I am over whelmed with options for LiPo battery protection circuits.

(Jon Burroughs) #1

I am over whelmed with options for LiPo battery protection circuits. I need something for 3 cell LiPo units and NOT, I repeat, NOT the buzzer alert type circuits that you plug into the battery’s balance cable. What have you used that is reliable, based upon hands-on use? Thank you!

(Chase McGriff) #2

Are you building your own battery pack? Have you looked at http://www.batteryspace.com/pcbfor108v111vpack.aspx

I personally ordered from http://www.batteryjunction.com/pcb.html but they don’t have 3 cell ones

(Jon Burroughs) #3

@Chase_McGriff I recently came upon 15 - 11.1v LiPo RC style batteries. They lack protection by design, however I want to make a more-safe wearable battery pack. Thanks for the link!

(Chase McGriff) #4

Do the connections on them already have leads for each cell? If so it should be simple to solder them to one of those circuits.

(Herb Smith) #5

More safe is a relative term…if you’re looking for safe and are willing to give up a little power density check out LiFePO4. They are a lot safer than than other LiPo batteries and don’t have that exothermic excitement feature.

(Jon Burroughs) #6

@Herb_Smith True, tiz the season for semantics. More safe, to me, means not catching fire from under voltage conditions, while it’s mounted to a person. That’s what PCM’s do.

Power density is important, especially when running LED’s. The price difference in battery chemistry vs safety is nowhere comparable to just buying a PCM.

(Herb Smith) #7

That I know of catching fire is due to over charging not over discharge; a reason to have some type of cell balancing circuit/charger. Over discharge just destroys the cell/battery, a reason for some type of under voltage detection/disconnect circuit.

(Robert Atkins) #8

I’m interested in your findings @Jon_Burroughs . All of the prebuilt protection circuits I’ve seen top out at 4A draw or so, which misses the point of the high current draw LiPos entirely.

(Synthetech) #9

Overdischarge is a potential unsafe condition… the pack will get hot and puff. If it bursts, it could ignite.

(Synthetech) #10

Jon, have you considered the possibility of creating a monitor system routine that will open a safety relay when one cell is detected below 3.3v? Thus shutting down the power entirely.