Test/review of Charger Folomov A4

HKJ

Flashaholic
Joined
Mar 26, 2008
Messages
9,715
Location
Copenhagen, Denmark
[size=+3]Charger Folomov A4[/size]

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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.

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

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The charger has one 12V input barrel connector.

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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.

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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.

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

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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.

supportedBatteryTypes.png

supportedBatterySizes.png


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



[size=+2]Measurements[/size]


  • 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


[size=+1]4.2V LiIon charging[/size]

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.

Folomov%20A4%201A%20%28SA18650-33%29%20%231.png


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

Folomov%20A4%201A%20%28SA18650-33%29%20%232.png

Folomov%20A4%201A%20%28SA18650-33%29%20%233.png

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The other 3 channel is the same.

Folomov%20A4%201A%20%28SA18650-26%29%20%231.png

Folomov%20A4%201A%20%28PA18650-31%29%20%231.png


The two other capacities works fine.

Folomov%20A4%201A%20%28BE18650-26%29%20%231.png


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

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Charging with 0.25A also works fine.

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Folomov%20A4%200.5A%20%28KP14500-08%29%20%231.png


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

Folomov%20A4%202A%20%28SA18650-33%29%20%232.png


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

Folomov%20A4%203A%20%28AWT18650-30%29%20%231.png


3A works the same way

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Four cells at 2A

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

Temp4666.png


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

Temp4667.png


M1: 61,8°C, HS1: 64,0°C

PoweronLiIon.png


The charger takes about 10 seconds to start.

PoweronLiIon3A.png


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




[size=+1]3.6V LiIon charging (LiFePO4)[/size]

Folomov%20A4%200.5A%20%28SO14500-LiFePO4%29%20%231.png


Folomov%20A4%201A%20%2818650-LiFePO4%29%20%231.png


The LiFePO4 charge curves looks good.



[size=+1]NiMH charging[/size]

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

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

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The other slots is the same.

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The two high capacity cells works the same way.

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The voltage termination also works fine at 0.25A.

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Here with an AAA cell.

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Voltage termination gives fast detection of a full cell.

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Fast charging at 3A.

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

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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.

Temp4674.png


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

Temp4675.png


M1: 62,8°C, M2: 48,7°C, HS1: 66,6°C

PoweronNiMH.png


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

PoweronNiMH3A.png


When adjusting the current the wait period is extended.


ChargingNiMH.png


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.



[size=+2]Conclusion[/size]

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.



[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
 

MAD777

Flashlight Enthusiast
Joined
Jul 31, 2015
Messages
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Location
White Mountains, NH, USA
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!
 

tripplec

Enlightened
Joined
Jun 2, 2013
Messages
397
Location
Belleville, Ontario
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.
 
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herektir

Newly Enlightened
Joined
Nov 16, 2015
Messages
104
Seems to get the nimh cells quite warm for my taste. The input jack is near the boiling point of water as well.
 

tripplec

Enlightened
Joined
Jun 2, 2013
Messages
397
Location
Belleville, Ontario
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.
 

HKJ

Flashaholic
Joined
Mar 26, 2008
Messages
9,715
Location
Copenhagen, Denmark
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.
 

TinderBox (UK)

Flashlight Enthusiast
Joined
Jan 14, 2006
Messages
3,488
Location
England, United Kingdom
I ordered one of these only £20 at the moment, and it come with an nice 12v 5amp psu.

I have had some C 5000mah battery hitting 60C when charging and i had to stop the charge.

Also some lifepo4 280mah charging at 250ma the voltage is rising to 4.2v even though it was lifepo4 on the display.

https://i.imgur.com/Zaxj3Az.jpg

This charger is dangerous and is getting returned.
 
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