs on the DNA 200, then in EScribe, disable cell monitoring?Or will I have to install the balance connector and do this resistor thing, in which case I think I'll just forget the idea and go for the battery instead Thanks! Link to comment Share on other sites More sharing options...
VapingBad Posted June 30, 2015 Report Share Posted June 30, 2015 The manual states The DNA 200 connects to the cell taps on the battery pack with a four position JST-XH connector. The tap connector must be connected for the DNA 200 to run.bottom of page 13.As you said it need the 3 resistors mentioned in the FAQ Link to comment Share on other sites More sharing options...
TheBloke Posted June 30, 2015 Author Report Share Posted June 30, 2015 Hmm. The FAQ states:The easiest way around that is set up a three resistor divider to generate "cell" voltages for the balancer to see. You can also disable battery monitoring entirely, which is for fixed installations only, but is useful if you're building the board into a research smoking machine, or something like that.It says "you can also disable battery monitoring entirely", which I took to mean that was an alternative to using the three resistors? But maybe it just means, having used the resistors, you can then disable cell monitoring (but why bother at that point?) Link to comment Share on other sites More sharing options...
mikepetro Posted June 30, 2015 Report Share Posted June 30, 2015 I just tested it on my software and it greys out the "Cell Soft Cutoff" automatically when you select Power Supply.John, is cell monitoring automatically turned off when you select this? It "appears" so. Link to comment Share on other sites More sharing options...
retird Posted June 30, 2015 Report Share Posted June 30, 2015 Noticed also that everything in the battery section greys out and no adjustments are available when power supply is selected... Link to comment Share on other sites More sharing options...
TheBloke Posted June 30, 2015 Author Report Share Posted June 30, 2015 Oh thanks Mike, that sounds promising.Though the manual does say that the Balance Charger must be connected, so it could be that it checks for the balance charger before it does anything else? Or it could just be incomplete documentation in that place I suppose (hope!) - written assuming a battery was being used or something. Link to comment Share on other sites More sharing options...
TheBloke Posted June 30, 2015 Author Report Share Posted June 30, 2015 Here's a second PSU question, rather a basic one! How do I work out what amps my 25A DC charger will draw from the AC? So I know what fuse to put on the AC side.The DC charger is going to send a maximum of 23A in 12V to the DNA 200. It's pulling that from 230V AC. So what's the calculation to find the 230V AC amp draw of a 23A 12V DC PSU? From my googling, I think it's something like: Power delivered = 12V * 23A = 276WPower required at 83% efficiency of PSU = 276 / 0.83 = 332WAC current in = 332 / 230V (AC) = 1.44 Amp ACSo my back of the envelope calculation seems to be I won't need more than about 1.5A. I think the smallest fuse I have is 3A so that's totally fine. But have I done all this correctly? Link to comment Share on other sites More sharing options...
Cisco Posted June 30, 2015 Report Share Posted June 30, 2015 When you are in power supply mode there is no cell monitoring or cell cutoff and a JST tap is NOT required. If you remove the board from power supply to 3S lipo make sure you change battery type back to Lipo's, there is no cut off voltage monitoring in power supply mode.-C Link to comment Share on other sites More sharing options...
alee132 Posted June 30, 2015 Report Share Posted June 30, 2015 I am also interested in doing a build with a power supply. Do I need to have basically one that will be over 55 amps that this dna 200 can draw? Because the guy above mentioned a 23amp one but is that going to be enough. I saw the RC power supplys that looks like they would be able to do the job. Like this one:http://www.ebay.com/itm/Power-Supply-12-Volt-DC-75AMP-900W-for-RC-Charger-Blue-Diamond-Plate-FREE-SHIP-/321552257880?pt=LH_DefaultDomain_0&hash=item4ade021358The only issue I see is there seems to be several wires coming off of it. I don't know if it would work. Link to comment Share on other sites More sharing options...
KTMRider Posted June 30, 2015 Report Share Posted June 30, 2015 50/55a is the output. Input (what the board needs from the power supply to run) is 23a. Link to comment Share on other sites More sharing options...
mikepetro Posted June 30, 2015 Report Share Posted June 30, 2015 23A on the input is all that is required.That power supply would be overkill for whats needed.The 55A is the OUTPUT max, not the INPUT. Link to comment Share on other sites More sharing options...
TheBloke Posted June 30, 2015 Author Report Share Posted June 30, 2015 Cisco said:When you are in power supply mode there is no cell monitoring or cell cutoff and a JST tap is NOT required. If you remove the board from power supply to 3S lipo make sure you change battery type back to Lipo's, there is no cut off voltage monitoring in power supply mode.-CAwesome! Thank you. That's great news. So I can get going quicker, not even bothering to solder on that balance port, just wiring directly into my PSU. I can switch it over to battery later, as and when I'm ready to try and make it portable Thanks again. Link to comment Share on other sites More sharing options...
TheBloke Posted June 30, 2015 Author Report Share Posted June 30, 2015 alee132 said:I am also interested in doing a build with a power supply. Do I need to have basically one that will be over 55 amps that this dna 200 can draw? Because the guy above mentioned a 23amp one but is that going to be enough. I saw the RC power supplys that looks like they would be able to do the job. Like this one:http://www.ebay.com/itm/Power-Supply-12-Volt-DC-75AMP-900W-for-RC-Charger-Blue-Diamond-Plate-FREE-SHIP-/321552257880?pt=LH_DefaultDomain_0&hash=item4ade021358The only issue I see is there seems to be several wires coming off of it. I don't know if it would work.As others said, the maximum power drawn is 23A so any power supply of 23A and above is fine - which in reality will mean a PSU of 25A or above.This is the one I bought, 12V 25A: http://www.ebay.co.uk/itm/DC-5-12-24V-Universal-Regulated-Switching-Power-Supply-for-LED-CCTV-3D-Printer-/111544566393?pt=LH_DefaultDomain_3&var=&hash=item19f8930279 Link to comment Share on other sites More sharing options...
VapingBad Posted June 30, 2015 Report Share Posted June 30, 2015 TheBloke said:[QUOTE=alee132]I am also interested in doing a build with a power supply. Do I need to have basically one that will be over 55 amps that this dna 200 can draw? Because the guy above mentioned a 23amp one but is that going to be enough. I saw the RC power supplys that looks like they would be able to do the job. Like this one:http://www.ebay.com/itm/Power-Supply-12-Volt-DC-75AMP-900W-for-RC-Charger-Blue-Diamond-Plate-FREE-SHIP-/321552257880?pt=LH_DefaultDomain_0&hash=item4ade021358The only issue I see is there seems to be several wires coming off of it. I don't know if it would work.As others said, you need max 23AThis is the one I bought, 12V 25A: http://www.ebay.co.uk/itm/DC-5-12-24V-Universal-Regulated-Switching-Power-Supply-for-LED-CCTV-3D-Printer-/111544566393?pt=LH_DefaultDomain_3&var=&hash=item19f8930279[/QUOTE]It's obviously a typo I think you meant "As others said, you need min 23A" as you linked to a 25 A supply. Link to comment Share on other sites More sharing options...
TheBloke Posted June 30, 2015 Author Report Share Posted June 30, 2015 I meant the other way around - the maximum power that will be drawn is 23A The max power you need is 23A, as opposed to the maximum power supply you need I will edit for clarity Link to comment Share on other sites More sharing options...
Bapgood Posted June 30, 2015 Report Share Posted June 30, 2015 I would just switch to power supply in escribe. Link to comment Share on other sites More sharing options...
VapingBad Posted June 30, 2015 Report Share Posted June 30, 2015 I would thought it needed a battery (or sudo battery) to connect the first time though wouldn't it @Bapgood? Link to comment Share on other sites More sharing options...
John Posted June 30, 2015 Report Share Posted June 30, 2015 Oh no, the thing will connect for Escribe purposes just powered from USB. Link to comment Share on other sites More sharing options...
VapingBad Posted June 30, 2015 Report Share Posted June 30, 2015 lol, the gift that keeps on giving, thought it may stay of as it would be below operational current, but I didn't really think hard enough as production and vendors need to be able to flash it quickly and easily :facepalm: Link to comment Share on other sites More sharing options...
VapingBad Posted June 30, 2015 Report Share Posted June 30, 2015 "the thing" secret internal code name for project lol Link to comment Share on other sites More sharing options...
SSV Posted June 30, 2015 Report Share Posted June 30, 2015 I would recommend staying away from a switching supply, as it will not mimic the characteristics of a battery or linear supply....is the switcher has inadequate decoupling it will potentially oscillate and cause some issues.....there is simply not enough real estate on the dna200 board for enough capacitance on the input stage to smooth a "dirty/cheap" switching supply....traditionally when I do dev work on DC/DC systems, we try and stay away from any uncertainty in the current source....most switching supplies don't act as constant current devices, as a linear PSU or battery would.... Link to comment Share on other sites More sharing options...
TheBloke Posted June 30, 2015 Author Report Share Posted June 30, 2015 SSV said:I would recommend staying away from a switching supply, as it will not mimic the characteristics of a battery or linear supply....is the switcher has inadequate decoupling it will potentially oscillate and cause some issues.....there is simply not enough real estate on the dna200 board for enough capacitance on the input stage to smooth a "dirty/cheap" switching supply....traditionally when I do dev work on DC/DC systems, we try and stay away from any uncertainty in the current source....most switching supplies don't act as constant current devices, as a linear PSU or battery would....Oh really? Can you elaborate on what sort of issues I might see?I just had a quick check on a few component sites and 12V 25+A linear supplies appear both to be rare, and horrendously expensive.So if it won't work out I'll just revert to using battery. But it'd be great to understand what might go wrong, so I can understand the risks and be on the look out for symptoms if I do go ahead.Thanks! Link to comment Share on other sites More sharing options...
John Posted June 30, 2015 Report Share Posted June 30, 2015 It works okay on the switching supplies that we've tested with...All the high precision stuff runs off of (one of three) well decoupled linear regulators from the 12v anyway, so anything interesting already has linear post-regulation. The 12v supply directly is just feeding the power stages, so that can be fairly dirty without causing any ill effects. If you're a research lab, might a linear supply be better? possibly. For any sort of end user I can't see it making a lick of difference. Link to comment Share on other sites More sharing options...
SSV Posted June 30, 2015 Report Share Posted June 30, 2015 TheBloke said:[QUOTE=SSV]I would recommend staying away from a switching supply, as it will not mimic the characteristics of a battery or linear supply....is the switcher has inadequate decoupling it will potentially oscillate and cause some issues.....there is simply not enough real estate on the dna200 board for enough capacitance on the input stage to smooth a "dirty/cheap" switching supply....traditionally when I do dev work on DC/DC systems, we try and stay away from any uncertainty in the current source....most switching supplies don't act as constant current devices, as a linear PSU or battery would....Oh really? Can you elaborate on what sort of issues I might see?I just had a quick check on a few component sites and 12V 25+A linear supplies appear both to be rare, and horrendously expensive.So if it won't work out I'll just revert to using battery. But it'd be great to understand what might go wrong, so I can understand the risks and be on the look out for symptoms if I do go ahead.Thanks![/QUOTE]It depends on how good the isolation from AC is....again, the issue is the uncertainty induced from non-linear sources. From a pure research standpoint, we typically don't use switchers in development. We want to remove as much external influence as possible. Some "cheap" switchers can ring/oscillate at specific load levels (usually midpoint dead times).The best way around all of this is to fully decouple from AC and just use a good 12V battery. I personally like to use this.... Link to comment Share on other sites More sharing options...
SSV Posted June 30, 2015 Report Share Posted June 30, 2015 John said:If you're a research lab, might a linear supply be better? possibly. For any sort of end user I can't see it making a lick of difference. agreed....for end user application it's not relevant....for calibrations or analytics it is Link to comment Share on other sites More sharing options...
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