Honda Generator Doesn’t Charge the Battery

1. Chase the battery charging wires back into the generator. There should be a voltage rectifier/regulator and an alternator. Expose the terminals.
2. Jump-start the generator off another 12V battery.
3. Check the output terminals at both places while the set is running, using a voltmeter set to appropriate ranges, and report back on this thread with the measurements.

Signode,

Most domestic self start back up generator systems have a battery charger fed by an AC line input, which which receives power from your domestic panel (and may also be part of your back up distribution). The battery charger DC output is protected, for the case where the charging wires or the battery shorts out. This protection (breaker or fuse) could be part of the charger or sometimes it is in a plastic in-line fuse cartridge.

If you follow PW's directions, you should locate the open line (or inoperative charger which would have to be repaired or replaced). Check out the lines for shorts and the battery (on a known good charger) before you reconnect to the generator's charger.

There are so many different versions of Honda generators and some are just Honda engines attached to other peoples alternators. Genuine Honda generators usually have alternators made by Sawafuji, notorious for complicated wiring. Have you checked for continuity of the charging output with engine stopped? An easy way is to get a 5 watt or 2.2 watt 12 volt bulb and connect it in series with your battery. If you now connect the charging output of the generator to battery and bulb the "wrong way round" the bulb should light. If the bulb doesn't light it suggests that someone has connected a battery to the genny the wrong way round before and blown either a fuse or the rectifier. Hopefully the rectifier will be a generic 35 amp bridge costing just a couple of dollars/euros/pounds. Possibly the faulty part will be an OEM Sawafuji black box. If so it could be a case of main dealer and $$$$s. Sorry I can't be more help. Best regards from Davey.