solar power to power phone and laptop

[gill2161]

i was wondering about solar power and how many i need to power my laptop and phone wile on the road and maybe a light and a fan.

[John61CT]

Best to get your battery bank first.

The best battery value by far is Duracell (actually Deka/East Penn) FLA deep cycle golf cart batteries, 2x6V, around $200 per 200+AH @12V pair from BatteriesPlus or Sam's Club. Deka labeled same batts also sold at Lowes.

Get that **fully** charged off shore power, and see how you go.

A DC coulometer, Ah-counting wattmeter will tell you exactly how many Ah you use per 24 hours.

Get 12V "car chargers" rather than using an inverter.

Best to stop at around 100Ah depleted, that and **fully** recharging as often / quickly as possible will help with bank longevity.

Depending how long you're away, might not even need to buy panels - controller. Possible to rig recharging from alternator while driving, might help if you do a lot of driving every few days, but you won't really get to Full that way, need shore power or solar for that.

Figure 100-200W panels if you need them, might be fine, obviously depends on the weather as much as your consumption. Can always add more later if you have room up top.

[tony.latham]

[quote]The best battery value by far...[quote]

John:

Why does this guy need 120 pounds of lead and 200 amps for a couple of LED's a fan that pulls 1.5 amps and a laptop?

Gill:

I'll argue for one 12V FLA Group 24 marine/RV battery. That'll give you 40 or so usable amps. That will be plenty at half the weight and cost.

Top that off with an 80 or 100-watt panel and PWM controller and you'll have plenty of power and recharging capability.

Two-bits says John will argue for a bigger and more expensive MPPT controller. I think we're talking teardrop, not a motor home with multiple batteries and panels.

Tony

[Cosmo]

I am using a Jackery 500 Watt (41amp hour and most of that is useable) to power my laptop. I can recharge the laptop 7 times with this unit. Its very handy while camping and other times. I am seeing people using power tools with this thing while camping. I plan on using it with a 12V box fan this summer.I can run my trailer fridge about 24 hours with this unit.

I have 125 amp hour AGM house battery in the trailer. Most of that goes to lighting, electric refrigerator and Propex HS200 heater.

The Jackery gives me lots of play time power. This unit has a low temp shutoff which deactivates the unit at 30F. With heat in the trailer thats not an issue for me this time of year. For un-heated Ice fishing - not so good.

I did recharge it with a 100 watt solar panel and the car 12V. Its not a fast recharge but adequate for my needs. I am still collecting data. It recharges at 41 watts an hour on 12V. Some people use an inverter in the car which recharges the Jackery at 81watts an hour on AC power.

If you are at the limit of your house battery and want a portable power augment this might be a solution.there are many other brands to choose from too!
Amazon Associate Links If you buy I earn https://amzn.to/30HDwZy 12Volt box fan draws 1.2 amps an hour. https://amzn.to/30JO8qI

Happy Camping
=Cosmo

[dmb90260]

I have used various Goal Zero products which keep me powered but I have never had to rely on it for more than a few hours.

[John61CT]

all those portable powerpaks

(soon as you see a scammer call them a "solar generator" without including any panels, grab your wallet and run)

are just terrible value, underpowered or overpriced or both.

The pair of GCs I posted is rated 200+Ah **at 12V**, so over 2500Wh, and usually for under $200.

Lots of those powerpaks give their Ah number at the voltage of the **individual cells** they use inside, very scammy deceptive, they really try to make it hard to even know their actual capacity to compare apples.

Once you know what's what, you can start spending more money on useful - to your use case - incremental improvements.

But starting out, KISS and choose old-school proven-good low cost / high value components.

[Vtec44]

I think you first have to determine how much power you will need in amp/hr, and then double that amount to determine the size of your battery bank, and then calculate out how many solar panels you will need. You will also need cushion room due to various factor like efficiency, thermal, conversion loss, etc.

I have a DIY solar system with 300w of solar panels and 100ah lithium ion battery. It's over kill for your situation but the same concept can be scaled down. I use it to power all the lighting in the trailer, a 12v DC fridge, a 12v water pump, 2 cell phones, and 2 laptops. I can go about 3 days without charging or indefinitely (when it comes to power) if I have a bit of sunlight. I also have a generator as a backup for those cloudy days.

[John61CT]

Note the only downside to a higher capacity bank is weight / space taken.

As long as you are balancing the energy you consume with the average daily inputs, more Ah capacity gives a longer buffer to be able to get past a few cloudy days.

And if you end up cycling shallower, that just accrues to a longer bank lifespan.

Lead GCs gets you that capacity **much** cheaper per Ah compared to an LI bank, like 80-90% cheaper.

Not saying it's "better" in all cases than a fancier LI bank, just best as a first bank while climbing the learning curve. And if you get it to last 6-8 years $25/year, all the better for saving up for the "better" option as your second bank, which your higher experience / skills / knowledge will then help you do it right and make it last maybe decades.

[RJ Howell]

Gill, the cellphone, lite and small fan can all be usb charged/run. It's the laptop that gets strange. Check yours, yet most are 17-19vdc to charge. That's the issue at hand..

This is where units like the Jackery come into play. Lithium battery with usb charging and built in inverter for ac charging and a charging port (typically a solar charge controller as well) all in one package. You do pay for this convenience.

The other route is to assemble your own and most times will be less or equal in costs with better components. Now you have a few components, wiring, fusing and ports/connections to deal with (as well as a dc step-up transformer for the laptop). Not everyone is willing or up to the challenge.

For the little your thinking of doing a 40ah LiPO, 80ah Pba or similar would be fine. Probably some around a 60w panel should suffice. Remember, it's watts used by items (phone, fan, etc) times the amount of hours a day times days hoped for. Then the panel size to recover those watts for the period of hours/days you hope for.

This is an example of 'my' Power/solar Audit. I suggest you do the same.

[noseoil]

100AH AGM battery & 100 watt solar panel for our teardrop. Runs the cell phones, fan, lights, coffee grinder in the galley (inverter), stereo, TV, DVD, & sound bar (inverter in the cabin) with plenty to spare. Lithium is fine, but the whole system can be installed for the cost of a Lithium battery, with $ to spare. There's not a right or wrong here, just what you need to get the job done, money, time & planning.

What Tony said above...

[greygoos]

Note the only downside to a higher capacity bank is weight / space taken.

As long as you are balancing the energy you consume with the average daily inputs, more Ah capacity gives a longer buffer to be able to get past a few cloudy days.

And if you end up cycling shallower, that just accrues to a longer bank lifespan.

Lead GCs gets you that capacity **much** cheaper per Ah compared to an LI bank, like 80-90% cheaper.

Not saying it's "better" in all cases than a fancier LI bank, just best as a first bank while climbing the learning curve. And if you get it to last 6-8 years $25/year, all the better for saving up for the "better" option as your second bank, which your higher experience / skills / knowledge will then help you do it right and make it last maybe decades.

Can you show us a picture of your setup? Thanks

[Cosmo]

To right size this solution it helps to know how much power is needed for the laptop.

With 20% of power left It takes about 71 watts to recharge my laptop once or 5.91 amps (I measured it). I can recharge it 7 times with a 500 watt Jackery. I can recharge twice with a 35AH AGM.

If the need is to recharge the laptop once or twice on a weekend trip or night a small power system storage system is fine. For $120 and probably less I can get a power storage that will recharge my laptop twice.

Amazon Associate Links If you buy I earn https://amzn.to/2TNooZj Solar is additional

My attempt at an apples to apples sanity test. I own several AGMs and this is my first all in one power unit.

Jackery 500 (41 amps) mostly usable amps Lithium. $500 13 pounds https://amzn.to/2tGdVUP
Solar controller and pure sine inverter are built in. I don’t think this is a good house battery replacement. I use mine for additional luxury power such as portable power, laptop recharging, wifi hotspot etc.

A comparable AGM setup I would use would look like this
AGM 85 amp AGM $240 weighing 60 pounds (about same usable amps) https://amzn.to/2RhYknq
500 watt pure sine Inverter $100 https://amzn.to/30L9c0f
Solar controller $20
$10 for USB adapter and connectors and cable stuff to make it work.
12V charger - $10
Total about $370

In that scenario the Jack is $130 extra for a matching capacity 60 pound AGM system compared to an all in one 13 pound portable package. I did this comparison in advance of making my decision. What did I miss?

My 120V drill works (340 watts under work load)! My home fridge did not. It drew too many amps. Trailer fridge works fine. Still testing.

I did look at the Apex What a monster 1100 watts can accept (5) 100 watts of solar and be recharges in 3 to 4 hours (wow) https://amzn.to/30HMk1I A tad expensive for my budget!


Happy camping
=Cosmo

[John61CT]

Yes the laptop usage of energy per day is the wildcard.

Ah@12V per 24hrs, being the unit for apples to apples comparison, could be 20Ah could be 100Ah if gaming

I have no idea why anyone is talking about putting an inverter into the picture here, DC direct is the way to go.

Same with solar for now, no idea if going to be needed or not.

Spending hundreds of dollars more for a lower capacity bank also seems foolish to me, even without fridge or power tools.

AGM costs a lot more per Ah, and even units properly designed for such deep cycling (those are not) won't last nearly as long as those Duracell GCs, so $/Ah per year will cost **much** more.

You want a decent charger, 30-40A would be right for those GCs.

[tony.latham]

...won't last nearly as long as those Duracell GCs...

John:

Did you put two golf cart batteries in your teardrop? Where'd you put them? Photos?



Tony

[noseoil]

"I have no idea why anyone is talking about putting an inverter into the picture here, DC direct is the way to go."

We use an inverter because the sound bar was an 18 volt model (go figure on that one, Bubba), the TV & BluRay player are both 12 volt units, but the TV speakers are junk, hence the inverter & sound system. I didn't bother to look for a 12 volt coffee grinder, so the house one is what we use on the road, a small inverter runs this quite well without trouble in the galley. It's hell getting old, needing all of these creature comforts for traveling, camping, hunting, salt-flat racing & enjoying life. It's more fun putting 10# of $hit in a 5# bag & having it work well enough, but hey, whatever blows your skirt up is fine with me.

As I typically say on these questions about building things in general, there's no right or wrong answer here, just what we did for our trailer. Haven't had any trouble with the system yet, after 20,000 miles, but there's still hope I guess!