Your last generator Maintenance Run

[3930dave]

A question for those who use a battery maintainer on their generator:

Is it safe to leave a maintainer connected to both the battery and A/C power while the generator is running? With vehicle batteries, either the A/C or DC side must be disconnected when the vehicle is moved. Not so with a stationary generator.

I had a BatteryMinder, which I used on dozens of batteries in boats, trailers and vehicles for over 30 years. I hooked it up the the battery on my generator and it worked fine leaving it connected to AC & DC while doing short maintenance runs. We had a 6+ hour outage a couple of days ago though and the BatteryMinder failed. It overheated and the case is noticeably swollen.

I'm planning on replacing it with a Noco Genius 10, which states in the manual that it is ok to leave both AC and DC connected.

Has anyone else had this problem? There is nothing in the BatteryMinder manual that says to disconnect it from a running engine. The unit was over 30 years old, maybe it was just its time.

Might have just been age.....

Modern chargers often prefer (crazy guy here, reads Owners Manuals...) to have DC connected before AC... guessing they use the DC to have the micro-controller Up, before AC arrives, but that doesn't sound like your sequence, and much of the older stuff never specified sequencing.

On my new chargers (like above), I usually add a label "DC First, DC Last", to remind myself.

Rgds, D.

 

[Fallon]

Might have just been age.....

Modern chargers often prefer (crazy guy here, reads Owners Manuals...) to have DC connected before AC... guessing they use the DC to have the micro-controller Up, before AC arrives, but that doesn't sound like your sequence, and much of the older stuff never specified sequencing.

On my new chargers (like above), I usually add a label "DC First, DC Last", to remind myself.

Rgds, D.

More likely they are relying on the battery to buffer the PWM output from the controller. You can run a car without a battery, at least older ones. But that is really hard on the voltage regulator & diodes.

If you have 2 controllers outputting exactly 12v both would push equal amperage to the battery. If one cut off at 12v & one at 12.1v, the 12v one wouldn't contribute anything as it would be below the cutoff voltage & the 12.1v one would drive things. In reality due to voltage loses in wiring & stuff, both would contribute some amperage.

 

[LittleBill21]

My toy hauler has 400watts of solar connected all the time. It stays live even when towing or plugged into shore power. Multiple charge controllers or converters output 12v nominal with each other just fine.

yep same here.

 

[LittleBill21]

Onan perhaps ?

I seem to recall seeing Elevation stickers on some RV Onans, once upon a time....

Rgds, D.

yes the onan 4k have the adjustment, i have the same generator.

 

[LittleBill21]

the thing that blew my mind after years of playing with this stuff, was when the dc negative, ac ground, and ac neutral for the generator were all attached to the same bolt, for reason i thought that would screw with things, but its been like that for 25 years.