Automatic, smart battery charger?
I would like to hear some comments and suggestions. In July 2017, I made some progress on understanding the settings in the MS SS MPPT 15L solar controller. I then modified several settings which ...
Forum Discussion
With the suggestion from MEXICOWANDERER, I analyzed my collected data and decided that the Abs times have been too short and need to be lengthened because the switch to float was too far above 0.5% = 1.35A on average. The bank is 270Ah and 0.5% is 1.35V. Having too short Abs times can result in slowly sulphating the battery over time. I do load capacity tests that seem to show the bank is in good health.
On 2 Feb 18, I began charging without float which leaves only Bulk and Abs. I have been observing how long in Abs it takes for the Amps to stay low. Next, I can make timer settings to the MPPT.
A Raspberry Pi 3 B(RPi) computer collects data from the Morningstar Sunsaver MPPT 15L(MPPT) 24/7/365 at one minute intervals. The Rpi is used to analyze the data and it could be used to make immediate adjustments to the MMPT. I am hoping I can find MPPT settings that can be more permanent without relying on the RPi to make ad-hoc changes. The RPi runs a web server and I can examine the data and change MPPT settings remotely as well.
With this analysis I hope to know what MPPT settings are needed to regularly top-up the bank and when the genny is needed to catch up. The main charging goal of the genny is to speed up the Bulk charge in the morning and let the MPPT finish the Abs and Float charging.
Below are two graphs which show the MPPT charging on 2 Feb:
Volts:
This shows the MPPT has no problem holding the battery at the Target Volts for 6 hours. Surely that is enough time to call the battery charged, or is it?
Amps:
Now we see the Amps in play. What I want to see is a flattening of the Amps which should indicate the appropriate time to switch to Float. This graph suggests that 2A and 4 hours Abs would be reasonable. You can see that morning is the best economic and strategic time to run a genny or use shore power to shorten the Bulk time.
HTH;
John
On 2 Feb 18, I began charging without float which leaves only Bulk and Abs. I have been observing how long in Abs it takes for the Amps to stay low. Next, I can make timer settings to the MPPT.
A Raspberry Pi 3 B(RPi) computer collects data from the Morningstar Sunsaver MPPT 15L(MPPT) 24/7/365 at one minute intervals. The Rpi is used to analyze the data and it could be used to make immediate adjustments to the MMPT. I am hoping I can find MPPT settings that can be more permanent without relying on the RPi to make ad-hoc changes. The RPi runs a web server and I can examine the data and change MPPT settings remotely as well.
With this analysis I hope to know what MPPT settings are needed to regularly top-up the bank and when the genny is needed to catch up. The main charging goal of the genny is to speed up the Bulk charge in the morning and let the MPPT finish the Abs and Float charging.
Below are two graphs which show the MPPT charging on 2 Feb:
Volts:
This shows the MPPT has no problem holding the battery at the Target Volts for 6 hours. Surely that is enough time to call the battery charged, or is it?
Amps:
Now we see the Amps in play. What I want to see is a flattening of the Amps which should indicate the appropriate time to switch to Float. This graph suggests that 2A and 4 hours Abs would be reasonable. You can see that morning is the best economic and strategic time to run a genny or use shore power to shorten the Bulk time.
HTH;
John
