[Jorn]

Hi Richard,

There is no fire hazard, but there is decrease in voltage (electrical pressure) and a decrease in terms of efficiency.
. It is not something I would normally recommend. Use a ‘voltage drop calculator’ to determine the correct size wire for your set up.

[Jorn]

There is some awesome tech out there and it is good to be aware of it. More challenging is learning for yourself how do more with less money and effort. I recently learned out to equalize my batteries with a generator and a hydrometer as the winter is too cloudy for solar in these parts. Also learned that a very long run of 200 feet with only 14awg to 270 watts on the ground is effective and efficient given the short over cast days of winter. Although the panels are capable of producing 13.5 amps in full sun, during the winter it is only a fraction of that, and the light wire could deliver the much lower amperage that was produced most of the time. It was therefore useful despite the usual recommendations based upon a voltage drop calculation. It was a practical and successful application given the conditions. The industry guidelines would indicate several hundreds of dollars of heavy gauge wiring that would have delivered little more power. Now that is not what I would consider smart, efficient design yes, but not smart. My solution cost me only a few wire nuts and some electrical tape.

I know the highly technical aspects, and now I am discovering the practical application. Learn also how to break the otherwise good guidelines to get the job done. Usually the lowest tech approach, the simplest approach, is best. My system cost only $500 as I used discarded extension cord for wiring and found the best deal on panels and batteries that are of adequate quality. If you can afford it, I’d recommend a pre wired set up from Wholesale Solar, but it will be spendy. DIY is not for everybody. Yet a low cost system that may not be as efficent, or the best, technically speaking, may however be a smart move. Get into solar sooner and you’ll start saving now.

[Jorn]

Yes, you can use an older battery or battery bank along side a different or newer set by using the Morning Star SunSaver Duo http://www.morningstarcorp.com/products/sunsaver-duo/ This is what I have. Get the remote temperature sensor as well. This charge controller can be set to charge your house battery and then the starting battery. or 2 sets of house batteries. 25 amp maximum input means it can handle no more than 400 watts 12vdc. Renology.com has the best price on 12vdc 100 watt panels, 150 bucks including shipping. For those living primarily in idea solar conditions, 200 watts is usually plenty and a good starting point. 200 watts is the minimum needed to properly recharge a set of two golf cart sized deep cycle batteries. The least expensive and good quality golf cart batteries are sold at CostCo. These are made by Johnson Controls and are rated for 700 cycles. and sell for about 90 dollars plus a core charge of about 10 bucks. The best lead acid is the Trojan T105re, a comparable with 750 cycles, runs about 160 bucks and 50 dollar core charge. If you want to get started, simply get 2 100 watt panels from Renology and their 30 LCD charge controller and use your old batteries for now. Renology does sell a kit that includes mounting brackets for the roof. The inexpensive charge controllers are best used with the very expensive AMG batteries as these do not require the periodic ‘equalization’. If you can afford those, go for it. There are numerous advantages. Read up. Lead acid types require equalization from time to time. To run the time test and much less expensive lead acid type, step up to the 45amp MorningStar TS45 http://www.wholesalesolar.com/3680302/morningstar-corporation/charge-controllers/morningstar-corporation-tristar-ts-45-charge-controller This charge controller will ensure that the batteries will perform at their best and last the longest. Make sure that the batteries are stored outside the RV living quarters so that the battery gases are vented the outside.

Fortunately the panels can also be set outside and a short line run to the RV, making the project quick and easy. Mounting them on the roof requires punching holes in the roof and increasing the likelihood that roof leaks may occur not necessary now, but in future years. Undetected roof leaks kill RVs.

I am new to the forum and just yesterday wrote some on solar for RVs in the Utilities section. Ask questions via PM jornjacobsen@gmail.com

Jørn is my alias

[Jorn]

The minimum would be a 200 watt system with 2 golf cart batteries from costco and a el cheapo 30 amp charge controller from Renology.com. Cost is around 600 bucks

Jørn

Hilsen til Pipi fra Montana. Loved your Mouse video. That is what brought me here.

[Jorn]

Also, avoid inverters as these are power hogs. Convert to 12vdc. With 2 golf cart deep cycle batteries you will only have 2 days of power if your consumption rate is conservative. Do not let batteries go below 12.1 volts if you can help it. Check batt voltage in the morning before sun rise to get an accurate reading.

jornjacobsen@gmailcom

[Jorn]

I’ve put together several systems. Flat on the roof, one looses deficiency so the rule that applies to installation for a home does not apply. I’d go with 400 watts, and 2 6v deep cycle batteries from Cost Co. These are made by Johnson Control and have a 700 cycle rating, yet cost a much less than a Trojan T-105RE that are rated at 750 cycles. The AMG batteries are very expensive, however if one can afford them, go for it. They do have certain advantages and they do not have to be equalized. Go to Renology.com and get their 100 watt panels for 150 bucks each including shipping, and their el cheapo charge controller with the LCD read out, or best yet , get a charge controller from Morning Star that can equalize the batteries and has a remote temperature sensor. They also offer kits.

200 watts in a sunny area will run most of watt RV’ers need, yet 400 watts will take much better care of you all year long and any place you might wander. I just spent a winter in Montana with only 270 watts and had to run a Honda everyday. Also, 400 watts has a better chance of charging up a small battery bank completely and that translates into longer battery life. I do not let my batteries go below 60 percent, and typically 70 percent,(12.4 volts) of a full charge even during the winter. I may get 3 or more years out of them. It is cheaper to save power than make power. Convert your lighting to LED and save tons of power. A netbook uses about half the power of a laptop. During the winter when using the Honda to make all the power, no more than .6 gallons of fuel is used….. I run a wood stove in the winter to heat and cook and do During party cloudy days the generator gets run perhaps an hour or two at most, and uses less than .2 tenths of a gallon to bulk charge the batts up to 14.1 volts. Then the panels are allowed to do the rest. Good Luck, Jørn

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