The Kinna Solar bluetooth speaker is a really nice product. Its fairly waterproof and can be used in the rain. Its great to use while working for tradespeople and outdoor workers and many different situations like at the beach or as a small portable party speaker. Solar means if its sunny it will keep on playing usually for much longer as it charges automatically whenever suns out, even when you not using it (in theory!)
But it has one design fault which is a pretty big one. The battery that comes with it is a lipo 3.2v 2000mah (2ah), just one of these doesnt store that much power for too long. Plus after 2 or more years it loses its power and basically becomes useless. I got this speaker at a recycling depot for the great price of just $20, but the battery just wasnt holding a good charge. Thats probably why the previous owner threw it away.
So I figured id have a look inside and see if I could upgrade the battery pack using some free old 18650 laptop batteries I picked up from the recycling depot for nothing. Ive also used these batteries to restore led lights, a solar radio and make custom battery packs for electric unicycles so im used to using these free awesome lithium batteries.
Step 1: Open Up
The trick to opening up the speaker casing is to first remove the grey
circular cover around the "ears" of the wire handle on both sides by rotating and forcing with a screwdriver.. not easy.. i broke the plastic stays but it doesnt matter.. one you have those off you unscrew the screw on each side and remove the rings and handle, then the bottom separates from the top...
You will see the single blue battery connected, cut the wires close to the battery and remove the battery and recycle it. Next you wanna connect longer wires to the battery wires so that the battery can now be put in the bottom compartment (base of the speaker) making sure you know which is positive (red) and which is negative (black).
You need to run the wires down the channel where the handle connects. To do this you need to break a small piece off the edge of the white rim next to where the handle connects so that there is a small gap for the wire where the rubber ring connects the white and blue parts together. So that when you put the speaker back in its cradle the wire pokes out like in the photo.
Step 3: Laptop Battery Pack
Ok so next you wanna break open a pack of laptop batteries or if you have some 18650s handy then its time to make a battery pack. Be careful when breaking open packs not to scratch or damage the battery. If you do cover it with insulation tape to avoid any shorts in the future.
I used sony 1600mah batteries for this project but id usually use 2200mah panasonics or samsungs if available but these sonys are ok for this low power project.
Use a multimeter and test the batteries.. You want 5 or 6 of these batteries to be roughly the same voltage. If they are 2 volts or lower they are possibly no good. Id go for any batteries that are 2.6v or higher..
Nominal voltage is around 3.7 for these but we are replacing a 2.3v battery so its not important for them to be like new. Even if they are 3.7 volts thats ok, they will drop to 3.2 after some use in the speaker.
So the next trick is to put 5 or 6 (i did 5 as it was a less snug fit, 6 is also possible) in series like in the pic and connect all positive using whatever means you can.. I used a soldering iron and small dabs of solder as in the pic..
Please be careful here, you want to use as little heat as possible on the batteries.. consult google or a friend who knows how to do this if your unsure. So once you have all the positive side connected together and all the negative sides connected together then your ready for the next step.
Step 4: Battery Compartment
Under the rubber feet on the underside of the base there are a few screws. Peel off the rubber and take the screws out and pull the base apart and you will see as in the photo the base area.. put the blue part back on the speaker as in the photo. Now you want to break off the plastic tabs using some good pliers to make space for the batteries and also remove the metal weight from inside the compartment.
It looks like the original design was to use the base for batteries otherwise why have these tabs for holding something and also the channels already there for a wire. Obviously the makers decided a small battery was sufficient so they scrapped using the base for battery storage. Great that we can now use it.
In the second pic you can see ive removed the extra plastic. Next step is to put some thin cardboard in there to create some padding for the battery pack, then place it in and connect the positive and negative wires that come from the main compartment and then put everything back together.
Step 5: All Done!
Now put your speaker in the sun or plug it into a usb socket and charge it up ready for your next adventure!
The larger battery pack will take longer to charge than the original one but it will also last a lot longer so enjoy!