Measure temperature with IR Thermometer

Molle123

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Hello! I waiting for my Arrma Kraton V2 to arrive with the post.
In the waiting I was out today and bought an IR Thermometer so I can measure the temperature at the motor, batteries and ESC. I'm going to run my Kraton with 2 x 3S Lipos = 6S.

But how many degrees Celsius is optimal for the motor, ESC and batteries?
Minimum - Maximum?

And also I wonder when to measure the temp. After I've run my batteries out of power? Or in the middle of the run?

Sorry for bad english. I'm swedish ;)
 

WoodiE

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@Molle123 I would suggest not getting the brushless motor over 150-160 F which is about 65-70 C. When I'm using new batteries, different gearing, or other changes I typically keep an eye on the motor temp throughout the run. Once I have a good idea then I might spot check it from time to time but will not check the temp every single time once I have it dialed in.
 

Molle123

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@Molle123 I would suggest not getting the brushless motor over 150-160 F which is about 65-70 C. When I'm using new batteries, different gearing, or other changes I typically keep an eye on the motor temp throughout the run. Once I have a good idea then I might spot check it from time to time but will not check the temp every single time once I have it dialed in.

Thank you WoodiE :)
Do you know max/min temp for the ESC and the batteries too?
The battery set-up I will use is 2 x Duratrax Onyx LiPo 3S 11.1V 5400mAh 50C.
 

yonzariq

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Most motors are best kept below 70C to prevent demagnetizing the rotor.
And I believe a lot of ESC's switch to thermal shutdown around 85C
Lipo's can handle 60C max, but mine never get more than a few (5-10) degrees above the outside temperature
 

mrfurious40k

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Get some low voltage alarms. Temperature is just one variable that you need to monitor. It's very easy to tax your batteries on a hard run and have them drop down far below the safe voltage before the ESC low voltage cutoff kicks in. You can destroy a pack in one run by doing that. I have a pair that I set for 3.5v on regular runs and 3.9v when I know I won't have time to put a storage charge on my packs. When the alarms sound, I know it's time to bring the truck in rather than waiting for the ESC voltage cut off to trip.

https://www.amazon.com/Voltage-Buzz...18287&sr=1-20&keywords=lipo+low+voltage+alarm
 

Molle123

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Get some low voltage alarms. Temperature is just one variable that you need to monitor. It's very easy to tax your batteries on a hard run and have them drop down far below the safe voltage before the ESC low voltage cutoff kicks in. You can destroy a pack in one run by doing that. I have a pair that I set for 3.5v on regular runs and 3.9v when I know I won't have time to put a storage charge on my packs. When the alarms sound, I know it's time to bring the truck in rather than waiting for the ESC voltage cut off to trip.

https://www.amazon.com/Voltage-Buzz...18287&sr=1-20&keywords=LiPo+low+voltage+alarm

Interesting! I always thought that the ESC low voltage cut did cut in the right time, before any damage could be done to the batteries.
At which voltage does ESC low voltage kick in?
 

mrfurious40k

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Interesting! I always thought that the ESC low voltage cut did cut in the right time, before any damage could be done to the batteries.
At which voltage does ESC low voltage kick in?

3.2v which is safe. The problem is that when you're running hard, it's possible to quickly dump one or more of the cells in a pack well below that safe voltage before you realize it. It's amazing how much power these rigs will pull from a pack especially under a load like running on grass. That's why I prefer the voltage alarms. It let's me know before I'm close and monitors each cell individually.
 

yonzariq

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I had always set my cut-off on 3,4v with my ESC's and never had issues so far.
Also no problems with hard running.
But as soon as the cut-off jumps in I stop and turn the vehicle off.
There are people who keep running their cars for some time after the cut-off sets in, that is which can be really deadly for your lipo.
I also always balance charge them, some people prefer to balance them only every few runs.

I do have seen some lipo issues with built-in cut-offs, but when that happens your lipo probably is already bad and out of balance.
A few weeks ago I had someone over whose 2s Lipo had the cells differ 0,7volts and he was wondering why it performed so bad and his charger wouldn't charge it anymore...
Simple balance charger, no voltage monitor or anything, and built-in cut-off set to 3,0volts.

It's all in the way you handle your lipo's :)

I do try to get my lipo's as powerful as possible to prevent issues also though.
When I have a motor/ESC setup that can pull 100amps, I want a Lipo that can supply at least 150amps continuous.
 

mrfurious40k

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I balance charge my packs every time. I'm never in a hurry to charge them so I'd rather keep them balanced. I prefer the alarms because I feel like it gives me more control and a live readout of each cell's voltage as I'm using it. They're $8 a pair so I didn't mind buying them.
 

yonzariq

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Agreed, everyone should do what they think is safest for them :)
I balance charge them every time, I feel it lengthens the lifespan of a lipo greatly, unbalanced lipo's lose performance really fast.

But some ESC's also do have crazy low cut-off values at 3.0volts and it is still hard for people new to the hobby to fully understand lipo's and how to charge, balance, use and store them properly.
I learned it the hard (read: expensive) way by burning over 300 bucks worth of electronics and the LHS could not help me enough...

Very scary to see that some people at meetings just toss their softcase lipos in their toolbox between the sharp screwdrivers, hobby knives etc. just waiting to go wrong one day...

3 things a lipo user should have with him, lipo storage bag/box, cell voltage meter to check the individual cells and an IR-thermometer :)
 
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