clusterfunk

I was wondering what you all use to test your packs. ive been looking into getting a multimeter or battery tester but im not sure whats better.I feel like the tester doesnt really give enough information.

Also, is there any way to check capacity? thats what I really want. to be able to check how much "charge" the pack has left, voltage is the second most important i guess. that why im leaning toward a miltimeter. any insight? thanks.

tomfiorentino

Clusterfunk,

Nixx Chemistries: A standard hobbico or similar voltmeter checks the voltage under the appropriate load for either 4.8 or 6 volts with the flip of a switch. Capacity is checked through cycling.

LiPoly: I'll let someone else speak to these as I only use them in my small foamies.

LiFe: Voltage checking is not as relevant because the discharge curves are too flat. Still good to do though. Capacity is monitored through compatible chargers that tell you mah put back into the pack upon recharge. Also check capacity by a process similar to cycling where you discharge and see how many mah the battery produces. But again, the charger helps with this.

Your question is fairly broad so it's hard to respond.

Hope that helps...

Tom

aminkul

for my LIPO battery checking i used hyperion EOS Sentry , i can have the folloing inf (total volt ,cell volt , capacity available %and balance ),its also can be used to check Nicd.NiMH,Li-Fe.Li-ion
for more details check the below link (pdf manuall)

http://www.hyperion.hk/dn/sentry/man...ryMan12-EN.pdf

Tombsy

Futaba has a version as well that's the same idea, works great.

clusterfunk

Using Lipo and Nimh, Capacity wise, im looking for more of a current state of mah, or a "fuel guage". not sure if this is possible, i might be shooting for the stars. my charger is hard to trust sometimes, it tells me my packs are full after 5 min of charging. Im just trying to get a second opinion on the charge status of my packs.

wow i type too slow, tom was the only reply when i started lol. that is exactly what i was looking for. am i correct in thinking the percentage in the lower right corner is battery life?

Tombsy

It is the capacity gauge, here is the Futaba
http://www3.towerhobbies.com/cgi-bin...?&I=LXBHZW&P=6

clusterfunk

thanks a lot, it seems like i would need some kind of adaptor for Nimh. My turnigy lipos should plug right up via the balance cable but im not sure what I need for the traxxas Nimh.

Tombsy

They are for small rx packs, I haven't found anything for the nimh car packs except by charging and seeing how many mah's you put back in.

tomfiorentino

Clusterfunk,

Please keep in mind that there is no majic to the "fuel gauge" jazz and generally speaking, the algortighm they bang against in the charger is so conservative it causes panic well before you should even be thinking about it (ie. "it tells me packs are full after 5 min of charging"). Definitely true on A123's.

The flatter the voltage discharge curve is the less predictive value voltage has in terms of charge state....short of looking at 1/10th of a volt difference and knowing you are either on the front 50% of capacity or the back 50% of capacity (again on A123's), and what does that really do for you?

Measuring mah in on recharge and or mah in after a discharge to verify capacity....different story in my opinion.

The NiCad world is built around voltage....because the discharge curve is steep; opposite of statement above. Voltage has predictive value in NiCads. Look at the curves.

But with these new chemistries the paradigm has changed. It is all what is left in the gas tank kind of evaluations. And the best way to figure that out is measuring mah in/out etc., tracking over time, understanding what a certain set-up typically draws etc.

Tis what I think anyways...others may have a slightly different take.

Tom

clusterfunk

thanks Tom, i will keep that in mind for the future as i get to know my new truck and packs. for now im just looking for a tool that will possibly help me to understand my chargers behavior. Im curious as to what the checker will tell me after my charger gives me that victorious "full" beep. I also thought my charger would be able to do what this checker does. seems odd that a charger cant give the reading that this cheap little chacker can...

tomfiorentino

Hey...hang on a minute...trucks?

If it don't fly...just run it until it stops. Who cares!

tomfiorentino

One too many Southern Comforts....

Tom

clusterfunk

hey who said trucks cant fly, i have to make you a video lol.

AmishWarlord

My Feedback: (5)

You can get a Quantum Telemetry device to use a fuel gage. That way you can watch your pack voltage as well as the cell voltage in the pack.

I'm uploading a video of mine on Youtube right now. It will be up in a bit.

Here is the link.

You need the receiver and a transmitter. You only need one transmitter as you clip them to the battery when you change batteries so you don't need to hard mount it in your truck or plane.

I's get the flexible antenna also.




Rx http://www.hobbyking.com/hobbyking/s...dProduct=10343

Flex antenna http://www.hobbyking.com/hobbyking/s...dProduct=10896

Temp / Voltage ad on, http://www.hobbyking.com/hobbyking/s...dProduct=11251



http://www.youtube.com/watch?v=ly8le...XBk0nWvxJAg%3D

Here is the Rx set up on my Tx. I have a 1,300mAh 3S pack set up on a 28-26 motor spinning a 8x4 prop at 10,900 RPM

Sorry for the quality but this is from a camera in movie mode. Need to get a HD vid cam!

You can see that the overall voltage drops to 10.6 well below the 11.1 I had planned for. One the bar graphs you can see the cell in the middle is weak and falling off allot faster than the other two cells. This packs only put out 726 mAh so I know it's not a good pack.

Test complete. Pack FAILED!

guver

My Feedback: (325)

For Lipos a tiny volt checker for a few bucks can tell pretty close to how much remaining capacity is left. http://www.hobbyking.com/hobbyking/s...cessories.html

eddieC

My Feedback: (2)

BDZ65

I see this,false peaks,with my NiMh packs sometimes, happens within about 2 min. of beginning a charge cycle. When I knowa pack isnot fully recharched I simply start another charge cycle, I only charge @ 500mA. I also measure my packs capacity at least 1x / year and I built expanded scale voltmeters and installed in each of my planes. The little voltwatch LED bar graph devices are an expanded scale voltmeter and if measured while the pack is in the plane under load it is a loaded voltmeter as well, can't get much better than that. I simply deflect several servos at one time and observe what the battery voltage does as a result, you will quickly learn what the bar graph looks like on a pack that is nearly discharged.

Brian

clusterfunk

Great ideas guys, thanks for all the info. For now I purchased the Hyperion Sentry pack checker. Sometimes I think I should have stuck to internal combustion engines, but it has been interesting learning about batteries and electrical. I think in the future I will add a couple digital volt meters or LED graphs in the truck, we shall see.

As far as the NiMH packs, thanks for the heads up. ill keep that in mind.