Introduction

For a long time, I had recommended the SkyRC Imax B6 to anyone asking what charger to get.

However, I’ve lost faith in them after my three all developed various faults recently – all terminal. Each were sold as genuine, at “genuine” prices from reputable sources.

The “four button” Lipo dis/charger is a very common proposition, appearing in many guises, including twin and quad versions, and many sizes of “single” charger from many manufacturers, with choices of power source. All have the same unfriendly user interface, but are able charge (and discharge) Lipo, Life, Ni-Cd and NiMH RC batteries, and even 6v and 12v lead acid.

I needed some replacements, but as with most small consumer products now, there’s an excess of choices. Looking at a couple of the usual UK suppliers narrowed the field, and the Etronix ET204 Powerpal Mini stood out for me, thanks to its small size, mains power, and affordable price tag. I paid 34.99 GBP each for these, plus 5.50 GBP post on the pair.

Unboxing

Opening the full colour printed corrugated cardboard box revealed:

  • the unit itself, protected by a polythene bag.
  • an English/French instruction manual. It’s a little small at only 140mm by 100 mm wide, but only the full Program Flow Chart page is verging on unclear.
  • a 1115mm long figure 8 mains lead with UK 3-pin mains plug. A lot of kit tends to come with a permanently attached flying lead, so this is something of a surprise.
  • a 200mm long, XT-60 male to T (aka Deans) male charging lead along with the mains lead, found under a card insert which stops them fretting against the charger in transit.

jr powerpal mini 002 jr powerpal mini 003

jr powerpal mini 004 jr powerpal mini 005

 

Features & Controls

The top panel features a two-line LCD display, and four buttons. These have dual (at least) functions depending on context (where you are in the menu structure), labelled (from left to right) as follows:

  Button 2 Button 2  Button 3 Button 4 
 Top line label  “Battery Type”  “< Status”  “Status >”  “Enter”
 Moulded graphic  Square ([] stop)  Minus sign (-)  Plus sign (+)  Play (|>)
 Bottom line label  “Stop”  “Decr.” (decrement, reduce by one)   “Incr.” (increment, increase by one)  “Start”

 

The front has a 5-pin slot for balance charging 2S to 4S Lipo batteries, a “male” XT-60 connector, and a 3-pin temperature probe connection slot. As noted above, only a XT-60 (female) to T (Deans, male) lead is included in the box.

Another serious omission in my view is the absence of an on/off switch – you need to unplug the unit from the mains when you’re done with it or use a mains extension/multiway adaptor with its own switches. Swapping the mains plug out for one with a switch built in would be another possibility.

The left side has a small round vent suggestive of a fan, and further tiny cooling slots. The right side is superficially the dame, but has an actual fan, and most of the other slots blocked off.

The base has a moulded in warning label, and four small rubber feet. The rear has a “figure 8” mains socket - something of a luxury on cheaper kit.

jr powerpal mini 006 jr powerpal mini 007

jr powerpal mini 008 jr powerpal mini 009 jr powerpal mini 010

  

Powering Up, and Typical Charge / Discharge Setups

Powering the Etronix Powerpal Mini up shows a welcome message on the bright, mid blue display in what you might call grey characters. Contrast isn’t great but seems to be adequate for all light levels.

The tiny (c.40mm) fan does not start at once, only once charging (or discharging) starts. Airflow is minimal – but it’s a small case – and it’s quiet as a result, although I have to say it got louder (without any increase in airflow) the longer it ran.

Any thoughts that it might also be temperature dependent and or responsive went out the window the first time charging ended, and the fan stopped with it.

The menu system is too complex to go into detail here (and would duplicate the manual anyway), but in general:

  • The leftmost button (“Battery Type”) lets you select the type of battery, and the rightmost button (“Enter”) selects it.
  • The + & - buttons (Incr., Decr.) let you select exactly what sort of charge you want to perform, and, again, “Enter” selects it.
  • At this point, in most instances you specify the charge rate using the + & - buttons (Incr., Decr.), ands “Enter” confirms it.
  • After a connection test (and/or sanity check), charging begins.

Having the different types of Lithium Battery (Lipo, LiFe, LiIo, LiHV*) on the “top level” menu is I think a bit of an improvement, previously you had to select Lithium as a class, then the actual type on a sub menu.

* a new option, at least to me: LiHV (Lithium Polymer, High Voltage) is a different type of Lipo battery that goes up to 4.35v per cell rather than the usual 4.2v.

There is scope for storing setups for several batteries of each type, but I didn’t explore those, finding in the previous version it was easier (and safer) to check & set each parameter before charging.

The “key” sounds (beeps) are loud enough to be annoying when setting, up but it is possible to mute them.

Supervising charging to me means being in the same room doing something else, not staring at the charger from close range, and the “Buzzer” (alarm) beeps are a little too quiet for me.

Example Lithium Battery Voltage Meter Reading

  • From the “top level” menu (power cycle or press “battery type” button to get there, if elsewhere in the menu):
  • Press the “Battery Type” button until the prompt “USER PROGRAM Meter” appears,
  • Press the “Enter” button,
  • Connect a (2S to 4S) Lithium type battery to the front left connector slot,
  • The screen will then show the voltages.

Example Lipo Balance Charge

For a 2S Lipo of 2,200 mAh capacity:

  • Connect main power connector & balance lead,
  • Use the “Battery Type” button until “PROGRAM MEMORY LiPo [0]” appears, then press the “ENTER” button
  • Use the + or – button until “LiPo [0] BALANCE” appears, then “ENTER”
  • Set the maximum charge rate to 2.2A using the + & - buttons, then “ENTER”
  • Set the voltage to 2S/7.4v using the + & - buttons, then press and hold “ENTER”
  • Press “ENTER” again to confirm the battery cell count
  • Charging will begin.

You wouldn’t expect to be able to balance charge a 1S Lipo – you need at least two of anything to balance them, but I noted that it’s not possible to select a 1S under the standard “charge” or “fast charge” options either.

Example Lipo Storage Charge

  • Connect main power connector & balance lead,
  • Use “BATTERY TYPE” and “ENTER” to select “PROGRAM MEMORY LiPo [0]”
  • Use + and – to display “Lipo [0] STORAGE”, then press “ENTER”
  • Set maximum discharge rate (+/-, ENTER), then number of cells in series e.g., 7.4V (2S), press & hold ENTER.
  • ENTER again to confirm.

Example NiMH Charge

For a 6N (6 cell, 7.2v) NiMH battery of 3300mAh capacity:

  • Connect main power connector
  • Use “BATTERY TYPE” and “ENTER” to select “PROGRAM MEMORY NiMH [0]”
  • Use + and – to display “NiMH [0] CHARGE A” (or “M”), then press “ENTER”
  • Use + and – to select “A” (automatic – charger varies the applied current up to the figure you select) or “M” (manual – charges the fixed rate you choose) – I’d always suggest “A” then press ENTER”
  • Set (maximum) charge rate (+/-): 1C is 3.3A for a 3,300mAh battery, then press & hold ENTER. 

Example NiMH Charge/Discharge Cycle

For a 6N (6 cell, 7.2v) NiMH battery of 3300mAh capacity:

  • Connect main power connector
  • Use “BATTERY TYPE” and “ENTER” to select “PROGRAM MEMORY NiMH [0]”
  • Use + and – to display “NiMH [0] CYCLE”, then press “ENTER”
  • Use + and – to select whether the process should start with a discharge and end with a charge “DCHG>CHG” (for a battery that’s already full (or nearly) and you want to leave full), or “CHG>DCHG” (for a battery that’s already empty (or nearly) and you want to leave it empty for some reason), then press “ENTER”
  • Set the number of times you want the discharge/charge cycle to repeat (from 1 to 5), then press & hold ENTER.

Depending on the capacity of the battery, and what you do it, you may find the “Safety Timer” and or “Capacity Cut-Off” parameters under “USER PROGRAM SETUP” cause your cycle to end prematurely.

 

jr powerpal mini 011

 

Quoted Charge and Discharge Rates

My previous (Imax B6) chargers allowed a maximum charge rate of 5 Amps, and a discharge rate of 1 Amp. Other variations I’ve seen of “4 button” chargers have a spec up to 5 or 6A, and 1A, up to 2A respectively, though these are both a theoretical maximum.

Since the birth of rechargeable batteries, the recommendation has been that charge rates should not exceed 1C - a “C” in this context being a rate equal to the capacity of the battery, e.g., for a 2000mAh NiMH pack, 1C would be 2A, and for a 4200mAh Lipo pack, 4.2A.

Having selected such a maximum charge rate, it’s then down to the charger itself to determine the actual rate, depending on the health of the battery, and the point in the charge cycle.

The Etronix Powerpal Mini claims a charge rate of up to 6A, and a discharge rate 2A – however it also states a maximum of 60 Watts, and 10 Watts, respectively.

Using Ohms law to calculate what that means at the sort of voltages the average RC enthusiast is likely to see while charging (8+v for 2S Lipo, 8v up to 10v and sometimes more at the limit of 6N (six cell) “7.2v” NiMH charging, and up to 12v on 7N (8.4v) NiMH, shows that only at the very end of NiMH charging – where the charge rate drops off dramatically anyway – could the 60W limit theoretically affect the number of amps delivered.

However, the discharge rate is another matter. A fully charged 2S Lipo battery is nominally 8.4v, at that voltage 10W is only 1.19A** – more than older chargers can do, but much less than the 2A maximum claimed.

At the 10v a freshly charged 6N NiMH is likely to deliver, 1A will be the limit. At the 12v of a fully charged 7N NiMH, 0.83A.

** In testing, the discharge rate of a charged 2S Lipo pack topped out a displayed 1.3A

 With that said, in the case of NiMH batteries, the discharge function is typically used to “cycle” a new pack (charge, discharge, repeat***) to achieve maximum capacity, or to attempt to restore lost capacity in a used pack – and that has always taken a very long time at 1A.

Performing a “storage” discharge cycle on a Lipo battery (reducing the voltage to around 3.85v per cell, so 7.7v on a 2S pack) also takes a long time on a full, high-capacity pack, but I tend to do that only with a part (or mostly) used pack, minimising discharge time.

In practical terms, you’re unlikely to see any loss of discharge performance over a “1A” rated charger, however you won’t see any benefit that the “2A” rating on this unit suggests.

*** up to five times, on this type of charger - with options to charge or discharge first, with time between cycles also user definable.

Reliability

It’s been three months since my Powerpal Minis arrived, and they’ve been perfectly dependable in light indoor use, though I did make extension leads (and various adaptor leads) for the front mounted connectors as they are replaceable, unlike the connectors mounted on the unit as I do see those as a weakness.

Price Comparisons

The typical retail price for the Etronix Powerpal Mini is around 35 GBP, plus post.

This compares very well to the other 4-button AC chargers out there and is not much of a premium over what the DC (or separate PSU) Imax B6s now sell at.

AC/DC chargers tend to be much more expensive, and only the newest dual or quad chargers don’t look poor value in comparison.

All the four button mini chargers have a similar layout of external components, use almost identical firmware, and very similar internal hardware. It’s difficult therefore to recommend this one over some other brand or model of similar spec and cost.

In the face of minimal differences but based on past positive experience of other Etronix products, I felt slightly more positive about this brand – and the retailer I bought them from – than the other, only very marginally different options.

Conclusion

Positives:

  • No need for separate power source.
  • Charges a wide range of battery types, no need for a new charger if you upgrade from NiMH to Lipo.
  • Can charge XT-60 and T (Deans) connector equipped batteries straight out of the box.
  • Built in fan.
  • Separate mains lead.
  • Diminutive size.

Neutral:

  • No option for 12v DC power
  • 4-button firmware is not that simple to use.
  • More expensive than a direct replacement Imax B6 would have been.
  • Claimed discharge rate of 2A a little misleading.
  • Doesn’t use the standard 4mm “banana” plug outputs.

Negative Points:

  • Can’t charge Tamiya connector equipped batteries without an adaptor.
  • No power switch.
  • Alarm volume inadequate.
  • No fan “run on” or temperature speed sensitivity.
  • Doesn’t appear to support 1S Lipo at all.

Overall Rating

While the “4 button” firmware has improved over time, it does add complication that a newcomer, someone returning to the hobby or youngster probably neither wants nor needs.

However, all those options do suit more advanced users, especially those with multiple types of battery, or users with aspirations of upgrading to Lipo at some point.

Mains power means no need for an extra adaptor or power supply, but it does mean you can’t power it from a car battery.

The supplied, separate, power lead is more than a lot of other manufacturers do, but not having an on/off switch is a flaw.

There’s no way to charge a battery with a “Tamiya” 7.2v connector – as found on most new NiMH packs – will add frustration, or at least cost for most users.

Overall, four out of 6 – good, especially at this price point, but with some issues. You might also want to consider the Etronix Powerpal 3.0 at c. 48 GBP which has more connectivity options and supports DC power too.

 dice 5 transp
(See our notes on rolling the dice.)

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Written by TB member Jonny Retro

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