Dismantling: Briggs & Stratton 10.8v Instart Battery | IS12B-593560

[Rach]

I recently brought a Qualcast petrol lawnmower which has the Briggs & Stratton 775iS Instart engine.

The lawnmower was a non runner, it came with two batteries, one which is working and one which is completely dead, these days a lot of us like to have a bash at fixing our own stuff, so... I decided to strip it down and see what's inside.

I did spend about an hour looking online through Google, forums, YouTube etc and I couldn't find any pictures or information about what's inside... which is why I have decided to post the pictures here because they may be useful to others.

I'm only allowed to attach 4 pics per post so the first post covers opening the battery up.

Top...


Bottom...


Inside...


Tool needed for opening... Torx T10 security screwdriver...


Note: The T10 security screwdriver needs to be one that has the hole in the middle.

[Rach]

Here you can see what is inside...

Bottom Cover...


Top...


Close Up...


Close Up...

[Rach]

Then I removed the circuit board and cells from the case...

2 Phillips Circuit Board Retaining Screws...


Plastic Terminal Trim Prizes Up...


Wiring Close Up...


Wiring Close Up...



After removing the screws, the circuit board and cells didn't seem to move so I used a plastic phone opening tool to wiggle around the edges in the areas it would fit and it eventually came free from the casing.

[Rach]

Here you can see the bottom of the circuit which is where the cells are contained...

3 Cells...


Cell Info...


Cell Info...


Cell Info...


Main Info From Cells... LGDAHB21865

At this point I Googled the information from the cells and found that they are just €3.65 euros each which is about £3.30 in GBP.

LGDAHB21865 Info

[Rach]

More pics of the cells...

Temp Sensor...


Temp Sensor Lifted Up...



Because I had no instructions on dismantling it, the only way I could see that would free the cells from the board was by de-soldering the 4 terminals that secure the plastic cell holder.

Terminals I De-Soldered...


Circuit Board With Cells Removed...

[Rach]

Bottom Of Cells...


Top Of Cells...


I was hopeful that the plastic cell retainers would just pull off the end and I could fit new cells and slide them back on again...

But I was wrong, the cells have tabs on them and I wasn't sure of the correct way to remove them. In the end I just pulled the plastic bits off so I could get a closer look knowing it would damage the tabs.

Cells Separated...


Cells Separated...

[Mick]

Nice. You got slightly further than I did, just two weeks ago I did exactly the same thing, dismantling one of these batteries, I have it sitting right in front of me.    I got everything out but didn't get as far as removing those black plastic battery retainers.  I figured like most of these things the metal strips on the batteries are spot welded to the batteries. 

There's loads of vids on repairing power tool battery packs on YT, so I guess similar applies. I was hoping a tutorial on these batteries would pop up.

[Rach]

Great minds I kinda thought if it was easy to do there would be people selling refurbished batteries for them already but was still intrigued to see what's in there.

You can buy cells with tabs already fitted on for an extra 50p, it's probably possible to somehow find a way to use the plastic cell holders to fit them.




I managed to tear off 2 of the tabs to get a look:





This guy on YouTube used a 3D printer to fit a Lidl battery onto his Instart mower:
https://myprojectcorner.com/instart-battery-alternative/
https://www.youtube.com/watch?v=sM8bHVu_H6M

[Mick]

Yep, you can see the little dots on the batteries where the tiny spot welds were. Apparently you can solder these tabs on, but it's quite tricky to do, and you need a pretty good soldering iron. There is also a risk of creating a short if the solder bridges +-

There is tuts on there how to make your own spot welder, or you can pick them up on https://www.aliexpress.com/ for about £20

This guy on YouTube used a 3D printer to fit a Lidl battery onto his Instart mower:

Yeah there's some clever people about.    I've seen adaptors for some of the power tools so they can share battery brands, but I love the idea of being able to print one.

[Mick]

I might actually have a go at fixing one of these one day, the one I have here was just completely dead no lights nothing.  I assumed it would be just a dead cell or cells.  I have a couple of these packs which flash the row of lights continuously, I'm guessing that might be an actual fault on the board, not sure.

A couple of pics of my partly disassembled one below.





 

[Rach]

Mine was also completely dead, when placed in the charger the red and green light on the charger were both flashing.

There was a drill battery hack online that suggested putting the battery in a sealed bag and then putting it in the freezer for 24 hours.

After doing that, I put the battery in the charger and it started charging, 1 light came on the battery, but after 10 minutes both charger lights started flashing and it stopped charging.

It probably didn't need to be in the freezer for 24 hours, doing that helped me decide the cells were the problem.

I tested all 3 cell with a multimeter and they were all totally dead so I decided to pull all the tabs off them and straighten them out, I'm tempted to get one of those cheap spot welders and see what happens

The end of one of the cells did get pierced in the process, it made a little hiss for a second but that was it, so it's worth being careful if attempting that  


With your battery which just flashes, I wonder if that could mean just 1 or 2 of the 3 cells are dead? what happens when you try to charge it?

[Mick]

With your battery which just flashes, I wonder if that could mean just 1 or 2 of the 3 cells are dead? what happens when you try to charge it?

I can't remember exactly what it was doing, think it was flashing on the charger, then charger just goes to green to say it was charged.  I'll take a video of it when I get back in the workshop tomorrow.   
 

[Mick]

With your battery which just flashes, I wonder if that could mean just 1 or 2 of the 3 cells are dead? what happens when you try to charge it?

Ok Rach, here's a video I took of it today, https://www.youtube.com/shorts/IfMtuh2vIk8

Had a couple of these in the last week or two doing this exact same thing. 
 

[Rach]

I was expecting the LED's to all flash at the same time rather than in a sequence, is it completely dead when it's not on charge?

Might be worth taking the back off and seeing if there is any sign of dry joints / swelling or damage that may have been caused by it overheating

[Mick]

Yes this one is completely dead no sign of life at all when not on the charger.  I will get around to checking it out at some point.  Like I said I've had a couple of these doing this in the last couple of weeks.