Kraton Kraton 4S V2.5 newbie

[Jo381]

Hi,

finally I got my new Kraton 2.5
Total new to that, I was unsure whether I should top up the diff fluid or not. Didn't want to destroy anything. Managed to disassemble the center diff and this is how it looked like:

So I filled it up with 500k but I didn't open the front and rear diffs. Didn't really find a manual how to do it
I then tested two brand new packs on a quite muddy lawn (at about 8°C): A Hoovo 6500 80C and a CNHL 5600 120C.
Starting slowly at 50%, then 75% then 100%. To my surprise the Hoovo didn't really manage the 100% and the car was all over sudden really slow. After a while, it stopped as if the battery was empty. The CNHL was much better but also didn't last that long. Back at home the charger (K4) said the Hoovo was still at 80% and the CNHL at 50%.
The packs were stored at storage voltage and have never been used before. Do these LiPos need some full cylces to unfold their full power or are these specific (quite cheap) ones not really made for such car?
Other than that, the car is so much fun and I can't wait to go to the dirt park

 

[Barmaleus]

Hey!

Also new here! And have K4S v2.5.
So, I've disassembled all diffs before running the car. Center diff was also very low on fluid. Topped it up.
https://www.arrmaforum.com/threads/kraton-4s-v2-5-center-diff-some-questions.68610/

Topped up front/rear diffs as well. Can't give you exact disassembly instructions, sorry. But if you look carefully what's holding what + search for some YT videos, you'll find a relatively easy way to open them up.
I also had kinda different problem after disassembling the front diff:
https://www.arrmaforum.com/threads/...g-after-adding-more-oil-and-reassembly.68533/

In terms of batteries.
Stock LVC (low voltage cutoff) is 8.5v, which is rather high, as a number of people say. You might want to lower it to 8.4v (this is one step lower in ESC settings). Check the ESC manual to check how to do it. Not hard. If battery sags hard (for whatever reason), LVC will turn on earlier, even though you still have quite some juice in.
Some people set it even lower.

 

[Jo381]

Thanks a lot! I will check the front and rear diffs as well.
Meanwhile I found a video which describes the issue I'm probably facing. I ordered an ESC programming card and will try to adjust the LVC.

 

[Saladshooter]

Thanks a lot! I will check the front and rear diffs as well.
Meanwhile I found a video which describes the issue I'm probably facing. I ordered an ESC programming card and will try to adjust the LVC

The programming card will make it convenient but if you don't want to wait you can use the ole beep method.... There should have been an addendum tucked into your manual on how to do it.

Welcome to AF !!

 

[danny1202]

you might have over heated it and it’s cut out. Mine did this on the first outing but never had a problem since.

I’ve heard people say the low cut off voltage is too high but I’ve never seen that as a problem with either of mine, I get plenty of run time and the batteries go as low as 9%

Get back out and have another bash ASAP

 

[EOTR]

Welcome to the club. Your concerns are valid and seem to be an ongoing theme within the Arrma community. My advice (take it if you so desire) is to top up your differentials, all three of them, get the Spektrum V2 programming card, follow the You Tube videos on how to upgrade the card itself with the latest firmware, then upgrade the firmware in your ESC. ChriswithaC RC has some very informative videos on the subject. Or, check out the Spektrum tutorials on YouTube. This will allow you to have everything prepared prior to having to 'put out fires' along the way. Good luck. Let us know how it goes...

 

[Jo381]

Thanks a lot! The card will arrive today. It's exactly the channel I found (ChriswithaC) so I will give it a try. Besides that, the one faulty pack will be exchanged as it seems not to be working well at high currents. While this one gave up at 60%, an identical one was down to 11% when the car stopped.
Other than that, I'm totally excited - the car has so much power. Really, I was not expecting that

 

[Jo381]

Quick update: Card arrived. Downloaded the software, updated the card itself, updated the ESC firmware from B5.07 to B5.09.
What I modified is the LVC from 3.5V to 3.4V/cell and the timing from 22.5° to 15°. I understood that with lower timing the risk of overheating will be reduced. As I do not (yet) operate at the limits of the system, I guess this will be ok for the time being
Can't wait to get out and give it a try

 

[EOTR]

I also reset my timing to 15 instead of the default 22.5. Plus I lowered my LVC as well. A great deal of the members here have made these exact suggestions, so I followed suit. Now my Kraton 4s is 'ready to rock' as they say. I truly can't say if all the upgrading has resolved anything because we are still knee deep in winter here. I've had it for five weeks already and I haven't had it out yet. Waiting, waiting...

 

[Jo381]

Right, the support is really great, thanks guys! Without all this information I would have been totally lost.
Temperatures here are rising now above 10°C which is great. I was also afraid to break things at low temperatures. Now I still need to find some good spots with ramps though.