Why does my S3B on battery drop out of network after 27 received packets?

Received PRO 900HP DigiMesh kit last week, working through labs in User Guide. Using transparent mode, one XBee remains connected to computer and repeatedly transmits (driven by XCTU) short ASCII string. Other XBee receives and RSSI lights (both XBees have RP set to 5) on both units flash. As long as both XBees are connected to the computer, this will go on apparently forever. But when the receiving XBee is on battery, it drops out of the network after it receives 27 transmissions. It is always 27 regardless of delay used in XCTU, so it is not a matter of time. I have a DMM on the battery voltage and that seems fine too. Also does not matter if the transmissions are sent as broadcast or to the specific address. Seems very strange to me. Any ideas? Thanks.

What do you need to do to get them back up on the network? It could be that the battery is not able to provide the proper current needed for the module to operate and you are getting into a brown out state.

I disconnect and reconnect the battery. Then it shows up again when I tell the XBee connected to the computer to find other XBees on the network. The battery pack is 3xAA, with a voltage when operating of around 4.9. I am not sure what current it can provide. I think I also have some 3.7V LiPo’s here that I can try, but I will have to charge them up first. Thanks.

Change your voltage regulator to one that can source up to 400mA or add a large CAP to the line.

Ok, I will try that. By the way, the XBee is on the Digi Grove development board (they cam with the kit I mentioned in the OP), which I assume includes some kind of voltage regulation. But I can breadboard in a large capacitor, good idea. Thanks.

The battery connection on the Grove board from Digi does not connect thru. That is you can’t power it from a Battery. It does not work.

Ok, thanks for the info. But I am confused. If I understand you correctly, it sounds like when I put an XBee / Grove board on a battery pack, nothing should happen. But it seems to power up normally and works properly until the originally reported problem happens. Where is the power coming from? Thanks.

No it should not work at all. The fact that you are getting anything is more than most. Simply put, the Grove board was not designed to operate off of a battery pack. That is, there needed to be additional circuitry on the board in order to properly power it form a battery packet that allows the USB chip to function properly. That circuitry simply is not there.

Ok, understood, thank you.