HC-40A Battery Charger problems. - Page 1
Forum section: electronics / repair

author: shaddow
author_rank: Newbie
timestamp: April 15, 2016, 08:45:56 am
content: I currently have a HC-40a Battery Charger, all was fine and working great.I even got it working great on a 700w generator,.But the problem was a few months ago I had it conected to the mains and charging a large battery that its done with out a problem, but on this day it was HOT out side.I had the unit coverd from direct sunlight and when I started it worked fine (Yes the fan is noisy and on its last legs but it worked) 30min later ai walked out and I did not hear the fan at all, I placed my hand on the unit and fmd it was so hot.I turned it off and brought the unit inside to cool down, once it was I pluged it back in and the fan refused to run, I then checked it and its volts at the fan and there was only 3volts dc Open and closed circuit, I then tested the fan in another device and the fan still worked, the volts go to zero when I turn the power off even in open circuit.I had then tested it last week again, unit all connected to battery & mains 0vdc and when I switch the power on the open circuit at the fan is now 23vdc and stays there till I remove the mains power fully ether at the mains switch or just the cord.I am wondering what I should do next, and so people know, I don't have much gear for testing, the main thing is my multimeter.I am trying to loan from a friend a clip on amp gauge to see if the current to the output is fine but the volts there all seem fine.It just seams like the problem is mainly at the fan side.

author: Fulcrum
author_rank: Regular Contributor
timestamp: April 18, 2016, 10:02:06 pm
content: Bit difficult to understand what you wrote, but if I understand you right: You left a charger outside to charge a battery, the fan stopped and the unit got hot. Then you later tested the voltage going to the fan, which was 3V both on an open and closed circuit. The fan works fine when testing it in other units.Seems to me charger in gonski. At least the part supplying power to the fan. Can you test if it can still charge batteries? Don't keep it running of course, it might overheat. But just a quick test.

author: oldway
author_rank: Super Contributor
timestamp: April 19, 2016, 03:52:33 pm
content: Welcome to the forum.An easy fix would be to supply the fan directly from the main output.But output voltage can raise up to 14.9V and it is too much for the fan.You should than add three 1N4004 diodes in serie to lower the voltage.

author: shaddow
author_rank: Newbie
timestamp: April 25, 2016, 04:58:30 am
content: I have done some more testing and found some crazy things happening.Open Voltage at fan is 23vdcBUTWhen the fan is connected it the voltage goes crazy Up and Down.When it was working fine the fan is meant to have variable voltage that is temp and load controlled.When switched on the fan is meant to be at low speed, but when hot or full load be at full speed.I did a few videos and have added the links for people to see. (It still has the original fan too)Part one ""Part two ""I found out it has one 16pin-din KA7500B and A 14pin-din LM324N.

author: Ron Hall
author_rank: Newbie
timestamp: May 10, 2017, 05:37:16 am
content: There is a Thermistor (silicone) fixed to the Toroidal Coil just check it is working, it failed on mine. I wouldn't connect the fan to the output as it will effect the battery sensing that the HC40A is supposed to do. If you do make sure it is via a separate switch so you can switch it off.