AC200 added battery capacity from 24Volt battery

Adding additional battery capacity to my AC200 from my Ecoflow EF1500 battery(s) using a step up converter from 24 to 48 volts. IT WORKS. I got a rock steady 573- 575 watts of incoming charge power into my AC200. With my (2) EF1500 batteries this will give my AC200 a usuable 4100 watt hours of battery capacity.

I started at 11% and ended at 92%. The AC200 received 1300 watts of incoming charge which is 83% of the advertised 1574 watt hours from the battery. Not bad considering the step up conversion and charging losses. This set up should work with any 24 volt batteries. The step up converter is also offered in 12 volt incoming voltage versions as well so it should be feasible to connect that unit directly to a vehicle battery and have fast car charging while traveling.

I purchased the step up converter (link below) through amazon and made a cable by purchasing a clothers drier cord from Lowes. The cable had (4) 10 ga wires inside a single sleeve and already had 4 ring connections crimped on one end. I cut the cable to about 30", added two ring connectors to the red and black wires on the other end of the cable (to attach to the EF1500 24 volt battery output) and soldered an XT90 connector to the two remaining wires. This XT90 is what I connect the AC200’s XT90 to Aviation input cable to and then to the AC200. The four wires with pre-crimped ring terminals attach to the votage step up converter. This gave me a single cable with minimal effort to build and kept the cable short and simple.

Even though the step up converter says it is capable of 20 amps output at 48 volts the Bluetti AC200 limits charging input to 12 amps.
That is why I am only getting 575 watts rather than the max of 700. In any case, 575 watts is plenty for my purpose of extending the battery capacity of my AC200. The converter has been running for about 90 minutes and while warm to the touch, is in no way hot. There is no fan and the unit is silent.

Step up converter link:

![Converter cable view|666x500]


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Intriguing. I’m interested in doing something similar as I have the Ac200p in a camper conversion. It would be good to be able to switch between solar and car charging with fewer changes to the settings. It’s a shame I can’t utilize the ac input for car charging.

The 12V converter is $200 for the 20a version though

Rob, they also had a 10 and a 15 amp version of the 12 volt step up converter. The 10 would most likely work because you would not want to pull more than 50 amps out of your alternator anyway and you will limited to 12 amps of input at 48 volts so you will max out at about 575 watts even with the 20 amp. I went with a 20 amp simply because I don’t like to run anything a capacity for long periods and didn’t want anything to heat up. I was thinking about getting the 10 or 15 amp 12 volt model down the road just to try it out with car charging. I have a 50 amp anderson connector directly connected to my vehicle battery and I could easily wire an anderson connector to the input side of the step up converter and just plug it in when I needed to step up 12 volts to 48 volts.

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I ran the above unit some more last night. I started with the AC200 at 100% state of charge and ran my TV for five hours which consumes 168 watts or so. I wanted to see if the AC200 will begin charging immediately after the SOC drops even 1%.

The AC200 remained at 100% during the entire five hours with the only thing I noticed was that the incoming charge would cycle from 0 watts to 573 watts when charging. So in summary, it looks like I can count on being able to keep the AC200 topped off with the extra battery being consumed first.

I also am thinking of connecting my Ecoflow R600 Pro connected to the EF1500 battery and then connecting the EF1500 to my AC200 as before. This would give me a theoretical 2300 extra watt capacity less the transfer losses of about 15%. This would also give me the option to use smaller loads on the Ecoflow R600 and the larger loads connected to the AC200 since the AC200 has a much higher overhead loss when running very small loads. I could simply turn off the AC200 or keep it in standby mode except for running large loads. This should maximize the wattage available and extend the runtime.

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I’m confused as to how this is all connected to your alternator??? I just purchased a 12v 100ah battery to add more user time to my Bluetti 200. I was planning on making a connector that went from the two terminals to a cigarette lighter? Confused!!!

Would love to see a picture of the engine setup with Anderson connector.

Would this work for me?

Read through this entire thread. There are details with pics of how to use the converter you mention. The voltage converter is connected to the vehicle battery and not the alternator.

GREAT Information!!! Thank you so much!


where did you find that ef1500 battery? can’t seem to locate it. thanks

It was only offered through the initial kickstarter with the Ecoflow R600 Pro. They did not put eight in general production. Too bad because it is a very good battery

HELP! I have the Bluetti 200 and have charged it with a 12.8V 100AH LifePo4 battery using a 48V15A converter. I have used it numerous times to charge with. I plugged it in the other day and within a minute I smelled something. There was actual smoke coming out of my unit!!! Of course I immediately unplugged it but now am not sure what to do. I’ve left a message with Bluetti but of course it is out of warranty. It will not let me input thru either the solar or AC. Any ideas???

What unit are you referring to specifically? Is it your 48 V step up converter that smoked or is it your AC 200?

Mine is the one that was offered on Indigo website.

Bluetti AC200 Specs
1700wh lithium battery, 2000w inverter
• AC200: LG Electric Vehicle Grade lithium battery cell (NCA)

The Bluetti started smoking!

Sounds like something definitely happened. Hard to say without any detail or facts surrounding the situation

Suggestions? I’m waiting on Bluetti Service but am tempted to open it up to see what happened.

What you want to do is examine exactly what was occurring immediately before the incident happened what was connected with the loads were and what was different than other times that may have contributed to this issue

If you open the case, just keep in mind that the lithium-ion battery in your Bluetti can produce very large short-circuit currents—enough to cause injury and fire. Poking around with a multi-meter should be fairly safe, but do not leave the opened unit where something conductive could fall on it or someone ignorant of the danger could go poking around. :frowning:

Thanks for the heads up! Hoping I can mail it in to Bluetti.