Thursday, September 3, 2009

mixed blessing

Got some welding in this morning before my GrubShack ice shift. Reckon I should be called Bearded Betty. To my surprise, the HOA road grader came out today to do my 2.5 miles. Kind of makes me wonder what's up - they usually do this area in December and we have lots of rain in the forecast for the next week or so. Could it be that some Realtors want to show off some land by way of smooth roads this weekend? I certainly didn't request the HOA to dredge my canals any deeper.

Put in my hour shift but only sold a couple of bags of ice and 2 cokes. Came home and got back to welding. Had to break at 3PM for a little passed quickly and I finished up welding the second half of truss 3. Just as I got set up to cut all the 6" pieces to join the two halves, the heavens let loose. Got about 1/4" of rain in an hour - just enough to swamp the road. Sure glad they graded today.....doubt if they will come back tomorrow to re-grade.

As for yesterdays photos: #1 The dumb ass that worked on this system bypassed the blown fuse with a cable - and tried to hide it by scooting the battery right up next to it (can you say FIRE). Ryan replaced it with a 12VDC breaker. #2 A volt meter does not give a good indication of charge. Ryan installed a tri-metric battery monitor programmed for the AmpHr capacity of the battery bank - telling amps in, amps out, percentage of charge, reminders to fully charge and equalize. #3 As for the mysterious wire coming out of the solar panel....the dumb ass that installed it cut the MC connector thereby voiding the warranty of the panel. Not much you can do about that blunder - the damage is done. #4 There are actually 2 panels with the same problem depending on the time of day. Each panel is shaded reducing the output to 1/3 during the morning or afternoon hours. Ryan cut off the offending shade. #5 AC breakers installed for a DC system. Ryan left the breakers for on /off switches but installed DC fuses inline inside the box. #6 All the electrical panels and hob-job wiring is inside the living space...not a good idea anytime but with proper fuses and breakers in place - less of a fire hazard. Two other things that Ryan found while repairing the system: Although the system was well grounded - the dumb ass that did the installation also attached all the negatives to ground as well - WRONG! The charge controller was never set properly and left in the default mode - just charging to 13.5 and holding. Ryan reset the controller for appropriate bulk and float charging and set the unit to automatically equalize the batteries once a month. One last poor choice - the batteries are all marine batteries - a set up of good ol' 6V golf cart batteries would have been much more efficient and cheaper. I know the dumb ass that installed this system and I only hope that he reads my blog so he can defend himself.


Kip said...

Go get 'em John! No excuse for poor workmanship in any job, let alone one where safety is involved!

denziel56 said...

jw ,

Glad Ryan went and replaced the system monitor with the tri code reader ,your really looking for charge amps and know if your actually harvesting the sun .one of the first thing"s I would have recommended in this case.

now I have more info to work with ,

battery bank sucks no storage or capacity for low sun days

if he has 2 panels he has a max charge 400 watt max(about 16 to 18 amps average) feeding a low amp-re hour bank ,

add a couple more panels and re-power the battery bank with a little more guts in them.

you got the small stuff done , your friend needs to up-grade his stuff and you give him a hand to finish what ya started .make sure they don't void any more warranties !

he has to live with his original design and all he can do now is better it !

well done



John Wells said...

Thanks DZ....thought you would appreciate the mess. 2 more 130W panels coming but that's it for the budget on this job for now. What is your take on the negative to ground fiasco?

denziel56 said...


not my style!
never seen this before . called a "phase ground to "neutral" in a/c power,

on d/c system's i don't see much difference from your old car with a common "ground" as the body and frame and a wiring harness with all the hots or positive's in one bundle !

problem , i don't see any grounding rods or lighting / surge protectors .and it's not
an "isolated ground" , that's a big problem, = total system failure , just one strike , bam!

evening to ya


neil said...

Good info on PV "System Grounding" here...

Billy Bob said...

Speak'n of grounding....where would an RV'er ground his panels since there is no earth ground?
I got my system up and running yesterday and now someone gonna tell me I need to ground the panels. To what????

neil said...

Saw the film "The Ballad of Cable Hogue" a classic by Sam Peckinpah. It reminded me of you running the Grub Shack. Let's hope you customer service is better...
Cable Hogue Youtube Clip

Grant Wagner said...

I agree with most of what you said John, but the last thing caught me for a loop.

"One last poor choice - the batteries are all marine batteries - a set up of good ol' 6V golf cart batteries would have been much more efficient and cheaper."

At least around here, I can get two Deep cycle marine batteries for the same cost (maybe a bit less) as two golf cart batteries, and they come out to about the same storage compacities. (105 20H AhH for the marines, x2 for a parallel connection, 220 20H AhH for the golf). Why would the golf inharently be "more efficient?"

denziel56 said...


marine battery's have a normal rating around 80 amp-re hours reserve , they are only available in 12 volt , so you need 2 in parallel for 160 amp-re hours = 298 minute's discharge time of only 25 amps continuous. also marine battery's are designed for a low amperage discharges of 25 amps OR LESS for rvs and trolling motors . not much demand on these type's of batteries and don't do well under high demands over the 25 amp rating ,20 hour at 80 x 2 = 160 reserve = 150 minutes discharge at 50 amps continuous.

Golf cart battery's series 6 volt x 2 rated at 220 amp-re hours each and designed for higher amp draws, typical inverters requires 10 amps d/c draw for 1 amp @ 120 a/c less 7% inverter loss ,you need to do the math , for you to draw 10 amps a/c continuous your battery bank must produce a hefty 100 amps discharge from it's storage bank ,T105 cart battery's are rated 20 hour at 240
so a 75 amp discharge = 140 minutes / and at 25 amp = 515 minutes. big difference

jW made a good call when he made that statement ,

Because the math tells everything , you would need 3 marine deep cycle paralleled to produce the same amount of power as only 2 of the 6 volt T105's in series ,its that simple , not to mention the cycling rate on cart verses marine deep cycle is twice as many recharges from a 50% state of
discharge than the marine 12 volt.

So its cheaper / less battery's

more reliable / longer reserve amps / higher discharge abilities for inverter draws /
longer battery life.

i read your profile and know you are an engineer ,these are the facts.

marine battery's are the "Last " choice for a renewable system . It's only a cheap way out .The battery's I install are rated 1340 amp hours each @ 4 volts in series for a 24 volt system with only 6 battery's. They cost 1150.00 each and weigh 315 pounds and assembled in the field. reference "SURRETTE HEAVY DUTY INDUSTRIAL BATTERIES" these are guaranteed for 10 years. I take no short cuts in my installations, you can recharge them 3200 + times
and yes the price for a 24 volt bank is 7000.00 bucks 3500.00 for a 12. this is no place to go cheap!

most folks don't have this much in there entire system .


denziel56 said...

Billy Bob

your system on the rv will be isolated from ground from your "tires" , don't attach any groung cables to your a/c system or shore power cable. you would require 1 - 12 volt lighting arester from pv panels output and before the battery's and charge controller. for added safety and protection from transient and sporadic surge voltages associated with lighting strikes .thats all


denziel56 said...


just fyi

Square D style "QO" or "QOB" type panels and circuit breakers are code correct for DC service for system voltages 48 and below.
these are the only one's that carry a "DC" rating
the QOB's are industral bolt-in's'
the QO are residential plugg-in's

they offer a little cleaner look instead of the many fuse blocks needed to protect the wiring.


linda said...

Hate to be the Dumb Ass :)

DIYer said...

There's a reason for positive-ground. In a word, electrochemistry. When you run positively charged wiring all over the place, it will corrode away to nothing in fairly short order -- any little drop of water and pffft, metal-to-crud.

The telephone company has known this for more than a century, in their 48VDC battery banks.

So you run the positive side to ground and route negatively charged wires everywhere. Tends to protect the metal.