- 36 Volt UPS (1x 30$). Recommended Tripp Lite Smart 1500. (No Battery needed, we will be replacing it)
- Note: that the UPS must use a 36 volt battery setup. Normally, this is three 12 volt Lead-Acid batteries in series. Trying to use Lithium Batteries on a 12 volt or 24 volt system is dangerous.
- Link: https://erc-green.com/shop?olsPage=products%2Ftripp-lite-smart-1500-950w-ups
- 36 Volt Hoverboard / Scooter Lithium Batteries (4x ~ $30 each)
- These batteries are available on ebay, and are packs made of 20 18650 battieries in a 36 volt (10s2p) configuration.
- They come built in with a BMS to prevent over charging and discharging and balance the cells.
- Link: https://www.ebay.com/itm/UFO-U18650-36V-158-4Wh-Battery-10s2p-for-Hoverboard-Balance-Board-Vape/323334808752?hash=item4b4841a4b0:g:1xUAAOSw0Lha55pP
- XT60 Parrallel Cable (4x ~ $4 each)
- Make sure wire is 14AWG or Lower (for safety)
- Link: (https://www.ebay.com/itm/XT60-1-Male-2-Female-Battery-Connector-14AWG-Charger-Cable-Parallel-x-2-set-P/392195761298?epid=16006858312&hash=item5b50b06492:g:NpoAAOSwpTBcAqd1)
- Multimeter for testing voltage of batteries
- Wire Stripper / Cutter
- Electrical Tape
- A soldering iron optional, but recommended
Check the voltage of all your battery packs. The max charge voltage is 42Volts, the minimum voltage should be about 30 volts.
If the voltages of the batteries are within 2-3 volts of each other, the batteries can be balanced by connecting them in paralell using the XT60 Parralel Connectors. It is recommended to add batteries to the chain in order of their voltage from lowest to highest.
You should have 1 left over XT60 Connector which will be used in Step 3.
Once all the batteries are connected, let them sit for 10 to 30 minutes. Make sure there is no heat coming from the packs, this is a bad sign. Occasionally remove one battery at a time from the string of batteries and check the voltage. After about an hour, all the batteries should be at the same voltage.
If the batteries have large voltage differences, it is probably best to charge each battery individually from the UPS. And then connect them in parallel. This is explained in the following steps.
Open the UPS where the battery is found. You should see a red wire and a black wire. This is where we will attach an XT60 Connector. Take your extra XT60 Connector and cut off one of the male ends so that it can be soldered or securely attached to the red and black wires of the UPS. Make sure that there are no exposed parts of the wire, wrap in electrical tape or heat shrink to prevent a short circuit.
Now that the UPS has an XT60 connector, the batteries can be attached to it. If your batteries had wildly different voltages, you can connect one at a time and charge it before connecting them all in parallel.
The UPS should turn on and begin charging the batteries. In my tests, the Tripp Lite 1500 charged the batteries to a maximum of 41.9 volts, which is absolutely perfect as the rated voltage for these packs is 42 fully charged. It is important to occassionally stop the process and check the voltage of each battery to make sure that it's not overcharging the batteries. This is why we use a 36Volt UPS, with a 10s 18650 configuration as the max charge is the roughly the same for the Lithium Ion batteries as lead acid when using 10s.