AC300 + B300 Part 2 - Lets talk about technic!

Hey everyone!

like i mentioned in my last post (AC300 + B300 Part 1). There will be a Part 2 for my AC300 + B300 powerstation…

Its ready!

This one is a bit more about setting it up and talk about some technical points. Hope you enjoy it!


warum ist die AC300 nicht mit dem Netz verbunden?

Hi @Akel

im using the AC300 as Off-Grid Machine. Which means that it dont have a connection to the public grid in any form.

You can use this unit as an Backup System (UPS, USV) too! But for my Part, i only feed it with clean solar energy :slight_smile:

If you have any more questions, let me know!

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ich habe die B300 so wie in der Anleitung von
Bluetti gezeigt angeschlossen.
Der obere Anschluß an der AC300 bleibt frei.
Nach Auskunft von Bluetti ist es jedoch völlig egal, wie man die Akkus anschließt, da das BMS der AC300 die Belegung automatisch erkennt und verwaltet.

Hi @Akel,

does any of the B300 get recognize? I cant see it 100% but it seems like you have three installed B300, right?

If something dont get recognize, i will first try to connect two of you B300 together to one port of the AC300 and the leftover third B300 connect to the leftover Port on AC300. Since it can only handle 4 B300 in total, maybe there is a problem with connecting all three B300 to one port.


Nice video, thanks! Helps me understand some of my hubby’s solar rantings.
Do you also experience a mismatch between the “UPS” setting, and the recharge patterns when plugged to the grid?
I know it’s a recurring topic where the battery charges up to 15% while we set a minimum SoC to 5%; and even then, at 15% with some solar input (say 100-200W range), the “pass through” makes the power consumption draw power from the grid rather than using available solar and/or battery power.

Hi @Chrissie

Thanks for you message! Glad you enjoy the video.

Many of the Bluetti Units, like the AC300 have too, offer different UPS modes. I assume your using the custom mode, since you set the limits for yourself.

When i understand you right, you dont want to use power from the Grid, when the SoC of the Battery is higher than 5%. Right?

I would try to set it to “PV Priority Mode”. Which prefers the incoming Solar. You also can set a SoC Border on the Bluetti App too in this mode.

Hope that answered your question


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Thank you @Selfmadestrom - I just checked and it’s indeed set to “PV Priority Mode”. Today, it didn’t charge past 5%, but at least one day a week, it keeps charging up to 15%, and once even up to 100% and wouldn’t use the solar power! Probably a glitch, but it’s causing some head scratching.

Hi Chrissie,
take 30% and it will be work’s. 5% are to low.
Bluetti is good but not perfect.

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@Chrissie Did you only set it via App or also on the Machines screen? The App only have limited settings.

On the Machine, you can also setup the mix between Grid and Solarcharge. Im not using my machines primary as UPS, so maybe im just missing something

Ok, thanks for the info. Is there a risk of damage or accelerated aging by allowing the battery to stay under 30%?

All settings can be made directly via the app or on the AC300.
Try it…it’s really true.

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via the AC300’s color screen

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Hello Chrissie,
no, it doesn’t.
The charging cycles of the batteries are cumulative.
Partial charges add up to 1 cycle with 100%.
It doesn’t matter whether you charge completely from 0 to 100% or in partial charges.
No worries.

Thats partly true. Your right with “it doesnt matter how you make the one cycle to reach a cycle”. But what does matter is how you charge and discharge the Unit. If your using your unit between 20% and 80% you may get a longer lifespan than discharge it to the dead end everytime you use it.

What you should avoid is to let the battery stay to long on 100% or complete empty. This might damage the cells

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you’re right.
The problem is not the battery but the many switching processes of the BMS and the inverter during many charging and discharging processes. The battery doesn’t really care.
I take 30% low limit and 80% high limit and i think that’s perfect vor me.

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Hello Selfmadestrom,
Can you write something about my battery connections?
Is that correct or do you have a different opinion?
Please look at the pictures.

@Akel I Already write something about your wiring :slight_smile:

Hello Selfmadestrom,
Everything is recognized and works perfectly.
That’s how I wrote it too.
I was just worried because you switched it differently.

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Ahh okay. As long the AC300 is able to recognize, i would say stay with you setup :slight_smile:

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