jucasan
san francisco
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I recently installed a 15W solar panel on my RV hoping to be able to keep my laptop running. Unfortunatelly I can't run the computer for more than 10/15 min after the inverter start beeping due to a low charge. I know 15W is not a lot but I think the problem is not the solar panel. I think the battery is not in a good condition. Can anybody tell me some hints about this. I wonder for example how many hours I should be able to run my laptop (17") with a deep cycle battery fully charged?
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Jagtech
Lethbridge, Alberta, Canada
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Joined: 06/11/2009
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If your battery is weak, you will not get more than a few minutes from an inverter - they are current hogs. Get a new battery, and the 15 watt solar panel should be sufficient to charge it, and run your laptop for several hours.
I run my laptop with one of those little 12 volt power-outlet plug-in inverters, have never run the battery down yet using that.
* This post was
edited 09/05/10 07:12pm by Jagtech *
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jucasan
san francisco
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Thanks, any recomendation about brands? I don't want to spend a lot of money but I don't want to spend money in a bad quality batery.
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pianotuna
Regina, SK, Canada
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Joined: 12/18/2004
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Hi,
First fully charge the RV battery.
15 watts is not enough to run a laptop. For solar to work well the range of wattage is best between 60 and 150 watts of panels per 100 amp-hours of storage. Less than 60 watts may not be able to equalize the battery bank (but even 15 watts per 100 will, given enough time, fully charge the bank). There are reasons to use more than 150 watts--but after the battery bank is 85% charged there is not much point in attempting to charge faster than the c/8 rate.
Charging a battery bank is somewhat like a frog on a log who can jump 1/2 to the end of the log in any jump. Every jump takes about the same time but the amp-hours returned to the battery become smaller and smaller. That's why solar, with a good charge controller, is one of the better ways to recharge batteries. It is not uncommon for me to see my solar panels "putting in" just one amp to 875 amp-hours of storage.
Regards, Don
Kustom Koach Class C 28'5" 256 watts solar, 875 amp hours in two battery banks 12 volt batteries 2500 watt inverter.
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bldrbuck
one or the other
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My laptop draws a bit over 3 amps. That is 3 times the current that you solar panel will provide. Go to one of the large stores and buy the largest capacity store brand battery they have. Get at least 50 watts of solar. Use your inverter. Good luck.
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RicJones
So. Cal.
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You probably have 2 problems, first the battery and second your expectations of what to expect out of a 15 watt panel. 15 watts won't do diddly.
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Salvo
California
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Joined: 06/01/2008
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As mentioned, you have multiple problems/issue.
The main issue is the inverter is telling you the battery voltage is low. You need to monitor battery voltage (best at the battery) and start charging when voltage drops to 12.1V.
There's a chance the battery voltage is OK, but your cabling from inverter to battery is not big enough. You may be getting a significant voltage drop across this cable, causing your inverter to *think* battery voltage is low. I would run some 14 awg cable from your power center to a cig plug. Use this plug to power your laptop.
The method you're using to power your laptop is very inefficient. Chuck the inverter and your laptop power supply (black brick). You don't need them. You can purchase a laptop DC/DC adapter for $15. Even with this approach I would still run 14 awg cables from power center to power the adapter. That's how I've been operating my laptop for years.
Sal
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jauguston
Bellingham, WA
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Your 15w solar panel will produce 15w under full sun for 5-6 hours in the middle of the day at the very best. All other conditions -time of day, trees or other obstructions, clouds will get you less. Solar is not a very reliable source of power. A cloudy day you will likely get nearly nothing.
Jim
2005 Coachman Sportscoach Elite 402 40'
350hp Cat C-7 w/MP-8
7500w Onan quiet diesel generator
6-Kyocera 130w solar panels SB3024i MPPT controller
Pressure Pro TPMS
1987 Suzuki Samurai tintop Toad w/VW 1.6 turbo diesel power
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MrWizard
Van Nuys, Ca
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Joined: 06/27/2004
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That 17inch laptop is burning how many watts? 50 or 60w ?
That's 5amps of 12v power from the battery,, that 15w panel is supplying 1 amp
Its a trickle charge to keep the battery from dying when the pup is stored, that's all it will do, and only with a good battery, it won't help a bad battery
Get your battery tested, then if needed get a new one, and if you want to camp more than 2 days, you will need a better way to charge it,
Options, always have options, and the journey goes much smoother
....
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atreis
IN
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15 watts (about 1 amp under ideal conditions) is likely not even enough to keep up with vampire loads - control circuits for the hot water heater, refrigerator, propane leak detector, radio, etc... let alone power consumed by other loads like lighting and water pump.
With my 115W panel, under real conditions (trees, not angled toward sun, etc...), I can go for about a week and a half before draining the batteries. It would be less if I tried to run a laptop for any significant amount of time.
2009 Trail-Sport TS21RBH
2008 Toyota Sienna
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