Why ESCs Fail....

[detox]

[I] It is always better to have at least 25% more capacity than you think you will need for a specific application. Inadequate or stressed batteries create excessive ripple current.

I will use my Hyperion charger to figure capacity used or replaced then add 25% of that figure. My two Hyperion 4s 45c 3300mah (4s2p 6600mah) packs should be plenty for my 4s setup.

[T.S.Davis]

We baked 5 Barracudas in a weekend on NiMh. Make sense really. NiMh would creat a nasty ripple under heavy load and then with the design flaw.

The Hydras have been really good to me. I beeat the tar out of them. The only one that failed was in an accedent. I've always run the best batteries I could buy though.

Does anyone know if the new Ice caps are larger? It would seem like a good idea for all the manufacturers to over build their controllers with gigantice caps. They have an idea what we're going to do with them.

[jingalls007]

"i mean whats affordable thats quality for us guys that dont have 150 bux for 1 hyperion pack[/QUOTE]"

Enerland, PolyRC packs. Granted I don't have years of experience with these particular packs, but for the money, $108 shipped, 4s, 35c, 5050mah, I don't know of another pack that I'd rather have for the money.. just my opinion

[T.S.Davis]

I was happy with my Poly Rc cells. I raced them for a whole season and then gave them to a club member who raced another season with them. Those were the old 20c5000 cells too.

[Doby]

[QUOTE=Fluid;310735]I have to wonder how many of the HV Hydras were run with low-end packs when they blew. With the high battery cost of 10S setups, I know many have gone the cheaper route with Chinese cells.


So which packs actually contain no "Chinese" cells

[davey]

I thought every lipo was made in China...they have the rites to them....i thought

[LiPo Power]

Do you really have to ask, NON!!!!






[QUOTE=Doby;310817]

I have to wonder how many of the HV Hydras were run with low-end packs when they blew. With the high battery cost of 10S setups, I know many have gone the cheaper route with Chinese cells.


So which packs actually contain no "Chinese" cells

[FighterCat57]

I thought it might be a good idea to revisit one major reason for ESC failure, and why some boaters seem to want twelve caps on their ESC. With the talk about poor LiPos recently this quote from a Castle tech on another site seems appropriate.


One of the most common causes of catastrophic failures in ESCS is using inadequate batteries or inappropriate plugs (too high resistance) between the battery and the ESC. Sizing batteries based on battery company’s claims of continuous current output is risky at best. It is always better to have at least 25% more capacity than you think you will need for a specific application. Inadequate or stressed batteries create excessive ripple current. The capacitors on the end of the ESC are there to handle ripple current. If there is too much ripple the capacitors become drained then overheat and either burn their leads, melt themselves off the board or explode. Once this occurs the ripple current cascades through the power boards burning the FETS.


.

This applies to aging lipos too. Last years 30c 5k lipo that's been used all season may stop short of delivering full capacity...

Here's a 101 formula that may help; (mah/1000 x C rate = Amps Constant)

A 5,000 mah pack at 30c is rated at 150 amps

So if run using a 180a ESC, there is a possible shortage of current.

A 5,000 mah pack at 45c is rated at 225 amps, which is more appropriate. Leaving a good percent of "head room".



I like to plan for max usages using what I call the max formula method. I take the motors watt rating (sometimes gathered from the amp rating x the volt rating) and work my way back from there.

So a 3,000 watt motor would use X amps and Y volts. From there I figure out what kv/voltage I want to run and it's a bit of trial an error, plugging the numbers in and seeing what works out. Possibilities;

3,000w = X amps * 8s (29.6v) or 3,000w / 8s (29.6v) = 101 amps

3,000w = X amps * 6s (22.2v) or 3,000w / 6s (22.2v) = 135 amps

3,000w = X amps * 4s (14.8v) or 3,000w / 4s (14.8v) = 204 amps

So depending on the motor KV, batteries and ESC's on hand, I would plug them in accordingly. For a sport setup, I would use the least amount of amps to get the job done. Mostly because amps = heat. Less amps = less heat.

I'll then choose a prop using FE Calc or an educated guess and work my way up, watching the amps and temps to find the "sweet spot" for a reliable and fun setup.

Anyways, I hope this helps. Thanks for posting Jay!

[raptor347]

The SAW guys have been adding caps for years. It was to buffer the ripple current from cells being pushed to the absolute limit (and beyond). With better quality cells, there's virtually no need for extra caps on this generation of ESC's. I didn't even add any on the SAW boats I ran last weekend, one boat was well into the 400 amp range.

The biggest problem I'm seeing at the moment is exaggerated C ratings for marketing purposes. Very much like the round cell days, it's very simple to print a label that says whatever a distributor wishes. Not many had equipment capable of running up in the 40+C discharge range and monitoring what was going on (data loggers have changed this). I can tell you this from all my SAW running (with a data logger that tracks voltage, ripple current, current etc.), very few cells live up to their ratings.

So here's my personal experience: Hyperion and Neu cells are rated accurately and will deliver at the stated C rating. If anything, they may be slightly under rated. So far the new GrimRacer Speed Packs are rated accurately (40C for the 5000's and 30C for the 4200's, limited pack selection), I'm looking forward to beating on them this season. The small capacity ThunderPower packs that Darin ran at the SAW's were very impressive.

As for the budget Chinese packs, take the burst rating and divide it in half and you have a better estimate of the packs capability. The 40C continuous/50C burst packs don't perform too badly if held below 25C continuous current. I've regularly had these pack drop below 3V/cell when pulsed with current levels approaching the rated "continuous" discharge current. Lots of guys running the 40C packs in the spec classes locally.

There's my .02!

Your mileage may vary.

[keithbradley]

The SAW guys have been adding caps for years. It was to buffer the ripple current from cells being pushed to the absolute limit (and beyond). With better quality cells, there's virtually no need for extra caps on this generation of ESC's. I didn't even add any on the SAW boats I ran last weekend, one boat was well into the 400 amp range.

The biggest problem I'm seeing at the moment is exaggerated C ratings for marketing purposes. Very much like the round cell days, it's very simple to print a label that says whatever a distributor wishes. Not many had equipment capable of running up in the 40+C discharge range and monitoring what was going on (data loggers have changed this). I can tell you this from all my SAW running (with a data logger that tracks voltage, ripple current, current etc.), very few cells live up to their ratings.

So here's my personal experience: Hyperion and Neu cells are rated accurately and will deliver at the stated C rating. If anything, they may be slightly under rated. So far the new GrimRacer Speed Packs are rated accurately (40C for the 5000's and 30C for the 4200's, limited pack selection), I'm looking forward to beating on them this season. The small capacity ThunderPower packs that Darin ran at the SAW's were very impressive.

As for the budget Chinese packs, take the burst rating and divide it in half and you have a better estimate of the packs capability. The 40C continuous/50C burst packs don't perform too badly if held below 25C continuous current. I've regularly had these pack drop below 3V/cell when pulsed with current levels approaching the rated "continuous" discharge current. Lots of guys running the 40C packs in the spec classes locally.

There's my .02!

Your mileage may vary.

I absolutely agree. I have had brand new 40C lipos that were outperformed by 20C lipos (less voltage drop under the same load, and higher speeds).
I too have had good luck with Neu lipos. My 5000mah 46/92C Neus held almost 4v/cell at 117A discharge. Granted that is nowhere near their rating, but I have done the same with cheaper lipos and dropped to about 3.5v/cell. Not only does this make a difference in esc life, but the difference is very pronounced in HV applications. My 8s boat has an extra 4v, which is actually more than what 9s would net me with the other batteries!

[FighterCat57]

Ah, one big misnomer; when we talk about "Chinese" it's easy to lump the entire 1.3 billion people into a single descriptor. But, just like in the US, there are higher quality and lower quality products from a very diverse group of makers. There is an uprising of a new "middle class" in China very similar to the US, there is also the initiative to increase the quality of products, so gradually we will see better quality over the next years.

[detox]

Is it safe to use Dean's connectors with 2p setups. Here is the 4s2p adaptor I used with my UL-1 Spec Hydro boat. Would it be safe to use this same connector with higher 4s amp draw setups such as 1515 1y 2200kv or 1518 1.5d 2340kv?

Other end of connector has 6.5 bullets.

[Boaterguy]

I find that some battery companies will exaggerate not realizing that we won't just get a pack and say "oh, that isn't what I thought it would be" but it will affect other components in the setup

[T.S.Davis]

Sad cells aren't an issue for most applications. They never get anywhere near the continuous C rating.

[keithbradley]

You mean those Maxamps packs arent really 150C?