looking for info on how expansion battery works

I have an ac200max and I’m thinking about buying an expansion battery but I can’t seem to find any information on how it actually works. For example, does the expansion battery charge simultaneously with the main unit from solar or does it wait to the main unit is full and then charge? Or does it need to be charged separately?And when drawing power from the main unit, when does the expansion battery kick in? Once the main unit is out of power? Or is the expansion battery constantly recharging the main unit?

If there is somewhere I can find information on these types of things it would be very helpful. thank you

The AC200MAX + B230 epansion battery, both batteries, the B230 and the internal AC200MAX batteries, charge and discharge at the same time :tipping_hand_man:.

I think the charging part of your question is in the manual. You would think these units are just like a couple batteries in series where they supply the load equally and drawdown and charge equally as well but that’s not the case. For starters they are not in series, I have an AC200Max and a B230 battery, When I attach a load, the main unit draws down first and the B230 second, but not exclusively, the B230 kicks in as the load is going down and both battery’s end up at zero at the same time. Charging is similar but there are some details about that in the manual that I don’t recall specifically. They refer to which port you charge from, (The B230 or main unit). They do work as advertised though my firmware is not identical or the most up to date between the 2 batteries but I have to admit I’m a little scared to update my firmware as everything is working at an acceptable level right now.

Thank you for the responses. With the b230, you’re basically doubling the ac200max’s capacity. From a real world standpoint, do you feel that’s accurate?

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I bought the AC200 Max with 2 B300 expansion batteries. I chose the B300 over the B230 after watching a youtube video Will Prowse did, he mentioned the B230’s do not power themselves
on with solar connected.
I have no personal experience with the b230’s but I do with the B300’s, the B300’s will come on
automatically with solar panels plugged in (when the sun comes up)
That feature and the extra capacity is why I chose the B300’s

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@snrvr thank you that’s great to know. I think I’ve watched that video in the past so I should definitely go back and rewatch it.

Yep no problem
Will is a sharp fella, I consider his reviews a trustworthy resource

Yes, absolutely, Thats true

I also watched that video. Just to clarify the solar array is connected to the AC200MAX only and the B300 comes on automatically? Just checking you don’t have a separate solar array connected to the B300 which is making it come on.

I think the solar stays plugged into the main unit and both charge unless the expansion battery zeros out. If that happens you have to manually turn on the expansion battery. Given I’m not sure when that video was and that might have been corrected with a software update. There must be another video as well because he didn’t mention the b230 in this video

I have solar plugged into AC200MAX and additionally into each B300.

the batteries in this video are B230 you can tell because they are the same footprint as
the AC200MAX, the B300 batteries are larger (because of the extra capacity over the B230)

In the video if I remember correctly he was using an over panelled single array connected to just the AC200MAX and was complaining that the Battery didn’t power on under those conditions.

If you have an array connected to the b300 as well that’s a different setup and the b230 might also power on under those conditions. I guess you could test by unplugging the solar from the b300 and see if it still automatically powers on.

Edit - I see the b230 doesn’t really have a solar charger outside of the charge enhancer so I guess it couldn’t work that way. So the b300 with a panel attached is a good way to get it to auto start.

that is one feature I wished was built into the b230, I’m going to buy a switch bot to remedy that problem. :slightly_smiling_face: