Run time of about 12mins when LVC hits?

[Edough13]

Just wondering if anyone else has similar run times or if I'm hitting LVC a bit soon? I'm running 2 Hoovo 5200mah 80c 3s packs in my K6s and I'm hitting LVC about 10-12mins in. Seems like I should get a bit closer to 15+ as I'm not even running full throttle except in the air for rotation during flips. Also unplugged fans and that hasn't made any difference either. Shorter run ups to my ramp, nothing long distance or running WOT for long pulls. Lipo's show 3.7-3.8v when LVC hits so don't think lag is the issue either? Just wondering if this is about normal run time, also have some 5200mah Goldbat 50c's I'll run as well and it's about the same. Thanks for any input I appreciate it!
Just filmed a run on the Hoovo's and start to finish was just over 14 mins total video. Going to run the Goldbat's and try to do as similar of a run as possible and see if I get the same run time.

 

[Exc3l]

It could be battery sag.

 

[SrC]

Hi @Edough13, I know you are experienced well enough. You pretty much covered most of the possiblities.
LVC appears to cut too soon IMHO. Are you using a cell checker just when it happens. You may have one cell that dumps fast. A poor lipo pack. Trips LVC. A cell checker right when it happens may show the bad cell. Also. When it happens, shut off the ESC and turn on again. See if she runs again. We are assuming Thermal cut is not any issue here. Correct?

Edit: Like @Exc3l stated could be just sag. It only takes one cell to sag and LVC trips. I had packs do that. also. Cell check immediately fater LVC, so you can see that one low cell before it recovers. That is a sign of a bad pack. Whether old or new it can happen. Is your gearing close to stock?
10-12 minutes is No good. Especially with the capacity of the packs you are using. Try different packs to confirm if you have.
Check the IR's of that pack. The bad cell is usually revealed in this way. And the bad cell usually takes the longest of group to balance. But not always. But a sign.

 

[Stokez]

Hi @Edough13, I know you are experienced well enough. You pretty much covered most of the possiblities.
LVC appears to cut too soon IMHO. Are you using a cell checker just when it happens. You may have one cell that dumps fast. A poor lipo pack. Trips LVC. A cell checker right when it happens may show the bad cell. Also. When it happens, shut off the ESC and turn on again. See if she runs again. We are assuming Thermal cut is not any issue here. Correct?

Edit: Like @Exc3l stated could be just sag. It only takes one cell to sag and LVC trips. I had packs do that. also. Cell check immediately fater LVC, so you can see that one low cell before it recovers. That is a sign of a bad pack. Whether old or new it can happen. Is your gearing close to stock?

Pretty much all of this.

 

[ARRMA King]

See how much mah the charger says it’s putting back in from say the 30-50% storage mark to 100% full.

Chances are I bet these lower priced relabeled brands are no where near their stated labels capacity, I’ve seen more like 50-66% mah charged back in, in real life charging values in my experience.

eg a ‘labeled’ 5200 from 0% 3.7 only took in ~3200 to hit 4.2v.

 

[Cheez]

Hmmm...this is the same but different ? I’ve been using this in my Mojave EXB about 6-7 times now and get around 25 minutes.

 

[Edough13]

@SrC thanks! Ya I don't have cell checker but I'll pull battery immediately and put on charger and will read 3.7-3.8 all cells really evenly balanced on both packs. I am running 15t pinion(sorry forgot to mention that) which I'm sure is attributing to some of it. And yes I can shut it off and back on and will run maybe 30sec to min more. Just wondering more so if this is about normal run times for these batteries or if I'm pulling to much out of them causing it to shorten run time also. Heat isn't an issue except motor sometimes but like I said I try not to go crazy on throttle except in air usually.

 

[skidmarkus]

What esc are you running bud? Maybe the LVC is just set too high. Some guys like running them at the highest setting to be sure to not deplete their batteries, but I like running my LVC way down, if the esc allows for adjustment.

 

[SrC]

I am getting 15-20 on my6S kraton and Noto. w/15T pin.
Like @skidmarkus asked, running what ESC? LVC is adjustable for most upgrade ESC's.
LVC @3.7-.3.8 is kind of high for a cutoff if the lipos are in fact not the issue with one dropping/sagging cell.

Edit: The fact you are describing immediate FULL LVC might be indicating a bad cell. Limp LVC ( driveable slowly) usually occurs before Full LVC does, with a known Good lipo pack. From my experience. ?‍

EDIT:
Fully charging and discharging that lipo on the bench with a decent discharge rate while monitoring all cell voltages, would identify the issue/bad cell if any.

 

[Edough13]

Just the stock BLX185 is what I'm running. I'll cycle the packs and see if something comes up, thanks for all the input everyone!!

 

[SrC]

>>>>One of my Balancing Dischargers flags a bad or sagging cell while it discharges.

 

[3d-rc.myshopify.com]

What color light blinks on the esc when this happens?

 

[SrC]

I am assuming the drivetrain is free with no undue binding. 15T pinion doesn't truly kill my run times at all. ?‍
I believe, Light should blink Red if its full LVC, Green for Thermal cut in the BLX 185's.
@Lovestricken, you agree??

 

[Edough13]

Ok so running second set of packs figured out the issue... Definitely hitting thermal as it is not going to limp mode for normal LVC but slowing to a stop. Also after looking closer ESC fan is done blades are toast. Hit thermal on second set of packs after about 10mins and again packs read just under 3.8, let it sit and cool ran another 6mins and then went to actual LVC in limp mode batteries read 3.6. Thanks for all the help guys I guess I need to pay more attention to what the ESC is telling me ?

 

[SrC]

Great glad its sorted out.
It's nothing a 35mm HobbyPark/Yeah Racing Turbo fan cant resolve. Skip using another stock fan replacement. The stockers can be hardly heard when they do work. Thats why you couldn't tell it was thermal and broken fan wasnt obvious initially. You will know when a highspeed fan is broken. Just by hearing the silence..
Been there just like you... Enjoy.
Remember Green light means Thermal cut. And while sitting there cooling off, it resets when the temp drops to a safe driving level if just left alone.

 

[3d-rc.myshopify.com]

Yeah was kinda figuring thermal when he said 15t lol. I used to have to change that dam fan every time I took it out. I am also known as fan killer lol. That heatsink on the 185 is way to small. I would thermal it with a working fan. Get yourself a bigger heatsink and real thermal paste if you plan on keeping that setup.

 

[SrC]

Can you really get any bigger HS on that 185. I disected one of my bricked 185's and i see that the stock HS barely touches the Mosfets. They use gobs of thermal paste to fill the air gap. Bad QC imho. Thats why many of the 185's crap out no matter if you put a monster fan on top or not.

 

[3d-rc.myshopify.com]

Can you really get any bigger HS on that 185. I disected one of my bricked 185's and i see that the stock HS barely touches the Mosfets. They use gobs of thermal paste to fill the air gap. Bad QC imho. Thats why many of the 185's crap out no matter if you put a monster fan on top or not.

Yes you can. Amazon or Ebay has them cheap. You may have to cut/grind to fit. But I changed mine on all the esc except my mmx8. It doesn't have heat issues like the rest. I use mx4 thermal paste or a thermal pad.

 

[SrC]

Yeah I use $Arctic Silver$ paste (best thermal transfer) I also have thermal glue and silicone pads. Thanks.

 

[slick2500]

See how much mah the charger says it’s putting back in from say the 30-50% storage mark to 100% full.

Chances are I bet these lower priced relabeled brands are no where near their stated labels capacity, I’ve seen more like 50-66% mah charged back in, in real life charging values in my experience.

eg a ‘labeled’ 5200 from 0% 3.7 only took in ~3200 to hit 4.2v.

I've had some cheap Floureon packs labeled as 6200mah most they would ever take it was around 4300mah then another set of Zop Power packs that were labeled as 5000mah one would take in ~5800mah and the other was ~5900mah I seriously think they just guess when making most of those cheap lipos.

Yeah I use $Arctic Silver$ paste (best thermal transfer) I also have thermal glue and silicone pads. Thanks.

AS5 is the best, I do miss OCZ Freeze though, it was usually within a few degrees of the AS5 but didn't require the break in period. I bought a bunch of tubes of Arctic Silver Ceramique when Jab-Tech went out of business, at 90 cents a pop I had to buy 4. I still have 3 laying around pretty sure it's probably gone bad by now though.