EB3A won't start solar charging under 18W / PV low voltage

Hi,
I already have an EB70 an like it very much (except for the missing SOC percentage).

I received an EB3A recently. It’s a european version (230V) and has got the latest firmware, which in Europe is
ARM v2053,07
DSP v2052,04

Short Version: As long as the solar panels deliver less than ca. 18W, it won’t start charging at all. The “Input” sign in the display blinks and the app says “PV low voltage error”.

The EB70 has no problem at all to start charging in this situation.

The open circuit voltage in this case is usually about 22,4 V, so it should be plenty enough.

One the EB3A has started to charge, it will continue to do so even when the power drops to 1W.
If I then unplug the panel and plug it back in, the error appears again and I have to wait till the power exceeds ca. 18W.

Conclusion: My EB3A has no problem to charge via solar, but it has problems to start charging.
My EB70 start charging even when there is only 1W available.

In real life this can mean that on a cloudy day the EB3A does never start to charge but instead uses up about 2% battery per hour and so loses power over the day instead of collecting e.g. 16 watts per hour.

This may seem like am minor problem because <18W is not much, but I guess that most of the small power stations will not be attached to huge solar arrays.
With this error the EB3A can’t just be left alone gathering watt hours…

Is this a known problem with the EB3A an can/will this be fixed in firmware? Or is my unit faulty?

By the way: I have charged and discharged the device twice and once it charges it works fine. AC charging also works fine.

I wish it would charge just as the EB70, then it would be a great litte device with only minor flaws (funny fan noises, noch charge under 10W displayed etc.).

Thanks to Bluetti and the community (hopefully) for answers.

Cheers from Germany,

Harry

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Hi @Riesling-Harry , sorry for inconvenience caused.
This should input wattage too low and not show up when charging (it is actually charging).
If you confirm that the EB3A does not have any charging input when performing PV charging, you can send a video and contact our support department via sale-eu@bluettipower.com for a more specific solution. Thank you very much for your cooperation

It should charge at 12 volts up to 28 volts. Disconnect the solar panel and Verify what your voltage is with a meter to the solar panel. When on the low end, it can take awhile for the mppt to lock in.

With such a small window, it is a challenge to overpanel, so that you get the voltage needed early in the morning and later in the evening. The victron starts at 5 vdc. A bit easier to match up. But it not portable.

Hi Admin, hi aly,

thanks for answering. As I said, the OC voltage was around 22V, I’ve tried dozens of times with the same result:
The EB3A has a problem to start charging when under ca. 18W, but once i has started, it will continue to charge even when there is only 1W left (or even 0W).

So I think that the hardware is ok, it just needs a firmware update to change the starting behaviour.

I have put a video on youtube to illustrate the problem and the difference to the EB70:

Yours,

Harry

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I have the same problem. I get 18.3 volts and still get input flashing. So I measured the current and found out that it must be > 1 amp before it stops flashing.

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Hey hey,

that is very useful information because it (hopefully) means that my EB3A is not broken.

1A at about 18-19V working voltage corresponds well with my 18W threshold.

Let’s hope for a firmware update.

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Just FYI, I have the “blinking input” 0w solar input, also. When it begins reaching 50 watts, it starts charging, properly via solar.

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Same issue here when I was using an extension cable for the solar

Bluetti tech specs for the EB3A says 12 to 28 volts. I tested that spec with my variable power supply. 12 volts works fine, it does not have to be 18+ volts. The problem is not the voltage, it is the current. If the current is less than 1 amp, the EB3A will not accept the voltage. It must be > 1amp. It is a bad design of a MPPT controller. Today with cloudy skies and 100 watt solar panel, I got 18.3 volts and .67 amps = 12.26 watts but my EB3A said 000 and the input was flashing.
Bluetti needs to fix this design problem !!!

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As gathering solar energy is the main purpose for my power stations, I sent back the EB3A and bought an EB55 as a second device. This behaves exactly like the EB70. I would really like to know if nobody at Bluetti tested the EB3A under various conditions.
I don’t think many EB3As will be connected to a huge solar array that always delivers lots of power.

Really a pity, because otherwise the EB3A would have been exactly what I wanted.

I just picked up a UK model EB3A and love it… well I did until I purchased a 100W solar panel expecting to use it in Scotland. My aim was to keep this topped up off grid and power a low wattage heater occasionally.

Sadly I’ve also found out the hard way that the Bluetti MPPT will happily just discharge your entire pack rather than charging, pretty poor design.

This has to be fixed with a simple firmware update surely? C’Mon Bluetti lets see some positive progress on this. There is literally hundreds of posts over various sites and now more increasing disgruntled youtube videos highlighting this pretty major flaw of the EB3A Charge controller.