Charging a Bluetti AC200 w Scooter Batteries 36v or 72v - Part 1

[@greengooseman]

Update: I talked to Bluetti tech support earlier today. I described my issue in great detail. What they told me to do to possibly fix it, made me roll my eyes. However, its now midnight and my AC200 is staying at 100% charge and 400+ Watts when it turns back on the PV (my 36v battery bank). I was reluctant to post the recommended solution but here I am way better than I have been thus far. He said to unplug everything. Go to Data, then to faults, hold the clear faults till the icon appears, select YES. Then turn off unit, wait 30 seconds, turn back on. I did all of this around 1pm this afternoon. I wouldnt have been able to tell if this fixes it until the wee hours of this morning. So far its doing well. *I really hope this fixed it.

[@sidjones-randomstuff2058]

Thanks for the update greengooseman. Sounds to me like that will just reset the fault notification but who knows. Do you have a way to drain down some of your Bluetti and try charging with the scooter batteries in series or at 72 volts? In parallel at 36 volts mine start out charging nicely but within a half hour to an hour hardly producing any current at all. I ordered two new dongles which should be here in a few days and I plan on trying that 72 volt test again. Just to try to determine is it the Bluetti or is it the battery's BMS. Thanks again. 👍

[@greengooseman]

@@sidjones-randomstuff2058 , Your issue is the same as i was having. Do what I just mentioned. I woke up this morning at 8am. Bluetti @ 100%, batteries drained to 36v. It’s officially fixed.

[@greengooseman]

I found this video while trying to see if others are having the same issue as me. I have 18 (36v scooter batteries) in parallel, each with their own BMS. I have 2000W of solar that charge my battery bank. For fun I wanted to see the same thing as you. How low can I go on voltage (BTW its about 32V for me). My issue is exactly the same as you. But i have a few more things to add to my test. When Im pumping solar into my battery bank, my ac200 will stay at 97%-100% and full 11.8+ amps on the PV (My battery bank in the morning is about 37v and 42v at full charge. Once the sun goes down, the current on the PV keeps dropping. By 2am (when i get home from work) my pv voltage is 39V but only 56W @ 1.x amps. If I remove the PV input and reconnect it, it goes up to almost 400W (11.*amps @ 39v) It will continue to deplete like this untill the ac200 reaches 0% charge. FOr fun I plugged my AC brick in when my PV input was around 8A. Amazingly, my PV current slowly started to increase. about 2 amps but then back down. Im still trying to solve this issue as well.

[@sidjones-randomstuff2058]

Thanks greenhooseman for your update. I have a question for you. How did you hook your solar into this arrangement? Are you using a solar charge controller and charging your 36 volt batteries? If so, do you use the discharge cables as your charging wires? I understand if your solar charging into your bluetti but I'm trying to figure out how to solar charge my scooter batteries. Thanks!

[@greengooseman]

​@@sidjones-randomstuff2058 I have 9 (325w) panels feeding a Victron 150/60 solar controller. This charges my 18 (36v) scooter batteries. I have a cheap 36v 3000W pure sine wave inverter that Ive put over a gigawatt of electricity thru. I took 8 gauge wire and made a 12' cable with an XT 90 connector on one end. On the other end, I put lugs and attached them to the input of the cheap inverter that is currently turned off. I have a 70a circuit breaker right before the inverter so this is my "battery disconnect". If you want to charge the batteries on the cheap. Buy a Mr. POW solar charger on Amazon for $99. The Victrons are very pricy but are worth every penny.

[@jonathansperb]

I think your Bluetti is not working as supposed. Makes no sense the power going low to almost nothing after some time and working again when you unplug and plug it back. I guess the solar MPPT (not sure if it has one) is bugged. Maybe being an early unit is the reason. A software update probably could fix it.

[@sidjones-randomstuff2058]

Yes it is an MPPT. I have had at least three other people reach out to me that also have had the same issue with their Bluetti and these batteries hooked up in a parallel. I'm not sure if it's at the Bluetti end or at the battery BMS end. I might just cut into a couple of batteries and bypass the BMS all together. That might save me a whole bunch of frustration with these silly dongles and BMS activator boards.

[@greengooseman]

Im having the same issue with 18 scooter packs. If im charging my batteries with solar, my ac200 stays charged, as soon as the sun goes down, my PV current starts to drop. My voltage is always there at the PV input so its not an BMS issue. Its a bluetti issue.

[@sidjones-randomstuff2058]

@@greengooseman Thanks for giving us an update at your end. I went ahead and ordered two more dongles from jehu and I'm going to try the 72 volt charging again. Hopefully this time I won't burn it up. I should have those in a few days. I guess we'll see if it's a under voltage issue with the Bluetti or a BMS issue with the battery pack. 👍

[@greengooseman]

@@sidjones-randomstuff2058 , im guessing your problem will remain the same. I believe the Bluetti MPPT does not like "static" voltage. It seems to like varying voltage, like when my batteries are being charged by my Victron solar controller.

[@greengooseman]

Update #2: Sorry to say, the fix that worked the first day, is no longer working. Last night it dropped in current after a day of fully charging in the previous 36 hrs. I am waiting for some solar input to my batteries and I will reset it like the first time and see if it lasts thru the night tonight.

[@sidjones-randomstuff2058]

Bummer, I was hoping your fix did it.

[@greengooseman]

@@sidjones-randomstuff2058 , i reset everything to same parameters as first day. One item in my setup was different. I had my original inverter on but nothing plugged in during the first night it kept the ac200 charging. Second night i had turned it off. Yesterday i reset it all kept my old inverter on ( connected to my 36v battery bank). First night it charges perfectly, im about to enter night 2. So far so good.

[@sidjones-randomstuff2058]

@@greengooseman Does your charging voltage & wattage on the Bluetti start high and then starts dropping? For example, starts charging at 440 watts and a half hour later is only at 30 watts? I guess now my dongles aren't going to be here until next Wednesday. Man Jehu is slow on shipping. Then I can do some more testing.

[@greengooseman]

@@sidjones-randomstuff2058 , unfortunately it’s doing it again. Yes, exactly as you stated. Sometimes it takes hours to drop in current, and sometimes just under 1 hour. I can’t wrap my head around why can sometimes go 2 days, and other times not even 1 day without doing this stupid thing

[@joshbrown2098]

It’s not cereal it’s series connection

[@sidjones-randomstuff2058]

I realized that after saying it... and if you look in the description of the video you'll see the very first line addresses this. But thank you for pointing that out.