**CubeCell Sleep Current Design / Sleep Issue**

#1

HI all
I have been doing some tests on the AB-01 boards, without sensors. I have 5 boards here for the test and was testing the sleep current for each, as I have been getting some strange battery life performance.

On investigation with the same sketch ( I am using a battery voltage reporting LoraWAN Sketch) and the same battery and same USB lead to charge, I have found that not all the boards behave the same.

While they all work in transmitting and receiving on LoRaWAN correctly to my gateways and work with sensors correctly, I have found:

• 3 of the boards behave ok with a battery powered sleep current of 22-24uA which is ok.
• One board has a sleep current of 290uA
• One board has a sleep current of 1.3mA

This leads me to consider what is causing the issue as I suspect it will not just affect me. There is either something wrong in the design or the component tolerances of the devices.

The issues could be in one of the following areas:
• Power circuit of the USB charge and switch circuit leading to the power 3v3 regulator or the regulator used , as not much info on this .
• CubeCell MCU unit
• Auto Boot circuit
• The Vext /ADC switching
• CP2102
• SDA line pull ups missing on board

Heltec do you test sleep current on every unit with a LoRaWAN test script?

Before I take apart the board to investigate has anyone any views. I would say that it is not the issues of putting the MCU unit in to sleep, as this works with 3 of the units and also the units perform normal activity its just the varying sleep current on 2 units . This is a DESIGN / QUALITY ISSUE.

Simon

1 Like
#2

I had problems like yours.

#3

I am also having very strange behaviors between different cards. Install 3 gaskets to report temperature, 2 stopped working after approximately 3 days and one of them has been without problems for 2 weeks. I will be attentive to this post.

Personally, I was very excited about this product, my company was considering using it as the only product for IoT, we bought about 30 units for integration, but the tests have been very disappointing. I sincerely hope that these problems can be solved and this project can be carried forward.

1 Like
#4

i have right now over 100 AB01 in the field.
all are running without these problem.

#5

We bought 4 AB-01 units, tested 2 of them, both had issues after a few days running. Maybe ours are early versions, don’t know if there are many versions of it. But we are trying others products.

#6

Frecuency ?
I think maybe there is a issue with US915.

#7

Hi all, I may have found the source of the issue. I normally fully charge the lipo cells before placing them with capsule or boards to power cycle the batter I have just had one board that Was working, now failed. I checked the voltage on the cell it was 4.275V. I plugged it in and then saw it the voltage drop to 4.205. And then found the cube cell board started to consume current. It looks like the TP4054(LTH7) try’s to clamp the cell voltage to its voltage and in the process causes partial damage to the TP4054 and it now draws a large quiescent current. •• I recommend that you do not put a fully charged battery into a CubeCell capsule or board as it may damage the unit and only place a battery with less than 4.00 v ** I have ordered replacement chips and will replace damaged ones and test to prove the issue. Simon

#8

That would be a big design failure.
Please report when you have replaced the chips

#9

My problem is different, because the device when can not revive ACK from the network in confirmed uplink retry many times so the battery are drain.

#10

I charged the batteries using the cubecell, via usb, and it ends with 4.2V plus. Can’t do it?

#11

Hi thanks for the comment . What you said is not the issue . When I charged on the board it worked fine.

The issues is when I have been fully charging batteries prior to plugging in the CubeCell board to check capacity off the board on a battery test recycler, This manages to charge the battery to a higher final voltage and when this higher voltage cell is plugged in to the board the cell is a higher voltage than the LHR7 maximum charge value and it seem that the internal circuit is then discharging the cell and causes damage to the chip. I am waiting for some LTH7 to replace the damaged ones to confirm the issue. I have now stopped charging off board and plugging them in and now only put in partly charged batteries on to the board…

Regard Simon