Narrative:

We received an aircraft with maintenance in the cockpit troubleshooting a dual IRS dc fail issue. He stated he had been working on it for a while. He was on the phone with mx working the problem. He went down to the east and east compartment and reset the battery charger circuit breaker. He came back up (dc fail lights were now off) and announced it was fixed and we could be on our way. He stated we were only going to XXX. I told him I would not take the aircraft until he figured out why that breaker had popped. He began to argue with me about taking the aircraft. About that time the dc fail lights came on again. He immediately went to the east and east compartment to find the breaker popped again and it was very hot. He then consulted someone over the phone and decided to change the battery charger. We took the aircraft with no abnormalities noted. We were at cruise altitude of 35;000 ft when both dc fail lights illuminated. I called for the QRH checklist. We read through the checklist and decided to divert as suggested in the QRH. We contacted dispatch and they requested we divert to ZZZ. The first officer and I agreed this was our best option. We landed in ZZZ. The number one reverser did not work; and the number two reverser would not stow after landing. The APU would not start and the aircraft would not take ground power at the gate. At the gate; on engine shut down; we had a complete power failure. Emergency exit lights were operating. All passengers exited the aircraft safely. Scheduling called and told us to go to another gate; where an aircraft was waiting for us. They stated they would be extending our duty day beyond 30 minutes. We refused the extension and declared ourselves fatigued. This was in the interest of safety.I feel a little more investigation into the problem should have been done. We spoke with the ZZZ maintenance that repaired the aircraft and he told us the battery was fried. I am very glad there was not a more serious issue that occurred in flight.

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Original NASA ASRS Text

Title: B737 Captain reported diverting due to the DC Fail lights illuminating. Maintenance had changed the battery charger before departure.

Narrative: We received an aircraft with maintenance in the cockpit troubleshooting a Dual IRS DC Fail issue. He stated he had been working on it for a while. He was on the phone with MX working the problem. He went down to the E and E compartment and reset the battery charger circuit breaker. He came back up (DC Fail lights were now off) and announced it was fixed and we could be on our way. He stated we were only going to XXX. I told him I would not take the aircraft until he figured out why that breaker had popped. He began to argue with me about taking the aircraft. About that time the DC Fail lights came on again. He immediately went to the E and E compartment to find the breaker popped again and it was very hot. He then consulted someone over the phone and decided to change the battery charger. We took the aircraft with no abnormalities noted. We were at cruise altitude of 35;000 ft when both DC Fail lights illuminated. I called for the QRH checklist. We read through the checklist and decided to divert as suggested in the QRH. We contacted Dispatch and they requested we divert to ZZZ. The FO and I agreed this was our best option. We landed in ZZZ. The number one reverser did not work; and the number two reverser would not stow after landing. The APU would not start and the aircraft would not take ground power at the gate. At the gate; on engine shut down; we had a complete power failure. Emergency exit lights were operating. All Passengers exited the aircraft safely. Scheduling called and told us to go to another gate; where an aircraft was waiting for us. They stated they would be extending our duty day beyond 30 minutes. We refused the extension and declared ourselves fatigued. This was in the interest of safety.I feel a little more investigation into the problem should have been done. We spoke with the ZZZ Maintenance that repaired the aircraft and he told us the battery was fried. I am very glad there was not a more serious issue that occurred in flight.

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.