What is the max temp a lipo battery can take with out damage.
1320 tp
2100 tp
etc
Is 150 to high

150 is generally considered the upper end of max.
140 is prefered.
Lower temp = longer life and less chance of imbalance

Larry

Larry

Well to get a lower temp you should change a your pinion for a slower head speed correct?

The TP safety sheet says the operating temperature range for discharging their batteries is 32 to 140F, and then goes on to say "during discharge and handling of batteries, do not exceed 160 degrees F". I think this means the battery may not meet its specification if discharged above 140F, and above 160F is dangerous.

If you're seeing 150F during the cooler months, you will have a problem during summer as battery temperature tracks air temperature with a constant difference.

Okay I got it so how do you get the temp lower
I have trex-x
hacker b20-15L
11 T pinion
1320 tp
cc 25 esc
hs 56 controls
hs 50 tail
401

using high gov mode at 100%
Heli flys great with this set up
just want the battery temp to be safe

Drop the pinion to 10 or go to larger battery capacity.
Also make sure you have good air flow over batts.
Dont fly them to the very end. Majority of extra heat is generated durring the tail end of discharge.

Larry

Larry

And how will that lower the battery temp ?

Lowering pinion size changes the gear ratio - its like shifting into a lower gear when driving. You will have a lower head speed and be drawing less power from the batteries. Performance will drop a little as well.

Adding to the battery capacity - bigger capacity batts can handle more amps without getting hot. Adding an extra set of batts in paralell spreads the amp load over more batteries, lowering each ones load and temp.

Good air flow should be obvious - air flow carries away the heat.

Not flying to the end is as I discribed. Lipo battery temps tend to jump up a lot near the end of the discharge cycle. So dont fly so much of the pack out may lower you temps.

How much MAHR do you typically put back in after a flight? How long are those flights? Knowing that you can calculate the average amp draw and do some more planning.

Larry

Larry

Larry's suggestions are all good.

Smaller pinion = less load = less current = less heat.

Larger battery capacity = less internal resistance = less heat (and more area to spread it from too!)

Not running the battery right down is a good one too. At the end of the pack, the govenor has to increase throttle to get the head speed to remain constant, so more current is taken. At the same time the battery internal resistance is higher near empty so the heat generated is larger still. Getting that last 30 seconds of flight can come at a high price to your lipos!

Hey Larry, looks like we were both typing replies at the same time!

Okay I will try changing the pinion to a 10 T to see if that helps.
Also I do not over discharge my batterys.

Out of 1320 I put back in 1000 mah after 10 minutes of flight

That is well within what those batteries should be able to handle with no problem. Its only a 6C average discharge and you are stopping well before the final drop off point.

What generation/how old are they? Any sign of puffing/swelling?

If they are older Gen 1 then you are at the upper limit. If they are the newer Gen II or Gen II lites, they should be on easy street.

Lowering the head speed may not help all that much since you are well under the max levels already.

Is there good airflow over the batteries?

IIRC, I have seen two other people recently with newer TP packs running too hot for the appearant conditions. Most report good results tho.

You may want to call/e-mail TP directly.

Good luck!

Larry

Larry

Larry3215

Batterys are all about a month old gen 2

No swelling they look normal just hot took temp after a minute of rest after a flight and battery was still 150

Battery is mounted under the canopy so there is no air flow over them speed control mounted under the frame between the skids

Hmmm. That would worry me. If they were still 150 after haveing a minute to cool...

Are your air temps cold like everyone elses or are you in tropical heat in Hawaii?

Open some air vents in the canopy. You need some good air flow over the batteries. Also make sure you have a little air space between the packs if they are stacked

People hate to cut holes in canopies, but your batteries will love you for it.

I would also contact TP.

Mabey try a 5 or 6 minute flight and check temps. You may need to fly two shorter flights.

Good luck!

Larry

Larry

Okay I will try that and will call tp for some info
Thanks

Dont take offence, but you dont by any chance have them wrapped in foam do you?

I heard about a guy do that in a zaggy to protect the pack from crashes. pack got way hot of course. He was also running them down like nicads. He only got 10 cycles or so and they failed. He was blaming the MFG ofcourse.

Good luck!

larry

Larry

No I dont take offense
No foam just a little peice of velcro to keep from moving around.

Larry and Rob, you guys are awesome, great techniques and good explanations. Man do we love our RunRyder.

Its guys like you that make it happen.

Twinsticks make sure and let us know the outcome, so as we can all learn.

XL

Thanks!

I, and Im sure Rob feels the same way, enjoy being able to return the many many favors of help I recieved when I was getting started.

Besides, its good for the ego

Larry

Larry

Thanks guys I will let you know what tp says