DIY 10ah 4s LifePo4 without a BMS V1.1

DIY 10ah 4s LifePo4 without a BMS V1.1

I had been toying with the idea of more power - either for longer operations or more power or even more devices which such as portable digital operations.

I could have gone the simple Zippy 8400mah blue brick that seems the next step up from my 4200 or.. there is the homebrew route.

Using headway 38120 lifepo 4 cells that are used in E-bikes, and some simple balance extension leads I made Big Bertha v1. 10AH 13.2v. This version does not have a Battery Management System (BMS) and for all intents and purposes, it is seen by balance chargers and even the little cell monitoring beepers that many use, like a big 4s pack.

Photo captions:

8486 - a partially built 4 cell pack comparing size with a 4200 zippy
8532 - I might have snapped up another 2x 4 cell lot on ebay that a company was getting rid of. The orange holders snap together giving the cells rigitiy
8577 - sitting on the bench testing connection to the balance charger - I took extension leads, clipped the socket end off and soldered ring terminals to the ends and connected to the negative of each cell, with one being positive - just the same as the zippy packs
8578 - v1 covered in packing foam, covered in light head shrink bags (x3)
8580 - testing my other balance charger to confirm 12v charging.

Possible improvements - increase the current handling of the load/charging cable for possible QRO operation of the 857.

Coming versions might will likely have a BMS going forward to auto cut off on low voltage.

Shopping list:

Cells, cell holders, bus bars :

The rest was either junk box or ebay

DIY Charging Station

No doubt you have guessed I love my gadgets. The downside is they seem to breed, taking up more and more power points along with migrating to new habitat - beside the bed, beside the TV and the kitchen bench. While in a local home wares store on the weekend I noticed a faux leather desk organiser. With a power drill and some wood-boring drill bit, the pics show the result.

Now my Pebble watch, my Fitbit Flex, my iPhone, my iPad mini, iPod Nano, Bluetooth headphones, and battery packs along with their cables have a home. nice and tidy. I can even fit my 11in Macbook Air in the rear 2 spots.


So for around 20 bucks it is all neat and tidy.