After we left for this Spring 2026 trip, I discovered that the 12 volt converter was failing to charge the battery. I ordered the new one from Amazon. The old converter was model PM3-45 Powermax which is not the original unit. The one I purchased is a PM4-55A Powermax which is the exact same form factor as the old one.
The converter is located behind the grill in the picture which is removed by 4 torx screws. Behind the grill is a sheet metal box with the front side open. It is held in with 1/4″ hex sheet metal screws. It is advisable to make the change with NO POWER (NO AC power AND NO DC power) to avoid shorts, sparks and the like.
Notice the 4 tabs at the top of the picture. I had to fold them down in order for the new converter to fit. The old one had the same tabs folded down on them. Had I been home, I would have cut slots in the mounting box to accommodate the tabs. Also the new converter comes with an AC cord with a plug on the end. Since my rig has a third party inverter in it, there was a relay added to disconnect the converter when the inverter is in use. I simply cut the plug off and wired it in exactly like the old one was.
After the change I was pleased at how the new converter keeps the battery pack charged. It has a 4 stage output that gives you bulk charging when needed and trickle charging for maintenance. It also has a switch for fixed voltage charging used with the newest Lithium batteries.
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