The morning and early afternoon of 4th March were unusual in that, rather than brilliant sunshine, they were overcast with heavy tropical rain showers throughout.
At 14:20, when I went to check how my two SmartSolar 100/30s were doing I was expecting to find them both still in bulk mode but instead I found them both in float mode and, further, the absorption time appeared to be minimal. See screen shots taken at 14:23/24. (I’ve included the screenshots from only one controller as the other one was essentially the same.)
At 07:40 the battery voltages were 12.6v, pretty much the same as always at that time in the morning.
The yield at 14:23 was 310 Wh. By the end of the day this was 580Wh. On a typical day, the yield is in the range 800-1050Wh and the controllers go from bulk to absorption when the yield is 500Wh or thereabouts. (Any other day where the yield is below 800Wh (eg 27 Feb and 1 & 3 March) I can tie back to having the boat’s engine on. And 6-12 Feb, we were in a marina connected to shore power.)
The 100/30s are connected in parallel. Each 100/30 supports 2 * 135 watt panels connected in series. The battery bank is 4 * 125Ah 12v Lifeline AGMs (in parallel). The set up is just over 18 months old.
Can anyone:
- explain why both controllers went from bulk to absorption when the yield was only 100Wh (vs 500Wh on a typical day) and why the absorption yield / time was so small (it barely registers on the histograms),
- suggest any tweaks to my 100/30 settings (second screenshot) that might improve things the next time.
Thank you
