Hobby Wing Max8-G2S giving wrong battery cell count

[desmobob]

I installed a Hobby Wing Max8-G2S combo in my Rlaarlo DSK roller and I'm pleased with its performance. The buggy is great on 4S and crazy on 6S, so I decided to try a 5S battery: the HRB "Premium" 5S 4500mah 100C. I purchased a pair of them for $80 from Amazon.

I'm not expecting much from these cheap batteries but the DSK's performance on them is really nice... it hits the nice middle ground between the DSK's controllability on 4S vs. wild behavior on 6S. (This is the first model that I've kept the punch setting of 5 rather than quickly upping it to the max punch value.)

I have always run the DSK on 4S and 6S batteries so I keep the ESC set to "auto-detect" cell count. It works as expected when a 4S or 6S battery is connected: I get four or six confirmation beeps from the ESC as the system powers up. But when I use the 5S battery, it gives six beeps. (I have my charger set to charge my LiPOs to 4.17 per cell to help maximize battery life.)

It seems to run fine on the 5S batteries but it does shut down a bit early. The battery voltage reads right at storage voltage when the ESC shuts down the DSK when I'm running the 5S packs. I'm thinking that if the ESC did detect the battery as 6S and set itself up to run with that cell count, then it shouldn't even run... it should be below the shut-down voltage as soon as it powers up, right?

I'm a little confused...

Does it matter? Am I doing something wrong? I did send a query to Hobby Wing.

 

[RustyUs]

Just use the Hobbywing Link app to set LiPo cell count. 30 seconds and you are done.

 

[desmobob]

Just use the Hobbywing Link app to set LiPo cell count. 30 seconds and you are done.

I do have the HobbyWing Link V2 app on my MacBook and my old iPod Touch. But I often run on different cell count batteries, so I'd prefer to have the ESC auto-detect work properly.

Since I don't own a mobile phone (mobile phone free since 1961 ), I would need to remember to bring along my old iPod Touch to change the ESC parameters -- and remember to change them each time I changed batteries. Not a big deal, but since the iPod is so old, I keep the Bluetooth turned off to prevent draining its old and weak battery. And since I'm so old, I'd likely forget to change the ESC settings anyway. Again, not a big deal, but certainly not as convenient as having the auto-detect feature work properly.

The buggy seems to run OK even with the ESC mis-identifying the battery cell count so I guess I can ignore the situation. I was thinking that I might have just been doing something wrong or that the situation could cause some kind of problem...

I'll post any response I get from HobbyWing regarding the issue.

 

[Lostinthewoods86]

https://cdn.shopify.com/s/files/1/0...25DUL_EZRUN_MAX8_G2_20220304.pdf?v=1650747513

In the manual it states auto detect will not work with 5s.

 

[desmobob]

https://cdn.shopify.com/s/files/1/0...25DUL_EZRUN_MAX8_G2_20220304.pdf?v=1650747513

In the manual it states auto detect will not work with 5s.

Ah ha! As someone who usually R's TFM, I'm embarrassed to say I missed this:

2. Lipo Cells:
Set the correct value according to the actual number of Lipo batteries used. The default is automatically calculated, and the “Auto” option will not recognize 5S, this is to avoid mis-calculation during actual use, for example, 5S Lipo without power may be incorrectly calculated as fully charged 4S Lipo. Therefore, this parameter value needs to be manually set when using 5S Lipo.

Thanks for pointing this out!

 

[desmobob]

Incidentally, those HRB "Premium" 5S 4500mah 100C batteries were $39.99 each when I bought a pair last week. The price is now listed as $71.32 each!

I'm not sure how they'll hold up. One of the batteries has cell internal resistance measurements ranging from 8.0 to 2.6 mΩ (Average of 4.8) and the other is a bit better with an average of 4.68). These are unscientific readings from my HOTA D6 Pro while charging them after they had been run for the first time.

 

[desmobob]

I'll post any response I get from HobbyWing regarding the issue.

From HobbyWing:

Thank you for contacting HOBBYWING.
That is sort of the "physics" of the various cells and "HV" or not situations. But, overall most of the "odd" HV cell cut offs, tend to be similar to the "next cell" non HV cutoff.

But overall, "Auto" is always going to be less safe, or I guess you'd say, "Easier isn't better" situation, and manually setting the voltage cutoff is the best way to use an ESC to provide lipo safety as the "Priority".

Thanks,
Karl

 

[desmobob]

Incidentally, those HRB "Premium" 5S 4500mah 100C batteries were $39.99 each when I bought a pair last week. The price is now listed as $71.32 each!

WT? I purchased two last week at $39.99 each. Yesterday, they were listed at $71.32 each. Today, $38.60. Good ol' Amazon and their crazy price fluctuations.

 

[RustyUs]

From HobbyWing:

Thank you for contacting HOBBYWING.
That is sort of the "physics" of the various cells and "HV" or not situations. But, overall most of the "odd" HV cell cut offs, tend to be similar to the "next cell" non HV cutoff.

But overall, "Auto" is always going to be less safe, or I guess you'd say, "Easier isn't better" situation, and manually setting the voltage cutoff is the best way to use an ESC to provide lipo safety as the "Priority".

Thanks,
Karl

And by "manually setting the voltage cutoff" means adjusting the Hobbywing EZRun Max8 G2S through the use of the Hobbywing Link app I guess, right? That is the only way to adjust parameters I assume as there is no mentioning of doing it through a LED program card/LCD program box.

Since you like the performance of a 5S LiPo battery in your buggy, set the ESC cell count to 5 and use your 4S/6S batteries in other platforms.

 

[desmobob]

And by "manually setting the voltage cutoff" means adjusting the Hobbywing EZRun Max8 G2S through the use of the Hobbywing Link app I guess, right? That is the only way to adjust parameters I assume as there is no mentioning of doing it through a LED program card/LCD program box.

Since you like the performance of a 5S LiPo battery in your buggy, set the ESC cell count to 5 and use your 4S/6S batteries in other platforms.

The latest versions of the Max8 ESCs are only programmable via Bluetooth and the HobbyWing app. I wish there was a really simple and quick on-board ESC adjustment for battery cell count, like some simple button-pushing on the ESC itself.

I'll very likely leave the ESC set to auto-detect as it will correctly identify my 4S and 6S batteries and will operate acceptably with my 5S batteries. My DSK's HobbyWing ESC is the only ESC I run that uses XT90 connectors and my battery selection for that model consists of two 4S, two 5S and one 6S battery.

My other models that take similar mah-rated batteries use only 2S or 3S cell counts.