Recent trip electrical

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A Rooney
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Joined: August 10th, 2014, 6:06 am

Recent trip electrical

Post by A Rooney »

My trips up till now involve mostly moving,and in the 10 day range.Just got back from the east coast,and thought I'd share for what it may be worth.Ended up boondocking or off grid for over 2 weeks,a week of which involved a blizzard and night time temps as low as 21 degrees.I have a single 150 watt panel,and have a roughly 200 watt battery bank...On most of the better days I ended up drawing down 7-10 percent,which I was capable of replacing solar wise.However on the colder nights I could draw as much as 15 percent....my 2 strategies to get back to 100 consisted of running the generator,( which involved several hours of noise) the progressive dynamics charger put in about a percent for every hour,or taking a quick short trip for supplies and returning.In every instance I found the alternator added more amps quicker than my charger and generator,and then Solar topped off.I have repeatedly read here about the advantages and disadvantages...but my experience is that the alternator without a b2b performs well and infact dramatically better than a generator running my charger.In addition I was surprised that for such an extended time in the overcast east coast 150 watt solar provided good service,and I did not come away wanting to install another panel. Rooney
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HoosierB
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Re: Recent trip electrical

Post by HoosierB »

Sounds as though your rig passed a pretty good field test. Out of curiosity, I found your other post which listed your solar set up and rough costs. Are you still using that set up? What are the names/manufacturers of the products used? And why did you "elevate" the 150w panel (also size and make?)... any pics?
Thanks
"Wanda" – '01 Chinook Concourse XL V10
A Rooney
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Joined: August 10th, 2014, 6:06 am

Re: Recent trip electrical

Post by A Rooney »

I am not even close to Solar savvy,I make my decisions in obscure roundabout ways,I respect those with greater experience,but also trust what I myself experience.When I started out I found a reference buried in the archive of the yahoo forum to HandyBobs solar blog,and a lot of what I did was based on my reading there.My monitor and charge controller are made by Bogart engineering (available at Bestconverters as well as other sites)These items work together in tandem,and are products of an incredible electrical engineer in California (Ralph)and yes they are pwm but for my setup Pwm works great....My panel is a solarland,made in China with Bosch cells manufactured in Germany,I adhere to Handy Bobs philosophy that low panels near Ac shrouds etc that cast shadows,are limited by those shadows,so the solution is to raise the panel and diminish shadows,I used a rail system I saw at a local Home Depot,that a sub contractor had at the entrance to the store on a display,I think it was a grape solar design and have seen it on eBay for $100..however the solar installer at the HD subs shape was an rv affectionado and gifted me.It is used for home roof installations and is sturdy...It raises my panel up quite a bit.As has been stated a lot by others here All this depends on the individual and their usage.My biggest power draws are fans for heaters and venting....doesn't everyone use a low power tv and lamps? Other people who use more power than I need to configure a system to their needs,not copy me.From the roof to the battery I connected with 6 gauge marine duplex wire,I didn't have a mind to look at charts and thought Why not? 6 gauge seems robust enough (not very scientific)As for fixed panel I am too lazy to adjust panels,and forgetful hitting the road.Do I think the 200watt system propounded by others is overkill? No I don't,I think it's sound advice...but I get by nicely with 150 and no one is more surprised than myself. Rooney
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Blue~Go
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Re: Recent trip electrical

Post by Blue~Go »

I always enjoy reading real world reports. Plus, Rooney, you have a way with words.

This is a tangential note about bigger charging sources (the alternator, a charger (and to some extent the stock charger).

So lead acid batteries charge up in phases. First you do the "bulk" phase. This is between 0% (heaven forbid) and around 85% charged. This is called a current limited stage, but with our relatively small chargers, in reality our batteries will take just about whatever we can throw at them. So they are sucking up the 60 amps from the alternator, or the 45 amps from the charger, or the 10 amps from your solar. Bring it on, baby!

Second is the "absorption" phase. At this point charging the batteries becomes like stuffing the power through the eye of a needle (technically it's "voltage limited"). So no matter what you are throwing at them, they'll start this phase taking in maybe 15 amps, then it will go to 10, then 8, then 5, then... you get the picture. This all happens at a snails pace. Fully charged will be about .05% of the bank (so say around 1 amp or so). This is why going from 85% to 100% basically takes forever (well, hours and hours). To make things "worse" this should happen at like 14.4 amps (varies with different battery brands/types).

All this to say that if you are down to say 70% charged and you are going to charge with a combination of alternator/charger/generator and solar, it's best to start out with the big gun (alternator/charger/generator) to get up to the 85% absorption threshold. Then solar can slowly (and silently) get you through the absorption phase from 85% to 100%. The big guns won't go any faster in this stage.

I can see where the alternator might do a little better than the generator-plus-factory-charger. That's 60 amps or more, going through 4 gauge wire over a ~ 15' distance. The (generator) charger is 45 amps going through 6 gauge wire over something like a 28' run.

But I also think that they might "seem" different depending on when you use them. Like say you were using the generator/charger during the latter stage (so it would take forever and get little done); but it just so happened you were using the alternator during the bulk stage (where either one could dump large numbers of amps in).

In summary, if one is not plugged in and has to use the generator/charger or the alternator, and there is a choice, it's better to use either of these when the batteries are lower, and then top off with the solar. So drive or run generator in the morning (well, as long as you're not near me :lol: ) if you are below 85% and then it can dump in gobs of power quickly, and then let solar take over. Vs. the less efficient way of letting solar run all day, and then running generator if you didn't make it to 100% (but then you have the generator stuffing the power through the needle eye and it will take FOREVER).
1999 Concourse
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HoosierB
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Re: Recent trip electrical

Post by HoosierB »

A Rooney wrote:...but I get by nicely with 150 and no one is more surprised than myself. Rooney
I love your approach and attitude!!! :D ...."What works for me, is good enough for me".
"Wanda" – '01 Chinook Concourse XL V10
A Rooney
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Joined: August 10th, 2014, 6:06 am

Re: Recent trip electrical

Post by A Rooney »

First,I can't claim to scientific method.....I wing it come up with what I deduce I think I am seeing....and then see how that bears out again and again... The generator is like Tai chi charging on a rack....1 percent in say 45 minutes to an hour.....note: None of this is even possible without some type of smart battery monitor....otherwise it is guessing....In my case that 55 amp charger running off a generator can only force in 2 amps or so into the batteries from 85-95 percent...painful,however drive to Walmart maybe 10miles each way and the percentage noticeably jumps,I don't know exactly because my monitor is mounted by where the original vcr was in the back,but I will guess three or four percentages,Ofcourse that includes the solar operating while I shop...Never went below 85 percent (what a wuss) during the cold I turn on the heat as the sun goes down cook eat,then bundle up under a sleeping bag and watch what's on the grit channel (typical) text,etc than turn down heat at say the 57 degrees (so it's on and off during the night) than wake up and turn up the heat....and that's why it's not everyone's cup of tea..but fine for me...and I figure that takes (with the fridge) a total of say 25 amps use (that's a guess) the one time I got to 85 I started the night at 97 percent gasp! I hate not getting back to 100 by day's end but it happens occasionally to my dismay....I hate to run the generator not to mention even on a friendly street (where I was) it's not worth aggravating a neighbor by running that beast.....I am sure I could get by ( since I don't use air c in summer,and only occasionally microwave With say a small Honda that purrs rather then roars....but I have that Onan beast for now...Rooney
A Rooney
Posts: 155
Joined: August 10th, 2014, 6:06 am

Re: Recent trip electrical

Post by A Rooney »

Duh,I guess what I am saying/deducing is....That the Alternator appears to force more thru the eye of that needle than the generator running the charger....Maybe that's because my pd charger isn't really that smart,and that yours truly confesses that I didn't bother to press the wizard button which might have upped the voltage to 14.1 from 13.6. While the alternator pumps in at 14.1 easy..Its the voltage that forces those amps thru the needle... I load up my floor space and I guess I was too lazy to open the panel and press the tiny green wizard button.Anyway like I have always stated,I am forgetful,and not a genius,and a tad lazy when it comes to fiddling with gizmos and tilting solar panels.But somehow the good Lord smiling kindly or fools.....I get by.. Rooney
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