A recent product test of the CSU2-50B unit by product tester and garage owner Des Davies:

“On taking delivery of this unit I could see that it was very well constructed, easy to use and looked solid.”
“The battery cable leads are approximately 2.7 metres long and the input supply cable is approximately 5 metres long, these proved to be very generous lengths and helped with connecting vehicles with hand-to-access battery locations. They are also of a good build quality.”

This CSU2-50B unit can be used with any 12V automotive battery including AGM, GEL and LiFePo4, which was very adaptable across a big range of batteries. The unit has two modes, BSU and SSU, which Des trialled:

Mercedes E220 2.2D Blutec battery connections for this unit

“The status of this unit is indicated by three LEDs: power, polarity and demand. When all three are illuminated, the BSU unit is supporting the battery for you. This was a nice and easy visual check to inform you that the unit was operating correctly and also that your connections to the battery are correct. “
“It has an output current display, reverse polarity protection and disconnect detection, therefore this unit is very safe to use. In BSU mode (battery support mode) a continuous power source is supplied to the battery until physically removed.”
“In SSU mode, when the battery is charged the CSU is a regulated power supply to sustain accessory loads and offset parasitic drain with battery state detection, ensuring safe prolonged use. It also features automatic current sensing in the SSU mode so that it knows when it is needed which is quite clever”
“To select the BSU function, turn the mains on without the battery connected and wait for two beeps within two seconds. Then connect to the battery by connecting the output leads to the unit via the yellow connector. To select the SSU function, connect to the battery with mains power off, then turn the mains on. It provides a stable voltage and up to 50 amps of fully regulated power to prevent loss of charge and damage to the battery, this was more than enough for most applications.”

Investigating it’s practicality on the shop floor:

Mercedes E220 2.2D Blutec battery connections for this unit

“The unit is only 90mm high and I found that it is quite heavy for such a small unit. This unit has been designed to slip under most vehicles without scratching the floor surface. It can also be trolley-mounted for workshop applications or fixed to a wall to vehicle lift which is quite useful.”
“Other conventional battery conditioners simply trickle charge the battery after it has been drained, but this unit provides instant support to the battery eliminating the need for recharging which was very good. It has intelligent sensing in the unit that determines exactly when support is required to minimise unnecessary noise and power consumption. When this support unit was connected to the vehicles on test, it was ready for demonstration and downloads making sure that the battery was kept in peak condition as well. This product provided constant voltage to prevent the loss of data and possible damage to control units during software updates, and module reprogramming as well as diagnostic processes when used in a key on, engine off position.”

Testing on a Mercedes E22 which needed diagnostic support:

“The first vehicle I used this unit on was a Mercedez E220 2.2D Blutec 2014 which had Stop/Start problems, battery draining and a fault code for the NOx sensor. I had the unit connected to the battery for most of the day, in order for me to diagnose these faults without worrying about battery drain and unstable readings with my test equipment.”
“I noticed that the cooling fan of this unit would operate when the load on the battery was increased providing the higher current to cope with the demand. To test in the showroom mode I switched on the sidelights, kept the doors and boot open and ignition on to stress the batteries and these were on most of the day supporting the vehicle battery with a constant voltage.”
“The next vehicle I tried it on was a KA2 1.3 with the check engine light on and with a fault with the engine management system. The unit was connected to the vehicle whilst I diagnosed and tested this vehicle and kept a stable voltage for my tests.

In conclusion:

“This unit is a must-have tool if you are regularly testing circuits under constant battery load, very good quality and robust keeping the vehicles under test at the correct voltages giving you safe and accurate testing results. An excellent product for supporting the battery whilst testing systems with the need for accurate results. “

Original Article published by PMM Magazine June 2022

CSU2-50B Case Study