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- Feb 1, 2015
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Most battery chargers are not constant current. If you watch the ammeter, the current tapers off as you approach full charge.I don't believe that my power supply is constant current. Perhaps I will have to see if I can find one. Are car battery charges constant current, or just current limited?
A bench type power supply is probably the best choice. Most of them have adjustable voltage and current. They will also have less ripple than a battery charger. A search on e-bay will turn up hundreds of options. There are some kits that will supply up to 3 amps and 30 volts for around $10 but you have to supply a transformer. I have pulled suitable transformers from defunct computer UPS. You can buy a complete bench supply starting around $30. I built my own, a 50 amp supply. I added a digital volt/ammeter, also from e-bay, for around $5. Otherwise, HF has digital multimeters for around $5 that can be used to monitor voltage and current.
You can anodize without a constant current supply. You would need a rheostat to control the current and adjust it from time to time during the anodizing process. Switching type power supplies are fairly common on e-bay and a 24 volt 3 amp supply can be found for around $10.
Another option would be to combine the 24 volt switching power supply with a kit based on the LM338 voltage regulator ( http://www.eleccircuit.com/adjustable-power-supply-1-2-30v-5a-using-lm338/ ) ( http://www.ebay.com/itm/1x-LM338K-3...760133?hash=item3ce79b6b05:g:KDwAAOSwq7JUAZid ) This kit could be modified to serve as a constant current source.