I bought it long ago so I assume it has no warranty. But what should I do first to try to repair it? The problem, for sure, is the battery inflated or got swollen, I have seen it before in RC batteries.
That is f**** ridiculous!! Sorry for the expression but those shipping prices are totally unacceptable.
My question is: where can I get a new battery and got shipped to Spain at an afordable price (Aliexpress is welcome, eBay from Europe too).
I don’t know if I can solve the battery replacement, seems difficult to find one and got shipped to home, but what can I do in the meanwhile? Should I de-solder the old battery and try to connect with a usb cable? Will it work this way without the battery or it is mandatory to have a battery connected to work? I hope the pcb is working ok because of the curvature it got I do not know if some component broke.
Yes, if you have the equipment and skills to remove and replace a surface mount resistor. Change resistor R7 (2Kohm), which sets the battery charge current, with one of a higher value. The new resistor should be between 5.6Kohm and 10Kohm.
The recommended charge rate for the type of LiPo battery used in the Arduboy is 1C or lower. The battery is 180mAh, so 1C is 180mA. A 5.6K resistor will give a charge current of 179mA and a 10K resistor will give 100mA.
The lower the charge current, the better it is for battery life but going less than about 0.5C won’t improve things much.
However, the lower the charge current, the longer the battery will take to charge. Charging at 1C will take something over an hour for a full charge whereas 0.5C will double that to something over 2 hours.
I used a 8.2K resistor for mine, which gives 122mA (about 0.68C).
The photo shows the resistor that needs to be replaced circled in red.
Yeah if you want to ship it to me, another option I realized… it does still cost a bit but if you can find a Micro Arcade near you then those use the same kind of battery and can be swapped over… haha, not a great option but cheaper than the ones you are discussing.
I don’t really thing the charging is what kills the batteries by the way, in fact most balloon batteries are reported after long periods without use. No lithium battery lasts forever, and this is one of the failure modes.
But charging at higher than the recommended current likely hastens the electrolyte degradation that causes bulging and failure. Almost everything you read about battery bulging states that it is aggravated by overcharging, overdischarging and heat. The Arduboy’s provided protection circuit will mostly prevent the battery from overdischarging.
Charging at high currents will cause the battery to heat up while charging. Also, with the charge chip’s charge current set too high it will provide too high of an idle/maintenance current, thus causing the battery to overcharge if left plugged in after full charge is reached.
I understand the theory, but I’m the one who is replacing Arduboys out of pocket. I don’t see a correlation between frequent use, I see a correlation between no-use.
From my anecdotal evidence it is worse to leave a depleted battery for a long time than it is frequent charging.
I also left an Arduboy plugged in for something like 8 months continuously, and never had a problem.
Furthermore, as your google studies indicate, the examples come from many products that are likely more properly engineered and still have failures. Also these articles often say this is a natural behavior of the battery aging.
How many un-used Arduboy batteries do you have in storage that you’ve had to throw out despite being never used? I have several dozen and I’ve had to toss a few over the years cuz they ballooned up.