Compartment Design for Volteq Plating Rectifiers

October 5th, 2014

One of the useful design features of our high power plating and anodizing rectifiers is the compartment design of the interior. This design consideration separates the control circuitry from getting in contact with the potentially corrosive environment (e.g. vapor from the tanks) of plating and anodizing shops, and exposes  to the air cooling of only the power components , which are much more corrosion resistant. You can see pictures below:

compartment design1

compartment design to reduce air corrosion

compartment design to reduce air corrosion

Four new rectifiers for commercial plating and anodizing needs

October 4th, 2014

Four models of high power high current power supplies are added to our product offerings from Mastech Power Supply and to address the needs of commercial plating and anodizing shops. The new models are HY30200EX, HY15200EX, HY12500EX, and HY061000EX, with output ranging from 200A to 1000A. All models come with over-voltage, over-current, and over-temperature protection, and can be operated in CC (constant current) or CV (constant Voltage protection) mode.

With these new additions, we now offer power supplies up to 300V, and up to 1000A range. At, you can find a wide selection of power supplies and rectifiers suitable for electroplating, anodizing, electropolishing, electrolysis, and hydrogen generation, ranging from low-cost small units for hobbyist to high power commercial grade power supplies for large operations.


30V 200A plating rectifier from Volteq

30V 200A plating rectifier from Volteq

10V 500A plating rectifier from Volteq

10V 500A plating rectifier from Volteq

5V 1000A plating anodizing rectifier

5V 1000A plating anodizing rectifier

15V 200A rectifier

15V 200A rectifier


How to charge lithium batteries?

May 9th, 2011

Fast Charging Lithium Batteries

There are two types of Lithium batteries, lithium ion and lithium polymer batteries.  The chemistry is basically the same for both types of batteries, so are the charging methods. The lithium ion battery is easy to charge, especially if you have a variable DC power supply from Mastech. Mastech has a new line of switching power supplies that are improved to handle battery charging needs. By adding over-voltage protection, the new “EX” models like HY3010EX can handle the reverse voltage without damage. Original models like the “E” or “D” models, e.g. HY3010E or HY3010D, can be damaged by the batteries via reverse bias, if the customer is not careful.

Charging lithuim iron phosphate 3.2 volt cells is identical, but the constant voltage phase is limited to 3.65 volts.

The basic method is to charge at constant current (0.2 C to 0.7 C depending on manufacturer) until the charge current has dropped to 10% of the initial charge rate. To do so, you can set the voltage of the power supply to 4.2V (if you are charging single cell, or multiple of 4.2V if you have multiple cells in series), and set the current limit to the max charging current allowed by the battery or at a level you want. If your battery is sufficiently discharged, you will see CC light of the power supply is lit when battery is connected, indicating that power supply is charging at constant current mode. As the charging progresses, the voltage will climb to 4.2V and the current will start to decrease, and the “CV” light will be lit. The termination condition is the drop in charge current to 10%. The top charging voltage and the termination current varies slightly with the manufacturer. All the “EX” models of Mastech power supplies come with an OV (short for Over-voltage) adjustment knob (second knob from the left), for battery charging, typically you can set that to maximum position. Charging for multi-pack batteries is similar, you just need to change the voltage and current setting accordingly.
The charge cannot be terminated on a voltage. The capacity reached at 4.2 Volts per cell is only 40 to 70% of full capacity unless charged very slowly. For this reason you need to continue to charge until the current drops, and to terminate on the low current.

It is important to note that trickle charging is not acceptable for lithium batteries. The Li-ion chemistry cannot accept an overcharge without causing damage to the cell, possibly plating out lithium metal and becoming hazardous.

Charging Lithium ion batteries at slow rates

When the charge rate during the constant current phase is low, the charger process will spend less time during the constant voltage tail. If you charge below about 0.18 C, the cell is virtually full when the 4.2 volts is reached. This can be used as an alternative charge algorithm. Just charge below 0.18C constant current and terminate the charge when the voltage reaches 4.2 volts per cell.

New Switching Power Supplies with over-voltage protection

February 6th, 2010

We are pleased to announce the arrival of EX models, a new line of switching power supplies that have built-in over-voltage protection, over-current protection, and over-temperature protection. The EX models are best suited for the following applications:

  • battery charging for Lithium Polymer (LiPo), Lithium Ion, Lithium Manganese, A123 (LiFePO4), NiCd, NiMH, Lead Acid batteries (Flooded, Gel, AGM, SLA), etc.
  • as electroplating and anodizing rectifiers
  • electrolysis, hydrogen generator, fuel cell applications, etc.
  • DC motors, slot cars, aviation applications, etc.

with the over-voltage protection, you no longer need to worry about reverse EMF feeding back into the Mastech power supplies and damaging the power supplies. You can even accidentally hook up the battery with the wrong polarity, and the power supplies will be fine. If you turn off the power supply while the DC motoring is running, that’s fine too. In a nutshell, much more robust and much more versatile.

We also added HY3080EX, and HY30100EX, capable of outputting up to 80A and 100A respectively, excellent for applications that require large current like anodizing, electro-plating, and hydrogen gernators.

Check out Mastech Switching Power Supplies

Mastech Power Supply Forum no longer maintained.

June 10th, 2009

Mastech forum is shutdown due to heavy load of spammers. You can find our technical FAQs here:

Mastech Variacs variable transformers now available

June 7th, 2009

We are pleased to announce the arrival of Mastech Variacs! We currently carry three models of Mastech Variacs, a 5KW or 5 KVA model, a 2KW or 2 KVA Variac, and a 500W or 500VA Variac. We also have two variations of the 5KVA and 2KVA variacs, using 110V AC input or 220V input.

Mastech Variacs are high quality variacs with voltmeter for easy setup, and with very wide range of ouput voltage: from 0V to 250V, to address a wide range of applictions. Please check them out here:

Mastech Variac

New Volteq power supplies available

June 7th, 2009
Volteq Linear Power Supply HY3010D

Volteq Linear Power Supply HY3010D

We have recently added the following Volteq power supplies to our inventory:

Volteq Linear variable DC Power Supply HY3010D

Volteq regulated power supply HY3020EX

Volteq Linear regulated power supply HY5005D


With these addition, we have expanded the choices of variable DC power supplies, especially the DC power supplies with higher current and high voltage outputs.