Adding DIY battery to Bluetti AC300

[ice69man2005]

Hey guys I have been looking into adding an additional pack to a Bluetti but they make it hard and seem to want you to buy theirs for some reason haha.

I don't own it but my grandfather in California bought one for all the brown out and grid outages they've have in recent years. I live across the country so I've been researching it on my own and can't seem to find much on anyone adding their own batteries to them. Which makes sense, if you could build the battery you could build the all in one equivalent.

My main hang up is the connectors. The AC300 is 48V so I figure I can tie the battery in through the P090D connector (two in right side of picture) that the Bluetti batteries plug into. Problem is that appears to be a fancy overpriced cable that a P090D to XT90 goes for $100 and is really right at the edge of supporting the 4000W continuous the unit can draw. I probably wouldn't be able to get it to talk to the Bluetti using that pre made cable and with a Bluetooth BMS I'm not worried about that. Just need to get the juice into the unit.

My other option is to tie in through the PV input as the input voltage can be 35-110V (middle plug on left side of picture). That appears to be a more standard plug and while it can only input like 2000W that should be more than enough to support his minimal loads in a blackout.

I thought the one unit could do split phase and it can, if you buy a second but he's on a limited budget to pull this off so I'm looking into an autotransformer next but should figure out how to hook up the batteries that I'm trying to buy right now first haha.

TLDR Has anyone bought a Bluetti but made a battery and have links to the cables? My grandfather is measuring things for me but didn't have calipers.

Thank you guys for the knowledge that got me this far!

 

[SunBlind02]

I Been wanting to do the same thing.

 

[Kremer]

I'm really close to trying the same thing. The ports are clearly straight DC bus voltage. My plan is to buy a factory battery cable, cut it in half and extend to a 100ah rackmount pack.

 

[Kremer]

I'm really close to trying the same thing. The ports are clearly straight DC bus voltage. My plan is to buy a factory battery cable, cut it in half and extend to a 100ah rackmount pack.

So I just did this last night... It WORKS PERFECTLY! It charges and discharges with the main unit and shares draw and charge amps in parallel with the OEM battery, just like you would think it should. You just need to have at least one B300 attached so the head unit has a BMS to talk to and keep happy. Same thing should work just fine with the AC500 also.

 

[sgthoskins]

So I just did this last night... It WORKS PERFECTLY! It charges and discharges with the main unit and shares draw and charge amps in parallel with the OEM battery, just like you would think it should. You just need to have at least one B300 attached so the head unit has a BMS to talk to and keep happy. Same thing should work just fine with the AC500 also.

Nice! Any pics/vid of the process?

 

[Tiger2380]

So I just did this last night... It WORKS PERFECTLY! It charges and discharges with the main unit and shares draw and charge amps in parallel with the OEM battery, just like you would think it should. You just need to have at least one B300 attached so the head unit has a BMS to talk to and keep happy. Same thing should work just fine with the AC500 also.

Come on. Don't leave us hanging. Lol..
I would like to do the same thing. I have 2 12v 100ah Hybrid deep cycle gel batteries. Can I do the same or I need LiFePo4 batteries?

 

[Kremer]

Come on. Don't leave us hanging. Lol..
I would like to do the same thing. I have 2 12v 100ah Hybrid deep cycle gel batteries. Can I do the same or I need LiFePo4 batteries?

I don't think I would try it with lead acid. It really should be 16S LiFePO4 matching the B300 or B300S OEM battery. I have only tried it so far as a proof of concept, not a permanently wired up thing.

 

[Tiger2380]

I don't think I would try it with lead acid. It really should be 16S LiFePO4 matching the B300 or B300S OEM battery. I have only tried it so far as a proof of concept, not a permanently wired up thing.

I'm a subscriber to your YouTube channel. I would love to see you do a video discussing this in details.

Thanks

 

[Kremer]

I'm a subscriber to your YouTube channel. I would love to see you do a video discussing this in details.

Thanks

Thank you for that. They have been pretty good to me so far and I think I would be disowned if I made that video. Maybe in the future.

 

[billvon]

I'm really close to trying the same thing. The ports are clearly straight DC bus voltage. My plan is to buy a factory battery cable, cut it in half and extend to a 100ah rackmount pack.

How did you manage to buy the factory cable? I haven't been able to find it anywhere.

 

[Kremer]

How did you manage to buy the factory cable? I haven't been able to find it anywhere.

I bought the P90D to P150D adapter cable for my testing. One end connects to the AC300/B300, the other end an AC500/B300S.

 

[ice69man2005]

Sorry just turned notifications back on after having them off when it was requested before. I see there has been some progress on the front though.

Are you able to ohm out the plug and see which pins corresponds to the positive and negative side of the battery? I'm guessing this plug only uses the two main pins but just did a little more googling and couldn't find any other non OEM sources for the cable. $160 on AliExpress and $100 on Amazon is a little steep but still probably cheaper than buying one of Bluettis prebuilt batteries.

 

[jtran69]

I don't think I would try it with lead acid. It really should be 16S LiFePO4 matching the B300 or B300S OEM battery. I have only tried it so far as a proof of concept, not a permanently wired up thing.

I find your your proof of concept very interesting and congrat Kremer! Do you recall if the display/app showing your new connected bat pack with capacity level status?

 

[Kremer]

I find your your proof of concept very interesting and congrat Kremer! Do you recall if the display/app showing your new connected bat pack with capacity level status?

The AC300 does not know the external pack is there, there is no BMS/computer connection, only the power leads. It properly shows the B300 battery, which is same voltage and being augmented with the external in parallel, in theory they are all at the same charge level.

 

[jtran69]

I have the P90D to P150D adapter cable, ECO-Worthy 48V 50AH lifepo4 16S ready to test with my AC300-B300.
@Kremer , Does it matter if the ECO pack is connected to the AC300 or B300?

 

[Kremer]

I have the P90D to P150D adapter cable, ECO-Worthy 48V 50AH lifepo4 16S ready to test with my AC300-B300.
@Kremer , Does it matter if the ECO pack is connected to the AC300 or B300?

No. Make sure the voltages match very closely, like +/- 0.2V. Be EXTREMELY careful, you are dealing with hundreds of amps of available current.

 

[Zedart]

Thank you @Kremer to be first brave man to test if third party battery can work with Bluetti AC300. Now I'm after connecting 5kWh Fogstar battery to my AC300 and looks like this solution working well.

 

[jtran69]

Hi Kremer,
Attached pics are the eco-worthy battery spec and the 4gauge wire crimped to the Bluetti cable, I hope that the max charge/discharge of 50A would work well. Also I have a 200A fuse attached, not sure what is the more proper size for this setup?
Any safety suggestions would be much appreciated! Thank you

Attachments​

• 
  IMG_8018.jpeg
  245.4 KB · Views: 4
• 

 

[jtran69]

I’ve tested 2 cases in the evening, hence no Solar charging.

Case1. While the AC 300 B300 are OFF, connecting the ECO battery to either battery port would cause the AC 300 to turn itself ON with the beeping alarm msg attached.

Case2. With the ac300 and the b300 idling, connecting the ECO Battery did not cause any alarm. I tested some ac loads without any issue for a few minutes.
I plan to test with daylight next.

Attachments​

• 
  

 

[Kremer]

I’ve tested 2 cases in the evening, hence no Solar charging.

Case1. While the AC 300 B300 are OFF, connecting the ECO battery to either battery port would cause the AC 300 to turn itself ON with the beeping alarm msg attached.

Case2. With the ac300 and the b300 idling, connecting the ECO Battery did not cause any alarm. I tested some ac loads without any issue for a few minutes.
I plan to test with daylight next.

Attachments​

• 

Yes, read post 4 of this thread. The AC300 NEEDS a B300 to talk to. The B300 and its BMS aren't an optional accessory, at least one attached is mandatory to have the AC300 work.