Decent Lipo balancer and modification

[BrianG]

Since I have multiple lipos now, I went out and got another balancer. I had the LBA10 and it works very well, but I wanted something simpler. My LHS had the Common Sense Balancer which I picked up at a reasonable bad price of ~$30.

First thing I noticed was the heatshrink was more like thin crinkly cellophane and did not trust it not to wear away, possibly shorting out cell on the pins if they contacted a metal surface.

I hooked it up to my 4s 8Ah maxamps packs anyway and it went to work. There is a nice feature where three seperate LEDs show the status of the cells. If any are below a certain value, it won't balance and cause more cells to discharge too low. Those three LEDs go from amber, to green, to red (red is not "bad" in this case) showing the charge level of the cells. Then, the 6 main LEDs blink depending on which cell needs discharging.

I did notice that if it had to balance more than two cells (drawing 0.15mA/cell) the power dissipated caused the unit to heat up quite a bit - both front and backsides. I measured temps up around 140*F. I don't know about you, but I don't like any electronics getting that hot, especially those small surface-mount devices. So, I affixed a small heatsink to the back of the balancer. To be extra cautious, I also hotglued the edges of the sink in case the heatsink adhesive let go. Wouldn't want a loose metal heatsink to move around and short out across the balance connector pins! I then reapplied some decent heatshrink and cut out a square hole over the heatsink to aid in cooling a la BK Warrior style. Since the heatshrink had to shrink quite a bit to fit snugly, it became quite thick, which offers more protection.

Now when it balances cells, the temperature never goes above 120*F. Even though the heatsink was attached to the varnish covered board, it still did quite well. Any slight airflow makes the temps drop quite a bit more to about 100*F. Since I'm using a computer power supply to power up my Xtrema charger, I use the exhaust fan as a cooling fan for the balancer too. :)

Anyway, here are a couple of pictures:



I want to note that the hotglue is NOT the only thing holding the sink in place - it's just a safety precaution. I am using Arctic Silver thermal adhesive to actually hold it in.