IMO, with regards to DIY or availing a service to fix them depends on a few factors:
- can you afford it?
- how many Mekas?
- short-term and long-term
- the main purpose of buying these robots
These factors vary for individuals, so I can only speak for mine.
For convenience, I would go for ckalkhof’s eBay battery replacement service, no question about it.
Consider also if its just a “fad” for you and/or the kids.
If it is, then its only for short-term, please read no further and go with the fix/replacement service.
It will save you time and frustration.
In terms of budget, personally I already over-spent last December. It’s not only for the 6 Mekas but other things in general.
When I bought them, they were priced at $50 (with shipping) and $35 (free shipping).
Now they are going as low as $28 (free shipping). Even with defective batteries, that’s a catch.
I’m pretty tempted still.
So on the practical side, they will cost substantially more for me to get the battery fixed.
On an added note, I also considered the long-term. As I mentioned earlier, li-ion based batteries (li-pos included) will eventually expire (self-discharge, charge cycles) and lose their capacity over time. This is inevitable.
If you happen to be still interested (not a “fad”) on Mekas when the batteries fail, whatever route you take (DIY/fix), you will have to do it again.
I have already considered that in my battery-mod.
Hence I opted to include a battery holder to make it easy for me to swap the batteries.
18650’s are a commodity that makes them cheap and widely available as opposed to the original li-pos used here.
I’m considering 3d printing a custom case in the future to improve the over-all design.
But that’s way down in my to-do list if I somehow get to it.
For knowledge/skill, I’m not an expert, but I’m fairly capable.
I also understand the dangers involved and I take precautions.
This is just another adventure for me.
Understanding everyone is different, it’s not for everybody.
Now for my main purpose of buying these robots, having to play with them is just a cool bonus, I look at them as parts that fit a bigger system/vision.
That’s why I purchased a lot.
The money I saved, makes up for the parts that I need to purchase later.
Anyway, that is just me.
Btw, there is a 3rd option, but I would admonish anybody else to do it.
I have 5/5 of the original batteries revived without opening them.
These were the new but DOA Mekas. IMO, their battery succumbed to self-discharged.
There is a 6th that I didn’t count because this is the I one opened when I studied my battery-mod options.
1/5 likely has a defective BMS since I cannot charge from the OEM charger directly.
But 4/5 so far, I have not any other problems.
Though I know, they will likely have reduced Capacity.
It’s just their nature.
About the battery indicator, I would second or third that the red lights on the rear of the V1 are not an indicator of battery charge. That got me too at first.
I would also check the Mekamon app or the Reach Edu app for it.
On a related note, 5/5 revived batteries are showing full capacity on the app.
This is compared to my battery-mod, where they are only showing about 70-80%.
Note, those are used 18650s too.
The BLE protocol actually advertises the battery charge in terms of millivolts and milliamps.
The battery indicator is computed in percentage based on these values and the difference to the minimum battery level.
The app indicator is not that accurate too though as per other threads in this forum and my experience as well.