G+_Tim Smith Posted June 8, 2018 Share Posted June 8, 2018 LiPi Ep 385 Would it be reasonable to add the wiring diagrams that were shown on-screen to the show notes, please? It feels like there were some instructions referenced in the show that did not ultimately make it to the show notes section. Link to comment Share on other sites More sharing options...
G+_John Sullivan Posted June 8, 2018 Share Posted June 8, 2018 Hello The wiring diagram is shown at about 22:42 in the video (and other places) and it's simple enough, so if your request doesn't get answered, you could just take a screenshot, or just pause the video at that point. The question I've been wanting answered, ever since Padre first introduced this back in Episode (?) is how does he run a 5v RasPi from 3.7v batteries? The RasPi spec sheet is very particular that the input voltage to the Pi be close to 5 v. The batteries are wired in parallel, so even with three of them, the most voltage one will get is still less that what the RasPi requires. My guess is that the charger board includes a "boost converter" circuit that raises the 3.7 v up to the board's pass through voltage of about 5.0 v, but I don't see where Padre mentions that. I also don't see it mentioned on the Banggood webpage. I wonder how much of Padre's expected Watt/Hours are lost doing this conversion, that is, what is the efficiency of doing this up-conversion? Link to comment Share on other sites More sharing options...
G+_Dan Hockey Posted June 8, 2018 Share Posted June 8, 2018 It's probably a buck/boost converter. But didn't he power the pi from the UBec? The specs say 5.5v-26v for input voltage. There's no way that the ubec he used would work if the cells were wired in parallel. The cells would have to be wired in series in order for that ubec to work. If that's the case the charger would have to be a boost converter. But I can't find any detailed specs for the one he used. Link to comment Share on other sites More sharing options...
G+_Tim Smith Posted June 8, 2018 Author Share Posted June 8, 2018 John Sullivan Check out this video: This explains how the protection board provides 5v to the Pi and regulates charging. Link to comment Share on other sites More sharing options...
G+_John Sullivan Posted June 8, 2018 Share Posted June 8, 2018 Dan Hockey Hi Dan .. .Yes, I mis-pronounced that .. meant to say a "boost" converter , not bump converter. (so I have corrected it). As for the Ubec, did you look at the circuit diagram? The external power supply connects to the Ubec Input, and the output of the Ubec connects to the battery charger board, not directly to the batteries. The charger board only provides approx 4 volts to the batteries, not whatever voltage is being applied from the external. Link to comment Share on other sites More sharing options...
G+_Hyrum Smith Posted June 14, 2018 Share Posted June 14, 2018 Tim Smith I have these boards and just put everything together (without the Pi) last night. The Output voltage is 4.2 volts and will drop as the batteries discharge. There are no components on this board to boost the voltage to 5 volts. Unless whatever you are putting in this box runs on 4.2 to 3 volts (cut off circut pops at 2.9? - see video above), this battery configuration is not for you or a RasPi 3B. The question is: How to have good battery protection from failed / bad single cells in a multi-cell battery pack AND provide 5v @ 2 Ah for at least 3 hours. (I'd love 4hrs w/ Pi 3B). Bonus points for maintaining the NUC format / dimensions and the very nice features of the Fr. Robert Ballecer, SJ LiPi Case R12. I love the case design! Well done! Best efficiency is obtained with DC voltage reduction rather than voltage boost devices. Two cells in series would provide enough voltage then determine how many "sets" of two batteries would be required for desired run time / backup capacity. Then best way to charge / monitor them. Using more than one of these charging circut boards may be an option. I will put the output of two of these charge controllers in series & see what I get. Comments? Link to comment Share on other sites More sharing options...
G+_Jeff Johnson Posted July 5, 2018 Share Posted July 5, 2018 I'm having the same issue with the output of all the components being only about 4.1vdc. There is no way that the circuit can have more than that. Has anyone actually tested the circuit that Fr. Robert put together? Something has to have changed. If you follow the video exactly, all you get is a dead Raspi. :-( Link to comment Share on other sites More sharing options...
G+_Hyrum Smith Posted July 8, 2018 Share Posted July 8, 2018 Jeff Johnson Well after poking around I discovered that these charge controller boards do not like to have their outputs wired in series so I gave up trying to go for a higher voltage to get down to 5V efficiently. The missing piece finally arrived. A DC Converter Li-ion Battery 3.7V 3-5V to 5V 3A Step Up Boost Power Supply Module. This takes the output of the Li-ion charge controller and provides 5V (up to 3A but I bet it will get pretty toasty). This will actually run the RasPi at the specified voltage. The charge controller will cut off the power to protect the batteries from this thing. Now I need to modify the case to include this additional board. Looks like it might fit right next to the charge controller where the retaining clip mount is currently located. If anyone comes up with a good way to mount the step up board, please share. ebay.com - Details about DC Converter Li-ion Battery 3.7V 3-5V to 5V 3A Step Up Boost Power Supply Module Link to comment Share on other sites More sharing options...
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