LVC kicks in often!

[hispeed10k]

Don't know if this is a battery issue but here goes....

35" DF Pirate mono with 2200kv Nue motor, Seaking 180 esc running 4s single pack at first then 2 2s packs in series. Prop is a 1814/3 or a x447. So the boat runs really great for like 2 laps and then the LVC kicks in. So i lowered the cut off in the esc from 3.4 to 3.2. It ran for about 3 laps then same thing....voltage cut off kicks in. So again i moved the cut off in the esc down to 2.8v(which i don't like) and the boat ran better and maybe 4 laps but the LVC kicked in again. So i got a parallel cable done and ran 2 4s packs in parallel. This time it ran to maybe 4-5 laps and then boom LVC kicked in!!! Oh the packs are 5000mah on the 4s and 6000mah on the 2s. Now the reason this is frustrating is i know i can't complete a 6 lap race(7 if you include the start mill) with it doing this. And i really don't want to turn the cut off in the esc to off.

My twin cat runs 2 2075kv SSS motors with the same 180a seaking esc's and i can run it on 4s or 6s all day pulling a 1716/2-45-19 or 1816/2-45-17 props all day and that doesn't happen. I don't fully understand the whole amp/current draw, but the temps on the mono are between 115 on the batteries and motor to 128/130 on the esc. While on my cat it never get hot hardly.

Help!!!

[NativePaul]

My guess was that it was a Seaking 180 before I clicked, the V3 are well documented here for having LVC issues, but the battery temp and the fact that you get more laps with different packs and even more with paralleled packs sounds like it may be hitting LVC for real and your packs aren't up to it, what packs are you using?

If you drop down a prop size does it still do it?

If you preheat your packs to 40c (100f) does it still do it?

[hispeed10k]

My guess was that it was a Seaking 180 before I clicked, the V3 are well documented here for having LVC issues, but the battery temp and the fact that you get more laps with different packs and even more with paralleled packs sounds like it may be hitting LVC for real and your packs aren't up to it, what packs are you using?

If you drop down a prop size does it still do it?

If you preheat your packs to 40c (100f) does it still do it?

The packs are from Promarine Rc so i don't know who did them. They are 5000mah 70-120c. I didn't drop the prop size yesterday when i ran it, but it will check it again this weekend. I tend to run a warm up lap before i hammer it.

[Fluid]

....I tend to run a warm up lap before i hammer it.

The OP is doing himself no favors with a ?warm up lap?, all that does is result in a higher motor and ESC temperatures by the end of his run, along with burning battery capacity. Warming just the packs to 100*-120*F prior to running will give a bit more more power but they risk being too hot by the end of the run, especially with high amp setups or long runtimes.

The OP doesn?t mention which Neu motor he is running, but his reasonably large, heavy, draggy mono running a 2200Kv motor on 4S may be over-taxed with an 1814/3 prop. A smaller prop may help him, as would a lower Kv motor. He also fails to tell us how much charge he puts back into his packs after the runs where the KVC kicks in, nor the resting voltage after a run. That ESC is known to have issues, but as Paul mentioned his amp draw may be too high with just 5000 mAh cells.

His twin cat runs cooler because he is using....two motors to share the load. No mystery there.



.

[hispeed10k]

The OP is doing himself no favors with a ?warm up lap?, all that does is result in a higher motor and ESC temperatures by the end of his run, along with burning battery capacity. Warming just the packs to 100*-120*F prior to running will give a bit more more power but they risk being too hot by the end of the run, especially with high amp setups or long runtimes.

The OP doesn?t mention which Neu motor he is running, but his reasonably large, heavy, draggy mono running a 2200Kv motor on 4S may be over-taxed with an 1814/3 prop. A smaller prop may help him, as would a lower Kv motor. He also fails to tell us how much charge he puts back into his packs after the runs where the KVC kicks in, nor the resting voltage after a run. That ESC is known to have issues, but as Paul mentioned his amp draw may be too high with just 5000 mAh cells.

His twin cat runs cooler because he is using....two motors to share the load. No mystery there.



.

The Neu is the 1515 - 1Y. The batteries were at 15.75v and 3.8v per cell after the run. The 2s series packs were at 15.87v and 3.9 per cell...don’t know if this is what you mean by resting voltage. I charged them back to 97/98% or 4.2v per cell. Now the 4s packs are 2 years old and the 2s packs are brand new. Hope that helps. Will try a smaller prop and see. Thanks!

[nhk750]

Also, dont forget about voltage sag, if the batteries are at 3.8volts after running and sitting, then they are probably dropping a lot under a full throttle load which will trigger lvc. They do make some voltage monitors that will keep track of your voltage high and low while running, I have one velcroed to my battery but it doesnt log it just beeps loudly when I go below a voltage setting which I have set to 3.6 volts per cell. Of course you cant hear it unless you're close to shore which I do after my set time just to make sure I'm not taking my batts to low. I use the voltage monitor to get my radio timer set to the optimum time (I get around 6 minutes of full throttle run with my Pursuit on 4s, 5000, 50c stock setup).

[nhk750]

Sorry, here is what I am talking about, this unit logs battery data and can fit in your boat and it only weighs 18 grams. It's kind of pricey, but takes the guessing game out of what your batteries are going through... Celllog 8S

[dannygonzalez0861]

Hi Guys,

I am new here but maybe my setup can help. I use Flysky RX and TX and stated off in Quads so I have an i6X (Air) and a GT5(Land) radio. I use the i6X for my blackjack 24 as it has telemetry built into the remote, I added the voltage module (CVT01) to my RX (FS-iA6B) and you can literally see the battery voltage sag under load. When I see the voltage while running drop to about 9.8V I know its time to come back. When I let off the gas, you can see the voltage go right back up but I am usually at shore or slowing making my way back by then.

[nhk750]

Yes, telemetry is definitely the way to go and I use it in my airplanes all the time, but I'm using the Spektrum boat receivers in my boats which are waterproof and they don't have telemetry...darn...But I do believe the Newer Spektrum surface receivers have telemetry and from what I hear they can work in boats too and cars.

[Nick1979]

I have the same LVC problem in my Pirate 35. 2-3 laps and it's done. My set up is 2x3S 5000Mah 50C in series, Leopard 1450KV and Seaking 180 ESC.
I think the batteries must have a voltage sag. I have another pair of 3S with 70C, but I haven't had a chance to try them yet as everything is frozen now.
Someone else had suggested to experiment with the timing on the motor - mine is set at 0. I will try 7.5 as someone suggested this might help in avoiding an early LVC issue. It's worth trying different timing settings, as well as batteries with a very high C rating.