MPPT 60 amp $70 and a question

[janice142]

Thought that would get your attention... (said while laughing) Okay, I just bought this: MPPT Solar Regulator Charge Controll 12V 24V Autoswitch Solar Panel 60A 1500W DH | eBay

It's says 60 amps, MPPT and what it lacks that my Morningstar ProStar-30 (plain old regulator) has is a display. I love that the Morningstar tells me how many amps are pumping into my batteries.

So, I went to Power Inverters and Solar Inverters for Home and Businesses - The Inverter Store and looked at their 60 amp MPPT controllers. For $450 I can have a display. That's not happening.

So I bought the $70 China knock-off. Now, what I wish for is a way to know how much is going into the batteries. I'm guessing I need to buy an ammeter?

What exactly do I need to pull this off? I will be swapping out the Morningstar30 for this one and want to be able to verify that it's putting more into my batts than the original unit. It SAYS it's MPPT... but I'm skeptical, especially at the price.

On the other hand, the 30 won't handle more panels and I do not have enough panels to support the level of decadence I seek. What say the experts?

 

[Bay Pelican]

I have the Morningside 30 and use a 25 amp Blue Sea System DC Ammeter to tell me the amps going in. If your setup stays below 26 amps that will be an inexpensive fix. $38 at Defender.

 

[janice142]

Thanks Bay Pelican. With the addition of two more 100 watt panels I do believe I'll trip over the Morningstar capabilities. Currently I have 275 in panels and will be adding 2 more 100 watt panels. (I'm doing this piecemeal.)

My Mornignstar has shown 17.7 amp hours incoming to the batts. Sunny day. Etc. With the addition of two more 100 watt panels, and heading south? I don't trust to stay below 30.

Plus I have the real estate for two more panels and wired for the next pair already when I did the intital 200 additional. (I'd started with 75 watts.)

Where exactly is your ammeter wired into the system? The morningstar and this new one both have the screws to attach my wires from solar and then to batts. Where's your ammeter in the setup?

And seriously, thank you. Even $26 is below the $100 mark. I've seen (yesterday) ammeters on ebay (Chinese ones) for less than $5. Two wires, but I'm not sure where to put 'em.

When I plug in my volt meter to the screws I see volts not amps. I do not yet own an ammeter.

 

[C lectric]

The ammeter should be wired into the output lead between the MPPT controller and the batteries. This can be trouble as the wiring must be connected directly to the gauge often needing long leads unless the gauge can acceptably be put some where that you may not normally want it.

There is another type of ammeter; shunt type. They are more money but it means the shunt, a highly accurate very low resistance resistor, can be mounted near the batteries OR the MPPT controller. Then two small light wires are lead between the guage and the shunt. Blue Seas offers one that should be suitable for example.

https://www.bluesea.com/products/8017/DC_Analog_Ammeter_-_0_to_100A_with_Shunt

There are many others available including from e-bay by googling shunt type ammeters. Quality ????? no idea but lots of cheap units.

 

[Bay Pelican]

There is another type of ammeter; shunt type. They are more money but it means the shunt, a highly accurate very low resistance resistor, can be mounted near the batteries OR the MPPT controller. Then two small light wires are lead between the guage and the shunt. Blue Seas offers one that should be suitable for example.

The ammeter I originally cited has a built-in shunt and the ammeter must be mounted someone along the cable from the solar panels to the battery. With Blue Sea Systems these ammeters are limited to 25 amps. The ammeters with a separate shunt are 1) more expensive and 2) easier to mount as the shunt can be located near where the output from the solar panels reaches the batteries. The meter can then be mounted anywhere in the boat and is connected to the shunt by a small twisted pair cable (18 gauge works).

With analog meters the smaller the capacity the more detailed is the scale for reading the amps. Think of a dial showing 0-50 or a dial in the same size space showing 0-200. It is thus beneficial to buy the smallest capacity ammeter that will meet your needs.

Digital ammeters don't have this problem but are much more expensive.

Blue Sea's 0-50 am DC ammeter is $68 at Defender. Item no 201558.

 

[FF]

Watching an amp meter is great fun , but it tells NOTHING about the state of charge the batts have.

More expensive , but a SOC , state of charge meter will have far more usefull information.

If full at sunset , how many amps dis the reefer eat?

How many days can I go before a charge is Required.

Is it worth the extra time powering to go from 85% to 100% full to obtain longest batt set life.

SOC meterwill also tell you how much the solar sustem is charging , so you can have that fun too.

Here is one , with out the boat price overide.

www.[B]bogartengineering[/B].com/

 

[DavidM]

So you bought a cheap $70 Chinese controller and now you need a $68 ammeter or a $200 battery monitor to see if it works?

There is a better way, but I don't think you want to hear it.

David

 

[DavidM]

Well instead of being snippy (above) I have consumed a couple of Sunday morning bloody Marys and will try to be more constructive.

There is a simple way to tell whether a controller is PWM or MPPT. A MPPT controller converts the solar panel voltage from its maximum power point of about 17 volts to what the battery needs. In so doing the current is higher going to the battery than incoming from the panel. So if you measure the solar panel output before the controller it will be a steady 17 volts or so if it a MPPT controller.

If it is a PWM controller it will pulse the voltage to limit the current to the batteries and reduce it to a small float current when it senses that the batteries are full. If you measure the voltage at the output of the panels when the batteries are full they will show a peak voltage of about 20 volts which will bounce around as the controller pulses. If you measure the output current with the batteries well discharged then the solar panel output voltage will be near the battery voltage or somewhere near 13 volts. Current in will be approximately equal to current out, less internal losses in the controller.

So you can tell the difference between controller types with just a voltmeter.

FWIW I have purchased 4-5 pieces of electronics gear direct from Chinese manufacturers in recent years. All of them didn't work at all or quickly failed.

That is different from my experience with electronics designed by name brand US companies but their manufacturing is outsourced to China. I have no doubt that Morningstar controllers are made in China. But they work.

And at $70 I seriously doubt that it is MPPT.

David

 

[janice142]

Thanks David... and yes, I too doubt that the 60 MPPT is truly MPPT. The thing is, with 475 watts of panels (once I add the next two 100 watt panels) my Morningstar30 will no longer suffice. I need more regulator capacity

So, I wished for/wanted an MPPT for a long time... and even if this is not MPPT as long as she'll carry the total panels I'll be okay with it. But I doggone will get a refund/rebate if the thing isn't as described. That's why I need to be able to test it.

Ideally, that gem they have over on Power Inverters and Solar Inverters for Home and Businesses - The Inverter Store would be great. It's also beyond my budget. I'm making do, you know?

Having the ability to test with my volt meter is a good option. I can/will when the knock-off arrives. Thank you for the how-to.

Currently the regulator is right next to my seat. The wire run from there to the batteries is 5', using 8 gauge. I could have opted for 4' -- but since I had 5' of spare wire...

In checking, it appears I need to buy a Shunt to go between the regulator and the batteries. Then attach the ammeter to the shunt. It seems straight forward and about $10. Shunt for 100 is $6 give or take. Ammeter is in the same price range.

Potential shunt: 1pcs FL 2 DC 75mV 100A Current Shunt Resistor for Ammeter Panel Meter | eBay

50 ammeter:
C27D Digital LED DC 0 50A Ammeter Blue Without The Shunt | eBay

100 ammeter:
C27D Digital LED DC 0 100A Ammeter Blue Without The Shunt | eBay

From above, having too large an analog ammeter is not a good idea? I prefer digital, so that's not important? If it is, which would you advise? (50 or 100?)

I wonder if I could add the ammeter wires to the top of the batt-out wires (without a shunt)?

Of course a less-than-$100 set-up may not last as long as a $450 one, however I hope to break even. Hope springs eternal when it comes to my Seaweed.

And I do appreciate the input David -- snippy is okay too. I've been married. Of course I'm now divorced!

Adding the next two panels on a separate regulator was an option. That seemed to add complication though and I was hoping to make this simple. In any event, soon enough I'll find out if I've saved money. I hope so.

And thank you gents, one and all. I appreciate your efforts/smarts in this endeavor. I am woman: there is a level of decadence I'm working toward. Thanks for helping make it so!

 

[Donsan]

there is a level of decadence I'm working toward.

Since when is being comfortable considered decadence?

 

[DavidM]

Unless you go beyond the 475 watts of panels you will be fine with a 50 amp meter, but make sure that you get a 50A 75mv shunt to go with it, not the 100A 75 mv shunt in your link.

Whether you put the shunt before the controller to measure panel current output or after to measure current going to the batteries depends on what you want to do. For a PWM controller, they will be approximately the same. For a MPPT controller the output to the batteries will be 20% higher.

You could buy two shunts, install one before and one after and then wire them to a spdt switch to select which one you want to use. You can wire both negative leads together and only switch the positive ones.

And finally when the Chinese controller fails ;-), then buy a second Morningstar Prostar 30 amp controller and parallel your new panels with that controller.

David

 

[janice142]

Thank you David. I did as you suggested (ended up buying two shunts at $2 and change each)

I will be opting for two ammeters (I like my data) (geekette wannabe from the days of Tandy 100) and thank you for your advice regarding the one to select. Even though I'm on a budget, I'm hoping this will work well.

Fortunately, the seller also had a green ammeter in 50 so I've got one with blue numbers and one with green. Incoming and then to the batts. Alphabetically, mounted side by side, ought to satisfy my need for order.

Blue equals incoming.
Green to the batteries.

And just in case, I'll hang on to my Morningstar30. Thanks again!

 

[janice142]

Update: Well, a year later my "MPPT controller" from China bit the dust. $70 for a year is unacceptable.

Neither can the budget swing another full capacity that can cover all the panels together so I'm going to do this piecemeal..

China functioned well for a year and today I smelled a welder. No one was welding. Eventually I tracked down the smell to the controller. It was overheating so I disconnected all the wires (marked them of course) and now here I sit.

So, I've got the Morningstar30 which will handle three of my panels.
I need a second controller for the other two panels.

I have two battery banks so can feed each separately.

Any advice? (Besides not going to eBay China for the next controller. I've learned that lesson.)

And thanks!

 

[SteveD]

"Watt's Up" is the ticket

You really need more than instantaneous amps. You need is the cumulative power generated by your panels. For that, a really simple solution is the Watt's Up, which measures eight DC values:

Amp-Hours: (0 - 65)
Watt-hours: (0 - 6554)
Amps: (0-100 peak)
Watts: (0 - 6554)
Peak Amps & peak Watts
Minimum voltage ("sags")
Voltage: (0 - 60)

All of this for about 60 dollars. I have one of these after my fancy solar controller, which also measures amps. But what I need to know is the number of watt and amp hours that my panels are generating in a day. This gadget does it. Highly recommended.

Digital DC Ammeter, Amp Hour Meter, Watt Hour Meter

 

[janice142]

Thank you Steve. I also did further exploring on the FF link here:
SC-2030 Solar Charger — 30 Amps Max- 12 or 24V PWM type - Bogart Engineering

I called 831-338-0616 and the nice lady did the math... my 445 watts of solar divided by 16 amps (includes wiggle room) works out to 27.8125A incoming -- which the Morningstar30 can handle.

The unit though, SC-2030 solar controller is definitely a Wish List item. I like it. It's $121 plus $14 UPS Ground to FL from Solar Electric Power Systems For On & Off Grid | Panels and More | NAWS (phone 800-383-0195)

I like that one, however in the meantime I'm going to use what I had already that worked well. For some reason I thought the Morningstar30 was only for up to 300 watts of panels. Obviously somewhere I missed the capacity boat.

Confirming SteveD -- that 14 gauge wire goes where exactly? After the solar I get -- I'm using 8 gauge from the solar controller to the batteries. Back to reinstalling the Morningstar30. A girl's got to have her power.

 

[SteveD]

Confirming SteveD -- that 14 gauge wire goes where exactly? After the solar I get -- I'm using 8 gauge from the solar controller to the batteries. Back to reinstalling the Morningstar30. A girl's got to have her power.

There is just a couple inches of low resistance thin stuff coming out of the gauge. I am using 8 gauge to the batteries as well. You just splice the two thin black leads into your negative going to the battery and you are all set. It requires power to the left red lead and I recommend that you put a momentary push button switch to the orange lead to reset the counters.

 

[High Wire]

I can't believe that company is ok with pushing up to 50 amps through #14 wire. Besides being well undersized per ABYC and CG standards, there will be a significant voltage drop and conductor heating above 15 amps.

 

[SteveD]

I can't believe that company is ok with pushing up to 50 amps through #14 wire. Besides being well undersized per ABYC and CG standards, there will be a significant voltage drop and conductor heating above 15 amps.

First, where are going to fit a solar array that will put out fifty amps on a boat? Second, the wires that come out that device are about 2" on each side. 4" of 14 gauge wire has a resistance of .001 ohms. Even at the outside case of 50 amps through there, I get a voltage drop of ~.7% at 12 volts.