I haven't totted it up but I reckon average current draw would be ~ 50mA total. The idea was that a battery would be charged elsewhere (with an off-the-shelf charger) and the trickle charge would just make up for self-discharge. In the event of power failure then the battery would need charging fully again when power was restored. I was just kicking the idea around to see how simple we could make it. I agree ronv's charger would be better.
That made me laugh out loud!
I did not get any notices-you guys have been busy. Wow, thanks.
It's good to see the features on this site coming back to life.
Happy New Year!
Who knows what the notice algorithm is, but unless you make a periodic visit, the notices stop. It's one of the problems with putting the actual messages in the notice. There is no reason to visit the site sometimes.
Read the bottom of the notices carefully: There MAY also be other replies, but you WILL NOT receive any more notifications until you visit the forum again.
I just ran 10.4V through the controller and two PDMs with two pumps hooked up. Both pumps toggled reliably.
I am having a little trouble with some of the terminal points though. Some of them that I have screwed down a lot of times are twisting in the solder joint. I wonder if I should have cleaned up the terminal point posts before soldering? Or maybe clean the posts, insert them, tin them and then solder. Any advice would be appreciated. Thanks.
They should not do that. I'm going to suspect a cold solder joint.
Unsolder and clean up the pins.
I'd have the screw loose so as to minimize the thermal conductivity. Attach the wire. Heat the terminal (larger mass) and apply the solder, let cool and try to move the wire.
If your not doing it already, when you solder a lead to a PCB Pad, use the soldering iron and push the pin to edge. Then apply solder to the "Other side" of the pin, opposite the iron. So it's iron - pin - solder.
I think you nailed it KISS-cold joint at the terminal points. Bad to me. It was not too awful to fix. I put the blunt tip on the soldering iron, cranked the heat up and held the tip to the end/bottom of the terminal point posts until the solder reflowed. Did not take long. Only a couple terminal points failed, but I re-flowed all of them. I think we're in good shape now.
Thanks a bunch.
Good. Was one of those pumps a 'fussy' one?
Sim shows the PDM should cope down to 9V or so without unwanted trip operation.
Glad the re-soldering went ok.
No, I don't think so. Certain pumps would never toggle more than a few times, mostly ony once. Pumps A and two others were always problematic until I installed the 2k2 resistor. The other three pumps never were a problem. But I think they were probably a problem waiting to happen. The second PDM had the exact problem with the exact pumps until I installed that 2K2 resistor. I'm not sure any terminal posts were loose enough to twist in the solder before adding the 2K2. Plus when I had cold joint trouble, the LEDs did not light up. When the pumps did not run, the LEDs lit up and the pump would hum. I could plug in any fussy pump and have trouble or any other pump and it would run. I know I can't prove it but there is no doubt in my mind that the 2k2 solved a big problem. Maybe having to make a fix for the fussy pumps was a blessing in disguise.
AAC has one that's well over 2000 posts long. But this is definitely the longest TECHNICAL thread I've seen anywhere, ESPECIALLY that's stayed on topic
Actually I was just hoping Joe had checked that even a 'fussy' pump would start reliably at ~10V, so that using a 12V backup battery rather than 24V would be possible.
Edit: Joe, can you remind us of the continuous current ratings of your two 24V power supplies? I'm thinking one of them might also power the charging of the backup battery.
It may also be possible to mod one of the OEM controllers to act as a charge controller for the battery; or would you prefer to go with Ronv's suggested LM317 charge controller?
You will need a pretty good sized battery if it needs to run 2 pumps for 24 hours. Maybe a 30 40 amp hour sealed lead acid.
Let us know if you have any questions.