How to refresh your Eneloops

Give them a cup of water or even a lollypop. Joking aside, you can do a refresh with the built-in Refresh function on some Panasonic and Sanyo Eneloop chargers (Panasonic BQ-CC65).

With a Refresh mode, the charger will charge, discharge, and then do a final charge to complete the cycle. This will normally boost the capacity back to its maximum possible capacity. You can use this method with all NiMH batteries, not just Eneloops. This is a very handy feature when reviving older / often used batteries! I usually recommend doing a refresh once or twice a year when you don`t use your Eneloops often.
BTW you can repeat this Refresh mode if you’re not satisfied with the results of the 1st Refresh cycle. Some advanced chargers will continue this cycle until the max capacity is reached. So the continuation of the process may depend on the charger.

Some Panasonic and Sanyo chargers have a built-in refresh function. This goes automatically, but you can’t really see whether the capacity has increased or not. The reason to do a Refresh is because the batteries have either been used a lot, or not so much at all. With a refresh you can maximize their capacity again.

I recommend using an advanced charger like the ones I mentioned in the Best Battery Chargers list. You can set your own parameters, and decide which charge currents and discharge currents you want.

It is recommended to set a refresh at between 1000-2000mA for the charge rate and 500-1000 mA for the discharge rate, for regular (white) AA Eneloops with a capacity of 1900mAh or 2000mAh.

Pro Tip! Some chargers like the Lacrosse BT C700 and Voltcraft IPC 1L have problems with refreshing Eneloop PRO batteries when set at 200 mA charge. It’s better to set the charge rate at max, in this case, 700mA.

But don’t go over 2000mAh for AA Eneloops.

Can I refresh Eneloops if I don’t have a charger with a refresh option?

Yes, you could. Just charge them up with the charger you have, and put them in an old-fashioned flashlight with an incandescent bulb, run it until they’re completely dead, then charge them up again. Repeat this about 2 or 3 times in a row.

You better use a flashlight with an incandescent bulb because most modern LED flashlights have different built-in digital power circuitry which will all work differently and probably quit working before the batteries are completely discharged. Therefore don’t use an LED flashlight for this, unless you know how much current it draws.

When to use the Analyze /  Refresh mode with Eneloops?

When you want to know the capacity, or when you want to give them a little boost. It can be very useful to match batteries for multi-cell applications. You check which Eneloops have the closest capacity and use those in an application to protect the batteries from an over-discharge / deep discharge.