solar panel help

[Deb1996]

I bought the Renology 200 watt solar panel kit, I am confused on which batty to use a 12 volt or two 6 volts. Mostly I need electric for a cpap machine a fan and maybe a small tv, any suggestions and tips would be greatly appreciated

 

[highdesertranger]

Welcome Deb to the CRVL forums! To help you learn the ins and outs of these forums, this "Tips & Tricks" post lists some helpful information to get you started. We look forward to hearing more from you. you are going to want a deep cycle battery. a true 12 volt deep cycle is kinda hard to find, but in 6 volt they are easy to find. this is the main reason for using 6 volt batteries. others will chime in and give a more detailed explanation. highdesertranger

 

[Trebor English]

Golf course owners have clients not generally expected to be patient with unreliable products.  Golf carts haul around heavy loads during the day, many watt hours, and recharge at night.  Golf cart batteries are designed and manufactured to deliver many charge cycles at low per cycle cost.

Marine and deep cycle 12 volt batteries have a low price point to make the sale.  Per cycle cost isn't a consideration in design and manufacture as that doesn't make the sale.

The overnight use of a CPAP could probably be handled (barely) by a 100 amp hour marine battery.  The double capacity of a pair of golf cart batteries would likely be better because the depth of discarge would be lower leading to longer battery life, lower cost per year. Reliability with regard to occasional rainy days would be better too.

 

[Almost There]

A pair of Trojan T105s or T105REs would be perfectly suited for the 200 watt solar kit you have...they'd provide 225 amp hours which I would expect should be enough for the cpap machine. I've not used one but if I remember correctly the machine draws enough that I wouldn't want to rely on anything smaller.

If you can swing the higher price of the T105REs they have much better life expectancy and warranty.

IMO, one should always have at least a second way of charging the battery bank. Most people don't drive enough each day (5 hours or more) to fully recharge their battery bank, unless they are on a road trip. Either planning on plugging in to shore power with a well matched battery charger or having a generator on hand is all part and parcel of dealing with off grid electrical needs. It's a mindful process radically unlike our many years of taking electricity for granted!

 

[berntout]

Having experimented quite a bit with solar panels on my RV the past years of being on the road, IMHO 200 watt could work well if you set them in direct bright sunlight throughout the day. I have seen travel cpap machines that are designed for your needs and can run multiple nights on a single charge. Like the above posts state a couple of good batteries are a great investment.

 

[Deb1996]

A pair of Trojan T105s or T105REs would be perfectly suited for the 200 watt solar kit you have...they'd provide 225 amp hours which I would expect should be enough for the cpap machine. I've not used one but if I remember correctly the machine draws enough that I wouldn't want to rely on anything smaller.

If you can swing the higher price of the T105REs they have much better life expectancy and warranty.

IMO, one should always have at least a second way of charging the battery bank. Most people don't drive enough each day (5 hours or more) to fully recharge their battery bank, unless they are on a road trip. Either planning on plugging in to shore power with a well matched battery charger or having a generator on hand is all part and parcel of dealing with off grid electrical needs. It's a mindful process radically unlike our many years of taking electricity for granted!

 

[Deb1996]

thanks, will check them out. We do have a generator we can use on cloudy days. We have a colmen popup and we plan n mounting on the roof

 

[Broomdweller]

Check out https://handybobsolar.wordpress.com. He gives really good explanations about solar and answers your question and more. Was a huge resource for my solar needs.

 

[akrvbob]

You'll be happier with two 6 volt golf carts, treat them well and they will last a very long time.

 

[GotSmart]

I would be shocked to find a modern CPAP that uses more than 5 to 10 Amps a night.   There is a start surge of about 5 amps, then one uses about .6 to 1.5  amp per hour.

 

[Trebor English]

A heated humidifier will add an amp or two depending on ambient temperature and humidity.

 

[GotSmart]

My CPAP will not run the humidifier on the 12V plug.