Solar RV for me or not

Channel:

Michael D

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Published on May 22, 2015 6:01:00 AM ● Video Link: https://www.youtube.com/watch?v=2_PXws6jLco

Duration: 18:17

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RV Solar for me...or not... this is all opinion with speculation on my part..
I am totally "for solar", But not going to pretend a 100-200 watt bundle is going to solve all my problems and needs in a RV 24/7 nor assume it is yet cost efficient compared to generators. But it is "stealthy" and will keep a couple lights on..

some battery use stuff.. hope its right because I understood it for a change: making a few assumptions like an efficiency of 90% and that the 250 watt is a peak and not continuous rating I get the following

250/0.9 = 277 pkW

277 / 12v = 23Amp pk

200 / 0,9 = 222 cont watts

222/12 = 18.5 Amp

assume a battery with 45 Amp Hr rating
45 / 18.5 = 2.4 hours battery life

Hmm was interesting and I followed along fine..

at 60ah
60 / 18.5 = 3.2 hours battery life
at 100ah
100 / 18.5 = 5.4 hours
at 200ah
200 / 18.5 = 10.8 hours

at 235ah (2 6v GC125 Golf batteries 130.00 seems like the only way to go price and performance wise realistically.)

235 / 18.5 = 12.7 hours for 222 continuous watts..

obviously a 200ah needed to last thru the night at just 222 cont. watts..basically what I use in wattage most nites without air, heat and microwave.

300 watts with a 200ah battery bank will last 8 hours.

for my full system at 800 continuous watts (67-74 amps at 90% with lows and peaks) for a nite (11-12 hours) it would take 800-940ah(8 235ah golfcart batteries) of battery power. that's air / microwave / lights / tv / computer..everything! that's 8 friggin 6v batteries!! at around 70 pounds each for 560 pounds!!

batteries without a AH rating usually have a RC rating.. use times .6 to get AH.. 100 x .6 = 60ah

now, on to solar panels needed to maintain these batteries..

a 60 watt panel kit would take 12 hours to fully charge a 60ah normal battery. Hope for sunlight and keep that panel out dawn to dusk.

a 100 watt panel kit would lower the charge time to 7.2 hours

a 200 watt kit would get it down to 3.6 hours

now that was just for the normal 1 battery hookup.

let's move on..

approximation: power = current x voltage. Energy = power x time. So a 12V battery of 150Ah needs 1800Wh of energy (12 x 150). So a 25W PV panel would need 72 hours at full output (1800Wh/25W).

now messing with a 2 6v golf cart setup at 235ah which seems to be the current rave and costing around 275.00 just for the 2 batteries combined:

12 x 235 = 2820Wh - 2820Wh/60w panel kit = 47 hours to get to full

2820Wh/100w panel kit = 28.5 hours..to long also..

2820Wh/160w panel combo kits = 17.5 hours..hmmm..

2820Wh/200w panel kit = 14.1 hours..still alot of charging!!

2820Wh/260 watt = 10.8 hours..possible.. 2 100 and a 60 folding kit..

2820Wh/300w panel kit = 9.5, sounds good..but most areas only get 5-6 hours charging sun..sigh

2820Wh/600w panel kit = 4.7 hours to remain at 235ah or 2820Wh

Sonofa...... and to top all this off.. it is suggested to only drain your batteries halfway or you may damage them.. WTH!! many inverters will automatically kick "off" when battery power goes down to one half remaining or 10.9 volts to save your batteries from damage. so everything I thought I knew I now cut in half because we don't want to ruin our expensive batteries. So do I now need 16 batteries? WTH!!

Sooo.. a basic 1 battery at 60ah(seems 45-60 is about average these days in "normal" sales of batteries) would take 160watt panel setup to maintain in 4.7 hours(about "average" sun time for many)..

cont..