What's the Latest Solar Tech?

[BurbMan]

I did a search and didn't find what I was looking for...The last time I looked at a solar system was a probably 5 years ago for our old Terry TT. Good systems were out of my budget range them and I stopped following the tech.

Fast forward to the Lance 811 truck camper we are rebuilding (water damage) and I'm once again looking into solar. The tech is moving so fast, stuff that's even a few years old is obsolete.

I've only got storage for one battery today, and that's a Costco Group 27 Marine/Deep Cycle. We're removing the microwave, so the only thing that will draw any power is phone recharging and a small TV at night. Which is just as well since I don't have much real estate on the roof this camper either.

Any suggestions for a good system for this small setup?

[ajriding]

I ran my solar wires down the fridge chimney. No holes, just double sided tape to hold the wires down, and VHB tape holding down the solar brackets.

With two panels you can run them in series. This doubles the voltage, but the charge controller can convert it back to what the batteries need. Going from 18 volts (used for 12v systems typically) to 37 volts (doubled) means you can use smaller wire, and just one pair of wires. The MPPT controller will bounce this down to the 14 volts needed.

There are lots and lots and lots of forum post about installing solar, so i wont go into any details further.

[n0arp]

Thermoguy wrote:
I haven't invested in solar as just don't want to put any holes in my roof

The fear of putting holes in your roof is overblown. Not a big deal.

[Thermoguy]

ajriding wrote:
you must have skipped over the post that talked about solar. Agree, the flexible ones are lower quality and more prone to damage and failuer and because there is no protective glass can be damaged by falling limbs or hail easier. They have their place if the situation calls for a thin and flexible panel, but the glass panels are the top choice.
mono is slightly better than poly but so close in performance it almost doesnt matter.
I cant imagine not having solar panels on my RV now.

I guess I did... I just re-read all the posts and still don't see it.

But, thanks for the info. I was unaware that the flexible ones were lower quality and more prone to damage. I was hoping the opposite. But, I haven't invested in solar as just don't want to put any holes in my roof. I also have a generator and can go a couple days without using it. I only use it if I want to run an AC component like Air or TV.

[time2roll]

Lithium is now available with internal heaters that should have them working fine in the cold.

[ajriding]

you must have skipped over the post that talked about solar. Agree, the flexible ones are lower quality and more prone to damage and failuer and because there is no protective glass can be damaged by falling limbs or hail easier. They have their place if the situation calls for a thin and flexible panel, but the glass panels are the top choice.
mono is slightly better than poly but so close in performance it almost doesnt matter.
I cant imagine not having solar panels on my RV now.

[n0arp]

Thermoguy wrote:
I surprised no one on here has talked about the advancements in solar panels? I'm not that familiar, but isn't there flexible as well as rigid? Aren't there multiple materials that solar panels are made of? Are some more efficient than others getting more use of reduced sunlight or shade and such?

I would be curious if anyone has any real experience with different types of solar panels and if any make sense in the RV market. Living in the Pacific NW anytime a company calls me to come to my house and talk about how I should add solar panels to my house to "save" money on electric costs, I tell them to go pound sand... I know there is no efficient way to use solar to offset our low cost of electricity. But things are changing fast and that statement may not be true for much longer.

Happy to hear if anyone has any real suggestions for the RV use.

thanks

There have been some improvements to cell design, but we're talking small, incremental improvements that tweak out a few extra watts per square meter for end users like us (there are some interesting advancements that aren't mass market). There are flexible panels but I know of several people who have used them and all have experienced premature failures and issues.

[Thermoguy]

I surprised no one on here has talked about the advancements in solar panels? I'm not that familiar, but isn't there flexible as well as rigid? Aren't there multiple materials that solar panels are made of? Are some more efficient than others getting more use of reduced sunlight or shade and such?

I would be curious if anyone has any real experience with different types of solar panels and if any make sense in the RV market. Living in the Pacific NW anytime a company calls me to come to my house and talk about how I should add solar panels to my house to "save" money on electric costs, I tell them to go pound sand... I know there is no efficient way to use solar to offset our low cost of electricity. But things are changing fast and that statement may not be true for much longer.

Happy to hear if anyone has any real suggestions for the RV use.

thanks

[phemens]

The concern with LifePO4 batteries in the cold is charging, not discharging. In fact they operate better than wet cell or AGM on discharge in the cold.
I don't see why you'd need to bring them inside when it's cold. Mine spent the winter in the 5'er without a hitch. Just make sure not to try and charge them when it's too cold (I avoid this below 5C).

[ajriding]

If concerned about the cold temps, then do consider that portable lithium battery. You can take it inside in the winter, and it is also available for lots of other things wherever you might take it.
I literally wish I could go back and get that from the beginning of my project.

I have 200 watts solar, and the batts usually recharged by the time I get up; I don't get up right at sunrise.

Good call on the 12v items

[BurbMan]

If I remember the 100w Renogy system will put out about 5 a/h. The only thing in use during the day may be cell phone chargers and possibly a radio and the water pump. So on a decently sunny day the battery should stay 100% charged by sundown.

Thinking more about the inverter set up, and looking at this 12v TV. At 39w / 12v = 3.25 a/h draw so for say 2-3 hrs of TV we should be fine.

Thinking about how we used the inverter in the TT, it was really only for the TV, so I'm thinking a 12v TV will save the overhead and expense of the inverter and transfer switch. All our devices are chargeable by USB.

[n0arp]

KD4UPL wrote:
My hesitation with Lithium batteries isn't based on fire. They also have a minimum temperature they should be exposed too. I'm sure it varies but the ones I've looked at had an absolute minimum temperature that was above what it often gets to on cold winter nights. If my camper is sitting outside all winter that would mean needing to unhook the batteries and bring them inside. With AGM or flooded batteries, as long as they are charged (and the solar will take care of that) there's no reason to unhook them and bring them inside during the winter.

True, but more of an issue with travel trailers where they are on the tongue. Mine are housed in passthrough storage with a furnace vent and a 200W heater that comes on if the passthrough temperature drops below 40F.

I just pulled a report for the last six months and the coldest reported battery temperature was 10C, or about 50F. Doesn’t look like the electric heater has ever been needed, and we’ve been below freezing many times.

[KD4UPL]

My hesitation with Lithium batteries isn't based on fire. They also have a minimum temperature they should be exposed too. I'm sure it varies but the ones I've looked at had an absolute minimum temperature that was above what it often gets to on cold winter nights. If my camper is sitting outside all winter that would mean needing to unhook the batteries and bring them inside. With AGM or flooded batteries, as long as they are charged (and the solar will take care of that) there's no reason to unhook them and bring them inside during the winter.

[n0arp]

ajriding wrote:
I was kidding about the battery fire, but some people worry on this forum about the most minute of things...

There are very real risks, especially associated with cobalt-containing chemistries such as most used EV batteries. LiFePO4 is benign and probably the safest of any batteries you will find available for RV use today. I think people who put used Tesla cells in their rigs, for instance, are asking for future trouble in all but the most sophisticated builds, which very few people do. By the time you get to a point where you've sufficiently mitigated the risks you might as well have gone with LiFePO4.

I went with a large Victron system and lots of residential panels and LiFePO4 batteries, and don't have to worry about energy management. The same equipment I'm using today was on the market in some variation or another five years ago, with very few differences. Solar tech is not changing that quickly, but costs of the existing technologies are slowly trending downwards.

[ajriding]

I was kidding about the battery fire, but some people worry on this forum about the most minute of things...

Agree, you don't want to just imp by with ever decreasing battery charge. If you have batteries, get solar!
It cost a few hundred up front, but power is free after that, and long-term much cheaper than a generator, gas and the hassles it brings.

You said 30 watt TV. Amps is the critical number, not watts. If you have solar and start the evening off with charged batteries, then TV will not be any problem at all.
I have two GC batts and run a big electric Danfoss compressor fridge/freezer and still have available power, and the fridge should be the biggest power consumption I ever use, though an inverter running something big will be a drain also. If you can get DC powered everything this is more efficient than using the inefficient inverter to turn DC into AC, and everything except lights and heaters will turn that AC back into DC anyway (your TV does).
You laptop will be the only thing that prob does not have a DC way to charge...

Also, with solar, use power early in the day so there is time to recharge before dark, if possible.