Attention all AC300 owners with Split Phase

Product Discussion BLUETTI AC Series
1

I have written to Bluetti sales to ask about the availability of the special charging cable identified as item 14 on page 6 of the AC300 user manual, since we need it to charge our AC300 at its maximum 30 A. The cables supplied with each AC300 is limited to only 15 A. I am expecting Bluetiti to reply. Up to now there has been no news or listings on their sales web pages.

Meanwhile, as an EE, I am investigating how to build this cable ourselves. The L14-30P male plug and the pair of 10 gage/4 wire (10/4) cables can be purchased at any hardware store. But the AC300 input uses the Weipu SP2911 male panel aviation connector while the supplied charging cable uses the Weipu SP2910 female plug aviation connector with the attaching ring, and five feet of 14 gage/3-wire cable ending with the normal NEMA 15A plug at the other end. I have checked other sources for the SP29 aviation connector, but each brand has its own design for the male-female attachment which is not compatible with the Weipu brand used by Bluetti.

So I have asked Weipu directly in China and one of their U.S. suppliers, and both sent me their quotes but for multiple units. I cannot buy so many and I only need four now, so If someone who has the AC300 and is also a hardware distributor/reseller or knows someone who is, please post back to me here as I can forward the two quotes to them. Then they can buy the Weipu SP2910 connectors in bulk, sell them individually to all AC300 owners, and make money, too.

The Chinese quote is much cheaper, but it may be for over 100 units. The local supplier has quoted for 20 units but at a much higher price. If this can become a business for someone, go for the Weipu quote. And someone else may start a business to fabricate and sell the completed charging cable, too.

So, please write and post here all who are interested until Bluetti replies about their cable. As a sample, here is the Weipu web page:
https://www.weipu-group.com/product/circular-connector/sp-serieswaterproof/sp2910-p-sp2910-s-cable-connector-ip68/

The correct Weipu part number is SP2910/S3-1.

Edit: I corrected some words above, and the Chinese contact at Weipu offered me to purchase one box of ten (10) SP2910/S3 female plug connectors. If I get replies from interested AC300 owners, I can buy one box and sell three sets of two each (I will keep four) for the original price plus shipping.

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2

Bluetti Service replied to my request about the charging cable:

service@bluettipower.com
Wed, Apr 20, 11:16 PM (21 hours ago)
to me

Hi Raymond,

Thank you for contacting us.

Sorry to keep you waiting. The AC charging cable for split phase will be released in May. Please wait with patience.

You can follow our Facebook group:BLUETTI Portable Power Station Club. We will post the latest news on it.

Best regards,
Winnie

So next month we may see the cable in their listing. My next worry is the cost. If it is too expensive I can consider buying the Weipu aviation connectors and built it myself. Then I can offer the same cable for less.

Edit: I have made contact with the Weipu sales rep in China and will attempt to buy the first two SP29 connectors. I will post here after they arrive.

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The two Weipu SP2910 connectors have arrived! Here is a picture of the new connector with blue rings next to the original SP2910 connector (all black) that came with the AC300:

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I have checked the fitting on the AC input port of my AC300 and it is perfect. So the new SP2910 connector is identical to the original used by Bluetti.

Here is the connector disassembled:

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The four parts are the three pin socket, the attachment ring, the main body, and the cable clamp ring. The three pins are solder cup terminals, which are identical to the pins in the original AC300 connector. This is where the three #10 wire connectors are attached for the 30 A supply to the AC300. The original pins also support 30 A but the attached cable is #14 wire for only 15 A and during long term usage they will warm up. If someone wants to sacrifice the original connectors, it can be done by opening the SP2910 connector, unsoldering the #14 wires and soldering the #10 wires in its place. The disassembly is simple but you can ask me if you need to do it.

Weipu sold me just two connectors but the shipping was $31 and this is my loss. The minimum shipment is a box of ten which makes five pairs. If four AC300 owners write to me to order the connectors, I can ask Weipu for a new quote for ten connectors, then post the correct price and share the shipping cost among all buyers per pair.

Meanwhile I will wire up the 10/3 cables to the two SP2910 connectors and to the L14-30P on the other end. After I test the new cable assembly, I will ask Bluetti service for the password to increase the AC charging current to 30 A and finally permit my AC300 Split Phase setup to charge at 30 A and input up to 7.2 kW for its UPS service and B300 charging.

Finally, you can “wait with patience” until Bluetti begins offering the AC Split Phase charging cable this month at their retail prices (I predict that it will cost over $150) or you can take up on my offer to buy the SP2910 connector pair from Weipu directly, and make the cable yourself (or have an electrician do it for a fee) which will cost less.

4

Hi Raymondjram,

I actually came to a similar conclusion a few weeks ago myself. However I have two of the 30amp AC charging cables from Bluetti for my AC300. On these cables are Home Depot Replacement L14-30p plugs to be connected to a 240v outlet. In reality this cable only pulls one leg (120v) from the 240v outlet. I verified this with a meter.

Therefore I bought a L14-30p to TT-30r y-adapter and confirmed that each of the TT-30r outlets on the y-adapter are on separate grid legs and has this configuration for each of the TT-30r outlets L1/N/Ground and L2/N/Ground.

Since the plug on the Bluetti 30 amp charging cable is literally a replaceable plug head, my plan is to change the plugs on the 30amp charging cables to TT-30p plugs, one for each unit (master/slave) outlets of the y-adapter.

David

5

I have finished the AC charging cable for split phase to supply 240 VAC at 30 A for the two AC300 units.

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I identified the"X" and “Y” aviation cables for each AC300 unit. The hardest part to do was soldering the 10 AWG stranded wires to each Weipu SP29 connector. The two 10/3 cables were wired by screw connectors inside the L14-30P. I tested it and it is working as expected. The total cost was less than $150.

The Bluetti sales page does not have this type of charging cable yet. They sell the single 120 VAC and 30 A cable with the Weipu SP29 aviation connector.
https://www.bluettipower.com/collections/accessories
One can buy two of these at $79 each, remove the single L6-30P on each cable, then wire both to the L14-30P connector. But it will cost much more than tbe $150 I spent.

6

Very nice work! If Bluetti doesn’t have theirs out by fall, I’ll do the same (winter is when I have repeated outages and I want to get as many watt-hours in as possible between outages).

Out of curiosity, do you care which unit is X and which is Y as long as you know they are on on different hots?

7

At the initial setup it does not care. But since I also have the Fusion Box Pro at the output, I had to identify the two lines at the inputs and outputs, so I can monitor each phase and try to keep them balanced, which presently are not. When they are not balanced, there is a current flow on the neutral wires. The wiring on the L14-30 plugs and receptacles have to match according to the phase, but you choose which AC300 goes to either phase “X” or “Y”.

A perfectly phase balance ( equal current flowing on each phase) will have zero current on the neutral, and thus more efficient power usage.

1 Like
8

Have you tested this yet? On the 30amp generator cable they have the white/black cables reversed on the receptacle side.

9

Yes, I discovered that when I removed the Weipu SP29 cover. I did a continuity trace from the NEMA plug to the AC300 and I confirmed that pin 1 on the SP29 is line, pin 2 is neutral, and pin 3 is ground. Somehow a Bluetti supplier for the 15 A, 14/3 AWG cable has the wire colors wrong from the plug. Anyway, I did not use the original 15 A cables.

I wired my 30 A, 10/3 cables correctly from the new SP29 aviation connectors to the L14-30 plug and it is working but only at 15 A. I have to contact Bluetti to give me the password so I can change the charging current to 30 A.

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This is why I like working with you… one of the few people that know what they are doing!

I actually created a video series on this finding:

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As an EE and working with 120 VAC since I was a child in the 1960s, and received my share of shocks, I have to check every wire, plug, and socket that I will use in my home. So you are as practical as I am.

This is my first time working with Bluetti equipment and I can easily find and see their mistakes, although the mistakes are not that bad because they depend on the suppliers who sell them parts and cables in the thousands. A layperson will not see these mistakes, but we who have training, experience, and cusiosity in this field can help these laypersons in tbe community to find the mistakes and help solving their needs.

BTW, I posted pictures of the Fusion Box Pro insides at another site here. You probably saw it. Soon I will open the AC300 and takes pictures of its insides to post here.

12

Bluetti warns users not to use the original AC charging cables in the split-phase system. But it seems as if the only thing the special cable does is ensure that one AC300 gets its power from L1 and the other from L2. Does the cable do anything else? Shouldn’t it work equally well to power the two AC300’s from two outlets from opposite sides of the main panel using the standard AC charging cables? That would save having to install a 240V outlet and purchasing (or making) a special cable.

By the way, I’ve been impressed by your posts, Raymond. Now that I’ve read your bio I see why!

13

You can build your own cable using their OEM cables.

I have a video series on this subject:

Links to the other videos are in the index of the description. My Split-Phase system is running on these cables, running 50% of my home.

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14

FYI…
I took advantage of the bluetti rewards and was able to order the bluetti split phase cable $99 with a $50 rewards credit . Final out of pocket total including tax is about $54. Waiting for shipment. I had already purchased and received one 30a non split phase cable at $79.

15

Hopefully you get it within a reasonable timeframe. I know no one that has gotten it since it became available on thier website.

16

Thanks. Hopefully Timeframe should be similar to the 30a non split cable. Although I am really not in a hurry since I have the 15a standard and now also the 30a non split. I ordered the split phase cable because I had the rewards credit and it seems like a reasonable discounted purchase.

17

Just received my 30a split phase charging cable from bluetti today. Much less waiting and much faster arrival than anticipated. $50 bluetti rewards so paid about $54 for this cable.

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18

It does work. I’ve been doing it this way, but I have the new cable now so I’ll be running a new 240V, 30A line to where my AC300s are. Two advantages to the 240V approach… it’s less error prone (impossible to have someone plug them both into plugs on the same side of the panel) and 120V, 30A circuits are rare (much less 2 of them near each other which are connected to different sides of the panel). Safer and 7,200 watts make a nice combination.

When I plug my AC300s into two outlets that are on different sides of the panel, I always stop and think to make sure I’m doing it right and not about to fry something expensive (or myself). After some of this thinking, my GUESS is that having the separate phases is not about charging (my initial assumption was that it was) as things need to be converted to DC for charging and there is no such thing as phase at that point. I think it’s about powering downstream 240V appliances as a UPS when the grid supply is live and being passed straight through by the AC300s’ relays. Who knows how a random appliance will react to having both legs of their “240V” input in phase with each other. It might not break things as there should be no potential between the “hots” (especially in appliances that don’t take a neutral). 120V subsystems on systems that do take a neutral would power up - how will the appliance handle having some subsystems powered but not others? I’m not about to test my guess by plugging both into the same side of the panel, even for charging only. I’d discourage others from testing this, too.

19

Excellent discussion and some very valid points. If I get a second AC300 and go this route I’ll definitely avail myself of the dual cable now that it’s available.

You aren’t by any chance running a well pump off your P030A are you? I keep hoping to find someone saying that he’s running a ¾-HP 240V well pump like mine using that system and that it’s handling the pump’s surge.

20

Nope, we have gravity fed water from a mutual water company. But I do run a 1/2-HP 240V evaporative cooler fan motor on it. The initial surge I see is 1,500 - 3,500 watts and steady state is about 750 watts (split between the two AC300s). I’ve had no problems at all with that.

I power the entire house when we have outages that last longer than an hour or two. Our peak sustained usage is probably ~3kW during those (average is ~750W) and we’ve never tripped the overcurrent protection. The biggest problem we have is that one side of our panel supplies MUCH more than the other so the batteries get way out of balance. Until I can move circuit breakers around for better balance, I power a 480W DC charger with one AC300 to charge the other during outages so I don’t have one B300 go dead while the other is still at 40%. It’s less efficient, but I get more runtime. By checking once an hour or so and plugging/unplugging the charger, I can keep them within ~5% of each other.

During outages longer than ~6kWh (the total capacity of my 2 B300s), I run a gasoline powered generator part time to power 2 of those chargers. Then I just move between both on a single AC300 or one on each AC300 to stay in balance - then there’s no real loss of efficiency (and it works on a 120V generator with no worry about phases). I love the flexibility of having 2 big DC inputs on each AC300 (plus more on the B300s if I ever need it). This setup means a ~1kW gasoline generator is enough to keep me topped up (running 5-10 hours a day) and the AC300s handle periods of 3-6kW that such a little generator couldn’t dream of. I’ll soon be adding enough solar panels to run all our 240V appliances off the AC300s full time in the summer and that will be a lot less gasoline usage during outages. But direct sunlight doesn’t touch our property for ~5 months in the winter. :frowning: