This site is now in read-only archive mode. Please move all discussion, and create a new account at the new Victron Community site.
I use the Blue smart Charger 220/12 -30Amp, which switches on and off according to the Soc percentage of the battery. For this, I added a contactor to the control panel, the contactor is connected to the relay output of the cerbo gx and is triggered from here. When the Soc reaches 20%, the smart Charger is activated. when it reaches to the 25% system, it is disabled automatically. Can I get your advice about this setting for system health?
This is mot really a question other people can answer for you. It depends on your system design and use and that is something only you would know.
The answer depends on a few basics:-
1. what batteries you have and
2. How far you discharge your batteries during normal use
3. What your intention is with its use
i.prevent a full discharge or
ii. give the system a boost as solar may not be adequate
4. how much solar or other charge sources will be able to contribute to a full charge If that is what you are aiming at
Dear Alexandra,
First of all, thank you very much for your answer. I do not have experience with my Solar system. I installed the system 3 months ago. My goal is to learn something new every day and make the system a little bigger and autonomous.
My battery is 12 V/ 400 Amp lifepo4, I Have Cerbo gx and smart shunt . My solar panels are 1.8 KW/hr consumption and production power are as in the chart. The blue smart charger soc stays on automatically between 20-25% (I set this up). What I want to ask is, what should this soc range be in general and ideally? I can set it between 90-100%, which option will be more efficient?This consumption graph is repeated almost every day. This system meets all kinds of consumption of the house except for the washing machine, dishwasher, iron and aircondition for a summer house. When the sun is insufficient, the blue smart charger is fed from the city network and performs the consumption and battery charging, and if this is not possible, my transfer switch automatically feeds the house from the city network.
Battery manufacturers design their bms to work cells in their optimal range. So you dont need to worry about the 20% / 100% SOC story that so many people get caught up on.
Make sure you batteries get to the 100% and stay there for at least a half hour to an hour, they are most likely passively balanced at the top of the charge (you will have to research your battery). The manufacturer might have a recommendation on how often they want it at a full charge.
Charge them according to the manufacturer recommendations.
If you want max life, look at cycles the battery is rated at -see their tech specs and see what lifespan or cycle life you want from them and set the max DOD to that.
Cycles these days on some manufacturers seem to measure energy in and energy out and count cumulative power for cycling. So check that as well. E.g 400AH battery you use 50% to 100% twice you have cycled once. So keeping them between percentages and not reaching 100% also does not change that.
The only thing it does affect is cell balancing which is important for battery health.
Some say lithium batteries should stay between 30 and 80 percent. But in official manuals, and blogs the general opinion is that the battery should not be discharged more then 80% to have a long lifespan. So if your charger kicks in at 20% and puts it up to 50 or more % this should prolong your batteries live span. But take that you don't get a lot of cycles between your lower and upper limit. I there for would put the upper (stop changer) higher. Essentially in periods with low solar yields.
I checked quite some time ago here, got an answer from a Victron tech. While there are significant service life gains with the Li-ion cells used in phones etc., there's only a small effect on LiFePO4 cells.
LiFePO4 batteries must be balanced regularly by the BMS. This generally starts only after SOC reaches about 90% and can take some time as only small balancing currents are used, so the batteries need to spend time charging after 90%.
Best to charge fully.
