Hi all. I’ve posted a few times as I was trying to work my way through a ‘cheap’ build but the more I read, it has become apparent the less I knew.
I had been building a 46" pintail cruiser. I had purchased almost all of my parts second hand (though new) but blew it thinking I could use some old 18650 batteries. Most were Samsung or LG but they suck. I tried using soldered battery sleds but during my first ‘real’ ride I had multiple failures. Kinda discouraging.
My goals are still 10-12 miles on a single charge with a weighted speed up to 25 mph. Can you all review this list and tell me if it looks ok? I’m struggling with the batteries most. Thanks…
Everything seems fine. You should hit almost 30mph (I’m assuming you meant 14/36 ratio, not 14/35) if not more. I’d consider dropping to 6s if you don’t want to go that fast.
I’d recommend getting a nice 18650 or 26650 pack instead, but lipos work as a cheaper alternative. You should get about 14 miles on flats on your battery.
Charger can only do 6s max reading from the specs. This would work if you put the 4s in parallel to charge. If you want to keep them in series while charging (==8s) you need to find a different charger.
Dropping to 6s (2x3s, 1x6s) like @jinra suggest would obviously work as well
since you mentioned you want to go at least 25 mph weighted this would not suffice.
8s would get you in the proximity of 25. Whilst 10s would definitely get you there. Problem with 10s is that you would have an eRPM of +/- 67000+ which as I remember is too much for the vesc to still be reliable
There are a few reasons for my going with the lipos…Mostly though, I don’t trust my own handywork. I’m sure I’ll have some bad soldering nail me about 5 miles into a ride! And then I’ll incur further costs to fix or have someone else do it.
Ok, this is what I needed to know! I was thinking I could just unhook the series and charge them separately, but that would be a pain. Any suggestions on a charger?
I like the 8s setup. What happens if I drop to constant discharge of 10C per pack like in this one?
Multistar High Capacity 4S 10000mAh Multi-Rotor Lipo Pack
http://www.hobbyking.com/hobbyking/store/_64438__Multistar_High_Capacity_4S_10000mAh_Multi_Rotor_Lipo_Pack_US_Warehouse.html
I know I’ll go about 25% further but what about speed? How much would it be affected?
Wow! I had a hard time even finding an 8S lipo charger. When I did, they are like 4 times the cost. Perhaps I should just put up with disconnecting the series to charge? What do others do?
A lot of people just put up with the disconnecting hassle for charging I believe. Other choices could be a more expensive charger of buying a BMS that you attach to the board/batteries to pair up with a simpler charger. BMS’s however do not seem to be that cheap either.
Perhaps you should start with the hassle of disconnecting first. Maybe it’s not that big of a hassle and you’ll be fine with it, and at least you get to ride! After that you can always opt for going a step further…
I usually run 8s (a good moderate setup w/o as much likelihood of DRV issues) - plenty of power for me even on a single motor setup (geared correctly). I also disconnect to charge - not a big deal and i find it plenty easy.
As for chargers - inexpensive ones i recommend is the iMax B6ACv2. If you can swing a nicer one - go for it. I especially like the advanced features of the iMax - similar to nicer ones like iCharger (great!) - like Internal Resistance testing.
I’d avoid any charger that charges via the balance plugs. They are usually much slower and moving 5-6 amps across those small wires seems like a bad idea… but others may do this and have no issues.
How did you attach/protect your gear? I didn’t find anything that would work with the deck’s curvature. I also wanted flex. I ended up using spray insulation sculpted down with silicone covering it. It’s ugly but it works.
a flexy deck is definitely a challenge. The best solution i’ve seen is top mount power so the middle is clean (okp, whitepony, and squad’s are all amazing). Separate your batteries and ESC front and back so the middle can flex. Less area for batteries - but let’s everything work w/o flexing the enclosure and killing a flexy deck.
enclosures - they’ve done custom CF, and abs(Vacuum formed) to fit the vanguard.
I can’t believe that my Zippy’s and charger have already arrived!!! Now I need VESC experts review my settings. I would rather be a little conservative then burn something up. I can’t pull screenshots (At work and didn’t expect overnight delivery) but have written down what is currently configure. The hardware is the same as listed at the top of this thread. Is this good?
Motor ConfigurationMotor TabCurrent Limits
Motor max: 70.00 A
Motor min: -30.00 A
Batt max: (not sure. 100 A? My 30c at 8000mAh says 240 A but Vedder says absolute max no higher than 150 A. So…?)
Batt min (regen): -15.00 A
Absolute max: 150.00 A ??
Slow absolute max: CHECKED
Temperature Limits
MOSFET Start: 80.00 C
Mosfet End: 100.00 C
Motor Start: 80.00 C
Motor End: 100.00 C
Other Limits
Minimum duty cycle: 0.005
Maximum duty cycle: 0.950
RMP Limits (BLDC Only)
Limit ERPM with negative torque: CHECKED
Min ERPM: -100000.00
Max ERPM: 100000.00
Max ERPMN at full brake: 300.00
Max ERPM at full brake in current control mode: 1500.00
Voltage Limits
Minimum input voltage: 8.00 V
Maximum input voltage: 57.00 V
Battery cutoff start: 26.00 V
Battery cutoff end: 24.00 V
BLDC Tab
Sensorless: SELECTED
Sensorless
Min ERPM: 600.00
BR ERPM: 80000.00
Phase advance at BR ERPM: 1.00
Max brake current at dir change: 10.00
Sensorless - Communication Mode
Comm Mode: Integrate
Integrator Limit: 72.00
Int Limit Min ERPM: 1100.00
BEMF Coupling: 920.00
Hall Sensors (failed during ALL attempted detections)
Table: -1/1/3/2/5/6/4/-1
Sensorless ERPM (hybrid mode): 2000.00
Detect Parameters
Current: 6.00 A
Min ERPM: 600.0
Low duty: 0.05
App ConfigurationPPM TabControl Mode
Current no reverse with brake: SELECTED
Settings
PID max ERPM: 15000.00
Deadband: 0.15
Minimum Pulsewidth (ms): 1.15
Maximum Pulsewidth (ms): 2.05
Use Median Filter: CHECKED
Safe Start: CHECKED
No other settings configured except Display for monitoring remote control
Battery cut off is a bit low for lipos. may want to take it to 3.5 or 3.6 per cell start with a 3.4 per cell end, though it really depends on your pack.
Have you done motor detection? Integrator limit seems a bit low.
And then I’ll incur further costs to fix or have someone else do it.