Hi All,
Using a SmartSolar 100/20 with 18650 lithium batteries(4.2/3.7) on a BMS and a 50 watt PV. The battery is in a 3S2P configuration. Everything works according to how it is configured except under Load output, user def algorithm 1, the system does not let me set "Load switch low voltage level" to less than 10 volts. I would like to set it to 9 volts as I am using Li-ion batteries and that is still within its range - can go as low as 8.5 volts. What options do I have? please help.
Indeed, the minimum is 10V for 12V system or 20V for 24V system.
I would have thought this design is intentional as it is a pretty low limit for MOST of the battery types available. 18650 LiPo cells are not commonly used in solar systems and are notoriously awkward to integrate into 12V systems. 3 cells is too few and 4 cells is too many. At least with 24V systems you can use 7 cells. Most of those "DIY Powerwall" guys are running 7S or 14S.
Is it possible to use 4 cells at all? Then the parameters can work for you (12V cutoff for load output) also you can set Absorb at 16.8V.
Sorry, not an ideal solution. You might be able to raise this as a feature request for a future firmware version, but it is there to protect most other users from damaging their batteries.
Thanks Wkirby for your response. Actually 3S configuration works great for my use case. I have a bunch of garden led lights at 9-12volt dc that turn on after sunset and stay on for a few hours. I understand most DIYers' use 7S or 14S but that is an overkill for my use. Ideally if a user chooses "user defined algorithm" user should be able to choose the low level cut off possibly after clicking on with a banner/alert notifying the user of going that low.
How do I submit a feature request do you know?
I have forwarded this question onto the developers for you.
