Xiaoxiang BMS App Miscalculates SOC and Decreases SOC when Charging (Happens on Two BATTS!)

[JJJJ]

Sometimes it may be helpful to do a multimeter walk through at the lead connection terminal if it can be accessed. The lead terminal is gently removed from the Bms. For a diy the negative lead of the multimeter goes on the metal lead for black. One then walks away from the black lead with the red terminals with the red multimeter lead and should see an incremental increase in voltage.

If this cannot be accessed then please disregard.

 

[jahman]

I'm trying out the Overkill Solar Android App. Alas there seems to be no documentation available and I find the interface confusing because there seems to be no standard regarding (+ve vs. -ve) the sign for battery charge vs. discharge.

Since my BMSs seem to be screwed-up and a picture is worth a thousand words, could a kind soul post a screen cap of the OverkillSolar App during charge so I have an independent party show how the App works? Many thanks!

During charge, what goes for my BMS shows negative power and a discharge current:



My setup: 10Ah LiFePO4 batt and 14.6V 6A charger:



So, again, a screen cap of the OverkillSolar App during charge would be really helpful!

Many thanks!

- jahman.

 

[Browneye]

It’s not changing, it’s discharging.
14.03V is full.
Or you have your bms leads hooked up to wrong terminals.

 

[jahman]

Hi, Chris!

Indeed, I suspect the BMS is on the fritz. But just to be sure I need a screen cap of the Overkill App during charging so I can go to the seller of the battery and request to have the BMS replaced.

Alternatively a user manual for the Overkill App would do as well, but I have not been able to find one.

Cheers,

- jahman.

 

[Bob B]

Hi, Chris!

Indeed, I suspect the BMS is on the fritz. But just to be sure I need a screen cap of the Overkill App during charging so I can go to the seller of the battery and request to have the BMS replaced.

Alternatively a user manual for the Overkill App would do as well, but I have not been able to find one.

Cheers,

- jahman.

Overkill support page is in link below .... I think the App operation is included as part of the BMS manual?
Or ... email a question to support at the bottom of the page.

Support/Downloads

User Manual User Manual: Download Manual (6.5mb PDF) Simplified 4 Cell Assembly Ultra simple view of a complete 4 cell battery assembly. – Click for full resolution. Bluetooth Mobile Apps iPh…

overkillsolar.com

 

[jahman]

Hi, Bob, many thanks for your post!

Indeed, the Overkill Support/Downloads page hosts a "Overkill Solar BMS Instruction Manual" bit, as the title says, it's a user manual for the BMS, not the BMS App. It does show a stylized version the screen of the Overkill App on p. 61 of the PDF, alas the battery is idle.

So I'm I'm still looking for a screen cap of the Overkill App during charging so I can go to the seller of the battery and request to have the BMS replaced.

Anyone care to assist?

Cheers,

- jahman.

 

[Bob B]

Here is mine charging. Iphone App

 

[jahman]

Eeeexcellent! That's excatly what I was looking for. Thanks so much, Bob!

So charge current and power are both shown as a positive numbers (and by extension discharge current and power are negative). Glad that's confirmed and settled!

I'm going to have my BattMan rebuild the battery pack without a BMS so I can hook-up an external Overkill Solar BMS and have more control over my batt and BMS. Only snag is I see the temperature sensor cable's plug is glued into it's socket on the BMS which is odd. Is there a reason for this, i.e. perhaps the sensor calibration is extremely sensistive to changing resistance in the plug to socket connection?

Cheers,

- jahman.

 

[Bob B]

I bought this small pack with the BMS installed .... have never had it opened up and have no idea what it looks like.
I have the Overkill App primarily as a backup in case they upgrade the Xiaoxiang App is upgraded and fails.

I like redundancy when possible.

 

[Browneye]

The OK app wouldn’t work for me, went back to the xioxiang one - works perfectly. [shrug]