More fun with batteries:UPS upgrade

March 31, 2019Dan No Comments »

2018 was a bad year for Uninterruptible Power Supplies at my house – I’ve got several old models that I’ve been nursing along with batteries sourced, free of cost, from various places. I finally ran out of free batteries, and am hesitant to buy more OEM SLA batteries to replace them. Lead acid batteries are big, heavy, and tend not to work very well for deep cycle use. Emergency/backup power is one of the few use cases where they still make sense – but I’d like to move to newer tech.

Pictured above is 1 of 4 of LiFePO4 32700 batteries that I ordered, to get my UPS going again. They are a big brother to the 18650’s I mentioned in my previous post. They support a higher amp load and are also a larger capacity (and a larger physical size) vs the 18650. I ordered a battery management system to keep the batteries at a consistent and safe state of charge, but haven’t quite got them hooked up yet. Stay tuned for some UPS upgrades!

Mining for milliwatts

March 15, 2019Dan No Comments »

Those who know me well, know that I like to tinker with electronics projects. And tend to have a lot of projects going at any given time. Lately, I’ve been playing with lithium ion batteries.

I’ve always enjoyed playing with batteries, using them to power remote control toys, or small electricity projects when I was a kid. I remember gutting 12v fans from HP desktop computers (386’s I think) and using them on hot summer days to try and stay cool, powered by 12v batteries. I’d use a big external battery pack, jankily wired into my gameboy, to keep it going on long car trips.

Much more recently, I learned about lithium-ion batteries, enjoying both their rechargeable nature and high power density. They keep my hexbright flashlight shining bright and allow it to recharge easily. I have a LiFePO4 battery in my motorcycle, which is one of the few batteries that will fit in its tiny pancake-shaped battery compartment and still have enough power to crank the engine. I also have a bicycle with an electric motor and large lithium ion battery pack – that pack uses 56 little 18650 lithium ion cells. The Tesla motor company famously uses hundreds of them to power their cars.

Back to the pictures above – I’ve had 2 old laptop battery packs kicking around my house for several years (14 years in fact, actually following me through 4 different moves). I’ve been meaning to recycle them, but then I started wondering if there were any useful cells inside of them. Many folks online are harvesting cells like the above from old battery packs they can find, and using them to power bikes or skateboards or even their house. It’s a rather common failure mode for 1 or 2 cells in a laptop battery to go bad, making the pack useless for powering a laptop. But there’s still life in the other cells.

…I was able to remove 15 18650’s from these 2 old packs – could they be any good?

Another broomball season wraps up

February 28, 2019Dan No Comments »

Winter at Michigan Tech means a few things – snow, Winter Carnival, and broomball! Thought I’d highlight that last one a bit here, as I have just wrapped up my 9th season of playing Michigan Tech broomball!

Michigan Tech takes broomball pretty seriously, with hundreds of (mostly) students taking part every season. Stats are kept and bragged about very seriously:

This last season was a good one, in fact my team won all of our games except for 1 – a pretty good record if I do say so myself. I look forward to broomball every year, it’s a nice excuse to be outside and be active, and engage in some friendly competition. I do also look forward to the time it frees up in my schedule, when it’s all done…

As an aside, one thing I look to be doing with this extra time is building out a new website – I’ll just leave that here for now, more coming later!