All lead acid batteries exhibit what I believe is called a surface charge immediately after charge. When doing any battery condition testing it is important to "burn off" the surface charge OR allow the batteries to rest for about 24 hours. At max charge rate (bulk charge stage) you will see voltage clime until it reaches as high as 14.6 or 14.7, particularly when on the engine or shore power charger (maybe not on a 50w solar panel.) Once the bulk is complete (80% charged) the voltage will hold at 14.7ish through the absorption stage and the max current will taper off until about 2amps. Once 2 amps is reached the charger changes to float stage which is usually ~13.3v. Assuming your charging system is large enough to fully make up for the usage, 13.3v is where you should normally find your batteries while on charge. After sundown 13.3v will decay to 12.7v.
I have one of these on my solar charge system. It makes seeing and understanding what is going on much easier. This particular model is nice since no external shunt is required. You could even get two and then monitor the loads and the charges. https://www.amazon.com/dp/B017FSED9I/ref=cm_sw_r_cp_apa_Yp1HBbFG41PCM Josh Muckley S/V Sea Hawk 1989 C&C 37+ Solomons, MD On Wed, Aug 29, 2018, 7:10 PM David via CnC-List <cnc-list@cnc-list.com> wrote: > So I set up my 50 watt solar panel and controller and when I come aboard > the boat the batteries are reading 13.1 13.2. I thought a battery at rest > read 12.7 fully charged. Even now at sunset they are reading over 13. > > Is my controller cooking the batteries? > > Thanks in advance. > > From my Android.... > > _______________________________________________ > > Thanks everyone for supporting this list with your contributions. Each > and every one is greatly appreciated. If you want to support the list - > use PayPal to send contribution -- https://www.paypal.me/stumurray > >
_______________________________________________ Thanks everyone for supporting this list with your contributions. Each and every one is greatly appreciated. If you want to support the list - use PayPal to send contribution -- https://www.paypal.me/stumurray
