Will pay anyone in Los Angeles who owns a Victron BMV712 & a Victron MTTP unit ...

[themexicandoctor]

If anyone who owns & understands these systems & you live in Los Angeles or within an hour's drive, I will gladly drive to you & pay you $100 Cash for 90 minutes of instruction.

Its not my area of expertise & I believed that I had bought the best possible equipment & yet I appear confused.

I was sitting Fat, Dumb & Happy wiyh my limited electrical knowledge until the last couple of weeks.

The fact that I was in a a Coma for 6 weeks with diffuse damage to parts of my brain doesn't help. I learn complex, new principles through pictures more effectively than the written word.

My new DC Fridge arrives next week & I believed that I had enough solar hardware up on the roof & the daily driving (sometimes an hour or more, sometimes not), that the new DC Fridge would not tax my system but merely exercise it.

ANY TAKERS?

I am not joking, understanding many concepts like this has been very difficult & so while I do what I think is adequate research, I then pay Professionals to do all the installation after conferring with them that my choices are on point.

And then I arrive here & look like a Fool.

[eric1514]

You hardly look like a fool.

[themexicandoctor]

Well I feel like I am standing at the Wrong End of the Horse ...

https://www.classbforum.com/forums/f...g-10753-2.html

[themexicandoctor]

And here for instance;

https://www.classbforum.com/forums/f...g-10753-2.html

[GallenH]

Lighten up! There are many of us here who are in the "learning" mode and there are often multiple opinions and solutions to problems based on preference and use. We benefit from those on the list who have more knowledge and have dealt with the issues and found some type of means to solve them.

I believe a lot of it is trial and error. You're probably not going to make a major mistake. You need to setup what you want and see how it plays out. Read rowiebowie's thread about his conversion. He set it up to the best of his knowledge and still needed some advice to tweak it to work properly. But he did. That's why the forum is invaluable. People generously helping each other.

Somewhere in the files is a stickie about booster's modifications and his work to refine them and make them work. Go to Interblog's site and read about her work to resolve the fridge issue.

Point is: don't panic. Try your best. Refine til you get it right. Ask for advice.

best.glenn

[themexicandoctor]

Gallen,

I appreciate those words & yet I also want to learn for myself. Probably need to watch some YouTube videos but I learn very quickly when someone is in front of me.

Have learnt a lot about the Dark Arts of Batteries over the years & thought everything I purchased took the guesswork out of the equation & was the best performance possible.

I thought this is great, my equalization time each day is a little narrow but I usually spend up to 50% of a summer's day in float & I simply aren't using my batteries at all, solar alone is keeping up real well.

Life is peachy, now is the time to add a DC Fridge - I have a suspicion though my system will handle the Novakool R3800 even in heatwave temps - its just a feeling.

So it would be with pleasure if one of you electrical guys are in the area to pay you for yhe Enlightenment $100 for 90 mimutes.

Once again, Thank You!

[booster]

My favorite line referring to this topic:



It is more like something your expect to hear out of Red Green (PBS tv show) from the past, but IMO says it all. The original version of it may actually have come from the show even, as he said a lot of this kind of stuff.



"If you never have any failures, you aren't trying hard enough".


I can tell you from experience that engineers that are so cautious that everything always works are likely to not be the ones that come up with solutions and innovations that really make a difference.

[JohnnyCLE]

Doc, I feel your pain. I am approach my 1st birthdate from six rounds of chemo and a stem cell transplant.

Practical response to your question includes knowing the ambient air temperature you expect inside your van while the refrigerator tries to keep things cool. If you have to run your AC so that the van interior is cool enough for the refrigerator compressor to work, you probably have a problem. If you are going to be boondocking in the Sierras at 50 degrees F, you are probably good.

As a practical matter isn't the answer, "some days it will and some days it won't" and what will you do under either scenario and how much is at risk?

If your life is at risk, ie; storing medication shots, don't trust any gauge and have a reliable safety tank storage. If it is about keeping beer cool, then it may be more or less important.

If I were trying to make a rough guess, with safety margin, I would take 80% of the max amp draw for the appliance X volts of the appliance X 24 hrs to get my projected watt hours of the refrigerator all day. Then take what your solar produces at peak in watts X 4 hours of sunshine per day. See if my batteries can sore enough excess during those 4 hours to carry through the other 16 and either feel happy or sad.

If you have gathered actuals for these devices from your battery monitor then the calculations would substitute these for a more practical confidence level.

[themexicandoctor]

A couple of weeks ago I did this but it was at 12.15, 45 minutes before 1pm during daylight savings.

I am with Booster & everyone else on this; Your actual experience as an Owner might be different than that of a Buyer. So I use these numbers with that adage in mind;

At 50% run time, 2.2amp draw, that's about 27ah.

Most people in Class B's in hot weather are finding an average draw of 21-28ah.

80% is 43ah.

I think that these photos I show you next aren't indicative of just how healthy my batteries are & they were already in Float before I started the car, drove & then took the readings in the full sun a week ago & sent this to my Guru;

Photo #1 of the Smart Meter at 11.39am shows the initial charge coming in from the Chassis Battery that has been sitting for 12 hours & the motor started up (have a high amp alternator)

Photo #2 at 11.59am shows the Smart Meter in sun with the loads of a couple of lights, fan at high speed & the inverter on applied after having driven for 15 minutes.

Photo #3 shows the Smart Solar sitting in your driveway, full sun, with no loads.

Photo #4 shows the Smart Solar with the loads of a couple of lights, the inverter & 3 fans at high speed

Photos to come.

I could have applied more loads, it wasn't 1pm during daylight savings, my batteries were already in Float earlier in the day & I have seen my Solar pull in 220 watts at one time before.

[themexicandoctor]

Here they are;

[themexicandoctor]

JohnnyCLE,

Congratulations Mate, Chemo Brain fog is a very real thing too.

A lot better problem than the boredoms of being buried.

Knowing that I can pull a P.Max of 234watts & a V.Max of 21.38 volts is the reason why I pulled the trigger on the DC Compressor Fridge. See new history picture where a month ago I pulled in 4 days of over 200 watts of peak power.

Or am I interpreting these #'s incorrectly also.

[JohnnyCLE]

Doc, so there you have gone and done it. Given me a bad case of Solar Controller envy!

If I am reading things right your solar controller is showing a line which says your average solar harvest is 405 watt-hours per day. I noted that your battery temps were showing around 77 degrees F, which I believe is close to the sweet spot for solar panels. Their yield goes down in higher heat so they may produce less when your refrigerator needs to work the hardest.

I take it that your calculation above is that you expect the refrigerator to draw 27 amp-hours per day at 12v. I believe this would be 324 watt-hours. The rest of the 12v draws are minor unless you are plugging secondary inverters in to the 12v circuit to run rechargers, TV, etc.

Attached is a pdf of a spreadsheet model which I am trying to flesh out and keep current for my configuration. The intent is to be able to model a peak day or average day for a trip to be able to see if I have a current generation problem or a current storage bottle neck.

If you would like to use this as a starting point - let me know and I can email it to you.

[themexicandoctor]

I looked at that PDF & was reminded of your quote & my present level of competency;

"If you don't know what you are doing, at least do it neatly..."

Question: are you getting the juice & being able to store enough based on your demands?

I understand the 77% rule, I might have to move North when I need solar the most.

I do have a very positive feeling*, that my system is going to respond to the demands adequately, that instead of giving me the present yields, the increased amp hour draw is going to merely exercise my solar system & batteries to accept more solar watts, spending longer in both Bulk & Absorption & less in Float instead of spilling** unused power.

*do everything by feeling once I have satisfied myself the logic is there.

**don't know if this is the correct term, what I mean is that when a bucket/battery bank is full*** of water ie; float then anymore solar energy/water is reduced by way of the control settings, spills over the top of the bucket.

***Booster & others have encouraged me to have a healthy degree of cynicism about the difference in performance when one is a perspective buyer looking through a glossy brochure versus the realities of being an owner. In Truth, owing Lifeline Batteries, using a Victron Controller & a Magnum**** MMS1012 inverter I believe closes the differences.

****2 years ago Victron didn't make a 12 Volt inverter that was small enough, they may do now.

[themexicandoctor]

As it is, I am now the Owner, armed to the teeth & DDay is next week - I do not want to fail at the beachhead landing if that makes sense.

[rowiebowie]

Doc and Johnny. Sending you wishes for full recovery and extended good health.

I haven't had nearly what either of you have gone through and I prefer pictures over words for understanding things. And I mean pictures, not complicated schematics that I can't comprehend anyway.

Here's my lithium wiring diagram, for example. It helps me remember which wire goes here and which wire goes there. Booster and other's advice were indispensable, but ultimately (and after several headaches from forcing my brain to contemplate things never before contemplated) I had to distill things down to a basic level. And I'm proud to add that nothing burned up.

[JohnnyCLE]

Doc, In the heat our Air Condition demands exceed our storage capacity, so we have to us the aux generator or shore power to fill in. Fall / Spring we are good.

rb, Thanks!

[themexicandoctor]

Originally Posted by JohnnyCLE

Doc, In the heat our Air Condition demands exceed our storage capacity, so we have to us the aux generator or shore power to fill in. Fall / Spring we are good.

rb, Thanks!

I hear you

And I feel for you - the ETREK Electrical sounds like multiple levels of difficulty

[Nic7320]

I could take a look. Need a Santa Barbara vacation?

Oh, wait. I own TWO BMV712s. Does that disqualify me?

[themexicandoctor]

Originally Posted by Nic7320

I could take a look. Need a Santa Barbara vacation?

Oh, wait. I own TWO BMV712s. Does that disqualify me?

Are you in SB Nic?

[Nic7320]

Very close to SB. 1.8 miles from UCSB.

After buying a Victron inverter and seeing how good it was, I got hooked and went all in. Now I have two Victron 20A/100v solar controllers, two battery disconnects (65A and 220A), two 24v inverters (375W and 1200W), two BMV712s and one 24 volt to 13.5 volt converter. All but one battery disconnect and the voltage converter are 'smart' versions with Bluetooth.

Doesn't make me the ultimate authority on all things Victron, but I also do have an electrical engineering degree.

PM me if you need me to take a look.