BLHeli amperage control possible? battery selection issue.

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stormtrupr

Member
ok, so after I saw an episode of DRL on TV I had to get into the sport, though I am pretty sure I will never go beyond recreational. I found the UAV ventures 100 dollar build. and have used that as guide, but I have come across a few other questions. I have purchased a racerstar 35A / 40A peak 4 in 1 ESC that was on sale. The ESC will be powering racerstar 2205 2300kv motors which based off what I can find uses 27.2A under full load(4S)...so that makes 108A plus say 2A for my FC, 5v fpv cam and 200mW vTX. so 110A. Prior to purchasing the quad, I have purchased a Zippy Compact 1300mah 4S 40C battery(50C burst) before i started my research so I think that means I can only provide 65A max for bursts. Thus is my 1st question.....
1. since my purchased battery cannot provide the proper max current can I configure the ESC through BLHeli to limit the current draw to a safe for battery level, and if so, is the approximate 16A per motor the battery can provide enough to fly around and learn to fly? I realize it may not be a big loss being that the battery is only 13 bucks, but being a beginner I planned to seriously tame the quad until I feel proficient. and while I am talking about this, with the ESC being 40A per channel capable, what would be a good future proof battery C rating to handle 35A continuous and 40A burst per channel so that I don't have to buy new batteries if I would change motors?

Thanks!
 
Jackson

Jackson

USA member at large
stormtrupr said:
cannot provide the proper max current can I configure the ESC through BLHeli to limit the current draw to a safe for battery level,
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The battery will provide what it can, no more. The ESC/motors aren't like vacuum cleaners.
stormtrupr said:
is the approximate 16A per motor the battery can provide enough to fly around and learn to fly?
Click to expand...
Sure, you just will have less grams of thrust.
 
GJH105775

GJH105775

Off and on
Moderator
Jackson said:
The battery will provide what it can, no more. The ESC/motors aren't like vacuum cleaners.

Sure, you just will have less grams of thrust.
Click to expand...


While that is true a LiPo batteries will generally provide more than enough current to damage themselves. What is a dead short if not an over-draw of current past the battery's rated capabilities? When going beyond these capabilities the battery's life span will shorten, and voltage drop may occur more suddenly. There is also the problem with these cells being really volatile; batteries when discharged over their rated current or capacity are a fire hazard. This applies when it is in the air and post flight while recharging.

Aside from the risk to the battery there are risk to the electronics due brownouts during flight. It really sucks to have one ESC go into low voltage mode or have a flight controller restart, or a lost-link event due to low voltage when you apply thrust. Could result in a crash that would damage other equipment.

As long as you take it easy with the throttle none of this should happen, but you will be better off with a more capable battery. KISS ESCS and flight controllers support ESC telemetry which could allow you to actually limit based on current being drawn. Realistically you would have the choice to just be gentle with the throttle and get a feel until you can get a better battery, or to just get either a higher C or higher capacity battery.
 
S

stormtrupr

Member
thanks for the replies. GJH hit my concern exactly as I don't want to damage the battery(had not considered the effect on the electronics but that is an even bigger concern than the battery) if not possible through BLHeli, I now am thinking I could I just make some adjustment in betaflight or cleanflight. If so, what would I adjust...(havn't picked up my FC yet, but the current one I am leaning toward is an OMNI F4 with built in BEC to power my rX, 5v camera, and vTX (Eachine VTX03 mini) so that I do not need a PDB or additional Reg. the Omni also should support Ibus and Dshot that my TX and ESC both support and reduce my config / calibration.
 
GJH105775

GJH105775

Off and on
Moderator
If you have a way to monitor voltage I'd just do that and not try to push it too much on the throttle. It would likely be really docile which could be fine to fly around a little on, you just will have to be careful. The voltage sagging should be a good indicator if you can't feel it in the response.
 
S

stormtrupr

Member
good point, I havn't thought much about what I want on the OSD, but Voltage definitely should be one of them. I may even hook up the Tgy 6C rX voltage monitor to have my Evolution buzz when voltage drops too low. I can't wait to do this build, but sadly everything I am ordering is actually a Christmas present, so I have a long while to wait :(

Thanks though! I just have to pick up a FC and another battery or two and I should be set!
 
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