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Thread: Test/review of Charger Folomov A4

  1. #1
    HKJ's Avatar
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    Default Test/review of Charger Folomov A4

    Charger Folomov A4





    Folomov is new on the charger market and has started with some fairly powerful chargers. This is a four slot charger that can charge with up to 3A, but also charge with low current for small cells.



    The cardboard box lists lot of specifications, battery types and features.



    The box contains the charger, a power supply and a instruction sheet.



    The charger has one 12V input barrel connector.



    The user interface has four buttons, one for each slot and large display.
    After putting a battery in a slot the current will flash for some time.
    When flashing a short press on the slot button will change current in this sequence 250-500-1000-2000-3000-2000-500-250, holding down the button will change chemistry between LiIon and LiFePO4.
    The user interface is slightly slow, i.e. a two fast presses is not detected.
    I have one complain about the interface: When a current is changed for one channel, the adjustment time for that channel is extended, but not for the other channels, i.e. with 4 batteries in the charger you do not have time to adjust each slot in sequence, before the last slot starts. The solution is to put one battery in at a time and select current for it, then the next.



    The display is fairly simple, each slot has a large animated (when charging) battery symbol, a chemistry text, a charge percent, the voltage and charge current.



    Display during charge, the bottom line will change between current and voltage.



    The slots uses the usual construction and works well. They can handle batteries from 29mm to 69.9mm long. The new 70mm cells are a very tight fit and very long protection 18650 will not fit.










    The charger can nearly handle 70 mm long batteries, there is no problems with flat top cells.



    Measurements


    • Charger will charge a LiIon with 0.4mA when full.
    • Charger will discharge a LiIon with 0.25mA when not powered.
    • Charger will discharge a NiMH with 0.05mA when not powered.
    • Below 0.7V the charger will show "Er" and charge with about 3mA
    • Between 0.8V and 2V NiMH is assumed
    • Above 2.0V LiIon is assumed
    • Voltmeter is within 0.02V in the full range.
    • Voltmeter will stop updating when charging is stopped.
    • Charger will restart if battery voltage drops to about 3.9V.
    • Charger will restart if battery is removed or power is cycled.
    • Power consumption when idle is 1.05 watt



    4.2V LiIon charging

    Charge current can be selected from 250mA, 500mA, 1000mA, 2000mA and slot #1 and #4 can do 3000mA, but not when the charger is filled.



    A nice CC/CV voltage charge curve with termination at about 100mA





    The other 3 channel is the same.




    The two other capacities works fine.



    This fairly old cell is handled nicely at 1A charge current.



    Charging with 0.25A also works fine.




    These two smaller cells I charged at 0.5A and it worked fine.



    A 2A charge, termination current is about the same. The charger do not have perfect control of the CV phase, but it works fine.



    3A works the same way



    Four cells at 2A



    When charging with a total current of 8A it needs nearly 4A from the 12V input.



    M1: 46,0C, M2: 47,5C, M3: 47,3C, M4: 43,1C, M5: 46,7C, HS1: 66,8C



    M1: 61,8C, HS1: 64,0C



    The charger takes about 10 seconds to start.



    If the button is pressed during that time the current is changed and the time is extended.




    3.6V LiIon charging (LiFePO4)





    The LiFePO4 charge curves looks good.



    NiMH charging

    Charge current can be selected from 250mA, 500mA, 1000mA, 2000mA and for slot #1 and #4 3000mA



    This is a voltage termination with no top-off charge and no trickle charge. This means the batteries will not be filled completely.





    The other slots is the same.




    The two high capacity cells works the same way.



    The voltage termination also works fine at 0.25A.



    Here with an AAA cell.



    Voltage termination gives fast detection of a full cell.



    Fast charging at 3A.



    With four cells the charger can do two cell at 2A and two at 3A.



    For charging NiMH at maximum speed it needs about 2.5A from 12V, it is easy to see on the input current when the 3A charge is finished.



    M1: 66,7C, M2: 62,5C, M3: 62,1C, M4: 64,9C, M5: 55,4C, M6: 63,3C, HS1: 92,2C



    M1: 62,8C, M2: 48,7C, HS1: 66,6C



    NiMH also needs about 10 seconds to start, the charger turns current off to measure voltage.



    When adjusting the current the wait period is extended.




    A closer look at the pauses, they are 0.1sec every second.


    Testing with 2830 volt and 4242 volt between mains and low volt side, did not show any safety problems.



    Conclusion

    This charger may look a bit simple, but it has what is needed for charging two types of LiIon and NiMH and it can do it slow or fast, depending on what is needed. I like the simplicity of the user interface, but would have liked it a bit more responsive and a longer timeout when using it.
    Because it terminates NiMH on voltage a one or two hour top-off charge would have been nice.

    I will rate it as a good charger.



    Notes

    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
    My website with battery and charger information: lygte-info.
    More than 1000 reviews of batteries, charges and other stuff.
    Compare 18650 LiIon batteries or smaller (RCR123, 16340, 14500, 10450) LiIon batteries.

  2. #2
    MAD777's Avatar
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    Default Re: Test/review of Charger Folomov A4

    Wow, 4 bays at 2 amps each, simultaneously! And 2 bays at 3 amps, simultaneously. That's very attractive to someone with 26650 cells. Thanks HKJ!

  3. #3
    Flashaholic
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    Default Re: Test/review of Charger Folomov A4

    Another real bummer on the restricted length for Protected 18650's. Too bad as it was looking good.

    As for the charge rate selection. Are you able to select the charge rate per slot before inserting the cells??? That's the way I do it in my SH4. I go through all 4 slots specifying the current I want it to run at (max is 1000mA) & then insert the cells. Each slot commences charging without any affect on the others being inserted.

    Also does it remember the previous selected rate that was used.

    Thx, maybe they'll stretch the unit to at least 71mm somehow in an update. Odd its so slow responding. Most ones I have used are responsive and can't say I wait at all.

    Well done in the review as usual.
    Last edited by tripplec; 10-11-2017 at 09:30 AM.

  4. #4
    HKJ's Avatar
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    Default Re: Test/review of Charger Folomov A4

    You can only select current with a cell in the slot and it reset to 250mA when the cell is removed.
    My website with battery and charger information: lygte-info.
    More than 1000 reviews of batteries, charges and other stuff.
    Compare 18650 LiIon batteries or smaller (RCR123, 16340, 14500, 10450) LiIon batteries.

  5. #5

    Default Re: Test/review of Charger Folomov A4

    Seems to get the nimh cells quite warm for my taste. The input jack is near the boiling point of water as well.

  6. #6
    Flashaholic
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    Default Re: Test/review of Charger Folomov A4

    Quote Originally Posted by herektir View Post
    Seems to get the nimh cells quite warm for my taste. The input jack is near the boiling point of water as well.
    I did not pay enough attention to the heat chart as it was fairly closing in bright orange/yellow, but yeah everything is cooking including the batteries. Odd it heat being very high was not pointed out in the verbal comments. Good call there HEREKTIR.

  7. #7
    HKJ's Avatar
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    Default Re: Test/review of Charger Folomov A4

    Quote Originally Posted by tripplec View Post
    I did not pay enough attention to the heat chart as it was fairly closing in bright orange/yellow, but yeah everything is cooking including the batteries. Odd it heat being very high was not pointed out in the verbal comments. Good call there HEREKTIR.
    A 2A or 3A charge current will heat the batteries and especially the AA are very warm, but at 1A they are not warm in any way. The area around the DC connector usual has close connection to the inside electronic and is often fairly warm when a charger is working hard.
    Maybe a comment about not using full current on AA batteries without some extra cooling would have been good to add.


    You cannot directly use the colors in the heat chart, there will always be orange/yellow in it, you have to look at the temperature scale.
    My website with battery and charger information: lygte-info.
    More than 1000 reviews of batteries, charges and other stuff.
    Compare 18650 LiIon batteries or smaller (RCR123, 16340, 14500, 10450) LiIon batteries.

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