Kraton Temp Control vs. LVC

[UK_Russ]

Hello again,

As usual, sorry if this is a completely noob question. But, how do I tell the difference between Temp Control and Low Voltage Control?

I’ve been giving my new K4S a few blasts in the communal area of my flats, it’s not ideal, ie; bumpy and the grass is a bit long, but it’s the only area I have at the min (damn quarantine). Understandably, I think the car is hitting temp control mode because after about 15mins or so of giving it hell and everything is pretty hot and it goes into a sort of slow limp mode.

It generally hoes a lot slower, everything is hit and the led on the ESC is blinking red. Usually when this happens I go back in and then forget about it, storage mode the battery and go out again another day.

So my question is, what does it do in LVC mode? As I’ve never actually seen it, at least I don’t think I have, does it do the same when the battery is low? Perhaps the best way to find out is to just let it cool down and use it again to find out?

 

[nino]

Duh. What voltage are the packs when it stops?

 

[UK_Russ]

Think last time they were at about 3.5-3.7 from what I remember.

 

[jkflow]

LVC will go into 'limp' mode before it completely shuts off. How long between is a matter of how good your pack is, can be anywhere from maybe a minute to a couple seconds, people have seen it happen mid-air.
Overtemp, the ESC will shut off completely and you either have to wait until it cools or a power cycle will do a reset, assuming that it cooled off enough. There is no limping, red LED is probably blinking but I never look at that.

Running in grass is power hungry, sounds like LVC if you see 3.5V per cell. If it's higher grass and it's warm outside you will most likely run into overheat first but that really depends on pinion size and drive style.

Please set your location, hard to guess at ambient conditions

 

[UK_Russ]

I’m in the UK, ambient temperature when using I’m guessing has been around 15-20 degrees Celsius. I’m presuming it must be hitting LVC then as it’s never stopped completely. Just goes a lot slower. I’m using a Voltz 5000mah 50c 4S battery and expected the grass to take a bit more juice out of the battery. And like I’ve said, I haven’t exactly been going easy on it, full throttle smashing up and down the yard non stop.

 

[jkflow]

I hit thermal on 6S in grass with ambient 40C on 15T pinion.
That is not your issue .
Time yourself and don't hit LVC, the Lipo's will thank you with longer life.

I've watched 3 or 4 videos from 'pro's lately and they all hit LVC mid-air and crashed horribly as a result. Lipo alarm would be a lot cheaper.
L:VC is set to low on all stock ESC and are only to prevent major damage to the Lipo, not the incremental minor damage.
Good stopping point would be ~ 3.6V under load, should recover to ~ 3.65V in rest. In those cases you would still have 1 min safety margin before hitting LVC. Just a rough stimate as it depends on Lipo capacity etc.

 

[UK_Russ]

Ok thanks for the info, I think for now I will just take it a bit easier on the car and try to stop before it hits LVC.

And I shall look into the lipo alarms for the future. I’m hoping it won’t be as bad once all this is over and I can get on some skate parks and soem decent terrain.

 

[jkflow]

I have a feeling that this will be the new normal until later in the year. I hope I'm wrong.?

 

[ph47mf]

Yeah when my battery gets low it goes into limp mode then a few minutes later it will stop dead and I believe that's when the LVC comes into play. A member on here said we should just call it a day or change battery when it's in limp mode, don't try to carry on.

 

[Jasonkw]

Is there any difference in the lights on the ESC when it goes to temp shutdown vs LVC? I think LVC is slow flash red, but is it different for temp cutoff?

 

[jondilly1974]

Limp mode is LVC. Your packs are done at 3.5v per cell. Grab another pack and let r rip tater chip

 

[UK_Russ]

Thanks for the help guys.

It’s definitely hitting LVC and not overheating, took it out again last night and got about 15-18mins of mixed running ( ie; bit of general driving getting used to handling and quite a bit of full throttle and hard braking) and again this was in fairly thick grass, so I don’t think that’s too bad. Should get more time out if it once we’re all allowed back out into the big wide world and I can choose where to run.

Only thing I will be doing is what @jkflow suggested and getting a LVC Alarm / Monitor. Because last night when I checked the cells, they were all at around 3.37v. So for longevity of the battery, I’ll definitely be making sure I’m stopping around 3.5v in the future.

Has any one had experience with these basic style LVC Alarms?

https://www.modelsport.co.uk/index....MI3LXh2P7f6AIVh-3tCh2yFw3YEAQYASABEgLvePD_BwE

 

[jkflow]

Yes, those will work but are a little annoying. If you set it to ~3.5V it should be ok and give you about the same run time, slightly less of course.
You want to be in the ~3.5-3.6V range when no load applied.
When punching, theLipo voltage will sag a little which triggers these alarms. If possible, get your hands on one of these (below), they address that problem. I've used both types and the standard ones take a little more experimenting to set the right volatge but at the end you just deal with 1-2 min difference. Secure them with some velcro or a rubber band around the connector.

https://www.smc-racing.net/index.php?route=product/product&product_id=559

Enjoy!