I would monitor the temps of your step up converter and wiring to insure that they are not running excessively hot. If you are getting too much heat, a small 12 volt van can be mounted and wiring connected directly to the step up converter lugs and the fan will come on anytime you turn on the step up converter. It is normal to be fairly warm, but not so hot you cannot keep your hand on it.
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Scott, fyi I followed your setup and things seem to be running well. I have the AC200Max in my ford transit. I purchased the 12-48v 20a step up converter, wired it via 120a relay and 100a circuit breaker to the battery using #2 awg. Relay is wired to one of the upfitter switches on the van. Out put of the 12-48v has #10 going to the aviation plug and into the Bluetti. Put a 12v computer fan on the dc converter too. While I was at it I rigged the van with shore power. Wife used the Bluetti on our air fryer to drain the battery down, fired up the alternator charging first, then added in shore power, all seems to work well and the Dc-Dc is staying cool. Thx for the guidance!!
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Sounds like you have a great set up installed with the appropriate size of hardware. The only issues I have heard about with this setup are when installed with undersized wire or undersized step up converter. I am always of the opinion that if you need for example 10 amps of power you size your equipment for 20 amps to insure long and problem free running.
I am in the process of getting a charging enhancer (DO50S) that will allow a second point of charging from a vehicle or could be used to allow solar panel input at the same time as “fast car charging” If running from 12V, it would add another 100 or so watts and depending on the solar installed could add those watts as well.
If you get time and want to post some pics and details of your install as well as an explanation of why this is an advantage, I think there are a lot of users out there that would benefit.
Glad you are getting good use from your Bluetti!
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Yep, I am going to keep an eye on the dc-dc and see how hot it runs. Please update when you see how the DO50S works out. Thx again
Ps let me know if the DO50S has a fan and, if so, how loud it is. The charging brick is really loud, which is really why I went with the dc step up instead of adding like a 1kW inverter to power the brick
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Scott, I have tried to get an answer on a different thread but not able. I am trying to use one inverter @1500 W to power two of the charging bricks for the AC200. Distance is less than 24" to the inverter so a 6AWG cable should be adequate. But I fear for my alternator. I have a Transit with the standard alternator and battery. Am I best to put in a HD alternator? What is the required Amperage going to be that the alternator has to put out in order to power two bricks through the inverter?
The two bricks should consume approx. 100 amps up and above what your vehicle consumes in its normal operation. I would not recommend to load your alternator to more than 50% of its rated capacity for extended periods (such as charging with dual power bricks).
Karl, you may know this already, but I’ll say it anyway …
For a commercial vehicle like the Transit, Ford publishes technical guides for a variety of electrical and mechanical modifications that are approved by Ford, such as adding additional electrical loads. Their Qualified Vehicle Modifiers (QVM) program certifies professional “upfitters” to implement such modifications.
I would think that a QVM upfitter near you could install an inverter that conforms to the Ford guidelines, and could install the Ford HD alternator if you decide to go that route. I know that these forums are all about DIY. That’s fine if you’re comfortable with the associated risk. But if you’re spending thousands on a new HD alternator, it might be prudent to protect that investment by consulting with a QVM upfitter to protect that alternator.
You can try to obtain the Ford upfitter documents for your Transit. I have glanced at one such document, and found it very difficult to understand.
thanks Scott, that is the detail I lacked
Thanks Landlocked. I was not aware of the QVM program that should be really helpful. I am not trying to reinvent the wheel. At 72 I have built houses, conference centers, developed educational programs and negotiated for hostages…but I don’t need to do everything on my Transit…I need to use it and take care of my wife 
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My fast-charge is built, and is working well on test runs. I have a transit with the standard alternator, using a 2000W inverter I can use two charge bricks and in two hours charge the Bluetti 200AC to full capacity. The Ford dealership has said that if I am traveling and only running the inverter for a couple of hours a day that there should be no damage to the alternator. It may give out sooner but if so then would go down slowly. I have used a 150A breaker fuse so it will be switchable when I am running. Since the inverter is just behind the seat, the wires are very short, but I still used #4 wire. No heat, just warm. Thanks to all on the chain for your help. Charging at around 900-1000W rate is the answer for me
Karl, I am happy to hear that you achieved the system you need to support your travels.
thanks Landlocked. I never managed to locate a QVM upfitter that would look at it. But following a number of leads…particularly on the transit forum…I decided to just go directly from the battery and not through any of the fused customer points. It was easier anyway I didn’t have to remove the seat, just had to wiggle a bit to get the cables attached to a positive terminal in the fuse area. I was more intimidated by the thought of it than the actual doing of it. It is high amperage so I quickly realized that I needed to install the fuse/switch first and then the inverter so I was working with a dead feed rather than a live one. I guess that should have been obvious, but wasn’t until I sparked on a connection. I have discovered, and will add to the transit forum, that Ford has a completely different set of information if one is a consumer vs a certified Ford Mechanic. Even the parts available are different. So the upfitter is definitely the way to go…but post-covid no one has staff. I had to just go to a dealer and wait. Three days of trying to make an appointment by phone didn’t work.
Back from a month-long trip. I can confirm my setup, as well as weak links. With a 2000W inverter connected directly to the battery on my Transit mid-roof van, I went through a 150A fuse/switch on the input side of the inverter and from its output fed two Bluetti bricks, one that could to to the PV input and one to the normal brick input. I found that the first 150A fuse switch broke down in the first few days, although the wires never got more than a little warm. A new and different brand fuse/switch worked fine. But since I still had a lot of sunlight, I kept the PV input going most of the time while I was driving, and then would turn on the switch/fuse to activate the brick. It seemed to run for about 20 minutes max and then it would trip. But waiting for another 20 minutes I could turn it on again and usually in three cycles I had a full AC200. (usually from about 50%) The system worked really well, but I am not sure why it cuts out as soon as it does. I might try going to a heavier gauge wire from the battery to inverter, but the #4 gauge should be adequate. If I had not been driving, then I would have still needed to run the engine to charge through the inverter so that the vehicle battery would not go down. I turned off the switch when the vehicle was parked.
Hello Karl,
Here’s one theory (with zero data to back it up) for the observed 20-minute interval before the circuit breaker trips.
Suppose that during the 20 minute charge period the total load on the vehicle’s system is more than the alternator can supply. In that situation the vehicle battery would slowly discharge. One could imagine that as the vehicle battery discharges, the voltage delivered to the input of the inverter would drop a little (because lead acid batteries are not constant-voltage devices). The inverter would respond to the decreasing input voltage by allowing a larger and larger current to flow through its input terminals (i.e. through your circuit breaker). If all that is true, and the circuit breaker’s rating is just barely adequate, then you could get a trip after a fairly consistent amount of run time.
As I said, it’s just a theory. With a “clamp” current meter you could measure the current present when the trip occurs.
Thanks Landlocked for the reply. It seems a reasonable theory to me. Particularly because when I attempt to power both bricks I get a shorter time of power. I would expect that at higher RPM I would generate higher amps but maybe the generator doesn’t work that way. I’m still trying my way forward so a clamp meter would give some data
Karl Dortzbach
443 570 3668
Thanks Scott for the testing to determine that the Bluetti units can handle the DC-DC convertors.
Below is a write up of my installation, I can’t add more pictures because I’m a new user.
I’ve successfully setup my AC200MAX for 700w DC-DC charging for about $150 USD.
In my case it’s from a 12V 560Ah Battery bank on my RV, but this is relevant to vehicles too, probably more so, I’m going to do the same in my car so when I leave the RV I’m topping up the AC200MAX when touring.
Setup in the RV is a bit simpler. I’ve measured the idle current of the WG-12S4820M DC-DC and it’s not worth any complex isolating, less than 1w.
This is all mounted externally.
Protected the battery with a waterproof 100A CB.
WG-12S4820M is IP67 waterproof and aircooled, it’s mounted externally too.
48V lines are protected with a simple 20A midi fuse.
I’ve tested it in use with the AC200 Max running my RV aircon, about a 1.3KW load starting from full with a 700w input from the WG-12S4820M DC-DC.
I can get about 5 hours of Aircon, when it stabilises the temperature and starts to draw less.
WG-12S4820M DC-DC draws approx 58A at 12.8V, and gets warm to hot.
It can definitely handle the load and stay passively air cooled in 100f/36c degree heat
AC200Max takes 14.75A consistently, with the WG-12S4820M DC-DC at 48.05V
Cabling is important, bluetti pv cabling gives quite the loss around 11W, and cables run warm, but not hot when using the solar connectors as an interface, I’ve got an aviation connector coming to make my own cable to get those losses down.
2AWG is around 4w loss.
Self usage on the WG-12S4820M is around 25w.
Total conversion power cost around 40W, AC200Max says 707w in, Battery BMS says 755w out, so more or less correlates, and I cant measure battery internal losses.
I’m very pleased with the setup, recharging the AC200MAX from 0 takes about a 3rd of my RV battery.
Links for the DC-DC below.