For many years, I have used a "take-out" UPS battery to keep my internet, WiFi and VoIP powered through regular power outages, always floating it to 13.5V except for the times that the power went. It has served me about 7 years now, starting as a take-out so it was already abused before, since this was in India with almost daily power loss, this battery gets the action during ~1 hour of power outage (about 1 Amp drain) and the quick refill (current limited to 2 Amps) up to float again, where it then spends over 95% of its time. I use a 25W Meanwell 12V power supply rated at 2.1A and tweaked the pot to set the voltage to 13.5V. Also, temperature is almost year-round very hot, car batteries die early but this AGM keeps ticking in long term 100+ deg heat. So, it appears that a simple LDO regulated at 13.5V output will allow your solar panel to charge but avoid over-charging. Since solar panels may go as high as 18V when there is little load, the regulator may see just over 2 Watts of dissipation 1 hour a day so it should have a small heatsink or be bolted to a metal piece/case if that does not create a short circuit. NOTE: to avoid back-feed, you might want to set the LDO to 13.8V and add a Schottky diode after it or test that the LDO does not sink current when input is removed or insufficient, you don't want to add an extra drain on this battery!
Cor van de Water Chief Scientist Proxim Wireless office +1 408 383 7626 Skype: cor_van_de_water XoIP +31 87 784 1130 private: cvandewater.info http://www.proxim.com This email message (including any attachments) contains confidential and proprietary information of Proxim Wireless Corporation. If you received this message in error, please delete it and notify the sender. Any unauthorized use, disclosure, distribution, or copying of any part of this message is prohibited. -----Original Message----- From: EV [mailto:[email protected]] On Behalf Of EVDL Administrator via EV Sent: Sunday, June 12, 2016 3:56 AM To: Electric Vehicle Discussion List Subject: Re: [EVDL] Lead Acid charging...(trickle overcharging?) On 12 Jun 2016 at 5:28, Robert Bruninga via EV wrote: > I added an unregulated solar panel that typically produces only 30 mA to a > very remote cabin car battery deep in the woods. The charge rate will give a > 2 hour per week use of the lights. > > But what happens if no one uses the cabin for months? Does it have to be unregulated? Couldn't you add a simple 3-terminal regulator at float voltage (~13.5v)? (I don't know much about PV, so I don't know whether that would work.) I would think that if the charge were regulated to float voltage, the battery should last as long as the battery in a computer UPS, which is floated continuously. That's usually around 3-4 years in my experience. David Roden - Akron, Ohio, USA EVDL Administrator = = = = = = = = = = = = = = = = = = = = = = = = = = = = = EVDL Information: http://www.evdl.org/help/ = = = = = = = = = = = = = = = = = = = = = = = = = = = = = Note: mail sent to "evpost" and "etpost" addresses will not reach me. To send a private message, please obtain my email address from the webpage http://www.evdl.org/help/ . = = = = = = = = = = = = = = = = = = = = = = = = = = = = = _______________________________________________ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org Read EVAngel's EV News at http://evdl.org/evln/ Please discuss EV drag racing at NEDRA (http://groups.yahoo.com/group/NEDRA) _______________________________________________ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org Read EVAngel's EV News at http://evdl.org/evln/ Please discuss EV drag racing at NEDRA (http://groups.yahoo.com/group/NEDRA)
