Does AC300 directly convert its PV DC input into AC without using the battery? I understand the excess is stored, but I want to make sure it’s not wasting energy and cycles by loading and discharing the battery at the same time.
I read the batteries of an AC200max would endure excessive levels of wear in case loads are connected on the AC outputs while PV in is active.
The bluetti app of my AC300 shows electricity entering the battery, then reaching AC loads.
I also noticed that the grid and ac out become green under some conditions (ups settings).
Hi @Derceto , sorry for late reply. Based on your question I went to consult with relevant engineers with following.
In any mode, under any operating conditions, PV charging is enabled in priority when PV energy is available
All UPS modes are based on the presence of utility power, without utility power are entered off-grid with load. When the status turns green, it means that the battery power is not used.
Would be interested in understanding exactly the same for the Ac200max as we have a fridge freezer running constantly on AC from the Ac200max. solar input during the day exceeds the fridge freezers power draw.
Can you just confirm the scenario where no grid power is available and PV input (1500Watts) is available while AC output is connected to loads (1200Watts).
the whole 1500Watts are stored in the batteries while 1200Watts are being pulled from the batteries for AC out?
-1200 Watts from PV input are directly inverted and supplies to AC (bypassing battery charge/discharge) and the remaining 300 Watts are injected in the battery?
First scenario would be a poor use of batteries (conversion loss + wear) while the second one is in line with our expectations (off-grid UPS).
I think bluetti documents that ups is only available when grid power is available. Pass through is a ups feature. So if you are not in ups mode, with grid power being up, there is no ac pass through. I think that pv charging is dc power in and not ac power in so that ac pass through on dc power in isn’t there/possible since dc must be inverted to ac and cannot pass through since it is not original ac in.
Unfortunate because it involves useless battery wear (store and pull energy at the same time).
One battery cycle = having pulled 100% of the battery capacity, in B300 terms that’s roughly pulling 3kWh. It also means 2 baskets of laundry in an average washing machine.
In a previous version of their FAQ, Bluetti recommended against storing and consuming battery energy at the same time (AC200P) due to resulting excessive wear. Given they recommended against it, I want to make sure AC300 is engineered as a “real” solar UPS: invert DC to supply AC loads then only store the excess DC in.
A Victron / Growatt / etc. as mentioned would only store the excess and keep battery wear to its minimum. They are “real” solar UPS devices. I want to make sure AC300 is as “real” as these are.
Even though 3000 cycles is a lot, I just don’t think it’s a good idea / choice to treat a device like a solar UPS while in reality it causes useless wear (+ energy loss due to battery in & out).
About your mention of becoming suspicious, I encourage not to go to that extent quite honestly. I want to trust their reputation first. After all, 3000+ cycles is a lot. Let’s think of it this way: 3 cycles per sunny day means 80% battery capacity is still available after 3-4 years. We purchase a product that has proprietary wires. We know that when an AC300 dies (the inverter and MPPT are the two weakest links in solar generators) then the B300 either needs a new AC300 OR it goes to the bin.
We’ll keep in mind that we buy a product that has 2 years warranty whereas Victron / Growatt / etc wall-mounted devices have 5 to 10 years warranty.
The only Bluetti product with 5 years warranty is EP500pro.
I’m patiently waiting for @BLUETTI 's answer regarding the “solar ups vs battery wear” question.
@BLUETTI , With the AC300, when there IS an AC Load, if the batteries are at 100% you mention that there isn’t any effect (assuming bypass of the battery); however, the APP shows an animation with NO PV entering (e.g. 0 watts), as long as the battery is at 100%, therefore it appears that the AC Load IS running off the batteries. When the Battery level goes to 99%, then the PV kicks back in until it reaches 100% and back and forth between 99% and 100%. I didn’t know if this situation is a limitation of the App. In my example photos (below) I would expect at least 235W + wattage used by the AC300 inverter to be displayed on the PV input. (also note, after 23 minutes I just had the 100% drop to 99% and is now charging via the PV)
@BLUETTI The number 2 point you have stated does not appear to be accurate in practice as the PV input stops accepting power when the battery reaches 100%. Please see the screenshots @wtytke has provided above. There is ~1.7KW coming in continuous via solar, but the AC300 does not accept it until the battery storage drops to 99%. This indicates repeated cycles of drain and charge cycle on the battery storage even when steady power is available via PV input. I am seeing the same behavior he has documented here.