Stepping Up a Single NiCad

Thread Starter

wbhowarth

Joined Mar 9, 2021
9
Hello all,

I'm working on a power supply for a DC solenoid which will operate very briefly at a minimum of 6V @ ~150mA. I'd like to use a single NiCad battery as the power source, but I am finding this may be an unrealistic design.

I do not think the discharge current of the battery will be a problem as the documentation provided by Energizer indicated the 2300 mAH battery can discharge at up to 4C; so if I am understanding correctly the battery can supply a few amps.

I started my search for a step-up regulator IC on Mouser and am finding very few devices capable of getting 1.2V to 6V, and those that might be suitable would accomplish the increase at low efficiencies and are not rated for the amount of power the solenoid will require.

Is this a dead-end?

Thanks!
 

Audioguru again

Joined Oct 21, 2019
4,536
Energizer has not made Ni-Cad batteries for many years because they are toxic (illegal?) and hold a charge for only a short time.
Your very old Ni-cad batteries are so old that they probably do not work anymore.
New Ni-MH batteries are rechargeable and hold a charge for 1 year.

Since the battery is used very briefly then why not use Energizer disposable alkaline batteries that have a shelf life of 10 years?
 

bassbindevil

Joined Jan 23, 2014
373
Maybe a "Joule Thief" to step up the voltage, and charge a big capacitor which has enough capacity to run the solenoid?
Or a single lithium-ion cell; they can deliver a lot of current, and hold a charge for long periods. And can be easily charged (TP4056), and can be scrounged from recycled battery packs. A fully charged 4.2 V may be close enough to run a 6V solenoid.
 

Thread Starter

wbhowarth

Joined Mar 9, 2021
9
Energizer has not made Ni-Cad batteries for many years because they are toxic (illegal?) and hold a charge for only a short time.
Your very old Ni-cad batteries are so old that they probably do not work anymore.
New Ni-MH batteries are rechargeable and hold a charge for 1 year.

Since the battery is used very briefly then why not use Energizer disposable alkaline batteries that have a shelf life of 10 years?
Thanks for the correction Audioguru, that was an error. Battery chemistry will in fact be NiMH. Recharge is necessary as the battery will also be driving a uC and Bluetooth SoC.
 

k1ng 1337

Joined Sep 11, 2020
439
Hello all,

I'm working on a power supply for a DC solenoid which will operate very briefly at a minimum of 6V @ ~150mA. I'd like to use a single NiCad battery as the power source, but I am finding this may be an unrealistic design.

I do not think the discharge current of the battery will be a problem as the documentation provided by Energizer indicated the 2300 mAH battery can discharge at up to 4C; so if I am understanding correctly the battery can supply a few amps.

I started my search for a step-up regulator IC on Mouser and am finding very few devices capable of getting 1.2V to 6V, and those that might be suitable would accomplish the increase at low efficiencies and are not rated for the amount of power the solenoid will require.

Is this a dead-end?

Thanks!
I made a basic boost converter that blacked out at less than 1V although there was a large efficiency gradient during discharge of the battery source and I don't know how feedback for a solenoid would be adapted. A capacitor array / super capacitor could be used to handle high current pulses that exceed the capability of the battery.

This is more of an idea than a suggestion. I got the idea from a railgun which uses capacitor banks to produce massive current to fire the projectile off the rails which is basically a solenoid.
 
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