Clarification on charging from batteries for AC series stations

I am going to attempt to charge some Bluetti Power Stations from LiFePO4 batteries and just wanted to clarify that my plans are valid before attempting anything on the stations themselves. Starting with the AC500, I was looking for pre-made cables to charge the station directly from battery and was not able to find much available other than Bluetti’s set of cables that have battery clamps on one end and an XT connector on the other end (Lead Acid battery cables that are marketed for the AC200 series). As a result, I am thinking of trying my hands at creating my own cables and wanted to start with creating a cable with M8 ring terminals on one end and MC4 connectors on the other end to plug into the DC to Aviation plug cable for the AC500. I believe that the DC input on the AC500 is capped at 15 amps so does that mean that if I hook that homemade cable up from a 12V battery to the aviation port on the AC500, it will charge at about 180 watts? Are there any issues anyone sees with making this type of cable? If I connect two of the batteries in series to make a 24V system, it should double that charge rate if I understand correctly. I also believe I would be able to use 10 gauge wire or less since it will only be a run of about 5 to 6 feet but want to be sure I am good on the cable size as well. Would this same setup work for the AC200 Max and other AC series stations (with obviously lower charge rates due to lower amperage limits for the smaller stations)? Is there a more efficient way to design a cable for charging these stations directly from a 12V or 24 battery bank? Thanks for any input in advance as I am a relative beginner so just trying to innovate without blowing up expensive stations.

Sounds like a Plan but 12V is to low to work.
My EB3A needs >14V to properly charge at rated current

I would go with a 24V system

You will fined MC4 to XT60 and everything to XT60 if you want to

You might want to think about using a chap “solar” charge controller between the bluetti and the battery.
You can uses the charge controller to charge, limit charge and discharge to the LiFePO4 battery.

Thanks for the feedback. It is very helpful as I did not realize that 12V would not work. I have multiple 12V batteries and some cable to wire them in series so a 24V system should not be an issue but I was hoping to also use them individually so I wonder what happens if you do not meet the 14V minimum. Does it still charge but just at a reduced rate or does it not charge at all? The EB3A is one of the units I was going to use. I looked at the XT connectors and moved away from that idea for a couple of reasons but I may be incorrect in my thinking so maybe you have some thoughts that can straighten me out. One of the thoughts was that I know if you want to use the XT connector directly to the stations (instead of an intermediate between the battery and another cable to the station), I believe the AC500 uses XT90 while the AC200 uses XT60 (not sure I remember correctly though).
The other thing that I noticed during my internet search was that it seemed like the XT to MC4 cables all seemed to be wired backward from what would be necessary for the aviation cables (ex. positive wire was female MC4 instead of male, etc.). I was a little confused as to why but it looks like they are trying to sell cables for panels instead of for inputs to power stations. Thanks again for bringing up the minimum voltage as that is something I had not thought about.

the current goes down and at around 13.4V it stops. so you would not be able to uses the full battery capacity and the power station would only charge if the 12V battery is charging.

A way around this is to use a 12 to 24V DCDC converter.

A 12.8v battery will work fine with the AC500 but will only draw about 8 amps to protect a cars 10 amp outlet. Same with two of them in series at 26v which will only net 215 watts. But combine three of them in series at 39v and you will get the full 15 amps which is 570 watts. That’s been my findings with my AC500 and the three 12.8v 100amp lithium batts I have.


You are on the right track and I would connect the batteries in series to get 24V or if you have more, 36, 48 or higher would work even better for higher transfer rate.

Thanks everybody. This is great information and exactly what I was needing. I have four separate 12.8V batteries so it sounds like I will be able to use a single battery at a time for something small like the EB3A but will need to wire the batteries in series for the larger stations (with reduced charge rate at 24 volts but full 15 amps if I go with at least 3 of the batteries in series). I am going to start small as I have access to a 12/24 Volt cigarette lighter socket with a 15 amp fuse right now so I will have to see how that works until I can build some cables (or find them for purchase). I am also going to put a Victron Smartshunt in line for battery monitoring but it sounds like I will need to build more cables as the batteries have M8 terminals and the shunt has M10 posts. I have heard that it is not advisable to use M10 ring terminals on M8 posts. I am eventually planning to possibly add a Victron solar charge controller to the mix but the budget is limited and I can use my Bluetti stations for solar collection at the moment.

If you have a Bluetti that accepts 48 volts, I would go with the higher voltage since the size of your wire conductor can be less as well as having less loss during transmission and less heat generated for a given wattage.

Sounds great. Can anyone suggest a particular fuse that I could put inline for wire protection? My understanding is that it would have to be a fuse rated for at least 48V if I plan to use this as a 48V system for even part of the time. If my understanding is correct, the same fuse would still be effective for a lower voltage system (12/24/36 Volts) so I would not need to swap out fuses if I were to use the bank at a lower voltage. I am thinking that I should get at least a 20 amp fuse (because the max the Bluetti would pull is 15 amps and I am planning to use at least 10 to 12 AWG wire for a relatively short run (less than 5 feet). I would likely also want to get one sized at 30 amps in case I ever need to wire up my 300 watt 12V inverter. If my math is correct, I would also need a 160 amp fuse if I ever decided to hook up a 2000 watt 12V inverter (that would also require a thicker wire). Just wanting to know if there is a fuse (or set of fuses) I could purchase that can be easily inserted into the circuit after the positive terminal on the battery. Thanks again for the discussion as this thread has helped me out tremendously to use my Bluetti stations and batteries even more.

Just an update and a few more questions for everybody. Using the great information I got from this forum, I was able to successfully hook up 2 of the 12V batteries in series and run a 24V cigarette lighter socket to charge a couple of my smaller Bluetti stations. They charged at around 199 watts, which is what I expected. The cigarette lighter socket has a 10 amp blade fuse inline right now and nothing got hot so I think that setup is going to work well to supplement my Bluetti stations.

I would like to monitor the state of charge on the batteries so I purchased a Victron SmartShunt. However, I realized that the SmartShunt bolts are M10 size and the Ring terminals on my cigarette lighter socket are only M8. Is there any way to use an adapter to keep the M8 Ring terminal on the lighter socket but get it to hook up the M10 bolt (without removing and replacing the Ring terminal)? I thought about adding a bus bar in between but I was not sure how to find a quality bus bar that would allow me to connect the M8 Ring terminal to it while connecting the shunt on the other side. Can anyone point me in the direction of a bus bar?

On another note, I am still planning to build a cable that would allow me to connect the bigger Bluetti stations via MC4 connectors to 4 of the batteries in series (48V). I would like to put a fuse/circuit breaker inline but was not sure where to find a good one. I am thinking it would not have to be very big as I am planning on using smaller gauge wire (thinking that Bluetti stations won’t pull more than 15 amps from the battery). Does anyone have a recommendation on a fuse?

Thanks for all of the help so far!

Amazon is a great source for circuit breakers and fuses. I would get one with approx. 25 to 35% higher fuse capacity than the maximum expected load. I personally would use a re-settable circuit breaker type of switch which come in a wide variety of amperages

Thanks again for the assistance. This forum has been a great help so far. I found one similar to what you describe as seen here so I will probably try it. It looks like the setup will be - Four 12.8V batteries in series connected to the breaker switch above with a short run of 10AWG stranded wire and continuing off of the breaker with about 3 or 4 feet of 10AWG wire to MC4 connector to the Bluetti DC input cables to the AC500 (or AC200 Max). That would be for the positive side. On the negative side, it will be the battery bank connected to a Victron Smartshunt with a short run of the 10AWG wire and then continuing on from the shunt with 3 or 4 feet of 10AWG wire to MC4 connector to the Bluetti DC input cables to one of the larger stations. I hope that sounds like an acceptable setup. Feel free to provide feedback. Thanks.

I’ve used breakers similar to that style and like them. Another advantage is pressing the yellow button on the right works as a disconnect switch. When you want to turn it back on, use the other yellow lever.

That sounds good. I hope this setup will work to enhance my Bluetti stations as I have really enjoyed the Bluettis so far. On a completely different topic but related to the setup I am currently using with the Bluetti stations, does anybody have recommendations for new rigid glass panels? There are a ton of different ones out there and I have heard that you can get new ones for $1 a watt or less. I am thinking about supplementing my portable Bluetti panels with a small array (maybe 300 to 400 watts) that can stay out in all weather conditions as the Bluetti portables are not designed for that use. I have seen a lot of different types but wondered if anybody had experience with ones they liked. Thanks.

I seem to have hit a snag when trying to find ring terminals with an M10 opening but that can connect to 10AWG wire (needed for Victron smart shunt). I have looked at the internet and even called several of my local electrical supply companies. I had no idea that they would be that difficult to find for 10AWG wire but maybe I am just not looking in the right places. I have found them for other sizes of wire so I thought I might have to put a butt splice connector inline just to convert wire sizes but that introduces additional resistance. Does anybody know where I might be able to find M10 (3/8) ring terminals for 10 AWG wire? Thanks again for all of the help.

On amazon I searched for “10 awg 3/8 ring terminal” and saw a few. Most are the copper tin plated with a yellow sleeve sized for 10-12 gauge.

Thanks. I ended up finding some and got everything put together. It works pretty well with 12 Volt but have not tested 24, 36, or 48 Volt yet. I suspect it will work fine. I am learning the intricacies of using a Victron Smart shunt on the batteries. It looks like the SOC information is not saved once power is cut to the Victron shunt but I don’t want to leave power on to the or it will take some power from the battery while not in use. I guess I will have to manually track the SOC and reset to that value each time I power up the Victron shunt. Thanks to everybody for the help on this successful project.