Yes, Lee has already pointed this out, so I am looking into putting the zener in parallel to the PV panel and then a schottky, etc. in series to the battery.
The problem I have with the cheap CV/CC circuits from china is that in my experience they have a high failure rate and, just like buttered toast, the failures tend to happen in the worst possible mode. June 2, 2020 3:17 PM, "Justin Kenny" <[email protected] (mailto:[email protected]?to=%22Justin%20Kenny%22%20<[email protected]>)> wrote: Not sure if you understood the previous 2 messages, the Zener diode will drain your battery, and a diode will not stop it from overcharging. I really suggest to use the right tool for the job, $3.25 for a constant-current constant-voltage converter isn't much cost to save your battery pack from being killed prematurely, or at worst preventing a fire/destruction by overcharging: https://www.amazon.com/dp/B00LPK0IKQ (https://www.amazon.com/dp/B00LPK0IKQ) - Justin On Tue, Jun 2, 2020 at 2:57 PM <[email protected] (mailto:[email protected])> wrote: I'm thinking of using two panels, one tilted 45 degs to the east, and the other tilted 45 deg to the west. That should provide a fairly flat power output through the day with something like .375 ma max. If I put a 4.3V zener across the panel, then that should bypass some of the current, so I should only see a swing from perhaps 0.2V to 0.3V and the 0.2V will likely occur when the panel voltage is lower. At any rate a 0.1V variation is close enough for my purposes. I've got a selection of diodes on order, so I'll see what happens when I test it on the bench. Pete. June 2, 2020 1:51 PM, "jkenny23 via EV" <[email protected] (mailto:[email protected])> wrote: > Another very important note; diodes don't drop voltage the same at all > current levels. Meaning; they will NOT stop your 4.5V panel from > overcharging your battery to 4.5V if you don't have a dedicated charging IC. > > If you want to charge your battery to an unusual voltage, I highly recommend > using an adjustable CC/CV (constant-current/constant-voltage) buck > converter. They're widely available from China on eBay and Aliexpress, and > probably available from the US through Amazon. This way you can set a safe > current limit (say 400mA), and a voltage limit that is lower than 4.2V (say > 3.9 or 4.0V). Then you could even use multiple panels in series and not > worry about charging, the input limit for the common LM2596 modules is 35V. > > Here's some data for a common 1N5819 Schottky diode illustrating the issue > of voltage drop as current tapers down at the end of charging: > 1.0A - 0.41V > 0.5A - 0.35V > 0.1A - 0.28V > 20mA - 0.23V > > -- > Sent from: http://electric-vehicle-discussion-list.413529.n4.nabble.com > (http://electric-vehicle-discussion-list.413529.n4.nabble.com) > _______________________________________________ > UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub > (http://www.evdl.org/help/index.html#usub) > ARCHIVE: http://www.evdl.org/archive/index.html > (http://www.evdl.org/archive/index.html) > INFO: http://lists.evdl.org/listinfo.cgi/ev-evdl.org > (http://lists.evdl.org/listinfo.cgi/ev-evdl.org) > Please discuss EV drag racing at NEDRA (http://groups.yahoo.com/group/NEDRA > (http://groups.yahoo.com/group/NEDRA)) -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20200602/9714388d/attachment.html> _______________________________________________ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub ARCHIVE: http://www.evdl.org/archive/index.html INFO: http://lists.evdl.org/listinfo.cgi/ev-evdl.org Please discuss EV drag racing at NEDRA (http://groups.yahoo.com/group/NEDRA)
