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36V (3x12V) Pb battery replacement

Posted: Sep 12 2020 5:17am
by nuxland
Got one old scooter to my son who is going to university. But it had 3x12V 12Ah Pb battery inside that only allowed around 12km of range. And the charger was 1,5A, so 8h to fully recharge again.
Goal was to put the replacement battery to the same place so I had size restriction. After calculation I sourced 120pcs of "Samsung INR18650-35E 3450mAh - 8A - refurbished" and configured it in 12p10s. nkon holders if combined to 8x15 arrangement were a little to big so bough from aliexpress ready made one pice 8x15 holder and also bough from the same place 6p wide nikkel. As 12p 8A cells can give over 100A but I only needed 30A (that is what brushed motor and 1kw dc controller was rated for) I bought 60A BMS from aliexpress because these were still in the right size. If you go over 80A or 100A they are to large.
This was my first time to use welder that was sitting in shelf from year 2017 :)
Used 100Ah car battery because my lipos were 7s and that is to high for welder mosfets.
36V_40Ah_Weld_Begin.jpg (397.83 KiB) Viewed 367 times
Added second layer nikkel where there was only 3 ribbon in series
36V_40Ah_Weld.jpg (290.61 KiB) Viewed 367 times
BMS installed and output wires done
36V_40Ah_BMS.jpg (299.87 KiB) Viewed 367 times
New Battery weight without bag and padding (add few hundred grams)
36V_40Ah_Weight.jpg (264.19 KiB) Viewed 367 times
Old Pb Battery weight
36V_12Ah_Weight.jpg (229.2 KiB) Viewed 367 times
Testing is it working before shrinkwrapping
36V_40Ah_Testing.jpg (261.76 KiB) Viewed 367 times
Shrink wrapping (also added extra balance wire just in case when I want to charge it with my 4010 duo)
36V_40Ah_ShrinkWrap.jpg (264.33 KiB) Viewed 367 times
Ready and installed in bag. Only difference from outside is XT90 connector
36V_40Ah_Ready.jpg (153.63 KiB) Viewed 367 times
In Calculations scooter should have now 4 times the range and battery is 5kg lighter.
Bought also 42V and 5A aliexpress charger to be able to charge it in 8h when empty.

Re: 36V (3x12V) Pb battery replacement

Posted: Jan 01 2021 6:58am
by nuxland
Made another one and now have two of these.