Measuring your Lipo's Internal Resistance

[nate80]

Do you measure and monitor your batteries Internal Resistance values?

After a few of my LiPo';s have started to puff a little I want to better monitor my batteries, so I';ve been looking at the easiest way of performing IR checks.

Hobbyking sell a Turnigy 7 in 1 Mega Meter that measures IR, but I';ve read contrasting reviews about it';s performance, and I think it can only check one cell at a time?  It does lots of other stuff too though, like measuring thrust, which could be very handy.

Hobbyking also sell a stand alone Turnigy IR meter that is super easy to use and checks all cells.

https://www.hobbyking.com/hobbyking/store/uh_viewitem.asp?idproduct=29669

http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idproduct=76782

Does anyone have either of these tools, or is there a better easy way to test IR values?

[guest325]

I use the 7 in 1, it';s a useful tool to have, like any cheaply made Chinese equipment it need not be as accurate as more expensive  ones but it';s a good indication if things are not right!

[nate80]

Thanks Darrell.    I';m really tempted by the 7 in 1.  I really like the fact it can do so much, and even measure thrust values. 

I';m not expecting perfection, but how accurate would you say it is at measuring IR values?  And am I right in thinking you have to measure each cell individually via the balance port, or does it measure all the cells at the same time?

[guest325]

From what I can remember you check each cell using the balance lead, It picks up batteries on their way out easily if you check them regularly and plot a graph - it soon shows up!

[nate80]

That';s great, thanks.   

I found the PDF instruction manual for the 7-in-1 Mega Meter online and it seems to show a make-shift lead (the cable isn';t shown on hobby king at least) that attached to 2 of the balance lead pins (+ and one of the cells, I guess) on the battery you want to test.  Then the 7-in-1 gets powered by the XT60 of another battery.  Seems an overly complicated way to test IR, and the cables used between the tester and the battery will surely have a negative impact on the reading.   

I';m not sure I';d want to rely on the Mega for IR results as I don';t plan to keep a log of each batteries figures throughout its lifespan, but I still could use it';s other functions so I bought it anyway.  And I also bought the stand alone IR tester, which looks far easier to use and is supposedly more accurate, plus it can test the IR of all a batteries cells in one go.   

[Two-Six]

I have this charger that measures the internal resistance of my batteries.  Its also a pretty nice dual port charger.  You can get them for cheaper than the RRP of £90 if you shop around.  That Turningy meter looks handy but for another £35 you can get a very capable charger as well as an IR meter.

http://www.overlander.co.uk/chargers/chargers/rc-d100-ac-dc-dual-balance-charger.html

[nate80]

I have this charger that measures the internal resistance of my batteries.  Its also a pretty nice dual port charger.  You can get them for cheaper than the RRP of £90 if you shop around.  That Turningy meter looks handy but for another £35 you can get a very capable charger as well as an IR meter.

http://www.overlander.co.uk/chargers/chargers/rc-d100-ac-dc-dual-balance-charger.html

Cheers Two-Six.     I had looked into potential chargers with IR features built in, but decided against it in the end as I already have 2 very capable charger which can safely charge 10 LiPo';s at once, so I don';t really need another.  And the turnigy IR meter';s small and easy to chuck in a flight bag.