Which batteries for 41CV?

[Dieter]

(10-17-2018 08:23 PM)burkhard Wrote:  In your link from Akkushop, it does show the rechargeable N cells have a 500 mA·hr capacity, but the BC700 style charger has a minimum setting of 200 mA charging current. Isn't the rule-of-thumb that the charging current (in mA) should be limited to about 1/10 the nominal battery capacity (in mA·hr)? If so, it's about 4× higher than optimal.

No, there is no such rule, let alone is this the "optimal" charging current. Only if a dumb charger without any charge control is used and you don't know when to stop charging, these 0,1 C are recommended as most NiCds and many NiMHs can withstand an overcharge with such a low current. The charging time then is 12 hours or slightly more.

But were are talking about smart chargers here. 200 mA : 500 mAh means a relative charging current of 0,4 C which is almost perfect. It allows good –dU detection by the charger while it does not significantly heat up the battery. Take a look at the data sheets for the N-size NiMH cell of your choice. Often even a current of 1 C is allowed (i.e. here 500 mA) as long as there is a decent end-of-charge detection.

The BC-700 is one of the few smart chargers that allows a charging current as low as 200 mA. It even defaults to this setting when you turn on the device. This makes it very suitable for charging N-cells.

Dieter