Help!!!!

arilans

 Oh my God I can’t believe I finally am able to make a post. I have one simple question that nobody can seem to answer for me I have a 12 V mighty max 200 amp hour battery and I need to set a voltage amount of where to stop charging the battery and I also need a voltage Amount  to stop using the load in order to not kill the battery. Please please please please somebody help me I am dying on the vine and I’ve been trying to get an answer for this for five weeks :(

arilans

 I even have the data sheets on the battery but I cannot decipher them. Please if I can email them to you and you can help me anybody that would be amazing literally I need power 

arilans

mcgivor

The voltage at which to stop discharge will be largely dependent on the amperage of the load, can you provide some details? 
The charging voltage would depend on wether the battery is used for cyclical or standby as displayed on the side, and the temperature of the battery.  The voltage published is at 25°C, cooler you increase voltage, hotter you decrease, or use a remote temperature sensor to dynamically change it, the latter being the best method.
 the  

Raj174

arilans said:

 I even have the data sheets on the battery but I cannot decipher them. Please if I can email them to you and you can help me anybody that would be amazing literally I need power 

As I read it, the bulk/absorb voltage is 14.4 to 14.6 and the float voltage is 13.4 to 13.6.  A safe low voltage depends on how much amperage has been drawn from the battery. The battery can be at 12 volts with a 5 amp load, but also at 12 volts with a 50 amp load. It depends on how much the battery has been discharged. As a general rule you don't want the voltage to stay at or below below 12 volts for very long, but more information about what is being powered (loads) and for how long is really required.

arilans

Wow!!! This is all great info ! I can provide you with any info you need to better help me.  I can’t tell you how hard it has been to find someone willing to help!:)  as far as cyclical and standby I use this battery once a week for about 36 hours. It’s for a solar system I fully trickle charge the battery in my garage during the week take it up to the cabin hook it to the one 100 W solar panel during the day and use the power in the evening and the next day. 
 As for the load basically it will always be a Wi-Fi enabled TV which is I believe about 100W and possibly a DVD player which is about 40w and possibly some light switches about 20w and  another 20W for miscellaneous. So around 180w load. 
I am very excited to hear back from you thank you so much once again!

BB.

Without knowing your exact loads/usage... It does become a bit difficult to design/understand what a solar power system will be capable of when trying to match these unknown loads against what hardware you already have.

But, let's start with your battery. I call it the "heart" of your system and understand what it can provide--On average.

A 12 volt 200 AH (probably) AGM battery. Assuming you fully charge it at home (trickle charging is an in-exact term--Need to better understand what you are using to charge the battery). In round numbers, assume that you use 1/4 of the battery capacity for the two days you are at the cabin and 50% maximum discharge (for longer battery life).

• 200 AH * 0.50 capacity = 100 AH for "use" over those two days
• 100 AH / 2 days = 50 AH per day of "useful" energy
• 12 volts * 50 AH = 600 Watt*Hours of "useful" 12 VDC energy

You did not say if you have 12 VDC TV and DVD Player or a 120 VAC TV and Player... And the other loads (20 Watts here and there) -- Don't know what those are either (12 VDC or 120 VAC)--But guess those are LED lighting. Guess that you want ~5 hours of lighting per night.

• 20 Watts * 5 hours = 100 WH
• 600 WH of battery energy per day - 100 WH for lighting = 500 WH of available power for TV+Player
• 100 Watt TV + 40 Watt DVD player = 140 Watt load
• 500 WH of available power / 140 Watt load = ~3.6 hours of TV+DVD per night

The above is a very rough calculation--But does seem to be somewhat inline with what you could expect to get from your battery with your loads.

HOWEVER, I do not know if these are 12 VDC or 120 VAC loads... If 120 VAC loads, then you have an AC inverter which draws extra power (more losses) just "turned on". And depending on what exact brand/model of AC inverter you chosen, these losses can be relatively small, or can be fairly large (and do you turn off the AC inverter when you are done for the evening, or do you leave it on the 36 hours you are there?).

Next, you have a 100 Watt solar panel... So you can get "extra power" during the weekend from the panel if you have a proper charge controller. Again, taking some guesses. Somewhere around Phoenix AZ, fixed array:
http://solarelectricityhandbook.com/solar-irradiance.html

Phoenix
Average Solar Insolation figures

Measured in kWh/m2/day onto a solar panel set at a 57° angle from vertical:
(For best year-round performance)

Jan	Feb	Mar	Apr	May	Jun
4.92	5.55	6.45	6.83	6.74	6.57
Jul	Aug	Sep	Oct	Nov	Dec
6.08	5.78	6.03	5.82	5.24	4.74

So, here we are in Mid-June, the average amount of sun per day is ~6.57 hours of sun:

• 100 Watt array * 0.52 average off grid system eff * 6.57 hours of sun per day (June) = 342 WH per day (June)

During the month of June, your 100 Watt solar array will "give you" and extra ~342 WH per day when it is sunny (over and above just discharging the battery bank by itself).

All of this is highly speculative--And we have not looked at the rest of your hardware (AC charge controller for during the week charging, solar charge controller for weekend, AC inverter or not, other loads like cell phone charging, running a radio/internet music/etc., etc.).

And simple issues like the AWG (diameter) and length of copper wire connecting your battery+inverter+loads together... Are you bolting up the electrical connections or using alligator clips (alligator clips do not make good/reliable connections for AC inverter power)...

The AGM battery you have--Generally these types are intended for UPS systems (sit in standby for months or longer at a time, then on for 30-60 minutes--And get replaced every ~2 years). They are a particularly sensitive to being overcharged -- Having a good Digital Voltmeter to double check charging/resting/discharging voltages will help you better understand how the battery is doing in your installation.

Do you have any other meters? Kill-a-Watt meter (to measure AC power/Watt*Hour)? A DMM (digital multimeter)? Other test gear (current clamp meter, DC AH/WH meter, etc.)?

Other issues--Generally, solar/battery power is relatively "expensive" and conservation would be a big help. Newer LED TVs generally use less than 100 Watts of power, DVD players should use less than 100 Watts (I have not measured any of my TV+DVD players with a Kill-a-Watt meter in years--But would be a good place to start).

Using a laptop+CD/DVD player may be closer to 30 Watts or less--And use HDMI from the laptop to a TV if you need a larger screen... etc...

Anyway, some basic information to start with.

-Bill

arilans

This is great guys just great!!! Can thank you enough.  The next thing I need some advice on is the charge controller. I bought the charge controller for $17 off of Amazon is highly reviewed and graded but the presets for the discharge and the recharge wouldn’t go high enough and lower enough for me. Can anyone recommend a inexpensive charge controller with an LCD display that I could buy? 

Estragon

Not a lot of inexpensive brand name controllers with displays.  There are some but likely spendier than you want (eg Morningstar 45a pwm, add $100 for an optional display).  One possibility is to get a dip-switch settable name brand controller (eg. midnite brat, Morningstar pwm) that can be set to values near what you want, and get a separate display if you just want basic voltage monitoring. 

Morningstar PS15M has a display and can be set up via computer software (~$150 from our hosts).

arilans

 So with a dip switch charge controller I would in essence set it and forget it and just trust that it is working properly? I was thinking if I had an LCD the display that it would allow me to possibly see something was going wrong before it got too bad. Does that make sense? 

mike95490

You can get a simple LED panel volt meter from flea bay and wire it to your battery via a push button.    viola - Readout

arilans

Yea that’s an idea. I think I need to get a controller for the solar portion as well. Any idea where I could find a decent controller? Like a website where I could find a reputable one?

Raj174

arilans said:

This is great guys just great!!! Can thank you enough.  The next thing I need some advice on is the charge controller. I bought the charge controller for $17 off of Amazon is highly reviewed and graded but the presets for the discharge and the recharge wouldn’t go high enough and lower enough for me. Can anyone recommend an inexpensive charge controller with an LCD display that I could buy? 

        I suggest a Victron 75/15 MPPT controller. It is a good quality controller and backed by a 5 year warranty. The controller settings are configured by jumpers. It does not have an LCD/LED display, but does have a blutooth app for your smartphone to monitor readings. This controller will only work with the addition of another 100 watt panel wired in series with the one you already have. This setup should provide around 10 charging amps to the 200AH battery. I believe that this would match the consumption amounts posted better than with one panel and a PWM controller. The only real issue with this controller is that it doesn't have a remote temperature sensor. That means, the battery and the controller need to be in the same environment so that any temperature compensation for charging voltage is accurate. 
A $118 controller plus an additional panel may be more than you wanted to spend, but success is more expensive when it's paid for by too many mistakes. Below is a link to the controller.

https://www.solar-electric.com/victron-energy-smartsolar-mppt-75-15-charge-controller.html

Rick  

Estragon

arilans said:

Yea that’s an idea. I think I need to get a controller for the solar portion as well. Any idea where I could find a decent controller? Like a website where I could find a reputable one?

I'd consider pretty much any controller sold by our host as reputable (I don't work for them or have any other conflicts, did buy most of my gear from them).