Solar Blvd Portable 160W Set

[Trebor English]

Even more odd is the further down the line I go toward the batteries the lower the V readings. Two feet from the SC I'm down 0.1V, and 19' down thr line at the battery connection I'm down 0.5V.

AWG #12 wire is .001588 ohms per foot.  50 feet, 25 each way, is .08 ohms.  8 amps gives a voltage drop of .64 volts.  Being down .5 volts at 19 feet is about right for about 8 amps, about the max the panels can make.

Watch the voltage at the battery.  As the battery gets charged the voltage at the battery will come up.  If the battery has been undercharged several days it might take a while to get it back up.  As the battery gets closer to full and the amps taper the volts will stabilize.  

If you are really impatient crank up the controller voltage setting.  If you are really really impatient you can bypass the controller and connect the battery directly.  Run a paper clip from the panel minus screw to the battery minus screw.  If you do that watch it like you would while equalizing.  Keep track of the battery temperature, volts, and amps.  The Lifeline pdf file is clear about the limits.  

How long was the controller set to only charge at 13.6 volts?  I suggest another day or 2 of good charging before replacing parts.  After the battery is charged you can better evaluate what parts, if any, to change.

 

[akrvbob]

^^^^ Does everyone see this post?? Stop and take a look!!!!!!!!!!!!

This is the way you reply to a post, you only put in what is actually important to your reply. Copying the whole post is aggravating to everyone else and a waste of everything.

As an act of courtesy, please follow this protocol.

 

[MarkK]

 How long was the controller set to only charge at 13.6 volts?  I suggest another day or 2 of good charging before replacing parts.  After the battery is charged you can better evaluate what parts, if any, to change.

About 3 days. As of yesterday, when I started to figure out what you have been saying I upped it to 14.3 for the absorb setting, and as we saw from the line drop you calculated, and I measured on my meter, at the battery the voltage is around 13.65 currently.

Now the lcd panel on the SC tells me I'm pushing 14.8, but the reading at the terminals is 14.3. Panel side was around 18.

Given this, I have 4 questions for anyone who understands my predicament:
1) should I dial up the absorb setting from 14.3 to 14.6 and still be under Lifeline's 14.3V absorb setting given the voltage drop reading?
2) Would you go any higher to try to get the reading at the battery closer to 14.3 which would be 14.9?
3) My other panel for the existing 50w system tells me the batteries are charged and that system shut off current to the batteries, but my portable systems is still pushing current. Does this cheap SC ever read full voltage and shut off current and if so is there a setting I need to make or has it just not happened yet?
4) Is there a way to set the float? 

FYI, it is my understanding charge sequences are bulk, absorb, and float. I haven't seen how this SC engages bulk given all I seem to see it in is absorb mode.

Thanks.

 

[jimindenver]

Jim,

It has taken me a while to appreciate what you have written here. Question, 1) any reason your Eco Friendly mppt is better than the Victron, and 2) given my situation, 2 panels and 2 - 12V batteries in parallel, would you wire the panels in series to the controller and let the controller deliver the appropriate voltage to the 12V batteries? As in can the mppt SC take in 34V and deliver 14.4V?

Actually the Victron looks much more advanced as far as connect-ability and customizing settings. The Eco-Worthy is more plug and play with basic settings and a screen to tell you what's going on. I am thrilled to see more options for small MPPT systems. It is about time the Eco-worthy saw some competition, maybe it will force a update.

 

[John61CT]

Bottom line is as long as the actual charging voltage at the batts is within specs, they don't care what's going on elsewhere.

But my advice is to get a better quality charger, ideally one that has a dedicated voltage sense wire, separate from that carrying charge output.

That will ensure the bank getting proper regulation automatically.

 

[MarkK]

But my advice is to get a better quality charger, ideally one that has a dedicated voltage sense wire, separate from that carrying charge output.

Doesn't a sensor require a shunt?

 

[John61CT]

No, shunt is for measuring current amps, not needed for voltage.

But a solar controller driven by a SoC monitor will do both.

 

[MarkK]

 But a solar controller driven by a SoC monitor will do both.

The existing SC has a SoC setting. My rig has a 50w panel with Specialty Concepts SC.

 

[Trebor English]

1) Yes, turn up the volts.
2) Yes, turn up the volts
The Lifeline battery doesn't care what the controller is set to.  Go for the 14.9.  You only have 13.6 at the battery.  That's not enough. 

3) Why did your old controller call it full and stop charging?  What are its settings?
The cheap controller holds the absorb level.  It doesn't shut off until the sun goes down.  It doesn't have information to tell it that the battery is full.  It doesn't have a current measuring shunt resistor at the battery to see that the battery charge current has tapered.  

4) The controller has one programmable voltage.  The instructions call it float.  If you set it to 14.6 then your battery gets charged.  If you set it to 13.5 it doesn't


If you bypass the controller (post # 21) and the battery voltage still doesn't get to 14.3 you need to do something else.  

I have a 25 foot $40 AWG #10 extension cord.  The safety ground and neutral conductors in parallel  are used for minus and the hot is used by itself for plus.  I made goofy plug adapters for solar panel use and I use it as a regular cord for AC when necessary.  25 feet of #10 plus 25 feet of doubled #10 is .00375 ohms, a little better than half the .008 ohms of the #12 you have.

The resistance between the controller and the hungry battery is likely causing the eratic behavior.  When the controller turns on the current the voltage at the controler goes up due to cable voltage drop.  It sees the high voltage and shuts off.  Then it repeats.


What is the battery voltage first thing in the morning?  

As long as you have serious voltage drop you are still getting a high charge rate.  There is no taper of charge current at 14.3 battery volts to indicate that the battery is full.  If you get the battery up to 14.3 at the battery and the cable voltage drop decreases indicating less charge current then the battery is actually getting full.  

Sternwake would tell you to charge the battery till it's full or accept the fact that it will die young.  

Jimindenver said that an MPPT controller will get the most out of the panels you have.

My advice is use the hardware you have to the best it can do before spending more money and then spend the money where it will give you the most bang for your buck.  A better cable would help.  A controller located close to the battery would help.  An MPPT controller would help.  Series connecting the 2 portable panels with an MPPT controller  would help.

 

[MarkK]

The cheap controller holds the absorb level.  It doesn't shut off until the sun goes down.  It doesn't have information to tell it that the battery is full.  It doesn't have a current measuring shunt resistor at the battery to see that the battery charge current has tapered off.

What is the battery voltage first thing in the morning?

I just checked at 5 am and the battery is indicating 12.83V. The batteries are connected to the rv, but with no loads other than small stuff like co2 detector. I upped the SC setting with about an hour of light last night to 14.9 and will see how it does today. I'm shaded until about 11 am, so what the batteries are getting is about 7 hours of current.

Even though the cheap charger isn't smart enough to know when to taper off can it cause any damage by pushing the current to the batteries?

 

[Trebor English]

Yes, serious ovrcharging will damage a battery.  It seems odd but corrosion is an issue.

If you keep an eye on the voltage at the battery you can make sure not to go beyond Lifeline's recommended absorb level.  A tenth volt or two for an hour or two isn't a problem.

If you keep track of the cable voltage drop you know what the current is.  25 feet of #12 wire is about .08 ohms.  You were getting .5 volts drop.  Ohms law :  I = E/R  Divide .5 volts by .08 ohms.  You have 6.25 amps, plus or minus 25%.  A solar panel that's 160 watts ought to put out 8 amps.  This "amp metrer" is in the ball park.

The two big batteries can each take 3 amps for a long time without damage.  Keep charging until the current drops some.  I would look for half the current you had before, looking for .25 volt drop on the cable instead of .5.  Then try adjusting the controller to get 14.3 at the battery.

 

[Trebor English]

The 12.83 volts at 5 AM is a good clue that the battery got some good charging.  I don't think you would ever get that good a charge sticking to 13.6 volts.  

Since you can't physically measure the specific gravity of the electrolyte all you can do is make sure it is full on a regular basis.  A good battery monitor can keep track of every electron that goes in and comes out.  Monitors other than a Balmar Smartgauge need a regular reset where they know the battery is full.

My opinion is that your less than perfect system is on the verge of working well enough.  Watch a few days adjusting the controller to not go too high and you're good.  The cable that is smaller than it could be and the low IQ but cheap controller located far from the battery might be adequate to keep the| batteries happy.

 

[MarkK]

My opinion is that your less than perfect system is on the verge of working well enough.  Watch a few days adjusting the controller to not go too high and you're good.

Yea, it's that "not too high" part that has me curious. Even with the recent change to 14.9, if I'm not over 14.3 at the battery then that is the "not too high" you are referring to?

 

[John61CT]

Again, the bank ONLY cares about voltage at the battery post.

But other devices in the circuit can get fried.

Why don't you have your controller mounted right near the bank where it's supposed to be?

 

[Trebor English]

The volts at the battery is what counts.  With the long wire the volts at the controller don't really matter and it is known to be wrong.  If the battery voltage fluctuates 14.2 to 14.4 and the controller is all over the place that's good.  If the battery is fluctuating from 14.4 to 14.6 then back off the controller a tenth volt.  If the early AM voltage is only 12.5, crank it up a tenth.  

Once you trust the system your electricity use will be higher and will stabilize.  Continue to watch the 2 PM max charge voltage and current and adjust as necessary.  There will be screws that get loose and wires that break.  You have to look at it daily.

 

[MarkK]

But other devices in the circuit can get fried.

Why don't you have your controller mounted right near the bank where it's supposed to be?

Hi John.

The controller came as part of the portable set. Removing it from the back of the panel it was stuck to using some ultra adhesive doesn't make sense given concern over damaging the panel.

This is why I'm contemplating getting a new controller and locating it closer to the bank, but this is all a cost and if I'm able to get 14.3 to the terminals then I may accept the loss in amps as long as my batteries are getting charged given the less than optimal conditions.

 

[Trebor English]

But other devices in the circuit can get fried.

The only things at the far end of the wire are the controller and the solar panel.  Nothing else is exposed to more than the battery voltage.

 

[John61CT]

Yes leave the kit SC there, just bypass and replace it.

Really, your bank is worth **so much** why are you messing around with a suboptimal charger and design? The price on the panels was good, even if you pretend you didn't get an included controller.

Jacking up the SC output volts can potentially damage the batt, you don't want to babysit the charge process all the time.

I think you need to run heavier wiring, but the first step is getting a Victron 75/15 controller, buy from a smaller outfit that will ship it out with your custom specs set as per Lifeline so you don't need to buy the dongle for now if you're on a budget.

Total with shipping shouldn't be much over $100, and that will get you **much** higher total output from your panels (wire the two in series) and most importantly, take care of that expensive battery bank **properly**.

Make it last just one extra year and you've paid of the extra investment many times over.

Also, that Victron controller will last a lot longer than almost everything in your system, likely longer than you'll keep your van.

 

[MarkK]

but the first step is getting a Victron 75/15 controller, buy from a smaller outfit that will ship it out with your custom specs set as per Lifeline so you don't need to buy the dongle for now if you're on a budget.

Total with shipping shouldn't be much over $100

I did see them available for $80 including shipping from a marine store. Makes sense.

 

[John61CT]

I've found Alan Farber at Bay-Marine to be very helpful. Bay Marine Supply, San Diego, CA 619-320-5899

Has shops on eBay and Amazon too, but they take a bite, IMO best to buy direct.