Originally Posted by Tekin Prez (Post 13418141)

We are listening, as always… This is the first we have heard of a gen1 to gen2 difference and there is no good engineering reason that I can immediately think of to explain it. There may be something hiding here that we do not understand yet and we are happy to try and figure it out.

Thus far all we know is that a group of SC4x4 oval drivers that push everything to the limit and drive full wood the entire race have puffed a few batteries, and they happen to be using Rx8gen2 units, and 1 of them actually did fail.

SC4x4 is the heaviest load in RC period! They are almost 1/8 scale weight cars on half the battery. Even offroad racers puff batteries now and then in these cars because they use almost all of the battery capacity each run and pull high currents. Now race them on an oval hammer down and you have the worst of the worst loads for a battery in RC.

Considering some of the drivers in your group are running 4000kv motors on 3s, and others are trying to keep up with 2s systems it is at least a possibility that you are just pushing too hard with setups and this is not a RX8gen2 design problem.

All of the other systems that ‘have’ puffed batteries appear to work normal and are not damaged indicating again that there is at least a decent possibility that the problem is not in the Rx8gen2.

Technically any battery rated 50C or higher should handle these loads without any issues. The reality of C rating accuracy on batteries is perhaps another conversation…

As we discussed on the phone we need more information. I thought we were going to work together to gather some real engineering facts and solve this isolated problem. Have to say I am disappointed to see this post immediately after our conversation considering the time I took to discuss it with you and the plan we had to actually measure some things to figure it out. Happy to do this publicly so everyone can learn from it, or you can answer my questions privately by email so we can make some sense of this.

To start with we need some settings in the unit, specifically the timing and gearing. Also need to know how much the batteries are taking when you recharge them. Motor temps and esc temp would be good. An actual data log of a good run and then a log of a run that puffs a battery would be awesome. Again when we are pushing the batteries to the limit already in a SC4x4 it does not take much to push them over the edge. In extreme applications user setup is critical…

Originally Posted by Randy_Pike (Post 13415606)

This is the Ve8 buggy right? I ran that car and know what gearing should be in it, trust me. You're going too far with your gearing "changes" in general.

The Ve8 is a car with a 50T Spur and 4.3 diff ratio. So with my suggested gearing of a 23T pinion, 50T spur and 4.3 diff ratio your'e at 9.3 FDR. A TLR in comparison with a 45T Spur, 16T pinion and 3.3 ratio is 9.2 FDR. Nearly identical.

If your deans melted it was a loose or bad connection and may be the shut down source in the first place. Deans are good connectors but if they get loose or the plates get burnt...they're done and should be replaced. What sucks is they're hard to see inside, especially the battery/female side.

Originally Posted by platgof (Post 13418155)

Thanks, I feel much better. I will be racing on an indoor track that is not wide open at all. I think the prez hit it on the nail, go to 3s to cool things off. You need a lot of fresh air moving, and fans on those. I have a friend who did burn one up and he also feels the Gen1 was better. He is running a Tekno, and those things are heavy and put quite a strain on the power system. I wonder if the high c rating is actually hurting it.

Originally Posted by markmartinbirdi (Post 13418364)

Question, would running 3 cell with much less gearing be easier on the ESC overall ? And maybe running a lower Kv motor on 3 cell ? Thanks Take no offence at my posts, just being honest that the Gen2 doesnt offer us the same as the Gen1 on the exact same setting

Originally Posted by beidle99 (Post 13419063)

lower Kv on 3S is the better set up. Every time I see a 4x4SC blow something up its related to drawing to many amps. higher voltage means less amps. In fact, IMHO, 4x4 SC should be something in the 3000 to 3200kv range on 3S bettery, not 4000Kv to 4800kv on 2S. I hate the class so I don't have to worry about it. :D

Originally Posted by Randy_Pike (Post 13419544)

@IMRob "185 for motor temp and 153 for the esc with out the fan on" is an acceptable motor temp on the Rx8 Gen2 and T8.

9 times out of 10 when I hear of someone having issues it's related to setup, gearing, etc. 4wd SC is the highest amp draw class we have in rc racing right now. As previously stated they're the heaviest cars, with the fastest lowest turn motors, and least amount of battery voltage at 2s.

4wd SC oval guys:

The 4wd Sc chassis was never designed for oval racing. So you're taking a car and using it in a manner it wasn't intended. Then you're using a 4000kv motor which is meant for 2s not 3s. While this "may" work at times you're dancing with an edge and you guys have found it.

I'd like to see some video of those trucks hustling around the track. Anyone have it?