I have been using my AC 200 Max to power toaster, kettle and induction hob, or charge phone and lap top with no problem at all whilst I am stationary in my Toyota Alphard campervan. However I realised whilst charging my phone that I wasn’t able to start my vehicle engine until I turned the Bluetti off. I tried on several occasions and this always happened.
Now it is a bigger problem because I want to power my fridge from it and obviously if it is on all the time I would never be able to drive anywhere!
Does anyone know how this could be affecting the vehicle electronics and if there is a way to prevent this?
Thanks!
Hi @seasidestar, Thank you for bringing this issue to our attention. It’s rare for us to receive such feedback, and we’re eager to understand and replicate the problem.
To assist with our investigation, could you please record a video comparing the impact on car starting when the AC200MAX is turned on versus off? Once recorded, kindly upload the video to Google Drive and share the link with us.
Additionally, could you let us know whether your car model is a gasoline version or a hybrid version? This information will help us better understand the context and potentially narrow down the causes of the issue you’re experiencing. Thank you for your cooperation!
Your cooperation is invaluable in helping us identify the root cause. We’ll make every effort to resolve the issue based on the evidence provided.
Dear @seasidestar please also state if, while the issue is happening:
your AC200MAX is charging from the vehicle or not connected to anything except your mobile phone
DC and AC on the AC200MAX are ON or OFF
What you exactly mean by “not able to start the vehicle”:
if you have a key start what happens when you turn the key?
if you have a keyless start, what happens when you press the brake and push the start button?
when starting is the vehicle trying to crank (you hear the engine start noise) but not actually starting?
do you see anything out of order on your dashboard?
One possible explanation is that if your van’s battery is already low and the Bluetti is charging and drawing power at the same time, the resulting voltage drop could keep the engine from cranking. But this is just a hypothesis.
.
Bluetti devices are certified FCC 15 and CE which comply to EMC Directive 2014/30/EU and that implies compliance with EN 55032 (emissions), EN 55035 (immunity), and EN 61000‑3‑2/3 (harmonics).
That means it’s extremely unlikely a Bluetti device can interfere with another electronic device and such a scenario is virtually unheard of, so please explain the issue more deeply so we can better understand how is that happening.
Did you use the grounding screw of the AC 200 Max to the chassis of the campervan? If so a grounding loop can occur.
You also said phone charging, which I assume you mean you were charging it via wireless charging pad, which may be causing RF interference with vehicle ignition system if its operated by a keyless fob. Can you recreate the issue by trying to start the engine WHILE charging a phone on wireless pad and again without?
Wireless chargers typically operate in the 100–205 kHz range using near-field magnetic induction and keyless fobs and vehicle immobilizer systems function at UHF frequencies like 316, 433 or 868 Mhz so their operating bands do not overlap, there is a very negligible coupling between the two technologies.
Also the inductive near‑field magnetic loop of a charging pad decays rapidly with distance, differently from a key fob that rely on far‑field propagation.
.
For this reasons I think the wireless charger is less likely to emit significative EM interferences for this case.
However the wireless charger of the AC200MAX is a custom implementation made with a Nuvoton MCU not Qi certified, so it will be interesting to consider it for the analysis.
Although the bands are different the waves are not pure sine, so it is very possible for the harmonics of the higher frequency wave (i.e the wireless charging pad on the Bluetti) to eventually land right at the 315MHz sweet spot of the key fob. It can interfere if there is no shielding, though I imagine the effect would be greater if the keyfob + Bluetti are very close by. Where in relation is the power station and the phone sitting on top of it to the key fob?
Talking about harmonics, for a 100-205 kHz wireless charger to interfere with a 315 MHz system you need the 1500th harmonic:
100 kHz * 1500 = 150 MHz or 210 * 1500 = more or less 315 MHz
And an harmonic in that high-order is often >60 dB down since a wireless charger is in fact a resonant LC circuit and key fobs has very narrowband RF front-ends with band-pass filters (and error correction protocols). Any residual harmonics at 315 MHz would be well below the noise floor.
Since the near-field magnetic field of the wireless charger drops as 1/r^3 it will require to literally push the key fob against the wireless pad to have a slighly minimal chance of an intetference, but anyway at that point the car will just signal “key not found”.
Ah the inverse cube law. Strong attenuation even with a little bit of distance. Makes perfect sense now. See I originally thought this was how it was but I doubted myself. Thanks for making it clear! I’m thinking if anything now my best guess would be EMI from the AC inverter causing some sort of noisy broadband signal, sort of like I’m going to give you the passcode to the door, as I vacuum the floor at the same exact time. The code is 3-4-VVRRRRRRRRRRRRROM-51. Did you get it?
Hi all who have responded and tried to help. I think I now have the answer but the reason is still a mystery. To be clearer about the issue and in answer to questions I wasn’t using the grounding screw. I wasn’t using wireless charging (haven’t been able to pair phone to Bluetti for some other unknown reason) so it was connected with a USB cable. The AC Max has never been charged from the vehicle so it wasn’t that interfering. I had nothing else using the Bluetti as I can’t cook whilst driving! To start the vehicle I put foot on the brake and the ignition button turns green, press that, engine starts. With Bluetti on (even with nothing plugged in) with foot on brake no green light came on and pressing button did not start engine. This is not me going mad as it happened several times over the winter when I forgot to unplug phone.
A couple of days ago I had a flat battery and discovered from breakdown man that it was in poor health and needed replacement. I didn’t answer here until I had that done as I thought there was a vague possibility that the very old starter battery could have been causing the problem. It turned out this was the case because now I can start the engine with the Bluetti on. I have no idea why but perhaps you experts can work it out! Thanks again for your time.
Denise
