Low AC voltage

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   Has anyone experienced low AC voltage when trying to run appliances off the inverter or generator. In USA boats, the 230 volt inverter voltage is stepped down to 115. In practice it measured closer to 113. Problem is that with voltage drop over the wiring, any 1000 to 1300 watt appliances will only see about 105 volts. Some will tolerate this and others will struggle. Specifically my microwave doesn’t power as it should and some coffee machines don’t work at all. 

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Arcadia Members Profile Send Private Message Find Members Posts Add to Buddy List Admiral Joined: 27 November 2017 Location: Sag Harbor, USA Status: Offline Points: 1112	Post Options Post Reply Quote Arcadia Report Post Thanks(0) Quote Reply Topic: Low AC voltage Posted: 10 June 2025 at 12:17
	Has anyone experienced low AC voltage when trying to run appliances off the inverter or generator. In USA boats, the 230 volt inverter voltage is stepped down to 115. In practice it measured closer to 113. Problem is that with voltage drop over the wiring, any 1000 to 1300 watt appliances will only see about 105 volts. Some will tolerate this and others will struggle. Specifically my microwave doesn’t power as it should and some coffee machines don’t work at all.
	Leon / ARCADIA 2018 Hanse 588 Sag Harbor, NY

Sounder Members Profile Send Private Message Find Members Posts Add to Buddy List Commander Joined: 11 February 2021 Location: New York Status: Offline Points: 130	Post Options Post Reply Quote Sounder Report Post Thanks(0) Quote Reply Posted: 10 June 2025 at 12:40
	I have definitely noticed the same. No idea how to improve that. When I've asked at McMichael they tell me the boat needs to be hooked up to shore power for appliances, coffee maker, etc.
	David S NADINE (Hanse 348 #199) Western Long Island Sound

32mike Members Profile Send Private Message Find Members Posts Add to Buddy List Commadore Joined: 26 March 2020 Location: FLorida, US Status: Offline Points: 453	Post Options Post Reply Quote 32mike Report Post Thanks(0) Quote Reply Posted: 10 June 2025 at 14:04
	Yeah, I’ve had the microwave not work properly off of the inverter from the battery. I’ve tucked an away inside my brain that I need to run the generator or be on shore power for the microwave (or upgrade to a better lithium setup.)
	Mike S/V Dulces Sueños 458 #087 Tampa, FL

Sounder Members Profile Send Private Message Find Members Posts Add to Buddy List Commander Joined: 11 February 2021 Location: New York Status: Offline Points: 130	Post Options Post Reply Quote Sounder Report Post Thanks(0) Quote Reply Posted: 10 June 2025 at 14:07
	Would running the diesel allow these appliances to run? I don't have a generator.
	David S NADINE (Hanse 348 #199) Western Long Island Sound

marsella Members Profile Send Private Message Find Members Posts Add to Buddy List Rear Admiral Joined: 21 June 2022 Location: Antigua Jolly H Status: Offline Points: 592	Post Options Post Reply Quote marsella Report Post Thanks(0) Quote Reply Posted: 10 June 2025 at 14:56
	Not sure I understood the setup with 240V needed to step down to 120V. Shouldnt it be just 12V DC to 120V AC inverter installed? For 1200W/120V appliance, the current is only 10A, any reasonably sized wire (12AWG or something) should carry it without any voltage drop, otherwise same problem would exist inside every house in US.

Black Diamond Members Profile Send Private Message Find Members Posts Add to Buddy List Admiral Joined: 24 October 2015 Location: Newport, RI, US Status: Offline Points: 1275	Post Options Post Reply Quote Black Diamond Report Post Thanks(0) Quote Reply Posted: 10 June 2025 at 16:11
	I've seen it, but only in combination based upon the amp draw. For example, if a coffee maker is taking 20amps and an icemaker is taking 15 amps, then you have likely maxed out the 32amps the 110 step-down seems able to provide. Even worse, there are two legs which (I believe) have 16amp maximums (for the 32) coming off the step-down. Max out the 16 and you have the issue even if you are far below 32. I replaced the Mastervolt inverter/charger that came with the boat, but the capabilities of any replacement unit are constrained by the above 110V setup. FWIW
	Rick S/V Black Diamond Hanse 575 Build #192, Hull# 161 Newport, RI

Arcadia Members Profile Send Private Message Find Members Posts Add to Buddy List Admiral Joined: 27 November 2017 Location: Sag Harbor, USA Status: Offline Points: 1112	Post Options Post Reply Quote Arcadia Report Post Thanks(0) Quote Reply Posted: 10 June 2025 at 19:46
	To answer Marsella, the inverter makes 230 volt from the batteries. From there it is stepped down to 115 by a separate transformer. And Rick, the Victron unit puts out one leg at 32 amps, not two at 16. The problem we are having is not because the units are being overloaded. It is because they are proving a low voltage to start with and a bit of wiring voltage drop to the appliance. BTW this occurs regardless of how many appliances are running. I’m working on a solution to bump the 115 up to a more usable 125.Ans Sounder, running the engine won’t help because the inverter already makes adjustments for DC voltage drop in order to provide a steady AC voltage.
	Leon / ARCADIA 2018 Hanse 588 Sag Harbor, NY

Black Diamond Members Profile Send Private Message Find Members Posts Add to Buddy List Admiral Joined: 24 October 2015 Location: Newport, RI, US Status: Offline Points: 1275	Post Options Post Reply Quote Black Diamond Report Post Thanks(0) Quote Reply Posted: 10 June 2025 at 19:58
	You are correct. Its 32amp. I was told it was 16amp by the post-sales tech guy from my dealer, but I just checked in the manual and its definitely 32.
	Rick S/V Black Diamond Hanse 575 Build #192, Hull# 161 Newport, RI

marsella Members Profile Send Private Message Find Members Posts Add to Buddy List Rear Admiral Joined: 21 June 2022 Location: Antigua Jolly H Status: Offline Points: 592	Post Options Post Reply Quote marsella Report Post Thanks(0) Quote Reply Posted: 10 June 2025 at 20:45
	Ok I understood about transformer In my setup, I have two separate inverters, one, 12V to 120V, that powers wall outlets and waterheater, and separate one, 12V to 240V that powers air conditioners. Never had a problem with 120V, (max tried 2kW for espresso machine and heat gun), but had a problem with 12- 240V inverter, where my 1.5kW saloon ac unit would stop after working 10 min or so with the error code "underpower' or something like that. My other two ac units take about 1kW and work without a problem if run separately. I was puzzled what would be the reason why the inverter rated at 3kW cannot handle more than 1 kW but eventually discovered the problem with one of 12V battery cables going to the inverter was loosely connected, and after I tightened the bolt, the problem disappeared.

Wayne's World Members Profile Send Private Message Find Members Posts Add to Buddy List Admiral Joined: 18 July 2012 Location: Cruising Status: Offline Points: 1434	Post Options Post Reply Quote Wayne's World Report Post Thanks(0) Quote Reply Posted: 10 June 2025 at 23:01
	We have 2 x 12V/3000W/120A-50 Victron inverter chargers running together. I have used the Victron VE Configure 3 software to make changes to the system including setting both to run together or to run just one. One of the settings is AC voltage output. Ours are 240AC 50 HZ units and the default voltage setting is 230, min value 210V, max value 245V and can be set in 1V increments. I have set ours as 240V. We run our coffee maker, TV, vacuum, washing machine, water heater and our new AC powered watermaker all off the inverter/chargers and often multiple items at the same time. You can also set the charger from 120amps downwards. I have set ours at 100 amps each (ie 200amps total) at our electricians suggestion who thought running the chargers for long periods to charge the lithiums at the max output may shorten their life. To run the VE Congif software (downloadable from Victron) you need a Interface dongle MK3 to USB.
	Wayne W Cruising, currently in the Pacific until the end of 2026.



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