Expanding the capacity of my EB3A

I’m generally happy with my EB3A as it provides excellent value.

I’ve been using it for:

  • Typical AC load of 150W and peak of 400W across 2 outlets
  • USB-C 30W PD charging
  • USB-A 10W charging
  • PV Charging using 2x 100W 19V Solar Panels wired in parallel. I don’t have space for more panels.

My issue now is that the battery capacity is too small and I don’t have more energy storage available after I’ve charged my EB3A to 100%. I also want to minimize the use of pass-through charging to pro-long the battery life. I wish I could hook up an additional battery. I spent some time researching ways to do this in a way that’s not too janky where I would be able to charge and discharge this additional battery using as few adapters and additional accessories as possible.

I have considered replacing my EB3A with larger power stations like the EB70. The dollars per watt-hour come out to around $0.92/Wh for the EB3A (based on the current Amazon price of $249 and its capacity of 268Wh) and $0.70/Wh for the EB70 (based on the current price of $499 for the teal version and its capacity of 716Wh). But I’m looking for more than 2.7x the battery capacity, more like 5-10x to have lots of buffer for storing energy on lots of consecutive sunny days and using it on non-sunny days.

There’s also the AC200P. It is $1499 on Amazon today with 2000Wh so that’s $0.75/Wh but it has a lot of bells and whistles I don’t need that I’d be paying extra for (albeit not that much more). The 2000W inverter is overkill, I don’t need that many outlets and I won’t be needing more than 200W of solar charging.

How about the Bluetti B230 expansion battery? Could I theoretically use it with the humble EB3A? It sells for $1,299 on Amazon US and sports 2048Wh which comes out to $0.63/Wh which is the best price per Wh thus far. The EB3A only has one DC input option though to receive DC power from the battery: 12-28VDC @8.5A via the DC7909 plug. The B230’s only reasonable outputs are the 12V @ 10A car port and the PD090D port. I could purchase the Bluetti Car to DC7909 cable and can expect 12V x 8.5A = 102W of max charging. But, there’s also the PD090D battery expansion port. However, my research suggests that the output volts from it are above the EB3A’s 28V max for the DC7909 port and thus this won’t work. I say this because of the compatible models mentioned in the PD090D user manual:

The EB120, EB150, EB180 and EB240 all support 60V DC7909 input so I suspect the it is outputting above 28V and at or below 60V so this won’t work without same DC buck converter. Then there’s the whole other topic of how to actually charge the B230. For that I would have to spend an additional $159 to buy a DC Charging Enhancer (D050S) to charge from my solar panels because I can’t use the EB3A to charge the B230.

Heck, after all the research and writing of this post there seems to be no simple integrated option here between the EB3A and B230 (especially for charging the B230) so I might just end up going with an AC200P and rewiring my solar panels from parallel to serial to hit the minimum 35V input requirement.

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How about the EB240? I see its down to $1,100 today on Amazon, that’s only 46 cents per wh. https://www.amazon.com/gp/product/B082CWRGTR/ref=ox_sc_saved_title_1?smid=A3H5DUG78CAIWF&psc=1

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The voltage output of the B230/B300 is in the low 50’s so they won’t work with the smaller Bluetti’s. I have the B300 and it outputs about 500 watts to my AC200P or EB150.

@eric102 Thanks for the suggestion, the EB240 might just be the perfect thing for me. I guess I had initially dismissed it but upon further research for the $ per Wh I’d be willing to sacrifice convenience features like mobile app integration and detailed percentage SoC. Given the overall great reputation and reviews of the EB240 I’m also less concerned that they don’t use LiFePo4 batteries; given my limited solar power generation and device utilization it is going to take much longer to go through one battery cycle so the rated 2500+ cycles is still outstanding.

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I agree @bxm6306 I think Eric’s @eric102 idea is a good one especially if just using to recharge the smaller bluetti’s at a good price point. I need to look into that cause sun availability is so fickle where I live. I need to see what connectors would be needed for each newer but smaller bluetti. Also wondering abot the EB150 (similar to EB240 but less watts). I know others do use the EB150 or EB240 to recharge their AC200P devices, why not the other devices as well. Let us know what you decide and how it works for you, if meets expectations.

@roxie60 oh I should’ve clarified that I would straight-up replace my EB3A with the EB240. Using the EB240 as a battery expansion for my EB3A is possible by connecting the 12V 9A car port of the EB240 to the DC7909 input of the EB3A but I want to maximize efficiency so I would use the EB240 as my sole storage of solar energy and plug my devices directly into its output ports. Transferring energy from one battery to another will always incur energy losses in the DC-DC converters, cables and connectors. I’ll resell the EB3A locally.

Thanks for the clarification. Yes there is loss charging one to another but I was considering in my case how challenging it is to solar charge these devices. I was looking at it myself as just a battery backup. It didnt have enough output ports and some (like USB) are very low watts.

I understand you are looking for a power station/genie that has more Wh available.

Some day I expect Bluetti to enter what I would expect to be the sweet spot, a device that offers the new amenities in the 1000Wh range. I was surprised they came out w/ the EB3A before a 1000 Wh version. At least they are active.

Lately, the last few weeks, Bluetti has been rocking their marketing. I get multiple youtube ads a day now and very professional so I expect their brand awareness to really spike. Maybe they wanted a better price point entry into their product line.

Good luck.