# What voltage to charge a single NiCd cell?

Ok. I have researched and not found any results abt this question. What is the voltage range for charging a single NiCd cell?

I also have another question: what is the recommended constant current amount (C) for a series of 10 NiCd cells, and are there any other things to consider when charging that many batteries in series?

You don't use input voltage as the metric for charging NiCd. Best results are gained by discharging to 1 V/cell, then charging at constant current of 0.1 of the A-hr rating for 16 hours. That is, if the cell is rated for 1 A-hr, charge at 0.1 A for 16 hours.

Peak cell voltage during this charge profile will be about 1.45 to 1.55 volts, which you can use to specify the minimum voltage compliance of the current source.

You can try for a fast-charge profile, using a 1C or .5C charge rate, and monitoring temperature. Normally termination of the charge cycle is done with a 1 deg C / minute temperature rise, OR a maximum temperature of 60 C. But this will cause long-term damage to the cell if a fully-charged cell is unnecessarily recharged on several occasions.

NiCD has the benefit of a higher resistance when charging comes up to 1.2 V per cell. This voltage has to be respected. If you can control the charging current try charging 10 cells at 200 mA and give it a go. Then, voltage will be spread over the cells evenly (the lower-charged cells will pull the voltage to their level until they match the next cell which will start charging along.) They can be charged at several different rates, depending on how the cell was manufactured. Refer to the datasheet from the supplier.

The nominal voltage of the Ni-Cd type battery is 1.2V, which is used to build your system.

In 10 NiCd cells configuration, 12V will be nominal voltage.

But normal working conditions are not the same because it is usually working on the float charge of 1.40V per cell (It depends on the type of Ni-Cd battery but most commonly 1.40V ~ 1.42V) and boost charge 1.45V per cell.

The main concern when charging batteries is the current limitation. You should set it to max 20% of your Ah value e.g. if your battery is 100Ah set it to max 20A(if possible, please refer to your battery datasheet). Another point monitoring battery temperatures. In some cases (mostly in industrial or any other critical projects) battery temperature compensation feature requested with charger equipment due to set current limitation lower.

P.S: I don't know your batteries are sealed (maintenance-free) or not. If not, you should check the electrolyte level too. Usually, there are marks on the case.

• Can you give an example of not sealed alcalne batteries? Jan 22, 2021 at 13:02
• @user263983 SAFT produces non-sealed Nickel–cadmium (electrolyte refillable) batteries and it has wide usage in the industrial area. You may check the brochure from SAFT website (Block battery: SBLE, SBM, SBH): Jan 22, 2021 at 13:42