Battery charger

[tx2sturgis]

My electrical needs in my previous camper van and now the current truck camper are modest...so far.

As of today, I don't have a 12v fridge or A/C.

And my total outlay for 2 100w solar panels, wiring, fuse panel, solar controller, one battery, and misc items is under $500. If you count the 300w PSW inverter I got for free, well, the cost might be closer to $600 or so.

So it's totally doable on a budget.  

If/when I buy a fridge, I will add my 120w portable panel, and probably add another battery.

This system will easily power a normal laptop, a roof fan, LED lights, charge the phone, power the cellular hotspot, and charge the flight batteries for my drone, as well as occasional use of my ham radios. 

It's NOT a huge amount of power, but it works for me. 

And on cloudy days, the power production is down by a fair amount. So I cut back on power use.

But it all works for me, and a similar system might work for the OP.

 

[mothercoder]

^^^^^

Thanks and I agree.  The only variation might be going with more batteries to start since I am quite sure I'll be adding a fridge.  I will also have AC but if I'm ever in need of it, I will find a place with shore power.  

My sticking point right now is that if I go with the larger battery bank, then I feel I should go with more solar to charge it.  How well will a 200 ah battery bank do with 200 watts of solar?

Moderator Note: Removed unnecessary quoting of post directly above - Nomadventurer

 

[John61CT]

I was talking about the inverter, not the solar or batteries.  

BTW, I can't find the Duracell (Deka) batteries you were talking about on BatteriesPlus.

I thought we realized the inverter is not (yet) needed? But yes, those get (usually optimistically) rated in max watts capacity.

https://www.google.com/search?q=site:batteriesplus.com+duracell+golf

Only look at FLA ones, and also check Sam's Club pricing if there's one near you.

 

[tx2sturgis]

I would advise 300 watts (minimum) of panels and 2 batteries for 24/7 use of a small 12v fridge, and occasional use of other low-power items which you can turn off on cloudy days or at night.

If you toss in an inverter to run a toaster oven, microwave, or induction cooktop for a half hour a day, then of course, this probably won't be anywhere near enough solar. 

That's when the shorepower connection to a power pedestal at a campground, or a genset, and the battery charger, will come into play.

 

[B and C]

I have 250Ah of battery and "mostly" use the 200 watts worth of panels I have on the roof. I only draw down to about 80-85% capacity though. Roughly 50 Ah's is what I use out of the batteries overnight. I charge the phone and laptop in the afternoon when the batteries are not accepting all the output of the panels (during float). When it goes lower due to heavy clouds, rain or parking under trees, I do run the generator 'till the batteries get out of bulk phase. I also have 200 watts of portable solar panels that I can put out when the sun comes back out or put in the sun when in the trees. Going into conservation mode helps with not depleting the batteries too much also.

Just be sure to get a solar charge controller that will handle all the panels you expect to throw at it with programmable setpoints and using a shunt so you can make it to full. Timer based controllers are notorious for under charging batteries.

 

[John61CT]

As long as you're making sure you're consuming less energy each day than your solar total input

you could have a single 50W panel with 20 of those GC pairs, no problem.

But you do need some way to measure AH in and out.

Many many people get by with 200W solar and a 200AH bank just fine in sunny places, but since your budget is so tight, I'm suggesting start with 100W and add later only as you find you need it.

If you consistently use more than you produce, then even with 800W of solar, you'd want to get the little gennie to supplement, in which case you wasted a lot of money on extra solar.

There's no substitute for actually measuring energy in/out to get biggest bang for your bucks.

 

[mothercoder]

I thought we realized the inverter is not (yet) needed? But yes, those get (usually optimistically) rated in max watts capacity.

https://www.google.com/search?q=site:batteriesplus.com+duracell+golf

Only look at FLA ones, and also check Sam's Club pricing if there's one near you.

So those I'd need to vent and add water to, right?

 

[John61CT]

Just be sure to get a solar charge controller that will handle all the panels you expect to throw at it with programmable setpoints and using a shunt so you can make it to full. Timer based controllers are notorious for under charging batteries.

I don't think there is a BM/shunt-based SC option available for a low enough price for OP.

Even the under-$100 Victrons are likely more than she'll want to spend when there are so much cheap options to get started.

As long as the Hold Absorb Time can be extended, usage patterns are pretty consistent and there is an ammeter showing trailing amps, that can be "good enough".

 

[mothercoder]

I don't think there is a BM/shunt-based SC option available for a low enough price for OP.

Even the under-$100 Victrons are likely more than she'll want to spend when there are so much cheap options to get started.

As long as the Hold Absorb Time can be extended, usage patterns are pretty consistent and there is an ammeter showing trailing amps, that can be "good enough".

All that right there?  Like Charlie Brown's mother.   :huh:

Brian Boone recommends the Go Power 30A controller with 525 watts of solar.  I'm thinking of 350 watts of solar.

 

[jimindenver]

Out here helping people for a year I can tell you that a shunt would not have helped any of them more than a settable controller and oh yeah...More panel. Not having enough power coming down, especially in the winter when the haul is 50% is the biggest culprit killing batteries.

Get a handle on your needs and having more panel than you need will always provide better than a expensive brand name or a fancy controller that in the end tells you that you should have spent your money on panel rather than it. The panels produce the power, that's where it starts.

 

[tx2sturgis]

Out here helping people for a year I can tell you that a shunt would not have helped any of them more than a settable controller and oh yeah...More panel. 

Get a handle on your needs and having more panel than you need will always provide better than a expensive brand name or a fancy controller that in the end tells you that you should have spent your money on panel rather than it. The panels produce the power, that's where it starts.

This is very similar advice I have given to a few others...yeah fancy controllers are nice, but if you spend $300 on 3 panels and $200 on a whiz-bang controller, you could have bought another $100 panel and a basic but functional $100 controller (for the same $500) and get more 'juice' to the battery...and all the other goodies on board. 

Sure, stats are nice, but for some users here and elsewhere, the darn thing just needs to work, and they don't really care that much about amps and volts.

 

[John61CT]

All that right there?  Like Charlie Brown's mother.   :huh:

Sorry no idea what that means.

200-250W serviced by a Victron 75/15 (under $100) will probably be more than enough for you.

Then if you find you need more after you put in the fridge, do that again.

Or, you can always go to a better controller later.

 

[jimindenver]

John

When suggesting the Victron please include in the price the dongle required to make it functional. Without it the controller is nuts and and can not be set properly. People lost batteries due to not knowing and that can turn it into a extremely expensive controller.

 

[John61CT]

If you consider it necessary to buy one, then the version where it's included is $20 more.

In this case with cheap FLA super-budget etc I figure I or someone else can lend it to her if it proves necessary.

If there are comparable SC recommendations in that price range I'd like to know too, even sacrificing MPPT since she likely won't be going high-voltage panels.

 

[safarivan]

I would get a generator first, they have built in inverters so you would have the 120v right there whenever you need it. then I would get a basic selectable 5-20-40 amp automotive battery charger.

figure out how to make that work for you and no worries when a week of bad weather comes along.

then when you get into the solar stuff later, this equipment will still be there for when you run out of juice with the solar stuff (and you will)

Ive read about a simple way to charge trailer batteries from an alternator that doesnt require thick cables and only a single wire too. lemme see if I can find that and I'll post a link if I can.

 

[jimindenver]

The Eco-worthy 20 MPPT controller has been around since 2012, has a onboard display, is easily settable, under $100 and NEEDS NO DONGLE!

The offer to loan one out is very generous but if someone doesn't know they need it in the first place it will cost them their batteries. Please do not suggest products that are not ready for use without including all of the needed info. Again the price sounds great until it cost you a battery or worse.

 

[safarivan]

im not sure if this will show up here but I will try:

here is the link to it https://www.the12volt.com/installbay/uploads/auxbatgra.gif

and more info about alternative alternator charging methods here: https://www.the12volt.com/installbay/forum_posts.asp?tid=115004&tpn=2

and here https://www.the12volt.com/installbay/forum_posts.asp?tid=115004&tpn=5

I cant find the topic from there that really gets into it yet but these show the basics of it.

 

[jimindenver]

The problem is her battery is in a trailer. By the time yje power comes through the tiny charge line there isn't much left. A set of jumper cables would do much better.

 

[tx2sturgis]

It is possible tho, to provide a charge line to the trailer battery that at least maintains the battery for the duration of an extended drive....its done all the time with RV's....and semi truck trailers equipped with electric/hydraulic liftgates....I drove one for 5 years.

The powered liftgate batteries on semi-trailers that have them, use this method to help maintain the liftgate batteries in the trailer. 

And that wire is on the order of 50 feet or so to the battery installed in the liftgate unit. 

Following this idea, back in the early 90's I had a pop-up tent trailer, and I ran a heavy wire directly from my alternator output down thru the frame of the pickup, all the way to the rear bumper, with a seperate anderson connector, and that mated with a connector on the trailer, for charging the battery in the pop-up trailer. 

Of course, the line was fused and had a disconnect switch under the hood. 

It all worked quite well.

 

[akrvbob]

I just posted a video today that I hope will help a lot of people with super simple and super cheap systems:


It won’t run your laptop but it sounds like it would take you a long ways.

But, for more advanced needs and for someone on a super tight budget I say keep it as simple as possible so I recommend you buy a solar suitcase. You can get a Ecoworthy 120 watt solar folding suitcase for $200 on Amazon.
http://amzn.to/2FOOvJG

Then, the only other thing you need to buy is a battery. If you’re sure you will be able to afford to grow the system in the future, the best bet is always a good pair of flooded golf carts. Just don’t be fooled into thinking you have two batteries so you can use more power. Being able to recharge them the next day is all-important and you’ll be limited by the single 120 watt panel.

As soon as you can afford it, you can add a second panel and you will have a great system.

You can build a cheaper and better system by buying individual pieces, but this is simple and easy and won’t leave you overwhelmed and paralyzed. That’s what happens to so many people and it doesn’t have to.

You only have to buy two things (suitcase panel and batteries) and you are done. Assembling it is no harder than attaching alligator clips positive to positive, negative to negative. And you’re done!

Honestly, you’ll need a few more things to get power out of the battery, but they are very simple and cheap and we can cover that then.