Charging Conundrum

[Andrew Brierley]

OK, here goes..... I have an 80 with two 12v batteries in the front, and 24v starting. I also have a leisure bettery in the rear.

I have a T-Max split charge system which connects to the front o/s and rear batteries. All OK so far...

I hope to not use the truck for chunks of time, so have gone completely over the top and fitted 3 CTEK charges - one for each battery. I have a croc clip on the supply, so that I can easily disconnect the supply before driving.

Here's the problem... the T-MAX solenoid clicks regularly and heats up when the batteries are on charge.

Why??????

 

[fridayman]

Are you turning all 3 chargers on at once? This could confuse the relay.

I thought that the better relays have anti-rattle functions to stop the repeated clicking when you get to their switching voltages?

 

[Andrew Brierley]

I already isolate the leisure battery from the solenoid when I charge it (due to solenoid heating up), and then when I connect either or both of the front batteries I get the same clicking problem.

 

[fridayman]

If you are isolating the leisure battery after the solenoid, and connecting 2 chargers at the same time for the front batteries, the solenoid will still "see" the voltage from the 2 chargers. Because most chargers nowadays are voltage sensing, the 2 chargers will be getting quite confused when they see each others voltages. Similarly, the relay will also be given a hard time with the voltages going up and down as the chargers sense each other rather than the battery voltages. Please take this from a non-qualified person though.

This wouldn't explain the clicking if there is only a single charger connected though...

 

[Andrew Brierley]

OK, so after much head scratching I still don't understand the whys and wherefores - everything seems to gravitate back to the mysterious control box/monitor. However..... in the feed from the control box to the solenoid is an in-line fuse. It appears that all I need to do to solve the solenoid heating/clicking problem is to remove this fuse when I connect the CTEK chargers. Simples!