Perfect timing since I need the multimeter hooked up to adjust the DC/DC buck converter - and I JUST hooked up the multimeter!
So without the DC/DC buck converter - I'm getting too much resistance (meaning my volts are too high to be converts to amps and yet staying under 3 ohms).
So I was working up a sweat big time - since the resistance on the load torque was too high.
I really wanted to downshift - but I didn't want to lose my amps. Also when I converted the multimeter to read the amps - suddenly the battery stopped charging!! Meaning the amp draw on the multimeter was sucking up the charge. oops.
OK so now I disconnected the battery and in the LOWEST gear I'm at 35 volts if I pedal as fast as possible but below thirty - around 28 volts if I take it easy.
So the DC/DC buck converter should now convert those high volts into low volts - and then I can increase the amp output up to 4.5 amps I think (for the standard running current).
I must have done a blog post on this DC/DC buck converter - analyzing the specs. Let's find that....
OK now to review.
I would use a dummy load resistor [connected to the output] to draw the maximum current at the desired voltage. With current pot at maximum, decrease until the [output] voltage drops.So I don't have a "dummy load" because the multimeter will cause too much torque - or maybe the DC/DC buck converter will change the load torque?
Sensorless Load Torque Estimation and Passivity Based Control of ...
by SG Kumar - 2015 - Cited by 11 - Related articles
Jump to Modelling and Control of Buck Converter Fed DC Motor - Under no-load and constant load torque conditions, buck converter inductor current alone is required for speed regulation. When load is applied on the motor side, the updated torque value is used for changing the reference values of armature current, inductor current, and armature voltage.I really don't want to read through all that stuff. haha. So back to my blogpost info:An algebraic approach is presented for the fast feed-forward adaptation of the angular velocity trajectory tracking task in a Boost-converter driven dc-motor ...Download Table | Specifications for buck converter fed DC motor. from publication: Sensorless Load Torque Estimation and Passivity Based Control of Buck ...of sensorless load torque estimation for buck converter fed DC motor is shown in Figure 1 in which í µí¼” * is considered as desired speed. Feedback signals V, í ...by L Xheladini - 2015 - Cited by 1 - Related articlesefficiency change as the load is increased. Index Terms — Series/Shunt DC Motor, buck converter, torque, speed, efficiency. I. INTRODUCTION. Recently, the...
Input Voltage:DC 4-30V (limit 36V)So I need to lower the output amps to 5A....
Output Voltage: DC 1.2-30V (adjustable,default 5V)
Minimum Voltage Difference: 1V
Output Current Range: 0-10A (default 6A)
Output Constant Current Range: 0.3-10A
Operating temperature: -40°c to +85°c
Working frequency: 150KHz
Conversion efficiency: up to 98%
Installation: 4x 3mm screws
Wiring: Terminals, Needn't solder, V-IN input, V-OUT output
Cutting size: 60mmx26mm
Have operating indicator
I guess I should increase the volts to 12 volts?
The lithium batteries charge at 3 volts - but the power converter takes up to 18 volts - in the Chafon.
hmmm....
I guess I'll just experiment with the torque load - and see what happens!
I can't measure the Amp current output.
Let's see if the Chafon charges at 6 amp - what happens.
https://elixirfield.blogspot.com/2019/01/5-times-more-power-from-dcdc-buck.html
OK so let's see what I posted there.
It's hard to believe my Treadmill motor could kick out such high amps at so low voltage!! But yesterday I posted someone else doing the same. It's the RESISTANCE that's the issue. That's what this DC/DC buck converter is supposed to fix.... (I hope)...22 volt = 2.75 amps = 60.5 watt12 volt = 5.041 ampsSo above 12 volts.22 volts is maximum with minimum as 12.2 volts
OK back to the Chafon post...2.18 V is the maximum.PER CELL FOR CELL BALANCING - 36 cells. So 97 volts total x 5 amp = 485 watts total storage.Lithium Ion battery
The question is - how does it balance the volts...
- built-in 36 pieces, 3.7 V, 26000 mAh 18650 lithium battery, so the theoretically capacity is 36 * 3.7*2.6 =346.32
O.K. so now we know why typically you want a 5 amp limitation on charging, to spread the 12 volt amps down to 2.7 amps.So what's the resistance again?
I forgot I'm going to have a load on the generator also while I'm charging!
I'll just try it with the presets...
I know it's crazy - so I'll watch for the magic smoke...
OK fine - I'll increase the volts to 12 - just as the factory says - but remember the battery has a load that will pull the voltage down. But that will increase the resistance I guess...
Yeah I don't want to do the math. I'll just experiment.
EXPERIMENT ONE
So I first had to use my fingernail to adjust the voltage. So then I was switching the multimeter between amps and voltage. Amazingly the DC/DC buck converter worked just as it is supposed to!! It was set at 5 volts - preset. Sure enough - the 36 volt max was brought down to 5.6 volts!!! And the amps were over 5 amps! Now keep in mind - this is at the LOWEST bicycle gear - just easy pedaling. Well yes when I switched to amps - since I had "no load" - then there was some resistance - but not as much. There is some kind of load torque by the DC/DC buck converter. So I got way higher amps than ever before - and in the lowest gear, easy cycling!!
So then I keep adjusting the voltage up with my thumb nail and the amps slowly went down as the voltage went up. When I got to about 8 volts - then the amps were under 5 (the limit). So I decided to just try it to see if it would charge. I hooked up the battery - generator - and no charge! So I thought dang I have to increase the volts! So I increased the volts and still no charge. In fact even the volts were not going up! So I switched back to just the multimeter by disconnecting the battery. Then I realized I was still in the "charge" setting - the amps - on the multimeter. So now my voltage was up to 13.4.
That is actually the PERFECT ideal voltage for charging lithium batteries - from what I have read. So then I switched back to the generator. Now as I cycled - the charge light was on. And sure enough the percentage on the charge was going up fast!!! I was cycling in lowest gear and just as the DC/DC buck converter is supposed to do - it tripled my power.
So now I was really excited - and the best test was to see if I could charge the TV (which is 125 watts) plus the DVD player - I mean take the load of those - so 150 watts - while I also charged the battery. So I plugged it all in - and had the TV and DVD player going and as I bicycled. First the load from the extra watts dropped the charge percentage by 10 points. That is what it always does. But as I kept cycling - the charge percentage slowly kept going down. Now I was kind of pissed. My goal was to be able to charge the TV plus the DVD player - and the battery all at the same time.
So the only way to fix this was to lower the voltage on the DC/DC converter - so I get more amps. I figured - since the battery had charged before - this morning - while the load of the battery pulled the voltage down to below 12 - then it should be able to charge at lower voltage.
So I used the thumbnail to keep lowering the voltage. I think I got it back down to about 9 volts. So I figured with the load of the TV/DVD then the amps could be higher the 5 - and it should be enough power to keep charging the battery. So I plugged back in the TV/DVD - and this was my big mistake.
I forgot about the SURGE wattage and since I had used up the battery - the surge wattage is maybe 400 watts - for DVD and TV. But the charge on the battery was below 50% which means I only had 200 watts. So suddenly I heard this loud alarm!!! And sure enough there was a magic smoke smell!
OK so I quickly unplugged the TV/DVD and also one of the wires accidentally disconnected from the DC/DC buck converter. So then I brought the Chafon inside and plugged it into the AC outlet and it is charging fine. So the AC power "works" - at least for charging. I'll have to try plugging in an AC load to see if that works.
OK so I got an AC load and so I reconnected the DC/DC Buck converter. Then I checked the voltage again - and it was at 10 volts - and I checked the amps. So I decided to see if it would charge the Chafon at 10 volts. The charge light did come on but the percentage did not increase and also - the multimeter showed NO load - the voltage did not go down at all even though I was "charging" the battery.
So that made me suspicious - that indeed you do have to be above 12 volts to activate charge. So I increased the voltage again with my thumbnail - so I was at 12.6 volts. This is what I measured above - to be the ideal for greatest charge. I hooked up the battery and sure enough NOW the voltage dropped on the multimeter - so the battery was taking a load. ALSO - suddenly the bicycle was harder to pedal - meaning the load torque of the battery resistance was kicking in!!
So I had just proven indeed you do need to be above the 12 volts to get a charge on the Chafon 500 watt. So then I plugged in the DVD player and watched while I was once again "Chillaxin'" in lowest gear - easy pedaling - and the percentage went up. But I need to experiment more - I had it plugged into the AC outlet - so now it's at 65% or so. So that means the regulator might be lowering the amps it can take in - beyond the "quick charge" rate. So I'll just keep seeing how fast it charges - it didn't charge noticeably faster - not by much. A little bit faster. But it might charge faster when the battery can take a great load with less resistance - at a lower percentage. I'm not sure.
No comments:
Post a Comment