Inverter Out to Batt Charge In - whoops

[S/V Elusive]

Inspired by Wheels' admission to 'whoopsing' his starter ... Yesterday we had a power outage and I thought: "what a great opportunity to test my inverter!" (Heart 2500)

Without going into complex details of wiring, I left a switch in the wrong position and turned on the inverter and started a loop of high current & voltage which fed the batt charger so then the inverter would attempt to shut off and then no input and the inverter would start up again ... well, you get the picture.

So, besides blowing out my dehumidifier, the output of the inverter (without the feedback loop) now sits at 155 VAC with a mild load on it (about 2 amps). So, I figure that I've fried my output voltage regulator. I'll be researching (hopefully finding a schematic) and seeing if I can repair the unit. (don't have a clue on the dehumidifier, but it is only an $80 unit - I can live with that).

Other than calling me a dumb A$$, any thoughts or ideas?

[coot]

Instead of switching all the on-board AC power, I installed a switch for each branch circuit that made sense to run off the inverter. Those two circuits are "ac outlets" and "microwave oven". To use the inverter, I throw the switch for one (or both) of those circuits to "inverter" and turn the inverter on. It is therefore impossible for me to run the battery charger from the inverter because that circuit doesn't have a switch.

(I could run the "ac outlets" from the inverter even while I run the battery charger from shore power. Not that it would be useful to do that...)

I chose this arrangement specifically because I knew I would be switching things when I was tired, and I wanted to make sure I wouldn't accidentally run my battery charger or my 20 amp air conditioner from my 15 amp inverter. The inverter doesn't switch on automatically, but I also don't want that to happen.

I figure any system where it is possible to make such a mistake will eventually experience a problem. It has everything to do with human factors and nothing to do with dumb asses. We put covers over moving blades for a really good reason...


How long did it take to do the damage you discovered? Did the battery charger come through it ok?

[RichT]

Thomas,
Hi, haven't seen you at the harbor lately. Don't know about the Heart inverters, but most inverters for aircraft use have an adjustable regulator. Is it possible that yours may have one? If not, it may be possible to take it to an electronics shop, and have them put it on an o scope. It may just be a matter of replacing a couple of resistors, or a burnt out transistor. Many inverters use a base voltage biasing transistor which can be adjusted. It shouldn't be that hard for a good shop to check it out, as the guts are actually pretty simple.
Don't know of any good shops right offhand, but I'll ask around. Ciao,

RichT

[Alan Wheeler]

I have a three way switch to select shorepower-Genset-Inverter, so in theory, nothing can be feedback anywhere. However, we do have one situation that theory goes out the window. We can have the charger pluged into the mains and forget about it. Then if inverter is selected, the inverter is powering the charger which is inturn trying to charge the bank the inverter is drawing from. Mate does it flatten the batteries fast.

[sv_makai]

Makai originally carried the Heart Freedom 25 charger invertor. The Invertor failed on it twice. It was a simple matter of plugging a new board in. Luckly we were under warrenty. If it is out of warrenty as stated above the repairs are fairly simple.

After the warrenty expired it was cheaper to replace the invertor when it failed again and the battery charger portion started acting up. We had the same problem that Alan id'd above. We just removed the Heart and I replaced the invertor with a stand alone unit and elected not to have a charger. Even now we are at home at the dock the solar and wind charging covers all the power we need.

[Kapena]

My Heart has the charger built in. Plug into shore power and the inverter automatically switches off, charger goes on. Unplugged from shore power and the inverter switches on, charger switches off. It's a no brainer.

Thomas...quite possible you are making a wrong measurment. Is your voltmeter measuring RMS AC voltage? 110 VAC (RMS) * 1.414 = 155VAC Peak. Just a note to make sure the measurement is correct. The numbers are too coincidental for my taste.

[S/V Elusive]

Thanks for the responses guys - I didn't want to get into the specifics of the wiring, but since Coot mentioned it... Coot - I have a very very simillar arrangement - I actually have a dual AC breaker set. Side one is the shore or GenSet (Ship/Shore Switch), Side two is the inverter (Ship of a separate Ship/Shore Switch). Both sides go to a Control Breaker for the individual circuit breakers below. On Side one, (normally used side), the individual breakers go to Portside Outlets, Starboard Outlets, Refrigerator, Microwave, and one for the Batt Charger side of the Heart 2500.

With side two, I wired ONLY those breakers I would need to the side one switches. When I get under way and disconnect my AC cord, I always shut off ALL switches on Side a and put the Ship/shore switch to off. So, previously, when I used the inverter, I would turn on the side b side switches and it would be fine. This time, I didn't leave the slip and didn't shut off all the 'a' side switches. when I turned on the b side, it fed back through the individual swith, to the enable switch, and down to the batt charger switch and to the batt charger.

Whewwww... long winded ... sorry.

The Batt charger portion seems to be okay.

As a past ET, I'm fairly competent in using a VOM, and I had checked ALL outlets when I first got the boat for AC readings at all outlets (to ensure no bad or high resistant wires), so while I would expect some difference in readings because of waveform differences, I would not expect that drastic of a change. And, last time I used the inverter, I remember that the readings were between 110 and 120 VAC. (I also have a meter on the panel that alerted me to check with the VOM). But - with that said, there is no reason not to double check that Kapena ... better to check twice than to be an idiot twice!!

As to repair, that is the option. The circuit boards are fairly accessable, and it will probably be pretty obvious (tuned for max smoke? ). I figure a reference diode or resister. The trick will be if I have the schematic and parts list to get replacement components.

Thanks again guys!