Harbor Freight Drill Charger Mod

WARNING: PERFORMING THIS MOD WILL PROBABLY COMPLETELY VOID ANY WARRANTY YOU MAY HAVE.

You may notice the charger included with Harbor Freight rechargeable drills (at least the Drill Master 66965) is not a "float" charger, meaning you CAN NOT leave the battery on the charger for too long otherwise you will destroy the battery.  

This Instructable fixes this issue.

This limits the charging current to approximately 100 milliamps which is less than 10 % of the 1200 milliamp rating of the battery thus OK for a constant “FLOAT” charger. Note - Allow no less than 14 hours for full recharge of a fully discharged battery but you may leave ON after that time.

Step 1 Open the charger

Turn the charger base over.  There are 4 screws. Take them out.  Remove bottom of charger.

Comments

[gsnoorky]

You're Leonardo Da Vinci with that iron compared to me--instead, I'm analogous to a little kid finger-painting!

Thanks, also, kill-a-watt: Many of us need to be reminded of the quality way--the right way to do such things--that saves future aggravation--and, time.

Thanks for this: It would have cost the PRC a fraction of a cent to do this. If HFT had insisted upon this from the PRC co. involved, they would have avoided great resentments and carping about this product. It seems that HFT would desire less resentment and more public satisfaction--spending a few cents and maybe even adding a $ to the purchase (for their trouble) would smooth things over with the public. It seems to me, at least, it's in their best interests.... Anyway, I'm certain that this solution may be easily incorporated into other such products which people buy. (I know!: It is what it is!)

PRC cos. copy and steal ideas from each other endlessly: Something which costs $20+ at a certain retailer costs $5+ elsewhere. (I can submit easy examples, if desired: I think that I'll join!)

I'm moving, and we have to sell our property, so I won't have as much time as I desire to contribute at this point. I can tell that the contributors here are great, though!: Thanks again! I wish that I had known about this site years ago!

[Phil B]

I think what you call poor soldering will work just fine for you. There is nothing that will disturb the joints or apply pressure to them, and the shrink tubing will strengthen the connections. I did something like what you did here. You can see it at this link.  Although it has been several years, the same battery is still in use and still working just fine.

[xrobevansx]

Awesome Phil! Thanks for your encouraging words.

[kill-a-watt]

Your soldering looks pretty good to me. There is, however, a lot of solder. Even though the picture is blurry, I can see that enough heat has been applied so there isn't a "cold joint" here.

A passive component like a resistor is the perfect thing to practice on though. As a practical manner you don't have to worry about too much heat destroying the part.  

Next time:  1) twist the leads together to make a mechanically strong joint. 2) "tin" the tip of your soldering iron, then wipe it on a sponge to clean it. 3) add one "drop" of solder directly to the freshly cleaned tip 4) touch the tip of the iron to the future solder joint and hold it there until you see that drop of solder wick into the joint 5) add a small amount of additional solder, but allow the joint (not the iron) to melt the solder and allow it to be wicked into the joint 6) remove solder and iron, allowing the joint to cool to solid without a bump or jarring,

[xrobevansx]

Thanks for the tips! I admit my soldering is BAD (even if your kind words say otherwise) but the charger is indeed working very well! Thanks again. I will practice using your directions!

[Phil B]

I just looked at all of your Instructables. I like your ideas and hope you will continue to post more.

[xrobevansx]

Thanks again Phil. I try to make instructables as I need to. Problem...fix...make instructable.