My Solar Installs - Now with Solar Output Data

[Chad Heiser]

So it is late Saturday night.  We have been dry camping at Doran Beach in Bodega Bay since Monday afternoon.  In the last five days we have had two days of rain with complete cloud cover all day, two days of mostly to complete cloud cover all day with no rain, and one day of mostly sun so far.  Tomorrow is going to be a mostly cloudy day and Monday (the day we are leaving) is supposed to rain again.

During this time, my wife worked remotely for a day and a half and I put in a days work on the computer.  We watched TV, ran the microwave, used the dishwasher, toaster, coffee pot, hair dryer (not for me) and the residential fridge was chugging along the whole time.  It has been cool enough that the heater has been used multiple times as well at night, and of course there are lights and other base 12 volt loads.  In other words we have been living our lives with out any restrictions.  We are being thoughtful about turning things off when not in use, but that’s about it.

Today was one of the rainy days with full cloud cover all day and the batteries were up to 90% at 4:00 pm (still coming up slowly from our overnight and day usage).  We were getting ready to head out to dinner and didn’t know if we would be back before quiet hours started, so I decided to run the generator for half an hour to give the batteries a little boost.  I didn’t really need this, but it made me “feel” a little better.  The batteries got to between 94-95% in that half hour.  We headed out to drinks and dinner with our friends at a local restaurant around 5:00 and got back some time after dark.  We had a nice evening with not much electrical usage because of being gone and then sitting by the fire when we got back (until the rain started again).

This is a lot of filler and explanation to basically say, I am very pleased with the new, larger solar array.  We could have easily survived without running the generator for the half hour this evening.  As of 11:30 pm, the battery state of charge is 84%.  That extra 4-5% I got in the AGM batteries from running the generator for half an hour was unnecessary.  We could easily have gone without it.  Like I said, I did it to make me feel better not because the batteries needed it.

In better sun conditions (although still cloud covered for multiple days) in the past with the old (smaller) array, I would have needed to run the generator for a few hours over the same time frame to keep up.  The extra solar wattage of the new array and slightly “over-paneling” the solar controller has really made a difference in harvesting power in the fringe production conditions we have experienced on this excursion.

I am looking forward to giving them a test in better sun conditions to see what they can really do.

[GlennWest]

On 10/27/2021 at 4:13 PM, Chad Heiser said:

I have run multiple AC’s on 12 volt inverters for hours at a time with no heat build up in the wiring or anywhere else.  If the system is designed and built properly, it is a non issue.  Also, many larger RV’s require more than one DC-DC converter run in parallel to provide enough amperage to power jacks and slides.  I have seen this personally and installed DC-DC converters in parallel to overcome the issue.

Like I said, additional components and wiring are required to go to a higher voltage battery bank in an RV.  These additional components add complexity (albeit minor) and additional points of potential failure (more components).  You have to get back to 12 volt for OEM components.  There is no compelling reason in an RV with an OEM 12 volt system to go to a higher voltage battery bank.  It is simply a matter of personal preference.

People talk about efficiency in smaller gauge wiring for higher voltage systems.  As I mentioned, if the 12 volt wiring is properly sized and built/installed, the system will be just as efficient at 12 volt as at a higher voltage.  Watts are Watts, no matter what voltage is run the watts stay the same.  Only the amperage changes.

Now if you are talking an off grid house/cabin or similar with no existing 12 volt system, then I am all for higher voltage battery banks because there is no need to convert back to 12 volt.  I have designed systems for off grid cabins and they were higher voltage battery banks.

Will you share with me the dc/dc you found reliable and functionable? One I bought won't do what it claims. 70 amp unit and it won't power the slides. And slide motor had 50 amp relays

[Chad Heiser]

4 hours ago, GlennWest said:

Will you share with me the dc/dc you found reliable and functionable? One I bought won't do what it claims. 70 amp unit and it won't power the slides. And slide motor had 50 amp relays

The only one I have any experience with is Victron’s Orion 24/12 70 amp unit.  Even at 70 amps, I still installed two of them in parallel to insure there was enough power to run the jacks and slides on that rig (a large diesel pusher).  As I stated several posts ago, I am not an advocate of higher voltage battery banks in RV’s, but I will do it if that is what someone really wants.

[GlennWest]

48 minutes ago, Chad Heiser said:

The only one I have any experience with is Victron’s Orion 24/12 70 amp unit.  Even at 70 amps, I still installed two of them in parallel to insure there was enough power to run the jacks and slides on that rig (a large diesel pusher).  As I stated several posts ago, I am not an advocate of higher voltage battery banks in RV’s, but I will do it if that is what someone really wants.

I am at 48v.

 

[bigboomer]

We have the Victron 24/12 70 amp DC to DC and have had no issues in the 2 plus years it has been installed running our leveling jacks or slides. 

Not even a burp. 

[GlennWest]

48 minutes ago, bigboomer said:

We have the Victron 24/12 70 amp DC to DC and have had no issues in the 2 plus years it has been installed running our leveling jacks or slides. 

Not even a burp. 

Be nice if Victron made a 48v/70 unit. 

[BlueLghtning]

On 11/4/2021 at 12:27 PM, bigboomer said:

We have the Victron 24/12 70 amp DC to DC and have had no issues in the 2 plus years it has been installed running our leveling jacks or slides. 

Not even a burp. 

Same here. 2 years on our 24/12-70 DC to DC and no issues with slides or jacks. 

[BlueLghtning]

On 11/4/2021 at 1:16 PM, GlennWest said:

Be nice if Victron made a 48v/70 unit. 

Yeah it really would. That's one of the negatives with a 48v system is there doesn't seem to be a lot of good options for a 48v->12v DC to DC with decent amperage.