Granite Granite Voltage 12t 550, stock srs, li-ion 6 cell

[icebearace]

Just wanted to let people know that the granite voltage will not blow up with the traxxas titan 550 motor and 19 tooth pinion gear. I had fun testing it out, it launches hard with good top speed and even tears through high grass decently. The temps were really no more than before with the 15t arrma motor and 16t pinion I was running before. The runtime.... I would recommend an upgrade in batteries at this point. the arrma's are excellent for the price and I will never knock them.. they work great even above the intended limit (I would recommend using 6 arrma's with the redcat 16t 550 motor. They run okay with the 15t .. but at higher loads.. you will notice the drop in performance faster and the batteries drain fast. I got my other battery trays.. I can finish mods for my orbtronics and now my lgh2 high discharge batteries. (3350 mah (tested) for the orbs... I have yet to bench the lg's) the lg's I'm really excited about. The money for this truck has been worth it to me just to learn more about the different types of lithium cells and how they perform. (it's really just an extension of my recent rechargable household battery and 18650 phase... and I have enough chargers to do 24 li-ion cells at once now)

 

[ThatDrewGuy]

Have you tried using a Lipo 2S battery yet?

 

[icebearace]

I have not... I may eventually, but my focus right now is the 18650's. (mostly because I don't have any lipo packs.. and my one charger while it can safely charge a lipo, it will only accept 3s packs. (I'm not really even sure why it has that feature.. it's mostly a li-ion and household battery charger) I think it's on my xstar dragon. I have a case coming for a lipo jump pack kit (yes I know.. dangerous if you aren't careful) I planned on assembling one eventually.. the case comes from china so it's taking forever. Plus... I'm addicted to power and speed like most people.. and it will start with 2s, 3s, 4s, 6s, and keep going up when it does happen lol. (not all for use in the voltage of course) I will finish the li-ion experimenting first.. then we will see

 

[icebearace]

An update… I got my other tray adapted (notched a bit and with tabs for better connection) and the orbtronics work amazing. I was almost worried that something was wrong with the truck the way it lost power so quick last time.. but these cells proved nothing was wrong. Everything seemed to run cooler too... I can only think this is because higher voltage equals less amp draw. These cells don't seem to lose anything until you could have drained 2 arrma sets. I still think the arrmas are an excellent buy.. the orbs were about $82 or so for 6 of them. Not very practical for most people. The LG flat top cells are next.. and they are much cheaper... with even more output. Obviously adaption must be done for this to work. I'm really pleased with the performance of this truck now.. I wish the tires had a bit more grip off the line, but maybe that would break the drivetrain... it's handling is on the edge now as it's overpowered much easier. Still.. I have another motor i'm going to try.. a 13t 540 which will again be.. a bit harder on the electronics. Let's see what will happen!

 

[icebearace]

Another update... I tried the lg flat tops. (Lot's of heat and slow performance (just like my first run with the orbs before modifying the tray) My low voltage mode kicked in and shutdown happened when I still had 4 volts in the cells. It's funny.. the truck doesn't act like it's starving for a connection, it just feels sluggish and everything runs hot. I used a brand new tray that was a bit snug but as tight a fit as the orbs were before expanding the slots. I will make some adjustments. I also installed the 13 turn motor.. but I can't comment on performace until I compare apples to apples (the orbtronics are my performing cells so far.. they are almost done charging back up)

 

[icebearace]

Another update... I tried the lg flat tops. (Lot's of heat and slow performance (just like my first run with the orbs before modifying the tray) My low voltage mode kicked in and shutdown happened when I still had 4 volts in the cells. It's funny.. the truck doesn't act like it's starving for a connection, it just feels sluggish and everything runs hot. I used a brand new tray that was a bit snug but as tight a fit as the orbs were before expanding the slots. I will make some adjustments. I also installed the 13 turn motor.. but I can't comment on performace until I compare apples to apples (the orbtronics are my performing cells so far.. they are almost done charging back up)

Nothing wrong with the truck... other than I found the 540 13 turn was getting too hot (way too fast, and not promising in performance). I re-installed the traxxas titan 12t 550 which is at home with the 19t pinion. I think this will be it for performance for this truck. I'm happy with the way it performs for the money, and all that see it are impressed. I wish there was bigger brushless truck that could handle another cell (like a 3s lipo- but using li-ion for kicks) I really think the motor is the holdup now... and I'm not sure if I want to convert this truck to brushless, it was never made to handle that much power... but .. I might anyway To anyone interested in getting 18650's for this truck other than arrma… make sure your length is at least 65mm. The lg's are 65 and I would not want them any shorter.. the button tops on the arrmas reach a decent amount.. and my 2mm adapter is barely enough with some cradle mods. Also... 18.5 is definitely max diameter for this cradle.. even then you will have to likely elongate the openings so the cells can be free... and you don't want the heatshrink coming off (it will) because it's tight and rubbing.

 

[icebearace]

I will try not to turn this into a battery forum As of now I don't recommend the lg's… the specs were great.. but they don't deliver so far in the rc application. the orbitronic cells are supposed to be rebranded Panasonic cells. I can recommend them when high output and long run times are needed. the orbs hold high voltage for much longer. The capacity is in the upper end of the usable voltage. the lg's stated mah was to discharge down to 2.5.. (way below shutdown) li nickel chemistry is new to me.. so maybe they need cycled some more and I will set the cut off voltage higher in the charger to see if they can condition. There was no mystery with the orbs, they perform well and are imr hybrids. so far.. imr wins I guess just like most scenerios… you get what you pay for and testing conditions to get the high ratings can be fabricated to a certain point (voltage cut points for mah, high current draw but it drops voltage drastically etc) I dug out my spare voltage li-ion battery board ends... maybe tomorrow I'll doctor them up and try them for even less loss to the deans connector.

 

[icebearace]

I may have jumped the gun on the flat tops... There were a couple of things occurring. Since I have got this truck.. the back of the tray always got really hot.. I even reflowed at the deans connector.. still hot. I got my other set of boards modified this morning.. I flowed in the rivets that reduce the surface area of the trace (and the other side was smoothed over and a dap of liquid electrical tape in case something crazy happens. (like using magnets or such with too small cells) I added 3 to 4mm of solder to the positive connectors so they are raised from the recess of the button top mold. I added maybe 1 to 2mm of solder to the negative spring ends. WOW not only does the tray and batteries stay cool now, the lg's had a chance to really perform for good connection and much less loss of energy wasted to heat. The truck sounds like a car pinging off the redline and the performance is even peppier. It was a damp morning so it's pretty uncontrollable on the concrete at full throttle launches. I stopped as soon as I though there was any noticeable difference in performance. I ran about 10 minutes. The batteries resting voltage was avg 3.93 per cell (for the first 4.. i'm hoping the other 2 match so it was an even drain) I have more chargers but I'm using the skyrc mc3000 so I can slightly overcharge to 4.25 (with a cost to battery life of course) I'm waiting for the first 4 to finish so I can check the other 2 using the same charger. For comparison of the cells I may be trying the lipo high cutoff voltage on the srs. I seem to average only using a 1/3 of the cells capacity. Having the high cutoff would help me know if the orb cells really do last much longer at high voltage or if it's just in my head. I e-mailed horizon hobby about a custom 550 motor 10t for this truck. It costs almost as much as the truck.. but I really want to find the limit of what it can do.. and I think I have to push a bit further. Brushed options are limited that suit my needs.. I will push it further until something gives Sometimes I choose an odd way of achieving a goal just to be different

Next run.. lipo jumper installed, under load cutoff of 7.1 instead of 6.1v will happen. Let's see what happens

 

[icebearace]

Update on the lipo setting... around 7 min 30 seconds with the lg cells (I waited a little bit for a cars to go by so I could see what it would do on the road as well) Let's call it 7 minutes. The low voltage cutoff kicked in abruptly locking the rear wheels at a good clip (not a fan of this, but for testing purposes it's okay) resting battery voltage was just over 4 volts per cell.. about .10 higher per cell of when I usually stop running it by feel. I will go back to the old way of shutdown after testing the orbs runtime on lipo setting cutoff. heat - it's hot out and nothing got that warm. speed - it dried up some.. I have wheelies on demand in thick grass and on the road from a stop (I need to stop this eventually.. I have no wheelie bar and the back of the body takes a beating) standstill to top speed seems around 3 seconds if you can keep the front down. Top speed.. i'm not sure.. but it's now in the ballpark of my old nitro stampede. Except the stampede needed longer to wind up enough rpm to lift the front (shorter wheelbase too.. it was also 2wd). Of course once moving.. the stampede was still wheelie king (it seemed designed for it...) my favorite thing of this truck.. I can let of the throttle and hit the brake at high speed without tumbling wrecks like the old stampede did... it was a fun but clumsy truck! More updates to come

 

[icebearace]

Well went to run the truck with the orbs.. I should have known.. that sudden stop was not just an abrupt cut of power. For some reason the brake is locked on and the steering always centers as soon as I turn on the transmitter. Is this the end for the srs? maybe....

 

[icebearace]

My srs is okay. I did have a bit of a scare. I found an issue (by smell and heat of course ) and took out my battery terminal end (the one with the t-plug) to check it out. To anyone who wants to run flat-tops... when you mod your battery terminal ends... pry up the positive terminal end from the plastic board before applying heat. At first I was really happy with how smooth and uniform I was able to build up the ends.. the button cell top mold held the solder in a semi circle nicely. What I could not see.. was on one of the ends.. it melted just enough to make a pinhole to the bottom bar (the opposite polarity or a direct short) Fortunately.. nothing blew up and I caught it in time.. it almost looked like flux residue coming out by the bottom bar for no reason (on the back) I repaired it.. but i'm probably going to have to get new ends again.. my last run only drained 4 cells again.. though with the flat tops it performed well. the plastic tabs that hold the terminal ends break easy if you have to change them multiple times which does not help my connection issues. To complicate things even more.. i'm trying to run button cell tops and flat tops. My orbs got really hot.. being close to the short it melted into the solder some and I'm not sure If I will get a replacement button top cell because they are so expensive. Soooo on the way is another 30amp continuous/50 amp peak (claimed) flat top set that will replace them.. if one cooks.. just like the lg's they are not as expensive to replace a cell. The additional 550 custom motor may have to wait a bit.. I had to get some car parts and it looks like I have some issues to iron out with my current setup. I have hope still

 

[icebearace]

I did not run too much this week.. I never heard back about the 550 10 turn motor so, it's going to wait. I have 2 new sets of cells.. I just tried the first set of imren 30/50 amp cells (just a taaad over-rated but.. they are promising 20 amp continuous contenders) I also have some icr high voltage flat tops coming (again.. stick with your button top arrma cells for kids please!) I have found.. for some reason that the cells furthest from the motor (front) need more length. I use 2mm magnet tabs just on these cells. It fixes my intermittent (only 4 cell drain) connection there. The imren's felt a tiny bit sluggish.. but it is their first run.. and first recorded speed run! Here is what you can expect from a voltage with the 12t 550 (traxxas closed bell) and some high output cells :

on the road : 30mph.. gearing would help yes, but... i'm already at 19t pinion and I like the offroad speed and acceleration too

on the heavy gravel driveway : 26 mph.. Note that the truck spends a good amount of time in the air off the bumps and it's hard for it to hit top speed because of this, i'm happy with this result.

in the thick grass : 21 mph.. Still better than I thought.. with the phone on the back it was a bit off balance and front in the air happy. This is where the truck gets worked hardest the grass drags constant on the bottom and works the electrical hard.

I'm not sure on the time of the run.. it was long. I kept checking my phone to compare results.. what I typed here is the closest average of many runs. Speeds were consistent for an impressive amount of time.

So what next? The high voltage cells did not arrive in time to test this weekend. They are nothing new... very old tech and actually the most dangerous of all my cells. Used in many laptops they can be charged a bit higher. Instead of 8.4v it will be about 8.7v. The downside : they are not rated for the type of drain I'm asking from them.. this will get interesting.

I don't expect the speeds to change much with this setup. It felt a bit sluggish first time out with these cells.. the lg's I think will create a couple mph more. I'm also going to try the 13turn motor again.. hope I didn't hurt it ( I got it really hot when I tried it first) I obviously have to drop to the 16tooth pinion and work with it some more.

The red flashing light on the esc... it was my throttle setting. I did it again today, I bump the trim up too much from the last run and it's trying to apply throttle when turning on the srs. Easy fix.. turn the trim back a bit and fixed.

Expectations for the future.. I think 35mph street, 30 heavy gravel and 25 heavy grass are a comfortable limit for a brushed setup. I'm also going to go back to the lipo setting on the srs now that I've got my connections solid for the cells.

I've read about driveline problems some have had with this truck. I don't hold anything back from my takeoffs.. but I never go from moving reverse to forward. Only when I'm stuck I use reverse.. maybe this is helping me... For plastic parts, i'm happy nothing has broken yet

I'm evaluating the Imren cells now... for some reason 2 of them are about .05 higher than the rest. Normally this is a connection problem.. and they did not drain equally. However I charged them during the week and do not remember if I broke them all in the same way. My adjustable charger will only do 4 at a time... I usually pre-charge the other 2 in another charger and finish it in the mc3000. This might have made the difference.. and It might account for the slightly off feeling of the first run.

I'm thinking of getting a garmin virb ultra 30 action cam. It has gps like the go pro 5 and 6 and has some cool overlays for g-force and speed. I've seen the image stabilization and was impressed how it compensates for vibration.. might be fun to see the trucks point of view and see some stats on it's run at the same time

That's it for this weekend..

 

[icebearace]

Very small update tonight. I cycled and raised the voltage slightly on the imren cells. The pep in the truck was spot on.. and I damaged my phone a bit from slamming it into the ground with wheelies (maybe I need to mount it on the front That pep... did not change top speed much. about 1.5 mph.. so a bit into the low 30's now. The truck really sounds like it's just pinging on redline.. I think i'm out of gear.. but this is a good ratio of acceleration and top speed for this rather mild motor. I wanted to log the increase in the grass and gravel drive as these should have been more impressive. My phone was out of whack and I lost the gps signal.. I decided it was pretty important to fix it (I ripped the bezel out of my droid turbo 2) and halt the progress for now.. as I need my phone. The action cam is sounding like a better and better idea now.. pretty good reputation for durability and I can stop endangering my cell phone. I will still use my phone for now.. maybe just a bit more careful!

 

[zoldos]

What kind of top speed do you get with that setup?

 

[icebearace]

What kind of top speed do you get with that setup?

Hi zoldos, with the li-ions just over 30mph. I did get a chance to run a 2s lipo today. There is no doubt lipos can produce a lot of current and hold voltage. The result... it's much easier? You don't have to modify the battery tray for high amp li-ions and double check your connections. (no fun!) it's very punchy and I flipped over backwards a few times. However, even though I didn't record the top speed.. I still believe the motor is at it's rpm limit on the road. So.. I'm going to say low 30's unverified. I had to stop the run, I was going through grass at high speed and I could tell the motor was not pulling as hard. It was starting to get too hot, I called it quits before I could record anything. I'm not sure how much I drained from the battery.. I'll find out soon, I actually just had this battery apart (don't recommend it.. and I keep this lipo in a fire bag rated for them outside the house) I wanted to check it because it was the victim of a brief short. This is something that is less scary with imr lithium ions (expecially protected ones) I had all my adapters for different packs.. this one was hexfly lipo and my others are deans. Redcat in all their wisdom says make sure to plug banana into right size end on other connector. What should raise alarm flags is.. since the moto uses 2 2s in series.. you have 4 connectors. and since I have adapters and I'm always changing ends.. I just had on my mind "simple.. plug male into female and done" usually sure, this works. but... in the flurry of trying to keep my wires neat I plugged one connector into the other and it was one battery right into the other battery. I got lucky.. a poof of smoke and a cell died on one battery.. I got the connectors apart after some hard pulls (welded) was left with .. 2 potential time bombs. The pack I just used I had apart and I think it is okay. It's a pain in the ass to separate hard packs safely and I'm not looking forward to the other one.. but I want to see what failed. My guess is the solder melted off a connection and saved me from a bad day. Both cells still looked okay, no swelling that I can tell (i'll let you know on the next pack) just a sharp spark, a tiny white poof of smoke and dead. I can live with this.. my esc and motor are okay. By the way.. while the moto has tremendous power.. the voltage is light and easy to control.. I ran it and found it was still a fun little truck... and it doesn't throw rocks like a lawnmower blade hit them which is a nice plus