Electronic load for charging/testing small batteries

[RiRaRi]

I test a lot of older camera batteries. The biggest ones are 8V 2A Li-ion ones. But most of them are much smaller found in compact cameras. I need load which could charge and discharge/test capacity as fast as possible. I want decent device but accuracy is not very important to me. What to get? Thanks everyone for help.

[macboy]

I would use a charger for RC such as the ToolkitRC M6, or any of many similar devices. The M6 can charge and discharge with balancing for multi-cell batteries, at up to 10 A. High rate discharge is accomplished by using an external load resistor, or if you use a big lead-acid (car) battery as the power source, it will dump the energy back into that battery.  For a small compact camera battery, you would not need either type of external load, the charger can internally dump up to 10 W (that's nearly 3 A for a one-cell battery). This type of charger is very versatile, it can be set up for any type of lithium chemistry (Li-ion, LiPo, LiFe, etc.) or NiMH, NiCd, or Pb. They can cycle the battery several times, and track the capacity each time, so you can see if the battery is benefitting from cycling. Generally, it is safe to charge and discharge at "1C" rate, which means the 1 mA per 1 mAH capacity (so 600 mA charge or discharge current for a 600 mAH capacity battery). So a charge/discharge cycle will take about 2+ hours. You can't really rush it faster than that, not all batteries can be safely charged any faster.  Don't forget that after discharging, you need to also do a storage charge, to bring the cell back to about 60% or so, in order to safely store it for a long time (storage completely empty or full WILL damage a Lithium battery).

[Kean]

There are many options, but note that most general purpose electronic loads do not support charging unless it is specifically a battery capacity tester.

One battery capacity tester that I use is the ZKETECH EBC-A05+.  I've had a couple of these for about 8 years (originally bought on ebay), and they perform reasonably well for smaller battery packs.  They can be used on a wide range of batteries, unlike some other testers which are intended just for single 18650 cell testing.  The ZKE computer interface isn't great, but I rarely use that.

In terms of testing as fast as possible, you are limited by the max charge and discharge currents of the battery (and the tester obviously).  Note that testing at higher currents for faster tests will not be indicative of the battery in actual usage, but it can help with determining battery performance.  Do not exceed the safe charge/discharge specifications for the battery.  With an old battery, I'd always start of with a gentle charge/discharge/charge cycle.

Another really useful tool for checking older batteries is a battery impedance meter.  Check out the YR1035+.  This will allow you to measure the internal resistance, which will increase with age and affect usable battery capacity.

[RiRaRi]

I got some good answers here, thank you. But to sum it up: what is best device for my job? It does not have to be electronic load but best device to check capacity and possibly charge the battery? Thanks

[helius]

I'm fond of the charger-analyzers from SkyRC. The MC3000 is very flexible for all single-cell cylindrical batteries, and they have a range of units that charge and analyze multiple-cell packs, most named "B6" or variations thereon.

[nctnico]

I got some good answers here, thank you. But to sum it up: what is best device for my job? It does not have to be electronic load but best device to check capacity and possibly charge the battery? Thanks

I recommend not to try and charge discharge batteries as fast as possible but I'd try to stay below charging and discharging rates of 0.5C . This will cause least wear on the batteries.

[sam_sam_sam]

I'm fond of the charger-analyzers from SkyRC. The MC3000 is very flexible for all single-cell cylindrical batteries, and they have a range of units that charge and analyze multiple-cell packs, most named "B6" or variations thereon.

This is a nice battery tester when it works
It has a couple of issues one is that Bluetooth module board is not the best quality and fails with little or no warning at all
The programming charging/discharging cycle is a little bit challenging you have to pay attention to how you set up this application

The one nice feature is the ability to turn off the charging/discharging cycles if you exceed the temperature limit but only if you programmed it in manually it is not by default also this feature is not available in the single mode charging or discharging mode

The SKYRC b6 is also a very nice battery testing machine but there a couple of things that you need to be aware of one you can use it in non balancing mode but you need to update the firmware if you have an older version of this device and can not be a clone version it does not have this feature

It has a temperature sensor that controls the cutoff point but you have to purchase the temperature sensor and you have adjust the temperature cutoff point because the default temperature setting is to high for me personally

One note about using the balancing function on this battery testing machine is that if firmware has it or you have updated it and you have it set to unbalanced mode and you hook up the balancing plug and you have not changed the settings back to balancing mode it will give you an connection error but it does not tell you what it

[RoGeorge]

Do you have a CV-CC lab power supply, and some LEDs?

With this trick:
https://www.eevblog.com/forum/projects/cc-cv-power-supply-as-a-contolled-load-for-batteries-(i-e-rigol-dp832)/
any lab power supply can be used as a constant current load, which also auto-disconnects the battery when the voltage drops under a certain value you can set from the power supply.

[Njk]

An electronic load seems overkill for the task. What you need is an advanced charger with discharging capability. Some time ago, HKJ made a great gob by reviewing many of such devices.
https://lygte-info.dk/info/roundCellChargerIndex%20UK.html

[RoGeorge]

Also this, the VeryLazyLogger (a battery in parallel with a discharging resistor or LED, while the battery powers an electromechanical clock that will memorize the stop hour):




https://www.eevblog.com/forum/projects/verylazylogger-(measure-usb-powerbank-capacity)/

[mawyatt]

That works 

Best,

[thm_w]

An electronic load seems overkill for the task. What you need is an advanced charger with discharging capability. Some time ago, HKJ made a great gob by reviewing many of such devices.
https://lygte-info.dk/info/roundCellChargerIndex%20UK.html

Yes those are great but they are all single cell 4V and OP is looking for 8V, which makes it much less common.