Generator and battery charger

[LionFRR]

Have any of you any idea why a generator is not powering a battery charger? The battery charger works fine while connected to shore power, but once out of the dock we turn the genset on, switch from shore to genset and the battery charger is simply not working - not even a light showing that is on! Thank you!

[Cavalier]

Has it ever worked?

If not then, silly question maybe, but are you sure that the charger is connected into the switch or sub-panel downstream of the switch? I've seen 'home' installations before where folk have connected the charger upstream of the shore/gen selector switch, thereby bypassing it. When you turn off shore power and switch over to the generator, the switching actually disconnects the charger. Worth following the charger inputs and see where they go.

Does all of the AC subpanel function correctly when the generator is on?

[colemj]

Well, you did not say whether you were getting voltage out of your generator…

Assuming your generator is supplying the correct AC voltage, another thought is that the frequency or cleanliness of the power is wrong. If it is an inverter/charger, many of those require the correct voltage and frequency to work, and some also match phase before switching on.

However, the "on" light should at least be lit if power is available. My guess is power is not available...

Mark

[LionFRR]

Yes, the generator is powering the 2 A/C's.

[skipmac]

Originally Posted by LionFRR

Yes, the generator is powering the 2 A/C's.

That is a start but go back to the post from Cavalier. Where in the circuit is the battery charger connected? As he said (and this is NOT a good idea), some times the battery charger is connected before the Shorepower/Generator switch. Basically that means the charger is connected directly to the shore power line so when running the generator the power isn't reaching the charger.

Also as colemj mentioned, perhaps the power out from the generator is not clean enough for the charger's circuits and it isn't starting.

First step is to check for power at the input of the charger. Do you have a volt meter? Do you feel competent working around 120 V AC electricity? Be careful, this can be deadly on a boat if you aren't careful?

If you want to test this, check voltage at the input to the charger with shore power connected and then with the generator running and see if you show power with both.

[smac999]

measure the voltage and freq at the battery charger AC input.

if you have ac voltage there. disconnect the charger wire to the gen battery.

I've had a faulty charger feed 60hz ripple into a gen battery, which feed into the gen, which looped back to the charger input. giving me a 120hz reading at the charger input. (probably just little spikes ontop of the 60hz wave but my meter saw it as 120hz) charger didn't work off gen. everything else on the boat worked. disconnect charger from gen battery. charger worked and charged other batteries. replaced charger.

[Cavalier]

Originally Posted by smac999

measure the voltage and freq at the battery charger AC input.

if you have ac voltage there. disconnect the charger wire to the gen battery.

I've had a faulty charger feed 60hz ripple into a gen battery, which feed into the gen, which looped back to the charger input. giving me a 120hz reading at the charger input. (probably just little spikes ontop of the 60hz wave but my meter saw it as 120hz) charger didn't work off gen. everything else on the boat worked. disconnect charger from gen battery. charger worked and charged other batteries. replaced charger.

Good point. Parasitics have to be considered here. A dirty signal could easily interpolate as a primary frequency even though it's a harmonic.

[smac999]

it was pretty strange to see the charger work on shore but not gen, both with 120v at the input. that was a head scratching day.