What is the Best Battery to use and Solar Charger

[cjkrause]

in our TD there is a small looks like a m/c battery
what has been the best battery used here in TDs
what has been the easiest solar charger to use that can be roof mounted for a reasonable price

i am thinking about changing out the lil battery for a Yellow Top Optima

any thoughts and all appreciated especially since i am new

[Autobo7]

Depends of your electrical usage. Are you just powering a few lights and a phone charger, or are you looking to power something more substantial(microwave, TV, toaster)? Golf cart true deep cycle batteries are a good idea if you need more juice because you can totally discharge them with little repercussion, car batteries can lose capacitance when they drop below even 80% . If you only have a few lights then its not that important and a car battery might suffice. I would also say the same about your solar panels. If you are on the go a lot then your car will probably charge the trailer just fine if you usage isn't too high. Harbor freight is a good place to look for cheap solar panels if you are planing on staying the same place for a while and are using you battery a lot.

So are you staying in place for more then a few days? and are you using a lot of wattage?

[cjkrause]

lights, small apt fridge and a 4 way convection oven.
fridge would be the only thing running all the time on trips
we are new to this and learning
i like the golf cart battery idea and any better than others?
i will check out Harbor Freight. got to love that place especially if you are a gearhead

[GuitarPhotog]

A fridge and a convection oven are usually high-wattage items that run only from 120 VAC. Do you plan to use an inverter to power these 120 VAC appliances when you are not plugged in to shore power?

If so, I recommend something on the order of 200-250 AH of battery capacity ($$$).

<Chas>

[Esteban]

Its usually better to use appliances in a camper that require less power. An apt. sized fridge (dorm fridge) needing AC power is not power thrifty. The cost and weight penalty of using 200-250 AH of battery capacity ($$$) in order to use an AC powered dorm fridge would be very substantial. Better power conserving appliances are available like some AC/DC fridge freezers.

A Truckfridge http://www.tnttt.com/viewtopic.php?f=32&t=57386 or one of its variants might be a good alternative. No inverter would be needed with one. Nor would such a large/heavy/costly battery. A single 100 AH battery could be enough, saving hundreds of $$. Lower cost fridge/freezers are available from Dometic and Waeco too.

If you already have one, the apt./dorm fridge could be nice to use in your garage, work shop, man cave, rec. room, etc.

ul-solar.com http://www.ul-solar.com/ has solar panels that can fit on the roof of a teardrop.

Aerodynamic solar panel corner mounts for a boat or rv http://www.emarineinc.com/products/Solar-Panel-Black-ABS-Corner-Mount-%28set-of-4%29.html

A Sears Die-Hard Platinum Marine Battery in either size 34M http://www.sears.com/diehard-platinum-marine-battery-group-size-34m-price/p-02850134000P?prdNo=2&blockNo=2&blockType=G2 or 31M http://www.sears.com/diehard-platinum-marine-battery-group-size-31m-price/p-02850131000P?prdNo=1&blockNo=1&blockType=G1 could power your cooler, lights, etc..

[Shadow Catcher]

As stated you will be hard pressed to power a dorm type fridge using solar. We have a 185W high voltage panel that powers our Waeco 12V refrigerator adequately using a Morningstar MPPT controller and a 150 AH battery. Anything using resistance heat i.e. your convection cooker, is out unless you have LOTS of power. A good place to start is http://www.solar-electric.com/deep-cycl ... y-faq.html Marine batteries are generally not true deep cycle, see write up in the FAQ.

[cjkrause]

thanks for all the tips and sources and posts
learning allot

the TD already has a inverter and has a plug to plug into a outside electricity source to power at the camp site
would be the odd times where there is no power camp sites available so we to look at budget and see what we can afford to add

[GuitarPhotog]

the TD already has a inverter

What is it connected to? An inverter converts 12 VDC to 120 VAC, and needs a 12 VDC battery to operate.

Are you sure it's an inverter?

<Chas>

[Esteban]

The Morningstar SunSaver 15 Amp MPPT Solar Charge Controller http://www.solar-electric.com/mosumpsochco.html looks to be the one
Shadow Catcher uses and is suggesting. When the time comes I'd like one too...probably used with a 125 watt 12 volt panel from UL Solar. The 125 watt panel easily fits across the roof of most teardrops.

UL solar 12 volt 125 watt panel
Weight: 26.46 lbs
Dimension: 48.5 in x 26 in x 1.97 in

Unfortunately UL Solars panels with a wattage rating greater than 125 are physically larger too. Almost 5 ft. long. Too long to fit across most teardrop trailer roofs without overhanging the sides.

If cost was not a factor (yeah right) a battery like a Sun Xtender PVX-1080T Sealed AGM Deep Cycle Battery, 108 Amp Hour 12 Volts http://www.solar-electric.com/concorde-sunxtender-pvx-1080t.html or a similar one from Lifeline (a GPL-31T with 105 AH)is what I'd like. Pushing it to the $$$ limit a Lifeline GPL-31XT with 125 AH would be highly desirable. Its extra storage power might allow almost an extra day of power usage in a pinch.

Getting somewhat off topic. With an efficient 12 volt fridge/freezer, Fantastic Fan and all LED lights I'm estimating using 20-30 amp hours of power daily. A 125 watt solar panel with a Morningstar Sunsacer 15 amp mppt controller should produce roughly as much power in a good sunny day. With an AC charger like the PD 4045 and by charging while towing I think/hope all together there would be enough storage and charging capacity to camp or travel comfortably.

[bdosborn]

There really isn't a good reason to go with an MPPT controller on a teardrop, if you pick the panel smartly. MPPT is very $$$$ and there isn't any payback with a small system (<500 watts). SC has an MPPT controller because he has a grid tie panel that wasn't designed to charge a 12V battery. I have one because I thought they were cool and would maximize my solar harvest. It is cool but the increased performance in'ts worth the additional $150 or so. The Sunsaver PWM type controller and a 12V panel is the better design for a teardrop...

Bruce

[working on it]

I have a Yellowtop Optima; I also have an inverter. My Optima got completely discharged over a month or so, by having the inverter hooked directly to the battery. Thanks to people here, especially Bruce, I was able to save the battery and restore it to good health. I also learned how to properly charge an AGM, which will really help keeping it good (damned expensive). Do not leave an inverter connected, unless you're using it! Another thing to watch out for: an average inverter is only 85-90% efficient, so whatever you power with one will draw 10-15% more amp-hrs than it's rated. I only intend to use mine (410 watt) to power a 3amp (ac) fan, or some Ikea 110vac LED lights (if no shore power is available, or the neighbors don't want me running the on-board generator). I do have some 12vdc only cabin and galley lighting and 12vdc computer case fans, too, so I really only need the 110vac for the A/C unit. Solar panels are not an option for me; I don't have an EE degree!

[Esteban]

Bruce, you are right that an mppt is kind of a luxury. One 125 watt 12 volt panel is the largest one that I can fit on the roof. It's 26" X 48". There is no room for a 2nd panel or a larger wattage panel. (I hope) the mppt may harvest a few more amp hours per day. From what I've read its a real possibility. I hope a 125 watt panel is enough and think it can be.

I've looked for solar panels from many, many sellers whether 12, 24, or 36? volt that could produce more power in the space available and come up with nothing better than a 125 watt 12 volt panel from UL Solar. Every other panel with more power output is physically too large. More powerful panels jump up to nearly 5 ft. long, often longer. Often wider too. They're just too big. So available roof space is my limitation

I wish I had real life experience with how much power I need per day and how much can be harvested per day from the sun. Not there yet.

Another option for more power (amp hours) is to get a portable solar setup too like your folding panels. A valid choice. Its an extra cost similar to the upgrade $$ from pwm to mppt, a complication to set up, move around, take down, guard from accidents or theft, adds weight, and takes up precious storage space. I lean to using an mppt as a an easier to live with "luxury." I fully admit I am only a "book read" (internet too) solar RV noob with no RL experience.

I don't want to thread-jack CJ's thread either.

[bdosborn]

Bruce, you are right that an mppt is kind of a luxury. One 125 watt 12 volt panel is the largest one that I can fit on the roof. There is no room for a 2nd or larger wattage panel. (I hope) the mppt may harvest a few more amp hours per day. From what I've read its a real possibility.

That's exactly why I went with MPPT too. But here's the rub; lets assume that you get 20% more harvest from your 125 watt panel (best case scenario, 10% is probably more typical). That's 25 extra watts for $150. I could buy another 120 watt panel for that price, or maybe a small portable to back up my roof panel.

This site seems to have the best prices lately on PV panels.

Solar Blvd

Bruce

[Esteban]

Thanks for your reply, Bruce. I just don't have the roof "real estate" for a physically larger panel. Maybe if higher wattage panels were no longer than 52-54" one would be ok. All the Solar Blvd. panels over 125 watts are too large (long)to fit. A 125 watt panel is more than enough for Led lights and a Fantastic Fan with a pwm. It's my desire to use a 12 volt fridge/freezer too which may use 20+ amp hours daily (again no real life experience with one yet) that leads me "want" a Sunsaver 15 amp mppt charge controller. A 10-20% greater daily amp hour harvest with one seems "worth it" if that harvest is enough for the above. All this is kind of speculating at this time as I plan. I want one solar panel mounted flat on the roof, with corner brackets like I linked to in a prior post. If I knew how many amp hours the 125 watt panel would harvest daily, in different realistic conditions, my speculation would be less intense.

MODEL: STP125P-NS

Power at STC(Pm): 125 WATT
Maximum power voltage (Vpm): 18 Volt
Maximum power current (Ipm): 7.11 Amp
Open circuit voltage (Voc): 21.9 Volt
Short circuit current (Isc): 7.68 Amp
Tolerance: ±5%MODEL: STP125P-NSn

How do I figure, or estimate, a daily harvest from this panel? Anyone want to take a stab at it?

(WAG) 4 peak hours x 7.11 = 28.44 amp hours harvest, which would be golden for a full day as I estimated daily power usage at 20-30 amp hours.The battery could stay full, or very near full with a daily 28 amp hour solar harvest. Additional charging from driving (alternator) or a 120 volt AC hookup (PD 4045) should keep the battery fully topped up.

I know in real life it would not always be that efficient or productive. Hours near noon in full summer sunlight would be closer to peak harvest. Daylight hours closer to dawn and dusk would harvest less. Time of year and cloud cover make a difference. I think I remember SC writing he got a measurable solar harvest even near dusk and dawn with his solar collector and Sunsaver mppt controller.

Trivia: Today's peak solar radiation where I live is:

Peak Solar Radiation 786 watts/m2 at 12:56pm

[Shadow Catcher]

The real test of our system was last year when we were in Big Basin Redwoods State Park with absolutely no direct sun ever. I did put the fridge in the car during the day so there was no drain on the trailer battery but we did watch a movie and power the XM receiver and stereo LED lights and computer case fans (MUCH less power draw than a Fantastic Fan). we were up to 100% SOC each day. At Lake Superior usable current from dawn to dusk in a shaded site. Right now, dawn through a neighbors tree I am seeing 39V. I have seen 14.5 V from a full moon.
I think the advantage particularly where we do have camp sites with lots of trees (natures AC) this works well. It is however a large panel and If CR were not a Grasshopper design (flat roof) that is 6' wide it would have been hard.

Big basin and LSPP


We were at LSPP for 8 days and took an ice chest as well as the refrigerator, used the food out of the ice chest first and finished with the refrigerator. If we did not have the solar to power the refrigerator very well I would settle for ice chests, we did for 38 years tending.