OK, OK. If I can keep you kids from spatting long enough and on subject, I'd appreciate your input on the rest of my thoughts as the Thread Starter.
Again, we just have a small Coachman 16B and we are not full time campers (will not retire until next year). In general, moving slowly, do you think this path is reasonable?
1) Add (yet to be fully determined) about 150 Watts of solar, properly sized and length wires, a good quality charge/controller, and true battery monitor now. (Use with my current group 24, 12V basic deep cycle battery.)
2) 6-12 months later (after retiring), upgrade to 2-6V TRUE deep cycle/golf cart type batteries.
Or should I reverse that order? Will the current camper charger/converter properly and fully charge the 2-6V TRUE deep cycle batteries as is and just plan on them being my supply/reserve since I only dry camp 3-4 days at a time right now?
With my 700W system, I run it through a Victron MPPT solar controller. Since I have them flat mounted, I can expect 25% less most of the time. In June, I can get in the 600W region.
With 25% derating for flat mounting, 700W x .75 = 525W. At a 14V charge, that is 37.5A. With a 5 or 6 equivalent sun hours that's 187AH or 225AH. More than enough to charge up my 200AH bank of Battleborn batteries. My batteries can be discharged almost completely vs flooded batteries which shouldn't be discharged past 50%
You can use similar calculations for your system based on your battery capacity
With 150W flat mounted and an MPPT controller, if you de-rate 25% for flat mount, you will get 8A. With 5 hours equivalent sun, that would be 40AH. For what you are describing as your usage, that would be fine if you had sun every day. If you wanted to fully recover from a 50% discharge with 2 6V batteries, you would obviously need more than that.
I had a pretty simple system on my last 5th wheel, I am in the process of upgrading it right now on my new 5th wheel. I am a full-timer, have been for 10 years, lovin every minute of it. I found that guide above recently, I liked it because it showed me how to build my own "Combiner Box" cheaply at Home Depot (which I did) and there were a ton of links on this site to explore which I liked. Very easy to understand. I am not going to re-hash everything everyone has already said - I am obviously pro-solar. One thing that has not been said, there are campgrounds out there that have limited full hookup sites but are very desirable - I am at 1 now - Key West - so there is a lot of Dry Camping. The catch is you can't run your generator's after a certain time at night, or before a certain time in the morning. Well, I don't care about that, I have fans, and I have batteries. I can watch TV all night long if I want. Anyway, just a thought, I am retired from the Military and I am on a Military Base. Not sure if there are other places with rules like this or not.
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God created the fishing pole to keep the truly gifted from ruling the world!
One additional note, I do not plan to mount the solar panel at this time. It will be portable and I will be able to better select the sun and the angle for more efficient charging.
One additional note, I do not plan to mount the solar panel at this time. It will be portable and I will be able to better select the sun and the angle for more efficient charging.
That will help a lot. You might get up to 10A then so 50AH with a 5 hour equivalent sun day.
Just to explain what equivalent hours is...Sun may be out 12 hours but since it is low on the horizon and is going through a lot of atmosphere while its not overhead, the output of the panel looks like a bell shaped curve over those 12 hours. Converting the area under that curve to a 100% output case is how the equivalent hours comes from.
In the discussion non engineers are unaware of the most difficult problem.
Since the invention of the wet cell batteries there has been little improvement in batteries since the 1800’s. The problem is we cannot store electricity well. Yes better now but, not enough. Diesel tractors will be around for a while.
People out west in the desert states think their solar farms are so cool. So do I.
But, did you notice their electricity rates are really high?
Well that is because of the storage issue. Thus all solar farms need a second large fossil fuel plant back up. They need back up likely 60% of the time. So they are environmentally friendly 40% of the time.
Second big engineering problem is transferring electricity from here to there has large losses. So you cannot buy our excess power in Ohio at night!
Solar collectors are sort of big. Rv’s are not big enough to do a lot of solar.
Likely except in limited situations solar is still an interesting dream for the rv world.
Until they figure out how to run my ac in Houston in the summer off of solar, I’m out.
In the discussion non engineers are unaware of the most difficult problem.
Since the invention of the wet cell batteries there has been little improvement in batteries since the 1800’s. The problem is we cannot store electricity well. Yes better now but, not enough. Diesel tractors will be around for a while.
People out west in the desert states think their solar farms are so cool. So do I.
But, did you notice their electricity rates are really high?
Well that is because of the storage issue. Thus all solar farms need a second large fossil fuel plant back up. They need back up likely 60% of the time. So they are environmentally friendly 40% of the time.
Second big engineering problem is transferring electricity from here to there has large losses. So you cannot buy our excess power in Ohio at night!
Solar collectors are sort of big. Rv’s are not big enough to do a lot of solar.
Likely except in limited situations solar is still an interesting dream for the rv world.
Until they figure out how to run my ac in Houston in the summer off of solar, I’m out.
You really don't think lithium batteries are an improvement over wet cells from the 1800s?
Of course the rest is mute since we are talking RV usage here for the OP's small trailer.
Want to add solar to my small Coachman 16b TT. Doing the planning now but can't find a good chart of what the power usages are on all the 12V items in the camper. I also plan to add a small inverter just for a little TV or radio/CD/DVD occasionally.
Anyone have a link to a good power usage chart?
Thanks.
Below are a couple images that might help, too. I see some formulas were already provided in a reply from someone else.
Look at the bottom of your appliances and such. Watts are usually put on the items. Then, you can convert to amps to calculate draw. Once you get used to your consumption needs and replenishment time, you will be able to tweak and adjust as necessary. Inverters draw power as well, and yes, as some have mentioned, depending on what you are running, your battery can go fast. See if you can get a DC TV. Might help lessen the inverter draw.
Fact is ...solar works. Don’t believe all the nay-sayers and negativity. Some here are so dead against it. They seem to become incensed and do not really help people that are wanting to use solar, for whatever reason.
I have 2 – 12v batteries and 2 – 100w solar panels, and I do not have a generator. One panel on the roof and one mobile to move around so I can park in the shade when I want to. I have no power issues and even pull charging amps in the rain.
As long as you do want to run your air conditioning or power a unit that takes more juice than your house, you don’t need to put much money into a system. My whole solar system is less than $500.
Lithium hold more per pound. Easier to charge. Not good in cold. But, better.
expensive.
We need a bigger step before the gasoline engine is put out of business. We need much more to make solar a reality anywhere. When California gets rid of fossil fuel back up. Not in my lifetime likely.
Note the lithium represents more that 100 years in the making. Closer to 200.
I like the term better.
The advantage for my fiver is faster charging and less weight. Not worth $2000+. My batteries cost $400. They will last five years. Likely I would have replaced my fiver by then.
If I lived in Cali I might feel different. I can last as long as you can without solar. 460 amps as I remember. Then I would have to run a tank of gas thru the generator or plug in.
In the Midwest residential refrigerators are the new thing. Everyone is plugged in all the time. Those fridges would wipe out our battery banks in a day in warm weather.
We engineers have to look at the total picture and all customers. I just think the solar thing for most of us is decades away. In your case I agree with your choice. But, you are the minority.
Ok, a few snarky replies here, but i’m now entering my second month, boondocking in a 39 foot motorhome on solar. I know what im talking about. Ive done this for 8 years now, at least two months a year
The bottom line is that there are too many variables to easily answer your question. What I can do is offer some guidelines.
First, plan on adding as much solar as you can stuff on your roof, even if you dont do it now. Use a good mppt controller that will handle all the panels you can fit. Use 8 gauge wire from the panels to the controller. Keep your wire length to a minimum. Wire the panels in parallel. There is a minor advantage to series, but its all lost if there is any shade on any panel and it flips to a huge disadvantage.
Next, replace every light with LED. This is a huge deal that dramatically reduces your consumption.
As for consumption, I burn about 135 amp hours a day. That runs my CPAP at night, runs my coffeepot in the morning, runs the hair dryer, the microwave for about 5-10 minutes a day, TV and lighting for 3-4 hours at night, and the computer and printer. Ive got 840 watts of panels and I top off every day -unless it rains. You could easily get by burning far less.
Dont even think about a residential fridge for boondocking. The math just doesnt work. 1 amp at 120 is 10 at 12 volts.
Dont forget that your inverter sucks power even if its not powering anything. Mine has a residual draw of about 4 amps. Cut it off if you don't need it.
Part two of the solar solution is batteries. Stuff as much battery onboard as you can. I run 4 LS16 AGMs. Expensive,but .i can run 3-4 days and still only use half my reserve. 6 volt batteries may provide more capacity, but run the numbers to be sure. Its really not that big a difference and its easier to run 12s.
Generators msy be a backup, but arent usually needed with a good solar system. I havent run mine at all in the past month.
Ok, a few snarky replies here, but i’m now entering my second month, boondocking in a 39 foot motorhome on solar. I know what im talking about. Ive done this for 8 years now, at least two months a year
The bottom line is that there are too many variables to easily answer your question. What I can do is offer some guidelines.
First, plan on adding as much solar as you can stuff on your roof, even if you dont do it now. Use a good mppt controller that will handle all the panels you can fit. Use 8 gauge wire from the panels to the controller. Keep your wire length to a minimum. Wire the panels in parallel. There is a minor advantage to series, but its all lost if there is any shade on any panel and it flips to a huge disadvantage.
Next, replace every light with LED. This is a huge deal that dramatically reduces your consumption.
As for consumption, I burn about 135 amp hours a day. That runs my CPAP at night, runs my coffeepot in the morning, runs the hair dryer, the microwave for about 5-10 minutes a day, TV and lighting for 3-4 hours at night, and the computer and printer. Ive got 840 watts of panels and I top off every day -unless it rains. You could easily get by burning far less.
Dont even think about a residential fridge for boondocking. The math just doesnt work. 1 amp at 120 is 10 at 12 volts.
Dont forget that your inverter sucks power even if its not powering anything. Mine has a residual draw of about 4 amps. Cut it off if you don't need it.
Part two of the solar solution is batteries. Stuff as much battery onboard as you can. I run 4 LS16 AGMs. Expensive,but .i can run 3-4 days and still only use half my reserve. 6 volt batteries may provide more capacity, but run the numbers to be sure. Its really not that big a difference and its easier to run 12s.
Generators msy be a backup, but arent usually needed with a good solar system. I havent run mine at all in the past month.
I agree with most of what you say except for parallel vs serial. If you have an MPPT you want to run serial. Panels have bypass diodes for a reason.
There is this guy Brian Boone that runs solar pages on Facebook. For some reason he has it in his mind that parallel is better than serial too. If you don't drink his koolaid, he boots you off his group. He basically knows how to install(kinda) but gives no technical reason behind his theories. Personally, he would be the last person installing anything in my RV.
OK, OK. If I can keep you kids from spatting long enough and on subject, I'd appreciate your input on the rest of my thoughts as the Thread Starter.
Again, we just have a small Coachman 16B and we are not full time campers (will not retire until next year). In general, moving slowly, do you think this path is reasonable?
1) Add (yet to be fully determined) about 150 Watts of solar, properly sized and length wires, a good quality charge/controller, and true battery monitor now. (Use with my current group 24, 12V basic deep cycle battery.)
2) 6-12 months later (after retiring), upgrade to 2-6V TRUE deep cycle/golf cart type batteries.
Or should I reverse that order? Will the current camper charger/converter properly and fully charge the 2-6V TRUE deep cycle batteries as is and just plan on them being my supply/reserve since I only dry camp 3-4 days at a time right now?
Thanks for you solid input.
Outsider, I would go with the 6v batteries first, nothing like available Amphours.
We have a Small RV(Coachmen 20CB). On a low budget. Original Type 24 12v battery was useless, six volt GC batteries would not fit in so i wound up with two rather inexpensive group 24 12v, 75ah.
Added:
-Renogy 200w kit including 30a PWM controller ($315) I hinged the two panels together and can move them to wherever the sun shines brightest.
-35 feet of 8awg wire and connectors, also from Renogy
-DROK digital charge/discharge meter with 100A shunt. $29
-Potek 1000w inverter $79
Fair amount of planning and labor to get the whole system wired in. Up here in the Northeast all campsites will have shade so rooftop mounting makes no sense IMO. With 75ah of battery available we can go two days and nights even if no sun is available. Our 200 watts of panel will usually push in 25-30ah in an average day. In full sun we may see 9 amps but in New England that's rare. Our electrical usage is fairly low. 12vdc fans run all night, the usual cell phone and laptop charging. Occasional furnace during the night (6amps) and of course the water pump (another 6amps). The Potek inverter powers the tv, laptop chargers, a 750w toaster (i gotta have toast in the morning, this puts 65amps drain on the batteries but only for two minutes, about 2ah). By the way, the Potek inverter has a negligible drain, less than .1a if no AC items are turned on.
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Woody & Cookie
2022 Coachmen Apex Remote 16R (Remo)
New Hampshire
Yep, I know that solar is not for everyone, that also it can be expensive, and needs to be well planned in order to work well.
We are somewhat of minimalists in most things. Small camper, in general we boondock only 3-4 days at a time, no big TVs or sound systems or hair dryers so I think we can make it work for us if I get the design right. I've studied it a good bit starting with "Handy Bob's" stuff.
Thanks again.
Outsider.
We are very much minimalists in our A-frame, with daily consumption less than 30AH with 5 hrs/day of heater use.
We don't use the stereo, and installed a switch to cut that parasitic drain.
Solar was not for us, given the winds in the Midwest and Rockies, an A-frame, and a preference for well-shaded sites. We don't use a generator, either, due to weight, having to carry fuel, and often being away from the campsite all day.
We did size our batteries to run up to 4 nights dry camping without recharging. 2 Costco/Interstate 210AH GC-2 batteries give us that capacity.
Hope this helps
Fred W
2019 Flagstaff T21TBHW A-frame
2008 Hyundai Entourage minivan
camping Colorado and adjacent states one weekend at a time
One of my questions has not been addressed directly. If I upgrade my batteries first from (1) 12V Group-24 Marine type to (2) 6V true deep cycle golf cart type (without adding any solar) will the original charger/converter in the camper FULLY charge those batteries and if so, will it take any longer? Apparently this is a true 3-stage charger (WFCO WF 8735-PB).
One of my questions has not been addressed directly. If I upgrade my batteries first from (1) 12V Group-24 Marine type to (2) true deep cycle golf cart type (without adding any solar) will the original charger/converter in the camper FULLY charge those batteries and if so, will it take any longer? Apparently this is a true 3-stage charger (WFCO WF 8735-PB).
Thanks for your input.
Outsider (The OP)
It won't matter really. Just be aware that those WFCO converters are notorious for never staying or even getting into bulk charge mode which is where the majority of the charging is done. What that mean is if you rely on a generator to charge up your batteries daily, It will take longer than a better converter would do like a Progressive Dynamics. If you aren't going to use a generator and you charge at home, that may not matter to you.
First thing I did when I bought my trailer was pull the converter and sell it on eBay.
One of my questions has not been addressed directly. If I upgrade my batteries first from (1) 12V Group-24 Marine type to (2) 6V true deep cycle golf cart type (without adding any solar) will the original charger/converter in the camper FULLY charge those batteries and if so, will it take any longer? Apparently this is a true 3-stage charger (WFCO WF 8735-PB).
Outsider (The OP)
I've been down that road on 2 A-frames both with WFCO 8735P converters as OEM. Both never left Normal mode (13.7V) for Trickle mode (13.2V). I had 2 Group 24 batteries in parallel at the time.
The over-charging may have caused a cascade of failures because I didn't pay attention to what was going on. For whatever reason, one battery failed (I suspect low water level from over-charging) and drained the other during a 3 day camping trip (with hook-ups). At some point, the battery circuit fuse (which I didn't know) on the panel blew so the WFCO could not recharge either battery. When I got home, rather than set up the camper to investigate, I used an old Sears battery charger to recharge. One battery would not take a charge - it kept popping the internal circuit breaker on the Sears charger. The other battery was OK if I started in 2 amp mode, and later switched to 10 amp mode. A few days later, I replaced the fuse in the WFCO, and went to re-parallel the batteries - forgetting they were at very unequal charges. I got an electrical fire in the single dual battery box. Cut the glowing red hot parallel cables which were causing the hydrogen gassing from the battery vents to flame, and the fire went out. I finally took the time to evaluate what happened.
I installed a battery cut-off switch on the battery box, and a voltmeter inside the door on the microwave cabinet (with an on/off switch because the thing is too bright at night). I also put a switch on the stereo power leads to eliminate the parasitic draw - pretty significant because the stereo would come full on with any sudden voltage change.
I replaced the batteries with Costco/Interstate GC-2s and started monitoring voltages. That's when I realized the WFCO never went into trickle mode - even after 3 weeks in normal mode with only the propane/CO detector on.
I replaced the WFCO with a Progressive Industries 4135 "drop-in" replacement even though I was still under the then 2 year warranty. Since I don't carry a generator, a bigger converter (I could use 40 or 45 amps for fastest achievable charging) wasn't necessary. The PI readily goes into all 3 modes, which I verify with the voltmeter. And the PI converter holds bulk mode until about 90% SOC.
On my 2nd A-frame, I installed new Costco/Interstate GC-2s from the get-go (dealer gave me a credit for giving back his battery). I measured voltages from the WFCO 8735P over 3 weeks, and sure enough, it never left normal mode for trickle mode. Again, replaced the WFCO with a PI 4135 (didn't bother with warranty), added a cut-off switch, a voltmeter, and power switch for the stereo.
With the Cool Cat venting into the space between the twin beds, I also moved one of the vents to face forward at the end of the bed, and improved the fridge installation.
Bottom line: measure the voltages and verify your WFCO 8735P is working correctly. Don't assume like I did.
Just my experiences
Fred W
2019 Flagstaff T21TBHW A-frame
prev 2014 Rockwood A122 A-frame
2008 Hyundai Entourage minivan
camping Colorado and adjacent states one weekend at a time
Yep, I verified that it goes into a float or trickle charge mode of 13.18 volts after 2-3 days of charging. Regular mode is 13.67 V.
That's good to hear.
No need to change the converter unless you need to charge the batteries with a generator while camping. The WFCO will waste a lot of generator time in normal mode instead of bulk mode - but that only matters when recharging with a short generator run.
Linear Mode
