Solar Panel Question ....

[themexicandoctor]

By the way, accepting his opinion that there can be an amperage difference between two batteries on the older Roadtreks (standard being the rear wheel, add on in front of rear wheel), is there a remedy?

ie; on a monthly basis switching the order of the batteries?

Mine are over a year old, would that help mine?

[themexicandoctor]

And I believe they used big enough wire (newer, more recent education leads to doubt).

This is also where we discovered a second Earth (?) that was throwing off my Victron BMV712 Meter.

[booster]

You should be able to get 20% range efficient 100 watt panels for $100-150 each. You need the smaller approx 41" by 20" ones to fit. If you controller can handle the 65v max voltage, in series would be a nice system.


The misbalance of the two batteries is real, we had it in our 07 and I saw it first hand.


It is pretty easy to fix by matching the cable lengths for each of the the batteries to each other. Use a single binding post for the positive, another for the ground and run both batteries to those posts with equal length and gauge cables. Then run a couple size larger single cable to the shunt on the negative side and another single larger cable to the the charging sources and loads on the positive side. As long at the cables are matched, the charging and discharging will be quite balanced, with the exception that the rear battery tends to run hotter because of it's location, which messes it up a little.

[themexicandoctor]

Would batteries that are over a year old benefit or would I need to throw them away & start again?

[themexicandoctor]

In the meantime, would changing the order be beneficial?

Over what time period would the mismatch prove irreversible?

Few people know this Booster.

[booster]

Originally Posted by themexicandoctor

Would batteries that are over a year old benefit or would I need to throw them away & start again?

I think that you should be able to have them capacity tested, not load tested and know if they are OK or not. Your guru may be able to do it, or a Lifeline dealer. There is a good chance they will be OK, I think, unless the charging has been very bad.

[booster]

Originally Posted by themexicandoctor

In the meantime, would changing the order be beneficial?

Over what time period would the mismatch prove irreversible?

Few people know this Booster.

If the mismatch if causing undercharge, it takes quite a while to show up as a reduced capacity of the least charged. Both could be loosing capacity from undercharge and one more than the other. If there is an overcharge situation of one or both, that causes damage faster. I don't think you would have chronic overcharging because you are on solar most of the time, or driving. If you do still have an isolator it drops the voltage about .7v so the charging is very slow and hard to overcharge driving unless driving a lot, repeatedly.

[themexicandoctor]

Originally Posted by booster

If the mismatch if causing undercharge, it takes quite a while to show up as a reduced capacity of the least charged. Both could be loosing capacity from undercharge and one more than the other. If there is an overcharge situation of one or both, that causes damage faster. I don't think you would have chronic overcharging because you are on solar most of the time, or driving. If you do still have an isolator it drops the voltage about .7v so the charging is very slow and hard to overcharge driving unless driving a lot, repeatedly.

Thank you.

I have a friendship with Andrew Finkelstein, the Sales Manager over there at Lifeline - its a 2 hour drive there so usually rather than testing the batteries for 24 hours, we usually just put two new ones in.

Yes, I am fortunate.

And Andrew is very knowledgeable & interested in helping RV owners - he is an owner himself.

But next time perhaps I will leave them with him & have him test them fully - without a battery, its park time.

PS. I always believed you still had the 07, what did you upgrade to?

[booster]

Originally Posted by themexicandoctor

Thank you.

I have a friendship with Andrew Finkelstein, the Sales Manager over there at Lifeline - its a 2 hour drive there so usually rather than testing the batteries for 24 hours, we usually just put two new ones in.

Yes, I am fortunate.

And Andrew is very knowledgeable & interested in helping RV owners - he is an owner himself.

But next time perhaps I will leave them with him & have him test them fully - without a battery, its park time.

PS. I always believed you still had the 07, what did you upgrade to?

We still have the 07, but it has been upgraded with lots of batteries, two alternators, no generator, big inverter, plus lots of convenience stuff. We have never found anything we liked better or even as well, so we will be sticking with it.

[themexicandoctor]

Originally Posted by booster

We still have the 07, but it has been upgraded with lots of batteries, two alternators, no generator, big inverter, plus lots of convenience stuff. We have never found anything we liked better or even as well, so we will be sticking with it.

I have to agree - the build quality went downhill even when the family still owned Roadtrek.

[themexicandoctor]

Nic,

What do you think of the Whynter unit?

And the Iceco?

I am considering a chest type I cancel the Novakool simply because of the heat here in Los Angeles, ideally the Engel MT45?

From what I have read, Iceco has a better reputation than Whynter?

Of course then I have to invest $400 in a slide out tray & then the unit would spend 4-8 inches in my hallway.

How easy is it to store & access individual food in the Chest Units ie; where do you store the vegetables, etc

[Winston]

A couple of observations on the videos referenced in this thread and on the issue whether there is an advantage to multiple charge controllers.

The “RV with Tito” video is interesting, but Tito is apparently running a pair of identical panels. Frankly we didn’t need Tito to tell us that it really doesn’t make a difference whether identical panels are configured in series or parallel. Tito, “opining” that placing dissimilar voltage panels in parallel would compromise operation and lower the overall power output, suggests that dissimilar panels should be run in series. Unfortunately Tito completely ignores the consequences of series connecting panels of similar voltage (but differing output current). In short, we hope Tito had a good time dry-camping adjacent the Columbia River, but his video provides very little useful information.

The “AltE” video is more helpful. It actually tests, importantly, dissimilar panels . . . but this particular video only goes half-way - - it test panels having dissimilar power output but of approximately equal current outputs (which implies that these panels were also of different voltage outputs). From an engineering point of view, its 'series connection is better' conclusion was also expected.

What the AltE video didn’t say is that neither configuration (parallel or series) is optimal. If one adds the power generated by each of the panels, alone, the sum is higher still - - 115+ watts. So, on the question of operating dissimilar panels . . . some loss in output will (likely) be sustained whether they are operated in series or parallel. And if one wants to achieve maximum output, separate charge controllers should be employed. (We researched other AltE videos but found nothing on ‘same voltage, different current/wattage’ panels. But AltE did say that when employing different sized panels, separate charge controllers will produce better results.)

[themexicandoctor]

Thank you for that perspective, Winston.

According to my Guru & my own feelings I see won't know if I have right set up until, the fridge goes in, despite the known 10% inefficiency.

Booster I am tired to reverse the order of my two batteries separated by 3 feet, 6 feet of cabling until I can find someone to do that wiring set up.

1. Am I likely to damage the batteries by doing so?

2. Or slowly reverse the difference?

3. Or should I get the wiring done & then start with two new batteries?

[booster]

Originally Posted by themexicandoctor

Thank you for that perspective, Winston.

According to my Guru & my own feelings I see won't know if I have right set up until, the fridge goes in, despite the known 10% inefficiency.

Booster I am tired to reverse the order of my two batteries separated by 3 feet, 6 feet of cabling until I can find someone to do that wiring set up.

1. Am I likely to damage the batteries by doing so?

2. Or slowly reverse the difference?

3. Or should I get the wiring done & then start with two new batteries?

If they have been in for a year, a while longer won't likely change much, I would say get the system all up to par first and make sure all is working right with the old batteries so you don't risk new ones getting things sorted out with the rest of the system. Once all is running well, then get the batteries tested, or as you mentioned before just replaced rather than kill 20 hours testing. Then all all should be good.

[themexicandoctor]

Originally Posted by booster

If they have been in for a year, a while longer won't likely change much, I would say get the system all up to par first and make sure all is working right with the old batteries so you don't risk new ones getting things sorted out with the rest of the system. Once all is running well, then get the batteries tested, or as you mentioned before just replaced rather than kill 20 hours testing. Then all all should be good.

Thank you Booster,

When you installed the second battery did you add the compensating wiring modification first or afterwards?

What was the difference in amps?

[booster]

Originally Posted by themexicandoctor

Thank you Booster,

When you installed the second battery did you add the compensating wiring modification first or afterwards?

What was the difference in amps?

Our original system was never balanced well, I didn't even know about the proper balancing of cables when we got the van. It had two batteries from the factory so we didn't do the add on. I did do a better job on the cable lengths when I added a third battery, but that was an intentional mixed battery setup that I wanted to test to see how much penalty there was in using mismatched batteries. It was two 6v batteries plus on 12v batteries.


When I went to our current setup of four 6v batteries, I made certain all the cable lengths were very well balanced.



With the original setup, I never did any detailed voltage or amperage difference data collection on it, but it was obvious from the water use and state of charge difference (wet cells so I could check specific gravity) that the rear battery was getting substantially more charge than the front battery was.

[themexicandoctor]

Booster,

I hear you - the first few years of ownership its as though expecting the Engineers* at Roadtrek to have already thought, worked through & tested those concepts before adding them.

*I must say that I always enjoyed stellar advice from Peter Lange in Roadtrek Customer Service who really knows his stuff.

And of course with the AGM's, unless you do very detailed, time consuming tests you just cannot tell the differences versus the wet cell units.

Were you as savvy then with those batteries or was there some learning curve for you also?

1. Where did you put the Third Battery?

2. Or do you recommend if* I add a third battery, that I place them under the bed on a Versatile, closest to the box** with the shunt, etc.

*if after adding the fridge my consumption demands more from my combined engine & solar charging

**when I took out the TrippLite 612 (the same joy & relief associated with removal of the Dometic 3 Way Fridge), I added the Magnum MMS 1012 unit (Pure Sine Wave), I had it installed to the rear of the box pictured & attached upside down on the upper housing of the bed & a computer fan installed in the flip dowm door under the bed. In hindsight, i probably always needed a fan for the TrippLite but not the Magnum.

[themexicandoctor]

Here is the upgraded box before & after/$500/4 hours other installers over the years who were competent for most work ie; installing the Magnum Inverter but that my Electrical Guru had to completely redo ie; I had two Earths that were giving my Victron BMV712 all kinds of incorrect info, this was before I installed the first Solar Panel.

[booster]

Originally Posted by themexicandoctor

Booster,

I hear you - the first few years of ownership its as though expecting the Engineers* at Roadtrek to have already thought, worked through & tested those concepts before adding them.

*I must say that I always enjoyed stellar advice from Peter Lange in Roadtrek Customer Service who really knows his stuff.

And of course with the AGM's, unless you do very detailed, time consuming tests you just cannot tell the differences versus the wet cell units.

Were you as savvy then with those batteries or was there some learning curve for you also?

1. Where did you put the Third Battery?

2. Or do you recommend if* I add a third battery, that I place them under the bed on a Versatile, closest to the box** with the shunt, etc.

*if after adding the fridge my consumption demands more from my combined engine & solar charging

**when I took out the TrippLite 612 (the same joy & relief associated with removal of the Dometic 3 Way Fridge), I added the Magnum MMS 1012 unit (Pure Sine Wave), I had it installed to the rear of the box pictured & attached upside down on the upper housing of the bed & a computer fan installed in the flip dowm door under the bed. In hindsight, i probably always needed a fan for the TrippLite but not the Magnum.

When we got the van, I had essentially no experience with 12v power systems or solar, so it has all been learning on the fly, trial and error as much of the information available was not exactly stellar.



The third battery came when we had damage to the fiberglass skirting in front of the right rear wheel. The corner got torn out. Since I had to do fiberglass repair and paintwork, I decided to modify the front battery box to take two 6v batteries there like the newer model 190s have. Bought a door from Roadtrek and cut out the existing box and support and built a new one big enough for the two batteries and fitting the bigger door.


I left the orphan single 12v battery behind the wheel to see how the mismatch behaved.


Most that have added battery(s) have put them inside the van, sometime putting all of them inside, sometimes just the added one(s). If inside, the wiring gets easier, but you lose space, outside is more complicated, but you lose less space, so neither is a perfect solution. That is why our current batteries are hung under the van where the generator was.

[themexicandoctor]

By golly Booster,

You are the last person on this site who I thought would have any kind of learning curve which makes your hard earned recommendations all the more valuable!

How did the mismatch behave?

I am assuming you now have three or four 6 volts? What* is the model & manufacturer?

*if you prefer to send me to a thread you created on this, that's okay too.

I probably am not going to.take my generator out now that I have invested $1200 in it the last couple of years & I like the idea of its utility & resale. Next time it turns Turtle, that is where I would put a new Battery system if I hadn't already.

But I might go 6 volt, with Lifeline products, next time knowing that they have better qualities for our needs.

I imagined that having them under the bed & closest to the wiring systems made them more efficient or is the effect, negligible?