Direct power servos getting killed by small 4s lipo

[Chingon]

The issues are from small capacity packs less then 650mah. For example, I was running 4s 300mah but my servos had issues as addressed in the thread but I swapped to 650mah 4s.

I hope if it hasn't been a problem yet that it won't become one, but it is a little concerning being so close to the threshold.

I don't think I would really want a pack much smaller than 650mAh anyway since it would give me anxiety about running out of juice before completing a course, but even a 650mAh pack is a tight fit on the axle.

 

[HouseFeces]

I hope if it hasn't been a problem yet that it won't become one, but it is a little concerning being so close to the threshold.

I don't think I would really want a pack much smaller than 650mAh anyway since it would give me anxiety about running out of juice before completing a course, but even a 650mAh pack is a tight fit on the axle.

Most won’t, the only reason I did was because the runtime was around 20 min slow crawling and I can fit it low by the bta mount on the vanquish f10 axles. That, I had a bunch already I used for fpv drones, partially tiny whoops and small 3” prop drones etc. I noticed others commented on having non branded Holmes hobbies servos on a video Holmes hobbies released earlier in the year in the comments of the video. Some people told me they are not fans of afgrc servos. Usually they last me a year but since I used the 4s 300mah they ran for 3 months each roughly before having the exact same issue.

 

[durok]

I'm sure it's hard manufacturing products that suit everyones desires and needs in the crawler scene.

For example, I got pretty gun-shy regarding expensive servos on my first few attempts, so now for my less expensive rigs I just run super-cheap Amazon DS3218 Pro servos - no issues with lighter brushed motor R/Cs.

If I destroy 'em I'll get another - but I don't get a ton of driving in and they have lasted me just fine in my TRX-4 Defender and Vaterra Ascender.

But I am not a comp guy, so I would be perfectly fine running a strong separate BEC (maybe 10A?) and servos in the 450-600oz-in range on my fancier rigs - I don't mind more weight and wiring.

I just really hate soldering, and it's not (just) being lazy - I have unfortunate issues with tremors from meds (and frankly age, too - now that I'm 60!)

So - I hate to say it, (as I've always been a Holmes guy for my nicer stuff) but I'm trying out a Reef's EZ-BEC because it's already got all the connectors and will supposedly provide 8.4v at current: 10A, Max: 15A - we'll see how it works, it will power a Reef's Raw 500, and I hope I didn't waste my money there - it's the first time I have bought from a Holmes competitor.

I do have one more unused Holmes Hobbies SHV650 and a spare set of gears for my old SHV500, I suppose I will try those out once I finish more of my builds.

For at least one of those I do have a new Castle Creations BEC 2.0 that I suppose I will try to get soldered up somewhere.

Lastly, I still have an old ProModeler servo that I am pretty unsure of how I plan to use, as the guys over there recommend a separate battery for them - it was pretty finicky connected to the BEC of a Mamba X ESC.

As many of you know, I'm a terrible procrastinator - who knows what will be available for purchase when I get around to my last couple vehicles - personally, I would love to see a high-quality plug-n-play Holmes BEC, and maybe some non-direct power HH servos!

 

[Col_Sanders]

I hope if it hasn't been a problem yet that it won't become one, but it is a little concerning being so close to the threshold.

I don't think I would really want a pack much smaller than 650mAh anyway since it would give me anxiety about running out of juice before completing a course, but even a 650mAh pack is a tight fit on the axle.

What's your time limit per course? Our comps have a 6 minute time limit per course. With a 550mah 4s, i usually have around 70% charge left after one course (according to my hitec battery checker) so running 2 courses would be no problem. Might be able to push it and run the third course if i had to, but i usually pop in a fresh pack between courses.


We do have some different style comps throughout the season. One is a 30 gate. Ill run an 850 for that.

 

[Chingon]

What's your time limit per course? Our comps have a 6 minute time limit per course. With a 550mah 4s, i usually have around 70% charge left after one course (according to my hitec battery checker) so running 2 courses would be no problem. Might be able to push it and run the third course if i had to, but i usually pop in a fresh pack between courses.


We do have some different style comps throughout the season. One is a 30 gate. Ill run an 850 for that.

I know I am being too conservative, but our courses are 6 minutes as well; 10 normal gates, and 3 bonuses per course. I have seen too many other people get burned trying to do more than one course with small battery packs that I just swap a fresh one in before each course. That way I don't have to worry about voltage drop through the run either. I don't have a battery checker, so that adds to my anxiety, but I have 5 650s anyway, so even at states I can run a fresh one on every course without having to recharge anything.

Running recreationally I would guess I get about 45 minutes of run time with the 650 packs and my small outrunner. The first year I went to the New Mexico state championship, I ran one 3S 1400mAh pack with an 11T 5 slot brushed motor and finished all 5 courses for my class on a single pack, with not a whole lot left before it gave out screwing around afterwards, so I estimate that setup used 200-300 mAh per course. The brushless setup seems more efficient so I could almost certainly get two courses out of the 650mAh pack.

EDIT: What do you run your low voltage cutoff at? I have mine set to 3.5V since I run LiHV packs charged to 4.35V.