AC200max: can I connect an external LifePo battery rather than an expansion battery unit?

I’m wondering if I could connect a standard LifePo battery to my AC 200 max rather than an expansion battery pack? Ideally, I’d like to run a DC to DC from that battery to the alternator while the battery’s connected to my AC200 max. I’m guessing this isn’t possible but I’m taking a shot in the dark here.

Also, I’m sure this has been discussed in other threads but I’m using the forum through the Bluetti app and I don’t see any options for searching. I’m not even sure if I’m going to receive notifications as I don’t see any options

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I wondered the same. I concluded if you use the leads to attach the car 12v supply and attach to the lithium battery instead what’s the difference. So I reckon it should work. I was also thinking of trying.

@djb It is possible to connect a standard LifePo battery to the AC200Max, which is equivalent to charging AC200Max with batteries.

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You can connect to any source within the correct voltage range. You will get higher transfer wattage with higher voltage batteries or by connecting several lower voltage batteries in series.

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Thanks for the response! How would I physically connect the battery to the power station?

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Connect a 12V cigarette lighter plug to the LifePo battery

Then connect the AC200MAX to that cigarette lighter port via the car
charging cable.

I would be interested in this as well, what do you recommend as far at connecting the bluetti to the external battery ? I would love to see bluetti come up with a cable similar to the one you have for lead acid to bluetti but specifically for lipo to bluetti … especially if you could design a voltage booster inline … you could make a lot of money because it could be universal for anyone wanting to run a dc-dc connection between their power station and an external lipo battery …since many of us have pre existing solar setups at home with large battery banks

There was an interesting video about this topic by Jasonoid and he shows some of the cables he used. The AC200MAX was able to input quite a bit of power from a 48v battery. I think it would be a better solution to use the charging enhancer with a 24v battery though so that the solar port can be kept free for actual solar. The 48V battery he tested overloaded the charging enhancer but possibly running 3 * 12v batteries in series for 36v would work well. I think using a single 12v battery would be too slow as it’s only about 100 watts input at that voltage. You should get about 210 watts with a 24 volt battery which is more useful.

Having said that there are quite big advantages to using the Bluetti expansion battery because it effectively doubles the charging cycles of your AC200MAX and doesn’t require an additional charge controller. It can push far more power and you get monitoring from within Bluetti software. The B230 is just slightly too expensive at the moment. I hope Bluetti can reduce the price to make it more attractive.

I would connect the batteries to the PV input port on your unit just as you would a solar panel. Just don’t exceed the maximum volts allowed. If you connect to a 12 volt source as suggested below you will be limited to around 100 watts and the socket will get very warm.

Here’s what I’m trying to do. I use my AC 200 max to power my van accessories such as fridge, roof fan, lights, etc… I have 300 w of solar charging the unit. If I get a few overcast days my battery levels get extremely low so I’m looking for alternate charging methods. I was considering getting an expansion battery but they’re extremely expensive so I was looking for a method that would also allow me to take advantage of alternator charging rather than just a 100w. So to reword my initial question, is there any method that would allow me to take advantage of alternator charging while I’m driving in addition to solar charging for my unit? I thought connecting an additional LifePo battery would be a way around this but maybe there is a better method?

A voltage step up converter can be used to step up your vehicle 12 volts to 48 volts and give you about 500 watts of charging input.

Really? Would that connect to the vans cigarette lighter?

You can for short term use, say, on a camping trip. But for everyday use there is no plug & play automatic recharging; you’ll have to disconnect them and hook up an appropriate charger. Not to mention you’ll have no feedback as to their SoC. You really should not run them until drained, so you’ll have to calculate your best guess.

They don’t mention that when car charging, the motor should be running or else you’ll have a dead car battery pretty quick. So it’s fine to use the car’s cigarette lighter for charging while traveling, but not while the car is parked with the motor off. So in reality, you are charging from the car’s alternator.

Car batteries are NOT designed to continuously produce current. Their thin lead plates are to provide a momentary burst of amps for cranking a motor. You shorten the battery life just by sitting in a parked car playing the radio for an extended time.

Real storage batteries are designed for continuous current draw; you NEVER want to use them to start a car as the high burst of amps needed can damage them or shorten their life. Not long ago lead acid storage batteries were the only feasible solution for solar off grid use. They have thick lead plates, as opposed to the thin lead plates of car batteries. They are big, heavy, and fairly expensive.

A lot of early off grid users found out quick that trying to use car batteries for solar was a bust. A stack of them became boat anchors in 2-3 days.:astonished::flushed:

The AC500 comes with the appropriate cable for connecting to a battery. The battery clamps however do get hot.

Thanks for the response! I have a cigarette port from the battery that’s only active when the car is running and I can pull about 100w from it which doesn’t result in much unless I’m on an extremely long drive. I do however need to exchange the solar input plug for the car charger plug and it’s a bit annoying. It’s seeming like the best route to go is biting the bullet and just getting an expansion battery. My AC200 max will last me about 3 days if I’m not getting any solar input. If I add the b300 then I should be good for about a week. In that amount of time the clouds should clear and I should be able to get some solar input. I could add another couple panels as well

Change the clamps to ring terminals, these are likely to offer lower resistance due to better contact surface.
During cloudy days I’m connecting a 300Ah LFP battery to my AC500 for night charging only.
This is 106W going into the AC500 and the terminals are not feeling warm at all.