MacBook Air battery intermittently not recognized

MacBook Air 7.2 13” Early 2015 Intel Core I5 1.6Ghz

Memory 8GB Storage capacity 250GB El Capitan 10.11.6

About two months ago upon startup my Mac occasionally showed the red low battery icon and would not start up without power cord. If I plugged the cord in, it would start up and show good battery indicators, and I could immediately unplug MagSafe and it would run and look fine.

That scenario hasn't happened for a while, and now occasionally upon startup and rarely even while plugged in and being used it shows a no battery icon [battery with X in it], and "No Available Battery" [via option & battery icon keystroke combination], as well as Battery Installed: No [in the System Report/Power info]. Still starts normally with MagSafe in, but when the no battery icon is showing and I unplug the MagSafe, the screen goes dark and I need to plug the power cord back in and press the power button for about three seconds to bring up the screen I was working on.

At all times the MagSafe shows orange [or green for a flash if I reset the SMC], and the clock shows the right time.

Same issue after running disc first aid and resetting SMC & PRAM several times, and starting in Safe Mode.

So far, if I wait awhile, the battery symbol comes back on as charging, I can unplug it, and it shows the following Battery Information:

Model Information:

Manufacturer: SMP

Device Name: bq20z451

Pack Lot Code: 0

PCB Lot Code: 0

Firmware Version: 511

Hardware Revision: 000a

Cell Revision: 1200

Charge Information:

Charge Remaining (mAh): 6279

Fully Charged: No

Charging: Yes

Full Charge Capacity (mAh): 6840

Health Information:

Cycle Count: 118

Condition: Normal

Battery Installed: Yes

Amperage (mA): -2

Voltage (mV): 8359

I live in South Africa, where mac repair centres are few and far away, so any help would be hugely appreciated.

thanks

Jesse