What did you do today?

[Col_Sanders]

Here's the follow up email. Looks like it was battery related like Tim said earlier. Lesson learned about power hungry servos; they don't match with comp batteries. $200 gone, lol.

View attachment 511806

That's some bs. Just because your esc is rated at 70 amps doesnt mean you are pulling that. Out of curiosity, id find the watt rating of the motor, convert to amps.

Good faith is a thing. They could have replaced it and said to upgrade batteries....I had two servos replaced by nsdrc and one by holmes last year. They asked me a couple questions and sent a replacement no problem. I'll continue to not run reefs steering servos.

 

[bgredjeep]

Here's the follow up email. Looks like it was battery related like Tim said earlier. Lesson learned about power hungry servos; they don't match with comp batteries. $200 gone, lol.

View attachment 511806

Holmes specifically talked about the small 4s packs (under 600mah) causing an issue. Didn't seem like there was any general issue with 3s.

It may be a completely different issue as that description doesn't sound like the same thing John was talking about.

Thread 'Direct power servos getting killed by small 4s lipo'

Jan 23, 2025

This is an issue that has been ongoing for a few years and some of yall may be aware of it. In a nutshell, packs smaller than about 600mah are a common denominator to "infantile death" or other very untimely failures of many direct power servos. Some models of 3bros dont get killed because they have higher voltage ratings, but finding good 35v driver circuits is tough. There are a good bit of 25v components and a huge plethora of 16v from the origional 8.4v servo designs. Pretty much all 4s direct power servos are 25v drivers.

So what is happening? In a nutshell, whenever a...

• JohnRobHolmes
• Replies: 24
• Forum: Electronics

• 
• 

 

[HVACTeacher]

Holmes specifically talked about the small 4s packs (under 600mah) causing an issue. Didn't seem like there was any general issue with 3s.

It may be a completely different issue as that description doesn't sound like the same thing John was talking about.

Thread 'Direct power servos getting killed by small 4s lipo'

Jan 23, 2025

This is an issue that has been ongoing for a few years and some of yall may be aware of it. In a nutshell, packs smaller than about 600mah are a common denominator to "infantile death" or other very untimely failures of many direct power servos. Some models of 3bros dont get killed because they have higher voltage ratings, but finding good 35v driver circuits is tough. There are a good bit of 25v components and a huge plethora of 16v from the origional 8.4v servo designs. Pretty much all 4s direct power servos are 25v drivers.

So what is happening? In a nutshell, whenever a...

• JohnRobHolmes
• Replies: 24
• Forum: Electronics

• 
• 

Thanks for sharing that. It was a good break down of the voltage spikes that can be experienced through back EMF, never thought of that one.

 

[Timmahh]

My understanding is its not as much when its maxed amp draw that is killing the servo, but the spike created when you let off the load all at one time, ie let off throatle and steering, that power has to go somewhere.
In my limited understanding, that is the cruxt of the spike, but I very well could be way off base and thrown out on that. lol

seems if a 4s is underpowered from being too small, same would happen on 3s being a smaller voltage out of the gate. no pun intended but it fits so.lol


When I saw the bit, I thought, what a crazy place to get a bit in the tire, thinking a small or short 2 inch bit. but DAYUM. that thing could impregnate someone. lol

 

[durok]

I just finished putting a spare on my wives SUV.
When I was out with my dogs an hour ago I heard a thumping sound, just as soon as it arrived it went away. I thought maybe I picked up a piece of rubber from an expansion joint or something.
Nope. A few moments later the TPMS alert went off, first yellow then switched to red. I pulled over right away, I could see a 1/4 bit sticking out of the tire. Crap.
Thankfully I was two minutes from home so I raced there before it went full flat in the driveway.

I messaged my salesman, he was supposed to be taking my truck back in for some paint work.
He said bring in the Pilot first and I'll get to take the loaner for this repair, than switch out the truck. Thankfully we had all this arranged so we still maintain two cars. Take a peak at this bit guys, like holy moly.

https://imgur.com/a/1Lh6Na8

I have to say, this thing has an amazing spare/flat tire situation. In the compartment for the tools/jack they give you a bag for the tire and the well in the trunk is semi shaped for it with some tie downs for a ratchet strap. Amazing.

Here's why the truck is going back.

https://imgur.com/a/FVvLbYk

It keeps growing outwards.

I've had 3 really crazy punctures in my 60 years...

1. Wooden golf tee went in the tread and out the sidewall of a nearly-new pricey mountain bike tire. That'll teach me to ride in the woods near a golf course!

2. One-half of a large pair of scissors went in the tread and out the sidewall of a tire on my Ford Festiva - it was pretty funny, though - the Festiva used a 145SR12 tire, and it was cheaper to replace than my mountain bike tire was! And skinnier than some of my motorcycle rear tires, too...

3. This was NOT a TIRE puncture - I drove over a big, jagged, and arched piece of a dump-truck leaf-spring. It went through the rocker panel of my Mazda Protege and continued puncturing into the driver's side door, to where I could NOT open it. I had to get out on the passenger side and crawl under the car in the middle of the night on the side of the highway to try to figure out what was making that godawful grinding noise and why was the driver's side of the car sitting higher than the passenger side. I was wearing steel-toe boots for work, so I kicked at it repeatedly after backing up a few feet until it finally came loose enough for me to pull it out and drive home. The insurance estimate was so high I traded the car in rather than fix it. I still miss that car, it was an ES model with the Miata-derived motor, 4-wheel discs, front and rear anti-sway bars, and a snappy 5speed transmission. I had nice Koenig J-spec wheels and slightly wider than stock 60-series Dunlop D60 tires on it and it was a BLAST to drive!

So, yeah - I feel ya on getting weird punctures!

 

[durok]

My understanding is its not as much when its maxed amp draw that is killing the servo, but the spike created when you let off the load all at one time, ie let off throatle and steering, that power has to go somewhere.
In my limited understanding, that is the cruxt of the spike, but I very well could be way off base and thrown out on that. lol

seems if a 4s is underpowered from being too small, same would happen on 3s being a smaller voltage out of the gate. no pun intended but it fits so.lol


When I saw the bit, I thought, what a crazy place to get a bit in the tire, thinking a small or short 2 inch bit. but DAYUM. that thing could impregnate someone. lol

Holmes Hobbies also sells this little beauty:

4s Lipo Direct Power Servo Protector - Wiring & Wiring Accessories

Taken from the product description on the site:


The 4s Lipo direct power servo protector will block voltage spikes above 20v, to prevent destroying your direct power servo or accessory.

We recommend this unit while running 1000mah 4s or smaller lipos if the servo does not have internal TVS protection. Smaller lipo packs do not absorb braking energy as fast, which cause higher voltage spikes, which can (and does) kill servos. The smaller or older your battery is, the worse the spikes! This can (and will) happen with any power system, regardless of brushed vs brushless or ESC type!

Dont get caught without protection

 

[Goro Majima]

Holmes Hobbies also sells this little beauty:

4s Lipo Direct Power Servo Protector - Wiring & Wiring Accessories

I'm gonna buy this, and buy another 900LP.

 

[cul8tr]

Well last night at 8pm I took off on a mtn bike ride. Yeah a lil late to ride in the woods with no light. All good been trying out a new clip pedal. Adj is good but the clipping in is a struggle. I'm thinking it's a new shoe issue, gonna try my old shoes next time. Rounded a corner and up a lil hill trying to get back in the pedal I glanced down and before you know it a tree reached out and grabbed my handlebar. Welp down I went dang it. Tweaked the bars and levers a lil but nothing a lil tap couldn't take care of. At least I cleaned a lil dirt and rock off the trail.

 

[Gula]

Did you donate some connective tissue to please the "bike gods" ?

 

[cul8tr]

Yes I did. Delivering yesterday my shoulder was not happy. I was feeling it last night in the neck.
Why is it you always remember why you don't like doing some things until after it happens.
The fall was great and graceful even, the sudden stop at the end wasn't bad.
The getting back up off the ground and the next day or 2 is when you remember why you don't like it.

 

[Gula]

The neck, ya, especially if you're over 40... pain, I know. Glad you're ok though! Naprosyn/Naprosxen, tried that yet?

 

[JatoTheRipper]

Yes I did. Delivering yesterday my shoulder was not happy. I was feeling it last night in the neck.
Why is it you always remember why you don't like doing some things until after it happens.
The fall was great and graceful even, the sudden stop at the end wasn't bad.
The getting back up off the ground and the next day or 2 is when you remember why you don't like it.

Wish you a speedy recovery. At 48, I struggle to get up off the ground. It happened over night. And I don't know how to change it...

 

[cul8tr]

Thanks guys I hit 60 this year. Staying active helps a lot.
My biggest hurtle is the heat in the delivery truck. This year has been rough. Floor runs 140* and the panel behind the pedals 130* with no air circulation in the truck.

 

[JatoTheRipper]

Thanks guys I hit 60 this year. Staying active helps a lot.
My biggest hurtle is the heat in the delivery truck. This year has been rough. Floor runs 140* and the panel behind the pedals 130* with no air circulation in the truck.

F that! Is it your delivery truck? If not, it's time for your employer to upgrade and get you some AC.