@BLUETTI_CARE @BLUETTI
I’ve been “toying” with this idea for a while, as I am doing this in a round about fashion anyway.
An “Expansion battery”, all in one. - That is to describe, an expansion battery in power bank mode, with something similar to the Charger 1 as an inbuilt output and an inbuilt MPPT input to charge it from solar and posibly even from the Charger 1. With Bluetooth connectivity to Adjust output, depending upon the Power Station being Charged. As the smallest inverter power station is the AC2A at 28V and the largest being the Elite 200 v2 without expansion ports, this is a range of 204.8Wh to 2,073.6 Wh. (Or in 12V terms 8Ah to 162Ah.)
However, I would be tempted to ignore the 2kWh range and perhaps limit to the 1kWh power station size and lower to enhance portability. The AC180 being the largest at 1,152Wh (90Ah in 12V terms). My preference for capacity, would be to double the AC180 capacity (or Elite 100), which then allows an even greater capacity for smaller units. The connection lead could be XT60 from the expansion, with that or barrel connector to fit whatever power station it is connected to.
To compare with what I am already doing with the Charger 1 and a spare LFP deep cycle, the pricing needs to be competitive.
To emphasise this, (all pricing is current special pricing, with RRP in (). A LiTime 100Ah Classic is currently on special for AUD$390 ($600) and Charger 1 is currently on special at AUD$349 ($599), for a total of AUD$739 ($1,199). A 50Ah Litime is currently on special for AUD$210 ($360). 100Ah = 1,280Wh and 50Ah = 640Wh. I would therefore suggest a capacity somewhere between 50 & 100Ah (640-1,280Wh).
Adding other output ports, such as cig socket and USB will increase cost, however of imense use, here in Australia would be a 12V Anderson output port rated at 20-30A. This could be done with an XT port and a patch cable - XT60 to Anderson.
Perhaps another aspect - 2 way use i.e. Primary use to expand a power station’s capacity and the ability to transfer from a power station to the proposed power Bank, depending on need.
Hi, that’s an interesting idea. I have several of the smaller Bluettis. I never bought the B80 though, as it’s the same size as the 70 size Bluetti range ( I preferred to just get another unit with the full range of outputs), but mainly as the B80 is too slow at recharging. I think much speedier recharging would be a good selling point. Would you include the means of separately AC charging your new expansion battery? I don’t have a vehicle, so limiting it to solar / Charger 1 charging would be a bit limiting for us non-drivers.
@Tezzabee Hi Tez, good to hear from you again. I took the same stance re the B80 as here in AU it is more expensive than the AC70. Therefore, to increase the AC70’s capacity it was far more economical to buy a second AC70. Apart from doubling capacity, it also doubled both DC & AC outlets as well as all of the recharging options.
The B80 can’t be charged from AC directly. With my above suggestion, I did consider 240VAC (120VAC in the U.S.) charging, but was aiming this at the off grid camping demographic. To keep such a battery at a price point, the adding of a VAC charging option, could be done with an optional charging brick, with an output to feed into the DC input port, to cater for someone like your needs.
I would reiterate that as I currnetly have the Charger 1 and a spare 100Ah LFP, at a known cost, that any such device from Bluetti would need to compete economically, something the B80 falls short of.
The primary design criteria of my suggestion was to keep it 100% DC in/out as its function is to expand battery capacity and then use the same off grid charging sources i.e. solar and or Charger 1 used for power stations. So, a charging brick option is an acceptable method and Bluetti likely already have existing “bricks” that would work. 
The only way an “end user” add on battery product can ever compete with a DIY setup is volume. The requirements for safety are much higher than for “I bought a bare battery and crimped some cables” for obvious reasons.
@EtchedPixels Alan, Partly the point of my post. As I pointed out, an AC70 is RRP AUD $1,099, but currently on special for AUD$649. A B80 is currently RRP AUD$1,058, but on special for AUD $499 and noted as about to be “Phased Out”.
Would I buy one even at the rediculous low price of $499? - NO. why not? because it can only charge in power bank mode at 200W max. (Other than the AC60, which is no longer available in AU).
I have never advocated “I bought a battery and crimped some cables” As a retired Mech/Elec designer in Vehicle and Aerospace industries, among others, I know what I am doing. In other posts, I have detailed some work arounds, but always with the Caveat, “At your own risk”.
Properly crimped, heatshrinked and fused cables of the correct wire gauge are always indicated in detailed options. A degree of user knowledge or experience is required for DIY. For those without that knowledge, I would advocate buying a commercial solution. Which was another point of my post, in pointing out my costs for a DIY, which many others have done, that any commercial option needs to compete price wise. i.e. if it cost me AUD $739 + wiring and effort to produce a solution, how much would I be prepared to pay for an equitable commercial option? The answer is different for everyone, but for me, a 1,200Wh battery with say a 500W DC output and MPPT charger included, I would pay around a $1,000AUD.
I should point out that I already had cable, fuses and crimps and a spare battery in the “shed”, as well as already having purchased the Charger 1. Yes, I did purchase these items over time and probably paid more then, as prices have come down, but it is what it is, lol.