diy solar

diy solar

DALY BMS, Charge and discharge at the same time?

I'm still trying to understand why you are trying to use 4 relay controlled chargers. Any off the shelf lifepo4 charger will work fine. The battery will only draw as much current as it needs, so no need to "stage" individual chargers.
What Im hearing is.... OP only wants surplus going to the 18650s and wants to manually control it the flow?
 
Exactly, I only want "solar" energy and no grid energy in my battery, and use this battery on line that are rarely use (shelter) or use a Automatic Transfer Switch (https://www.amazon.fr/dp/B0CJC8TMYN...rial&sp_csd=d2lkZ2V0TmFtZT1zcF9kZXRhaWwy&th=1) to use the battery on some of my house lines, when it's full, at night, instead of grid energy
I don't know if my idea is correct but inverters that I saw with AC coupled functions ( that can know how many amps to send to the battery to avoid grid energy) cost 800e for 3KW
Is it better to take a simple 3kw inverters like this one (https://www.vevor.fr/onduleurs-sola...IC-wcRu5Kl_pah5obWsoiT-Ye68N5C0xoC2v4QAvD_BwE) and plug my chargers to the AC input?

In summary, someone have a not most costly solution to charge and discharge a battery with no more than solar surplus, with apsystem micro inverters?
 
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Exactly, I only want "solar" energy in my battery, and use this battery on line that are rarely use (shelter) or use a Automatic Transfer Switch (https://www.amazon.fr/dp/B0CJC8TMYN...rial&sp_csd=d2lkZ2V0TmFtZT1zcF9kZXRhaWwy&th=1) to use the battery on some of my house lines, when it's full, at night, instead of grid energy
I don't know if my idea is correct but inverters that I saw with AC coupled functions ( that can know how many amps to send to the battery to avoid grid energy) cost 800e for 3KW
I think I see your idea. I do not know the best way to do that.

I hope someone else can help.
 
OP only wants surplus going to the 18650s and wants to manually control it the flow?

How is he even determining what "excess" is?

What do you meen by "any off the shelf lifepo4 charger will work fine"?

When lifepo4 batteries are nearing full charge, the current tapers off.
As I asked above, how are you determining when there is excess? And why not just turn on/off a single charger then?
 
After batteries are full is my understanding

Now I am even more confused. Is this a second set of batteries? If so, then again, just turn on a single changer designed for the batteries one is trying to charge.

If a single set of batteries, again just turn on a single charger. If the batteries are already charged, the charger will feed the load and keep the battery topped up. The charger would only supply the current needed to do both.
 
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I determining the excess with CT clamp on PV output and house principal income line. I also have the apsystem ECU-C in my system that calculate that.
Those datas are transfer to Home Assistant, and from there I can calculate excess (PV production - house consomption). This part is OK for me.
Now that I have my instant excess in Watts (minus communication delai), I know how many "solar energy" I can sent to the battery without using "grid energy".
So what I have in mind is to use multiple little AC-DC chargers, that I know they will not draw more than 60W each when turned on, and adjust how many chargers I supply electricity with relais connected to a esp32 connected to Home Assitant, right back to my excess data, actualized by this new load on my house consomption.
Charging process will draw maximum 2a per chargers on, except if my battery is full and the BMS cut current...Right?
My main concern is about connecting several ac-dc chargers in parallele, . That can appen bad if there are all same model, same voltage?
 
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