Delta Q Charger Failure and Resolution

[bluwtr49]

My Delta Q charger has been acting odd since I bought the car a year ago. The first thing I noticed was that it would start flashing the yellow alert suggesting the internal temperature was high. No big deal I figured it was just doing it's thing when the charging current was running at max for some time. It was still charging but at a reduced rate and would go through all the charging steps and finish correctly. A couple of months ago it began flashing the yellow even at the second step when the current was well below max.
Last month it decided to not charge hardly at all...like 1.5 to 2 amp even though the batteries were in the normal after golf discharge levels and didn't seem to go to a high enough voltage to allow some gassing. At this point, I was very concerned and went online to look at repair facilities and found very little. Flight Sytems seems to be the only choice, and the repair charge is about 80% of the new cost. However, I did stumble across a website where a chap that had the same issue was able to affect a DIY repair. It seems this is a known issue with bad solder joints on a current shunt. The temporary fix was to beat the top of the charger with a rubber mallet until all the lights came on correctly. Selecting the proper mallet, I lovingly rapped the bejeebers out of it, and it worked. While not a fix it strongly suggested my issue was the same as his.
Here is the link to the project:

https://hackaday.io/project/18376-re...926-the-repair

Yesterday I pulled the charger. Here are some Columbia specific points:
• If you have to do this project, the first thing is to open the front and rear clamshells and thank Columbia for there foresight if providing this feature.
• If you have hydraulic brakes, you will find the handbrake won't let the front part open very far, so you have to remove the nut (used for adjusting the handbrake) and pull the brake cable from it's retaining bracket. This was the most difficult part of the project as it's a captive nut with minimal room to swing a wrench. I'm seriously considering using a standard nut with a lock nut when putting it back together.
• Aside from the handbrake issue the rest of the removal is pretty straightforward even though accessing the lower charging mounting bolts is awkward and required using a vice grip to hold the bolt head.

Repairing the charger:

• Just follow the directions in the link above. Do not do what I did and remove all the screws from the back cover and try to pry it off. Super bad idea and I had a hell of a time getting it back together.
• Once I recovered from the above aw shucks the rest of the repair went quite well. You need a good soldering iron, and I used 60/40 solder with "no clean" flux. It's a tight fit getting at both ends of the shunt and cleaning away some of the goop they use to protect components.
• Once that I finished the soldering, it was just a matter of looking it over, checking that my ham-fisted reassembly had not obviously caused more damage, and buttoning it back up.

The Results:

• I temporarily reinstalled the charge with just the top two bolts, hooked up the input and output, and plugged it in.
• It worked great. Much better than it ever has since I bought the cart.
• I took several hours to replace the 60 AHs that were discharged, but it did it without any flashing amber and went through all the steps without any issue.

If I can do this job anone can.