B-G431B-ESC1 Max voltage

[Choibogue]

Is it possible to input 7S into a B-G431B-ESC1 EVM with a voltage specification that says up to 6S?
If not, if I replace some parts with a high rated voltage as below, can I input 7S into EVM?
 1. Power Section, TVS diode, SMM4F26A (D20) -> SMM4F33A
 2. Power Section, Capacitor, 15uF 35V (C27 to C40) -> (I will keep this.)
 3. Bemf Detection & Sensor Input, Schottky diode, BAT30KFILM (D10~D15, D17~D19) -> BAT48

Thank you!

[Peter BENSCH · Accepted solution]

Please refer to this thread where almost the same question is asked.

Hope that helps?

Regards
/Peter

[Choibogue]

I saw your previous reply in the thread you linked.
If you ask me if I want to do it because I have a lot of work to do, like your previous reply,
I will do it. (even if I make custom PCB...)

What's important to me is,
can ST or equivalent guarantee that if I change EVM like this without any problems, I can safely achieve my goal(use 7S battery).

So, in order to input the voltage up to 30V, is it correct that I understand as below?

1. Power Section, TVS diode, SMM4F26A (D20) -> SMM4F33A
2. Power Section, Capacitor, 15uF 35V (C27 to C40) -> (I will keep this.)
3. Bemf Detection & Sensor Input, Schottky diode, BAT30KFILM (D10 to D15, D17 to D19) -> BAT48 ??? (Does this have to be replaced as mandatory? Or can I just leave it?)
4. I don't need to modify the L7986 related circuit. It originally supports up to 38V. However, I need to check the  voltage spec of C41, the input capacitor.
5. I need to change the voltage divider R68/R76 value for VBUS monitoring.

[Richard Li]

Hi, Choiboque,

Your maximum input voltage for 7S isn't right.

Do you know Lipo battery can charge to 4.35V for one cell?

Normally, design should give at least  +/-10%,

So if you want your design safe enough, you need count  7s for 4.35 * 7 *.1.1 ~ 33.5V.  

Richard

[Richard Li]

We did use Maccor validation one vendor battery 4.35V 500 circles, no any problem,

[Choibogue]

OK, Thank you.

I knew that some lithium batteries, such as Li-HVs, had a maximum voltage of 4.35V.
My condition setting was not appropriate. What I considered was 4.2V * 7S = 29.4V.
If I add a 10% margin, it will be 32.34V.

By the way, I don't understand what you said as below.
"We did use Maccor validation one vendor battery 4.35V 500 circles, no any problem,"
Can you explain it a little more?

[Richard Li]

If you work for battery, you need select good vendor, most people work for battery only short time, short than 10 years, include me,

But battery used for government; military; industry long time ago, they use equipment test-validate battery, Maccor is one good tester use for them. I use it <2 years, I very like this tester.

Batter test normally request 500 circles, after 500 circles, capacitor should >80%, different vendor gave test condition different, most like they only use <0.5C charge.

That one I noticed, we tested 500 circles, capacitor still good, inside resistance OK.

Richard Li 

[Choibogue]

Okay.
I will consider Maccor-Tested batteries when developing products that run on long-term batteries.
Thank you. You know a lot !
If you also know anything about my question regarding B-G431B-ESC1, could you share it?

[Richard Li]

My suggestion for your reference:

"2. Power Section, Capacitor, 15uF 35V (C27 to C40) -> (I will keep this.)"  

  Should change to 15 uF 50V.

"3. Bemf Detection & Sensor Input, Schottky diode, BAT30KFILM (D10 to D15, D17 to D19) -> BAT48 ??? (Does this have to be replaced as mandatory? Or can I just leave it?)"

 No need change.

.4. I don't need to modify the L7986 related circuit. It originally supports up to 38V. However, I need to check the  voltage spec of C41, the input capacitor.

 This need pay attention for change., DC-DC switch regulator not so easy like LDO, please study the datasheet, you need change feedback and compensation network.

Please check C51,C59,C65 voltage rating.

One more is for resistor change, beside value, you need count power consume, you don't want after voltage rising, resistor smoke.

[Choibogue]

Thank you for taking the time to pay attention to me, and for giving me a clear answer !!
I will check more with L7986 DC-DC switch regulator and related circuit.