Adding solar - thoughts please

[Vermilye]

Originally Posted by UncleTim

So if I were to switch out the 12 volt system with a Battle Born battery and system, would I need to just switch out the batteries, solar controller and electrical panel? Anything else?

If you have this type of system, do you notice the benefits?

I am just wondering because I know the standard 12 volt batteries have a limited lifespan. I am wondering if it makes sense to think about this for a replacement system. I have two panels providing 380 watts. I pick it up in a couple of weeks.

Depending on your tow vehicle, you might want to add a DC to DC converter to the trailer charge line. Two reasons - Modern automobile voltage regulators tend to drop the charging voltage as soon as possible to improve fuel mileage. Preferred charging voltage for Battleborn lithium batteries is around 14.4V. It is unlikely that, unless you have a truck that adjusts the alternator output when a trailer is attached, you will do much charging from the tow vehicle.

The second problem - if your tow vehicle does not have a charge line disconnect when the ignition is off, the lithium batteries will try to "charge" the tow vehicle battery because its typical resting voltage is over a volt higher than a lead acid battery. The DC to DC converter is one way so no back charge to the tow vehicle. That does present an interesting additional problem. Your break away switch and, if you have one, power tongue jack are powered by the trailer charge line. If you put the DC to DC converter close to the trailer batteries, you will need to add wiring to power the break away & tongue jack.

I've noted the benefits in a number of posts, but the highlights are: Faster charging because there is no absorption phase until the batteries are 98% full. Very little SOC loss during storage. With no load, I have lost less than .1V over a month. Plenty of voltage as the battery SOC drops - you will be able to run your inverter with the batteries at 30%. Lighter weight 31 pounds each. No more hydrogen gas produced propane alarm alerts. No need to stand on your head to check & fill the lead acid batteries under the seat (21 & 5.0TA).

[UncleTim]

I read your posts previously and I use them to educate myself. I really like the sound of this. I love the extra depth of reserve in the batteries.

For now, something to watch. I gotta go smell some lead-acid fumes for a year or two.

[Eggscape]

Originally Posted by rubicon327

I have thought about solar on the tow vehicle so the trailer could be parked in the shade and tow vehicle moved into the sun (where possible). Obviously would only work on big sites with partial shade.

I do like the idea of easily removable rooftop panels that could double as a portable if parked in shade. Seems to me it would just take the right mounts and quick connect wiring.

Just brainstorming....

I was also thinking thinking about solar attached to the truck bed cover or stored hanging below on brackets so they slide out for portable use. This way I would have charging with me on communications events and at the cabin.

I also thought about roof top storage at the rear of the trailer. On each side mount a u shape aluminium rail that extends a few inches beyond the rear of the trailer. The solar would have small wheels on each end corner that would slide in the u shape channels.

If the sun was from the front of the trailer you could pull a pin and allow the panel to roll to the rear a few inches where the rear wheels came loose and the rear of the panel could be raised.

If the sun was from the rear of the trailer you could roll the panel further just before the front wheels came out of the track. Put the pin in the rear of the track to hold the wheels there and hang the panel down in a supported position.

If parked in the shade or need at another location you could remove the panel and place it where you wanted.

However glass panels are heavy compared to the flexible ones. I have also been thinking on how to support a flexible panel in a portable environment to ensure a longer life. What I am toying with is attaching a flex panel to a 2 x 4 ft plastic type ceiling light grid material. This would give decent support and allow good cooling at the rear of the panel.

I am just not impressed by the warranty offered for the flex panels. For us, we would probably only use the flex panels a few times before they were out of warranty as we seldom stay in one spot more than a few days and don’t have an inverter.

[UncleTim]

So in my very short time as an Escape owner with an actual trailer, I am willing to make a few battery related observations as we camp in the driveway.

1. It seems you can draw down batteries fairly quickly. A few microwave bursts along with some TV and additional lights on, can bring battery capacity down a third quickly. I got a wife that likes popcorn in the evening.

2. The charge time to recover is unbelievably fast. It is recharging the third capacity lost by 8 am. And there is only a small fraction of the panels getting direct light. This is impressive.

This system user (me), seems to be prone to battery anxiety once the system is between a third and half discharged, during the night. So I go thru an informal energy audit as the evening proceeds so as to not use too much power. Not sure if this is even justified yet. It seems odd that 'half drawn down' is an important number yet the monitoring panel reports back in thirds.

256 amp hours, 127 of which is available for consumption is not all that much. You can drain it pretty quickly. But by 8 am, it seems power is fully restored and freely available. Even the big speaker and guitar batteries can be easily charged. I have a 300 watt power inverter I am playing with just to see if I can take a load from the big inverter and extend it's life for small uses. It uses the 12 v connector.

The real management problem are the evening hours, when power is being consumed at a high rate and is not being replenished until the Sun comes out. Longer days may mitigate this to some extent.

In a very preliminary way, this starts to make the case for a more advanced set of lithium ion batteries and solar charger controller so deeper reserves ensure more power is available when it is needed most.

I get battery anxiety! I am currently working on this personal issue.

[MyronL]

For me the practical solution is reserve battery power for the few appliances that cannot serve without it, and use the other power source available, propane, for everything else.

[UncleTim]

I agree, and that external 500 watt power supply is actually coming in pretty handy at night.

[fudge_brownie]

It appears that you are using the built in monitoring system, the one that monitors fresh and gray water? I guess that because you mention 1/3 rds. If so, that battery monitor is very unreliable. I would not put an stock in the measurements that you are obtaining.

Can you obtain a voltage reading off the solar controller? That would be more accurate.

To get an accurate reading you need the actual volts of charge. The most inexpensive method, but not the easiest, is a multi meter reading off the batteries. Another method would be checking your solar controller, if so equipped. Some solar controllers allow you to purchase an inexpensive remote monitor or as mine using an app on my phone. Look into that. Then there are the units that have a specific purpose to measure such as Victron, Trimetric and a slew of imports.

When using an inverter there is a large draw during use and then a slow recovery after stopping. I find it difficult to use my inverter when the batteries (dual 6 volt AGM) are below 80%.

Here is a sample of voltages, note this varies by manufacturer and model:


Interstate Battery "State of Charge"
100% 12.84
90% 12.72
80% 12.64
70% 12.56
60% 12.48
50% 12.20

Measured after resting for two hours

[cpaharley2008]

I purposely set up my trailer to be all 12v except for the a/c. No inverter, no 120v appliances nor a/c unless hooked up. Cook and cool on propane, heat is 12v and propane, water is 12v, lights is 12v. All accessories operate off 12v or recharge with 12v, like computers, phones and fans. Never get below 80%. Check you battery water levels regularly also.

[UncleTim]

Jim, do you have a TV?



Does it run on 12 V too?


Thanks.

[Perry Butler]

Originally Posted by UncleTim

256 amp hours, 127 of which is available for consumption is not all that much. You can drain it pretty quickly. But by 8 am, it seems power is fully restored and freely available. Even the big speaker and guitar batteries can be easily charged. I have a 300 watt power inverter I am playing with just to see if I can take a load from the big inverter and extend it's life for small uses. It uses the 12 v connector.

Are you saying you're using up 127 ah's by morning? If so, your batteries aren't going to last as long as they can.

We have 220ah's of AGM batteries. To get maximum battery life we want to use 55ah's or less a day, not 110 ah's.

Enjoy,

Perry

[UncleTim]

No, that is the total. I use at most a third of that.
We have a maximum of 256 amp hours and you can only use half of that. That was just a calculation.

[Vermilye]

Originally Posted by UncleTim

No, that is the total. I use at most a third of that.
We have a maximum of 256 amp hours and you can only use half of that. That was just a calculation.

What batteries do you have? Escape rates their dual 6v batteries at 225 amp hours: "Dual 6V Batteries (225 amp hrs) +$275.00"

If you are down 1/3 (75 amp hours), your solar controller may tell you you are back at 100% by 8:00AM, but remember the GoPower solar controller shows 90% (what they call full) well before the batteries are actually full.

Even if the controller stayed in bulk for the entire morning, assuming you had 3 hours of daylight between dawn & 8:00AM, your panels would have to produce 25 amps the entire time. That isn't going to happen with 190 watts or ever 380 watts (2 panels) of flat mounted roof top panels. If the controller switches to absorption, (which they generally do at 80%), the current will be well under 10 amps to prevent gassing.

I'm not saying you can't put back 75 amp hours by the end of the day, but I don't see how it is possible by 8:00AM.

[UncleTim]

I actually have no idea how much I am using or getting back. So far I am just using the small battery and tank indicator. So I really do not know. How do you determine that? I have not gotten that far yet. Thru the solar charger?


I just have the standard batteries supplied by Escape so I guess I have 225 amp hours. I was recalling from memory.

[padlin]

You can either do the math and figure out how long you are using each item and it's power requirements, or you can measure it for the actual figures. In the past I've used a DC current meter but now I use a good power/battery monitor, like many others.

[Patandlinda]

Originally Posted by rubicon327

Found this. Pretty neat...
https://www.rvwithtito.com/articles/...window-awning/

Saw that Dave and really like and may use for more solar . Pat

[UncleTim]

Tito uses a Battle Born battery system. He put it in about 120 days ago. He has a nice system.

[fudge_brownie]

Originally Posted by UncleTim

I actually have no idea how much I am using or getting back. So far I am just using the small battery and tank indicator. So I really do not know. How do you determine that? I have not gotten that far yet. Thru the solar charger?

I just have the standard batteries supplied by Escape so I guess I have 225 amp hours. I was recalling from memory.

see post No. 27

[UncleTim]

Right. I am looking for the manual now.



Thanks, every little bit helps.