after endless hours of reading through others building threads and hours of building my deck and wiring everthing i´ve
finaly rode my board for the first time ! I could´nt be happier and want to share some of my experiences.
This is a low budget board so if you question some of my descisions, most of them were to keep costs down.
Here is where the magic happend and i can totaly understand that a lot of ppl wont like this but it was the only wayto make a battery pack without soldering it and untill now everything works "good"wiring the BMS was horrible since there were 3 different explenations on their website. C- for charge/discharge was the way to go
Even if i shit my pants because of the wet track had to go for my first ride and it was
a lot of fun, the programable ESC is good imo, smooth acceleration/breaks and a lot of
options via program card. The Performance is sufficient for me. It drives pretty stable and had no
performance los at all.
Still the Voltage sag is relevant in my case, at full speed i lose like 25% - 30% battery which will probably
be a problem if i go under 30% charge. I hope an upgrade to 6s4p will help.
If you have any questions or suggestions just go for it.
Big thanks to the community for helping me out especially @rojitor , @krloz , @wafflejock and @bartroosen12 .
Your help is really appreciated and i would´nt have been able do it without your help, THANKS !
as i already mentioned before voltage sag is kinda a bigger deal on my setup and i want to overcome the problem at least a little. But at first i would like to understand the problem. And have several questions on this topic.
What does voltage sag cause ?
2 .How do i overcome/avoid it ?
3 . Does it damage my cells if the V of my system sags under 3.3V (per cell) under usage but stays at 3.8V in idle ?
My battery usally sags betwen 25% - 40% at full throttle so i can only use until 55% charge at idle
So my plan is now to upgrade my battery to 6s5p.
I would really appreciate any help.
36A is what’s the manufacturer decided to rate the motor, but nothing prevents it from drawing more when a high load is placed, which is the case when starting from slow speed
Yes, this high current is bad for the batteries, that’s why most people here will say that going cheap in the long run will be more expensive, you saved a little bit of money found with an FVT esc, but maybe because you can’t limit the current you will kill the batteries way faster than expected
But for now, you could measure you’re entire pack internal resistance, this way we can see where the problem is
Just get a few ceramic resistors, a 5 ohm one will pul about 4A from the battery at 22v
Knowing the rest voltage, the voltage under the resistor load and the precise resistor resistance, measured with a multimeter we can easily measure the internal resistance, is not the most precise method, but will give some idea if something is really odd, for example if the battery holders have a tô high contact resistance
So if i have to buy some resisstors anyway which would cost about 5$ at least shouldnt i buy an internal ressistant messure tester if they can do what i think they can? i saw some on amazon for like 10 bucks, also isint my multimeter capable to do this for me it has ?
Sorry for the question im havent worked with electric that much yet.
You may also be drawing more power than needed due to the 140kv motor on 6s. Especially if you are riding at max speed quite often. A higher kv motor on 6s could possibly give you less current draw at speed(but more current draw during acceleration)
how is that motor mount holding up?
On another note: the board looks great dude. I love the enclosure.
Yeah @Pedrodemio mentioned that already and i will defenitly get a vesc very soonish but at first i want to get rid of this battery holders first by getting a spot welder, its pricy but this wont be my last build thats for sure.
And also i would really like to meassure its internal resistance before i build a new pack so i can compare it and see how good these holders does their job, it could be helpfull for others who also dont have a spot welder.
The motor mount does a pretty good job compared to its cost, had to Tweak it a little but now everything fits tight.
And thx m8 i put a lot of effort into this deck and enclosure, still not happy with it but thats another story