Help with 3s batteries and charger

[AH09]

Hey everyone,

I purchased my first RC truck a few weeks ago - an Arrma Big Rock 3s BLX. I have (2) common sense rc lectron pro 50c 11.1V 5200mah batteries along with a common sense 1s-6s 10a balancing charger.

Does anyone have an idea how long of run times I should see on these batteries? I was told 30-45 min. but I’m seeing 7-15 min. at most.

I believe I’m balance charging them correctly with these settings:

Any help is appreciated. Thanks!

 

[K-BASH]

When fully charged all 3 cells should be at 4.20....

 

[Mr.Vylan]

You will not get 45 minutes unless you are running at 25-50% power.
I get around 25-30 on the 5200mAh 3s
occasionally 35 minutes.

 

[K-BASH]

You should be getting more run time than that.when battery is dead an you put it on charger what ar the cells at??????should be around 3.60 dead an 4.20 charged.make sure its fully charged run it dead an it'll be around 3.60.an all 3 cells must be about same or battery is junk
Buy 30$ hrb batteries instead of hobby shop lectron 70$ for basic bashing.perform bout the same imo..get 2 for the price of one

 

[AH09]

All cells are charged to 4.20

 

[K-BASH]

View attachment 107382
View attachment 107383

All cells are charged to 4.20

Where are cells when you plug dead battery in?

 

[AH09]

You should be getting more run time than that.when battery is dead an you put it on charger what ar the cells at??????should be around 3.60 dead an 4.20 charged.make sure its fully charged run it dead an it'll be around 3.60.an all 3 cells must be about same or battery is junk
Buy 30$ hrb batteries instead of hobby shop lectron 70$ for basic bashing.perform bout the same imo..get 2 for the price of one

Yea I thought I should be getting at least 30 min. of run time, even driving pretty aggressively. I’ll take a look tomorrow and see what the cells are at before I start to charge.

 

[K-BASH]

Is it a v3 or v2 BIG ROCK BLX100 OR FIRMA

 

[AH09]

You will not get 45 minutes unless you are running at 25-50% power.
I get around 25-30 on the 5200mAh 3s
occasionally 35 minutes.

That’s what I expected but I’m nowhere near that.

Is it a v3 or v2 BIG ROCK BLX100 OR FIRMA

V3 BLX100

 

[K-BASH]

Blx100 will hit low voltage cutoff easy if system is strained.meaning it basically goes into LIMP mode cause esc thinks battery is dead when it's really not.premature limp mode.shut esc off then on an full power again.but u must be careful. Run battery to low an ruin it.must now where packs are at 3.50-4.20 when it goes into LIMP mode.(LVC)

 

[jondilly1974]

Step one, fully charge your packs to 4.2v

Step two, run them all the way until LVC, and take note of runtime and how hard you feel you ran it. If you have a GoPro, you could video the run for more help there.

Step three, check the cell voltages immediately after LVC. The sooner the better. The longer the cells recover, the higher this value will be.

Step four, put the battery back on a balance charge to 4.2v and see how many MAH the charger puts back in.

 

[olds97_lss]

I find that when I run in grass, I get about 25% less run time than when I run at the skate park, regardless what I'm driving. When I run in grass, it's a lot more WOT running, longer run ups, big jumps. At the skate park, the run ups are short and not a lot of WOT running.

I don't have a 3S arrma, but I do have a couple 3S trucks. When I ran 1/10th electronics in my stampede 4x4, I'd get about 28 minutes at the grass bmx with the max10 sct/3660sl 3200kv motor and 7200mah 3S SMC lipo. Then I changed to a 3665/3100kv motor went up 1 on the pinion and it dropped to 20 minutes, but ran cooler. Could be the grass was taller or I ran harder, etc.

Now I run a blx185 and 2200kv 4074 and get 18 minutes on a 6200mah 3S pack at the same place... but I tend to drive it like I stole it and it's geared taller now that I have more torque. Geared for 45mph. At the skate park, I get 22-24 minutes with the exact same truck/setup. So, the place you drive and how you drive impacts it quite a bit.