Low voltage cut-off settings questions
10-24-2023, 11:43 AM
#1
Thread Starter
Low voltage cut-off settings questions
With my micro-helis, airplanes, and boat, I try to set the ESC's low voltage cut-off so that the battery is left at storage charge after it "rebounds." I try for a final voltage of 3.75-3.85V per cell and my micro-helis' LVC is set at 3.5V to achieve that. I don't recall what I have my boat set at.
I just got the wonderful new Losi Baja Rey 2.0 Isenhouer F100 trophy truck. When I saw that its LVC is default at 3.0V, I was surprised. As surprising was the range of choices to set the LVC: 2.6V, 2.8V, 3.0V, 3.2V and 3.4V. I changed it to 3.4V right away. I haven't run the same battery twice to find out how many mAh I'm putting back in to get from where the battery settles after LVC back to 4.2V.
Is that low default 3.0V LVC setting typical for a brushless truck using a 2S or 3S 5200mAh LiPo? Isn't it hard on the batteries? Am I losing a bunch of run time by not using it? What do you folks prefer for a low voltage cut-off setting?
Thanks,
Bob
I just got the wonderful new Losi Baja Rey 2.0 Isenhouer F100 trophy truck. When I saw that its LVC is default at 3.0V, I was surprised. As surprising was the range of choices to set the LVC: 2.6V, 2.8V, 3.0V, 3.2V and 3.4V. I changed it to 3.4V right away. I haven't run the same battery twice to find out how many mAh I'm putting back in to get from where the battery settles after LVC back to 4.2V.
Is that low default 3.0V LVC setting typical for a brushless truck using a 2S or 3S 5200mAh LiPo? Isn't it hard on the batteries? Am I losing a bunch of run time by not using it? What do you folks prefer for a low voltage cut-off setting?
Thanks,
Bob
10-24-2023, 11:46 AM
#2
Thread Starter
PS: I was a very active forum member starting in the 1990s but haven't been active in a long while. I asked to have my account updated to my new e-mail address but was denied... I guess it's been too long. So I'm back to being a "junior member." 
Bob
Bob
10-25-2023, 08:05 PM
#3
Thread Starter
I got some numbers today. I was running the truck in my driveway and yard, so it was "mild" running. I don't know if running it harder would make a big difference in the battery measurements I got.
Starting with a fully-charged Zeee brand 2S 5200mAh 80C, I ran until the low Voltage cut-off, set at 3.4V, kicked in. A few minutes later, that battery voltage was measured at 3.72V per cell... just a little below what I'd prefer as ready for storage. The bigger news: charging it back up to 4.2V per cell only took 2650mah.
Apparently, I am sacrificing a lot of run time by trying to adjust my LVC setting to leave the batteries ready for storage after use. I'll do some more experimenting on my next outing.
Bob
Starting with a fully-charged Zeee brand 2S 5200mAh 80C, I ran until the low Voltage cut-off, set at 3.4V, kicked in. A few minutes later, that battery voltage was measured at 3.72V per cell... just a little below what I'd prefer as ready for storage. The bigger news: charging it back up to 4.2V per cell only took 2650mah.
Apparently, I am sacrificing a lot of run time by trying to adjust my LVC setting to leave the batteries ready for storage after use. I'll do some more experimenting on my next outing.
Bob
10-27-2023, 08:06 AM
#4
Thread Starter
More numbers from this morning:
LVC set at 3.2V, battery after LVC and rest: 3.5V (very noticeable increase in run time from my previous 3.4V LVC setting)
mAh to get back to 4.2V: 4420mAh
Wow... dropping the LVC setting by one increment (from 3.4V to 3.2V) let me use almost 70% more battery capacity! That's a lot of run time. I guess it's worth it to have to top off the used batteries to get them back up to a good storage voltage. I can imagine that dropping the LVC down another notch to the default 3.0V setting would bump up the run time even more but I prefer to keep my batteries happy and not drop their voltage any lower than the 3.5V resting voltage I'm getting now.
I really like this truck. It's a lot of fun to run.
Bob
LVC set at 3.2V, battery after LVC and rest: 3.5V (very noticeable increase in run time from my previous 3.4V LVC setting)
mAh to get back to 4.2V: 4420mAh
Wow... dropping the LVC setting by one increment (from 3.4V to 3.2V) let me use almost 70% more battery capacity! That's a lot of run time. I guess it's worth it to have to top off the used batteries to get them back up to a good storage voltage. I can imagine that dropping the LVC down another notch to the default 3.0V setting would bump up the run time even more but I prefer to keep my batteries happy and not drop their voltage any lower than the 3.5V resting voltage I'm getting now.
I really like this truck. It's a lot of fun to run.
Bob
10-28-2023, 09:56 PM
#5
More numbers from this morning:
LVC set at 3.2V, battery after LVC and rest: 3.5V (very noticeable increase in run time from my previous 3.4V LVC setting)
mAh to get back to 4.2V: 4420mAh
Wow... dropping the LVC setting by one increment (from 3.4V to 3.2V) let me use almost 70% more battery capacity! That's a lot of run time. I guess it's worth it to have to top off the used batteries to get them back up to a good storage voltage. I can imagine that dropping the LVC down another notch to the default 3.0V setting would bump up the run time even more but I prefer to keep my batteries happy and not drop their voltage any lower than the 3.5V resting voltage I'm getting now.
I really like this truck. It's a lot of fun to run.
Bob
LVC set at 3.2V, battery after LVC and rest: 3.5V (very noticeable increase in run time from my previous 3.4V LVC setting)
mAh to get back to 4.2V: 4420mAh
Wow... dropping the LVC setting by one increment (from 3.4V to 3.2V) let me use almost 70% more battery capacity! That's a lot of run time. I guess it's worth it to have to top off the used batteries to get them back up to a good storage voltage. I can imagine that dropping the LVC down another notch to the default 3.0V setting would bump up the run time even more but I prefer to keep my batteries happy and not drop their voltage any lower than the 3.5V resting voltage I'm getting now.
I really like this truck. It's a lot of fun to run.
Bob
10-29-2023, 03:19 AM
#6
Thread Starter
10-30-2023, 11:48 PM
#7
After I had ordered them, (they were inexpensive; the 2S 5200mAh 80c were less than $20 each) I remembered the excellent LiPo testing/comparison MCSGUY has posted here. I probably would have picked another brand, but they seem to be working fine for me so far. The buyer feedback on them was decent, also.
10-31-2023, 03:07 AM
#8
Thread Starter
10-31-2023, 05:35 AM
#9
Amazon has them for that price. I sorted through all their offerings and picked the Zeee batteries. When I ordered them, I was wondering why the 2S version was more expensive than the 3S version. It was because I didn't realize the price of the 2S battery was for a two-pack! That was a nice surprise. I can't post a link because I had to re-register here and don't have enough posts with my new account. Just search on Amazon and you should be able to find them.
