Test/review of Folomov A1

[SIZE=+3]Folomov A1[/SIZE]



Folomov is new on the charger market and has started with some fairly powerful chargers. This is a very small charger and power bank.





The box lists lot of specifications, battery types and features, there is only the charger in the box.



Input and output is in the same block and is basically a pass through connector.




The electronic is in this block, the gray plastic is partly transparent and where the wires go out to the battery is a fully transparent piece of plastic. This makes it possible to see the internal leds:
Blinking green: Charging or no battery connected
Steady green: Battery full
Blinking blue: Usb output is delivering power.
The green led will only light up when usb power is supplied to the charger.



The magnetic connection to the battery with clearly marked polarity.



Connected to a battery.





The charger can handle just about any size battery, including most flat top cells, but the current is too large for regular use on smaller cells, except some IMR types.



[SIZE=+2]Measurements[/SIZE]

• Power consumption when idle is up to 6mA from usb (Average 3.3mA).
• Charger will charge a LiIon with 0.02mA when full.
• Charger will discharge a LiIon with 0.1mA when not powered.
• The charger will charge from 0V with about 200mA
• Charger will restart if battery voltage drops to about 4V.
• Charger will restart if battery is removed or power is cycled.
• It can handle up to about 150mm long cells
• Weight: 20.8g

[SIZE=+1]Charging[/SIZE]



The charge current starts at around 1.2A and termination current is around 150mA, this is fine for larger cells and for some small IMR cells.
There is a problem with the voltage, it stops charging at 4.1V, it is way to low.



I got two for testing, the second one stops at 4.15V, it is better, but not perfect.




These two cells looks fine enough, except the final voltage is too low.



With this older cell the charger restarted a couple of times due to voltage drop.



M1: 40,6°C, HS1: 51,1°C
The charger stays fairly cool.



M1: 37,5°C, HS1: 49,8°C
The connection to the plus warms up a bit, probably because it has a bit of resistance.



The charger takes about 4 seconds to start.




[SIZE=+1]USB output[/SIZE]

• Blue light will turn on at around 22mA draw from usb output.
• Usb output is coded as Apple 2.1A
• Charger will discharge a LiIon with 0.1mA when not powered.
• Usb input current is charger current + any usb output current
• It cannot be used as a UPS

When input power is switched off it takes some time before the power bank functions will take over.



The power bank function can deliver about 1.2A before the output drops, but the voltage is at the low end for a usb charger.



With a 10ohm load (0.5A) the output voltage is nearly stable until the battery is empty.



But at about 1A (5ohm) the output cannot be maintained until the battery is empty.



At 0.5 the noise is 11mV rms and 106mVpp



At 1A the noise is 19mV rms and 172mVpp



[SIZE=+2]Conclusion[/SIZE]

This type of charger do not take up much space, but there are some limitations, here the current is too high for small cells.
Adding a power bank function to the charger is an interesting idea, it works fine, but it will not charge a smart phone at high speed.

The charge voltage is rather low, it can be used in an emergency, but is not really good enough for a regular charger.
The same with the usb output voltage, I would also a liked that a bit higher.

Due to the low voltages I will only call it fairly good.



[SIZE=+2]Notes[/SIZE]

The charger was supplied by a Folomov for review.

Here is an explanation on how I did the above charge curves: How do I test a charger

That's literally thinking outside of the box!

This would be good to have "in the field."

Steady green: Battery full or no battery connected

Click to expand...

Can you verify that? Mine blinks green even if there's no battery connected. Green also blinks if the magnet ends are shorted. At first, I though mine was defective, but saw the same thing on this YouTube video HERE, which also shows the green LED blinking with nothing connected and/or shorted. He was also confused by this, as I was.

And as in the YouTube video, I measured current while charging an 18650 and got 1.4A

So, it appears everything is working. However, there's really no visual indication that it's recognized the battery.

terryoregon said:

Can you verify that?

Click to expand...

No, review fixed.

I had one of these in my amazon cart ready to order. But I really wish it did NIMH as well, like the Olight magnetic charger (current is too low for what I want). And the low voltage pretty much sealed the deal for me so I'll pass. I really wish that Olight charger did 1000mA.

Thanks for the review. I have the Olight charger and it sounds like this isn't an improvement so I'm going to pass.

magellan said:

Thanks for the review. I have the Olight charger and it sounds like this isn't an improvement so I'm going to pass.

Click to expand...

Yeah, if Olight bumped theirs up to 1000mA I'd buy a few more.

Right on.

This might be a silly question, but why would the positive connection possibly have more resistance than the negative?

Reminds me of years ago when I read why they switched from positive to negative grounds. At one time 6V positive ground systems were common. Eventually as batteries got better the voltage was upped to 12V, but the switch to negative ground always puzzled me.

The explanation was that, at least in our universe, there was less resistance for electrons to flow from positive to negative vs. negative to positive. The figure that was cited was about 15%. But I always wondered why the difference and why they weren't the same. That seemed like a lot to me, but anyway, it was explained that was what motivated the change.