Victron 100/30 voltage measurement

[Yellowjacket]

John, for me my goal is two-fold: When I'm on the hook for several days in one location, I'd rather not run my main engine with little load. It doesn't like it. I don't like it. On my sail boat, it beomes a demanding presence. The genset is cranky, old, leaky, and has not been dependable. Perhaps we are brothers in spririt.

If I get offshore next season for warmer climates, as is my hope, and can sail en route, I'd like to have enouogh available solar electricity to run my refrgeration, watermaker, and my autopilot without running either engine, to say nothing of being anchored in a quiet bay some place.

The math says it's possible if I minimize waste. We'll see.

[Paul L]

Originally Posted by noelex 77

John, I think you have this backwards.

ICE are noisy, unreliable, add heat, consume fuel etc etc. The nirvana for most cruising sailors is to eliminate the need for ICE input.

This is not always possible, but with availability of cheap, efficient solar panels (and other technologies) the goal is entirely realistic.

You seem convinced that alternative energy can only supplement ICE power. While most yachts have an ICE for propulsion making some contribution inevitable, there are plenty of cruising yachts where the contribution from ICE is minimal.

That is my experience too. I've tried to argue this point with John before - I guess his experience with long distance cruisers is different. Running a genset throwing heat and noise into a tropical cabin sux and can often be avoided with a good solar setup.

[Paul L]

Originally Posted by Erik Dolson

.......
If I get offshore next season for warmer climates, as is my hope, and can sail en route, I'd like to have enouogh available solar electricity to run my refrgeration, watermaker, and my autopilot without running either engine, to say nothing of being anchored in a quiet bay some place.

The math says it's possible if I minimize waste. We'll see.

Erik
It is far easier to get covered by solar while at anchor than when on passage. While on passage tbete is a lot of shading that occurs due to tbe sails. Depends on basic direction N-S vs E-W and where the suns path takes it, the wind direction........
In reasonable sun our solar runs the boat. Offshore with the increased load of autopilot and chartplotter along with shading and we usually run an hour of genset in the moring.

[Yellowjacket]

I have friends with trawlers that run mostly on 120 v ac. I think thier experience would be similar to Johns.

[john61ct]

For those able to cover most or even all their offgrid power needs without relying on ICE for much, that's fantastic and certainly a worthy goal to strive toward for the rest of us.

But that does not change anything about the main point of my last post.

Originally Posted by Erik Dolson

it becomes clear that if I'm reading temp from a battery, I should receive voltage from that battery.

Voltage should be measured right at the same posts where all the charge inputs and load outputs are connected.

Note most large banks are composed of units of a lower voltage than the bank as a whole, maybe dozens of individual batteries.

But in effect that bank is now one big battery, and with lead chemistries, is usually only monitored that way.

[Jim Cate]

Well, in our case, I just upsized our solar array specifically to avoid as many hours of ICE generation as possible. The previous setup was adequate in summertime, mostly... unless we had a few too cloudy days in a row. I'm hoping that the new setup will cover 100% in summer and mostly in winter, especially if we get up to the tropics during that season.

A larger battery bank capacity would help with the cloudy day thing, but cost and available space have prevented that approach so far. We'll reevaluate that option after some experience with the new array.

I suspect this sort of attitude is typical of anchor-out type sailing cruisers. Trawler type cruising is quite different in mind set IME, and will favor more ICE solutions.

Jim

PS The shading from sails is a big factor when under way. When heading south (Oz east coast) as we are now, life is good with the sun coming over the stern all day. Coming north in the fall the reverse is true, and we get unshaded sun only early and late in the day... not a good choice for solar generation!

[john61ct]

Space to mount panels is often the limiting factor.

Windage issues and aesthetic considerations may prevail even if there's enough room in theory.

[john61ct]

Originally Posted by Erik Dolson

I have friends with trawlers that run mostly on 120 v ac. I think thier experience would be similar to Johns.

If you mean me, that is not the case, neither in load types nor using a lot of ICE propulsion.

Using a lot of power does not necessarily imply many AC appliances, personally I consider that approach very wasteful and minimize it.

But I certainly believe when ICE power sources are being run for other reasons, they should also recharge the bank as much as possible while they're at it.

With a large enough LFP bank, that can be enough that other sources are hardly **needed**; but of course they may be "desired", your rig your choice.

[noelex 77]

Originally Posted by john61ct

Voltage should be measured right at the same posts where all the charge inputs and load outputs are connected.

Battery voltage measured at the battery is most important parameter. Measuring voltge elsewhere is subject to voltage drop, so it is not a true reflection of the real battery voltage.

One advantage of the Victron smart battery sense is it alows the controller to know the true battery voltage.

[Paul L]

Originally Posted by john61ct

Space to mount panels is often the limiting factor.

Windage issues and aesthetic considerations may prevail even if there's enough room in theory.

Of course there are limitations. But your statement below that you regularly post is not true for longdistance cruisers who often go to great pains to avoid the evil internal combustion engine hours while in the tropics. You've had 3 very experienced cruisers refute it here, as your experience is primarily reading google you might want to pair it back a little

john61ct: Most owners do not truly rely on their solar, mostly it just helps reduce ICE runtime for a small number of days per year.

[john61ct]

Originally Posted by Erik Dolson

I'd like to have enouogh available solar electricity to run my refrgeration, watermaker, and my autopilot without running either engine, to say nothing of being anchored in a quiet bay some place.

The math says it's possible if I minimize waste. We'll see.

Yes I in no way intended to derail the thread into a "Solar vs ICE vs both" debate.

Just a reality-check, aside mention and very small factor in making my main point about load dumping and monitoring the charging process.

[Yellowjacket]

Paul L., I think John may have agreed with you in his statement "For those able to cover most or even all their offgrid power needs without relying on ICE for much, that's fantastic and certainly a worthy goal to strive toward for the rest of us."

But it's clear that some of you have histroy that I'm unaware of.

John, much of my load is served via a buss bar in the engine room, to which I've connected the Victron for charging. I think measuring voltage at the battery, where the temperature of battery is taken, and where the measurement is most meaningful in terms of state of charge, or actually, phase of charging (absorption), would give me a more accurate picture of what I need to know. That's why Victron's Smart Sense is appealing. Remote measurement.

Look at me pretend to know what I'm talking about!

I do have accurate (I hope!) voltage meters now hooked to the batteries, after learning the panel voltmeter was off by .25 volts. I suppose I can do the same with termperature, even if Victron is lacking accuracy there. Balmar, where are you? Then add temp values manually and do voltage adjustments manually as needed.

Hopefully that's not a dynamic situation. I would like also to sit in the cockpit and enjoy the sun on my weathered face in the morning, in the quiet, and not simply chase its productiopn in the engine room.

[Yellowjacket]

Does this mean equipment (VHS, wind instruments, etc) are tolerant of voltages from 50% to equalization?

[thomm225]

Originally Posted by Paul L

Erik
It is far easier to get covered by solar while at anchor than when on passage. While on passage tbete is a lot of shading that occurs due to tbe sails. Depends on basic direction N-S vs E-W and where the suns path takes it, the wind direction........

Not necessarily, it all depends on how you have your panels set up. I try to point mine in the general direction of the sun while sailing. Not much Sun here but you can see my point

It was very Sunny a couple hours earlier but with almost no wind. Then the front started to come in bringing me the breeze I needed to cross the 20 mile bay but taking away most of the solar power

By morning though after running my fan all night on a very inefficient ac inverter, (plus depth on 12 volts and lights at times) I had to run the autopilot, depth, GPS, and my laptop via the inverter on 11.8 volts for a few hours in the am until the sun got above the horizon

https://www.youtube.com/watch?v=Q3I2zc0_7wY

[Paul L]

Originally Posted by thomm225

Not necessarily, it all depends on how you have your panels set up. I try to point mine in the general direction of the sun while sailing. Not much Sun here but you can see my point

It was very Sunny a couple hours earlier but with almost no wind. Then the front started to come in bringing me the breeze I need to cross the 20 mile bay but taking away most of the solar power

By morning after running my fan all night on a very inefficient ac inverter, I had to run on 11.8 volts for a few hours

On a limited connection so I don't watch any YouTube videos.
When making a multiday passage shading from sails is an issue with solar and much more difficult to solve than when anchored.