Hi, I read and read and read everything I can about solar systems.  But no where do I see how to read and use my own charge controller effectively!  Please, I just need some simple info in a format I can save to laminate and post near my controller until this becomes second nature if that's possible?  

I have a 40 watt MPPT charge controller, 640 watts of solar panels on my RV roof (flexible ones) and I have a 2000 watt pure sine wave Inverter, battery temp sensor, and remote inverter monitor/controller.  I also have two 100 amh 12v AGM size 31 batteries.  So, for example, in my set up, what is the amp or watts reading on my controller that I need to watch when I am running things to be sure that I am not letting my batteries get too low?  ie, I thought 50% meant 6 volts of a 12 volt battery.  See what I mean?  I realize that if I add additional batteries this how too guide will change as I will have more solar storage correct?  I cannot be the only one that does not understand this stuff and needs this help.  Please?????  

Thank you in advance, I am new at all of this sort of.  I do not have a partner that is better at this stuff than I am anymore either.  So please keep the lectures to a minimum and don't question the size system I bought pretty please.  I needed solar and I needed it now with a faster recharging rate.  Hopefully, that's what I have.  The battery configuration confuses the heck out of me too.  So for now, I stay with what I have until somewhere I find something that will finally help me understand the various configurations.  for example, how the heck can two 6 volt batteries give me more AMH hours than two 12v batteries?  Makes no sense to me.  So, please don't even try at this point on that issue either.  I am overwhelmed already.  

Thank you for your understanding and help.  Happy camping.

Rayne

Hi Rayne-

With two, 100 amp-hour batteries you've got a total of 200 amp-hours of capacity, but the 50% recommendation would be to only use 100 amp-hours to prolong battery life. Here is what 100 amp-hours of available capacity means: You can pull 100 amps for one hour, 25 amps for 4 hours, 10 amps for 10 hours, etc. Think of it as a milkshake. The harder you suck on the straw the faster the milkshake is gone!! Realistically you will draw different amounts of power at different times, so it is difficult to go by amps or time without keeping close track of what is happening minute-by-minute.

Voltage can be somewhat useful for determining state-of-charge (how much energy remains in your batteries) For AGM type batteries 12.3 volts at rest is considered an indication that the batteries are down to about half charge, but the at rest part is the catch. You will almost always be drawing at least some power from your batteries, and perhaps charging with solar as well, so they are not "at rest" unless you make a specific effort to disconnect all loads and let them sit for a while. Which is hardly convenient while you are trying to live.

And knowing amp draw only tells you how much power you are pulling from the batteries at that moment (how hard you are sucking on the straw...), so is not an indicator of overall remaining capacity either. 

The best way to track battery state-of-charge is with a battery monitor. It keeps track of how many amps you are pulling at any given time, and subtracts it from the capacity. If wired correctly, it will also keep track of how much your solar is putting back in, and knowing those two things you have total knowledge of where you are in terms of remaining battery capacity. 

You mention a 2000W pure sine wave inverter with a monitor/controller. Many of those devices will do exactly what I described as a battery monitor, so you may already have what you need. If you let us know what brand of inverter you have, along with model number/designation of the monitor/controller perhaps we can give more specific advice. 

Edited April 30 by mptjelgin

Wow, that was really helpful Mark & Teri, not sure which one of you wrote this.  Anyhow, I purchased the Go power IC2000 Inverter/charger with a remote monitor, built in transfer switch, power sharing (?), and I did not get it through GP dealer, got it through Amazon but not at full price either.  I do not know the brand name for sure of the Charge Controller that my RV place has ordered, just that it is an MPPT and a 40 watt or is it amps?  LOL.  I wish my brain would hold onto those and keep them straight somehow.  I have tried everything I have learned through the years to make it stick, but not good so far.  Anyhow, I think the brand is one that starts with a vowel, but I will have to ask my RV place tomorrow.  Sorry I can't tell you more than this.  

Rayne

I am no solar expert, but just to give you a feel for what battery voltages should be, take a look at these battery voltage charts which show you what you can expect from your battery readings. 

Hi Rayne,

The primary item you need to monitor the state of charge of your batteries is an amp-hour battery monitor that measures all of the current flowing in or out of the batteries.  It keeps a running total of how many amp-hours you've taken out of the batteries, counting down as you use power, counting up as the solar panels push power back into them.

Comparing this to the Amp-hour capacity of the batteries will tell you how much capacity remains in the batteries.

Your charge controller only knows how much voltage and current it's pushing out, it doesn't know the size of the battery bank, it doesn't know if all of the power it's putting out is going into the batteries or is being used elsewhere.  As such, it can't tell you the battery's state of charge, all it knows is to shut down when the battery voltage rises to a level that says the batteries are full.

Amps are instantaneous measurements.  Amp-hours are Amps X (time), an indication of how much power you've used.  For example, using 5 amps for 30 minutes is 2.5 amp-hours, using 5 amps for 1 hour is 5 amp-hours, etc.

The same holds true when charging the batteries.  Push in 5 amps from the solar panels for one hour and the batteries will gain 5 amp-hours of charge.

An amp-hour meter counts up and down as you charge and then use power from the batteries.  You'll know at a glance what state your batteries are in, for example if you've taken 50 a-h out of the batteries the meter will read -50.

When the solar panels are charging the batteries, the amp-hour meter will climb towards zero, which indicates the batteries are full.  

Tell me what kinds of charge controller, inverter and monitor panel you have and I'll take a look at them and see if they'll give you the necessary information or if you need to purchase a separate amp-hour meter.

Here's a link to the manual for the Trace/Xantrex Battery Status Monitor.  Unfortunately, it's discontinued but the manual provides a good, easy to understand description of how an amp-hour meter works.

http://www.xantrex.com/documents/Discontinued-Products/3507TraceMeterRevB.pdf

Edited May 1 by Lou Schneider

Hi Rayne-

I've looked at the on-line documentation available for your GoPower IC2000 Inverter/Charger  and the remote display/control unit. It looks like a good quality inverter/charger with many features, but it does not appear to have the capability of measuring amp-hours in/out like a battery monitor. 

As far as settings for the inverter/charger, it appears that the factory default settings will work perfectly with your AGM batteries. 

It is unlikely that your 40 amp MPPT solar controller will have the battery monitoring capability, but once you find out the brand name we can see. 

Mark

Rayne,

Lot of excellent info and detail provided in the replies so far.  Be sure to spend some time working to digest the details and come back with questions for what is not clear to you.

In addition here are two links to some good detailed info on RV 12V electrical systems, batteries, battery charging and solar.  As you read through these websites, try to relate the information to what you have in your RV.  Reading each part of the info in the links as you look at what is in your RV will really help you understand your systems.   This is a many hour project over some number of days as you have time, not just an hour or two of time. 

Copy and paste info from the replies above and from the links with your comments about what is not clear to you and many of us will work to assist you.   

http://www.marxrv.com/12volt/12volt.htm

http://www.marxrv.com/12volt/12volta.htm

Thanks everyone, I feel like I am drowning though.  The link from Kirk is extremely overwhelming to me, and I haven't opened the latest ones yet from Al & Sharon.  I'm sort of getting "some" more of it though.  I would definitely like to get a battery monitoring device if one isn't incorporated into my charge controller already.  Praying that it is.  Unfortunately, I still do not have my system in front of me in my rig to see what it can bring in on a given day, and what I use up on a basic day versus a heavy use day type scenario.  Darn mice!  

I sent an email to the RV place that is doing my solar system today, but found out I used the wrong email address for them.  So I will check tomorrow.  I know the Xantrex that Al mentions is a name I know the solar guy was talking about liking and having used in the past.  Hoping it isn't discontinued like the system monitor Al also mentions.  

Al, when you mention copy and paste all the good info I am getting from all of you, do you mean into a saveable format in my computer so I can digest it offline, or do you mean to copy and paste it all each time I reply to one of you?  

Oh, and another question if I may, not solar exactly, but it will be affected by my solar installation.  

I have a fancy satellite antenna on the top of my rig. Winnegard something or other.  I cannot find anywhere in the instructions for it where I would need to have any type of subscription to a TV service to use it, and inside my rig is one of the digital antenna that is flat and affixes to an exterior window or wall.  That is all I have used so far and it has at least given me something to watch wherever I have been.  So, my question is, do I still need this other fancy satellite antenna, is it that much better or even still used if it isn't collecting digital signals since nearly all stations have gone to being digital?  I ask, because my plan is to have them remove the rooftop satellite setup so that we can put another solar panel on the roof that will need that roof space. I realize the RV place will have to do a super job of making sure that my roof is sealed up where they have removed the satellite antenna so it doesn't leak.  I would really like to be able to take the wind up thing off of the ceiling of the inside of my rig too.   Thoughts? 

Thanks so much.  NOT: I am not getting notifications in my email when any of your reply, so I have to keep checking here each evening once my grandchildren are all asleep to see.  I have all of the notifications set to alert me when I get posts to any of the topics I have started or that I am watching, but I still get nothing!  I am checking my spam folder too.  Suggestions on this issue?  

Rayne

The most important part of any system is a battery monitor system as noted by Lou.  I use a Bogart Engineering Pentametric monitor and find it very informative.  They also have a Trimetric battery monitor that does many of the same things the Pentametric does.  Both to a great job of informing us of battery status.

Lenp

I don't speak much of this language either so haven't read most of the answers but I can tell you I had a Trimetric battery monitor that worked for me. It had capabilities I never used but it would give me enough information to know whether or not I needed to worry about my batteries getting too low.

One of the things I did learn was to charge my phone and laptop early in the day then unplug them so the solar panels had all afternoon to recharge my house batteries.

And having house batteries you don't have to water was wonderful!

Linda Sand

  On 5/1/2019 at 10:09 AM, Rayne said:

Thanks everyone, I feel like I am drowning though.  The link from Kirk is extremely overwhelming to me, and I haven't opened the latest ones yet from Al & Sharon.  I'm sort of getting "some" more of it though.  I would definitely like to get a battery monitoring device if one isn't incorporated into my charge controller already.  Praying that it is.  Unfortunately, I still do not have my system in front of me in my rig to see what it can bring in on a given day, and what I use up on a basic day versus a heavy use day type scenario.  Darn mice!  

I sent an email to the RV place that is doing my solar system today, but found out I used the wrong email address for them.  So I will check tomorrow.  I know the Xantrex that Al mentions is a name I know the solar guy was talking about liking and having used in the past.  Hoping it isn't discontinued like the system monitor Al also mentions.  

Al, when you mention copy and paste all the good info I am getting from all of you, do you mean into a saveable format in my computer so I can digest it offline, or do you mean to copy and paste it all each time I reply to one of you?  

Reply:  When you are reading the info in the links and the replies and you come across a paragraph or statement you don't understand, copy and paste the info, along with a description of what is not clear to you.  Additionally it is a good idea to copy and paste into a document the info provided in the replies in this topic.  This way you have the copy easily at hand and don't have to go online to find it.  

Oh, and another question if I may, not solar exactly, but it will be affected by my solar installation.  

I have a fancy satellite antenna on the top of my rig. Winnegard something or other.  I cannot find anywhere in the instructions for it where I would need to have any type of subscription to a TV service to use it, and inside my rig is one of the digital antenna that is flat and affixes to an exterior window or wall.  That is all I have used so far and it has at least given me something to watch wherever I have been.  So, my question is, do I still need this other fancy satellite antenna, is it that much better or even still used if it isn't collecting digital signals since nearly all stations have gone to being digital?  I ask, because my plan is to have them remove the rooftop satellite setup so that we can put another solar panel on the roof that will need that roof space. I realize the RV place will have to do a super job of making sure that my roof is sealed up where they have removed the satellite antenna so it doesn't leak.  I would really like to be able to take the wind up thing off of the ceiling of the inside of my rig too.   Thoughts? 

Reply:  The Winegard satellite antenna on the roof.  Assuming this is a large round or oval dish like this:  https://www.amazon.com/Winegard-SK-1000-TRAVLER-Automatic-Multi-Satellite/dp/B002N5RZOY/ref=sr_1_1_sspa?crid=F1T143GNQ1RB&keywords=tra v'ler+dish&qid=1556709059&s=gateway&sprefix=trav'ler%2Caps%2C338&sr=8-1-spons&psc=1  It could be Dish Network or Direct TV, both provide excellent satellite TV reception with some 200-300 TV channels available from a subscription from either provider. If you want excellent TV service then I would keep the satellite dish.

I think the "wind up thing off the ceiling" is the over the air (OTA) TV antenna.  Either that antenna or the one you hang in the window should give you pretty good TV reception from the free OTA local TV broadcast stations.  

Thanks so much.  NOT: I am not getting notifications in my email when any of your reply, so I have to keep checking here each evening once my grandchildren are all asleep to see.  I have all of the notifications set to alert me when I get posts to any of the topics I have started or that I am watching, but I still get nothing!  I am checking my spam folder too.  Suggestions on this issue?  

Rayne

  On 4/30/2019 at 4:47 AM, Rayne said:

Hi, I read and read and read everything I can about solar systems.  But no where do I see how to read and use my own charge controller effectively!  Please, I just need some simple info in a format I can save to laminate and post near my controller until this becomes second nature if that's possible?  

I have a 40 watt MPPT charge controller, 640 watts of solar panels on my RV roof (flexible ones) and I have a 2000 watt pure sine wave Inverter, battery temp sensor, and remote inverter monitor/controller.  I also have two 100 amh 12v AGM size 31 batteries.  So, for example, in my set up, what is the amp or watts reading on my controller that I need to watch when I am running things to be sure that I am not letting my batteries get too low?  ie, I thought 50% meant 6 volts of a 12 volt battery.  See what I mean?  I realize that if I add additional batteries this how too guide will change as I will have more solar storage correct?  I cannot be the only one that does not understand this stuff and needs this help.  Please?????  

Thank you in advance, I am new at all of this sort of.  I do not have a partner that is better at this stuff than I am anymore either.  So please keep the lectures to a minimum and don't question the size system I bought pretty please.  I needed solar and I needed it now with a faster recharging rate.  Hopefully, that's what I have.  The battery configuration confuses the heck out of me too.  So for now, I stay with what I have until somewhere I find something that will finally help me understand the various configurations.  for example, how the heck can two 6 volt batteries give me more AMH hours than two 12v batteries?  Makes no sense to me.  So, please don't even try at this point on that issue either.  I am overwhelmed already.  

Thank you for your understanding and help.  Happy camping.

Rayne

You seem to have or will have (it is not clear if you are in the process of installing this system, or if it is already installed) a very robust solar system with far more solar than you need to keep the two batteries you have installed fully charged.  

You don't state what your planned power usage will be when not hooked to shore power so it is hard to assess how adequate your system will be for you.  In the two links I gave earlier there is quite a bit of info about how much battery power is required to operate various household devices through the inverter. Things like the microwave, TV, coffee maker, toaster, hair dryer, etc.  

Your inverter is nicely sized to operate at microwave, toaster, coffee maker, each, one at a time.  However your two batteries are sized too small to operate those devices.   To operate those devices you should have 4 golf cart batteries installed.  Additionally with your 640 watts of solar you could support 6 golf cart batteries if you have the room for them AND your RV can take the 400 pounds the 6 batteries will weigh.  

If you are just going to operate the RV, lights, furnace, laptops, smart phones with your system then the two batteries would be the least amount of battery you should have.  4 batteries would be much better though.

You have a 40 amp MPPT solar controller which is properly sized for your 640 watts of solar panels, but would be undersized if you added more solar.  Keep that in mind if you plan on adding more solar.  

Hi Al, I am in the process still of absorbing all of this.  So far, I have added a Battery monitor to be compatible with my Xantrex Solar Charge controller, and I am now seriously looking at adding batteries.  I'm thinking of two of the 6 volt in addition to my current 12 v ones, but I am thinking that it may not be a good combo, right?  Reason to keep my two current ones is that I was thinking of adding the two more 6 volt ones in the bed of the truck directly below the camper battery compartment in the section between the camper wall and my truck bed wall.  I would of course need a quick disconnect there for when I may someday be able to take my rig off my truck to camp (this is a rear stair issue being worked on by someone for me).  

The info you sent to me via the links was very helpful.  Thank you.  But it still makes me nuts on the batteries and their various Amh hours versus their sizes etc.  Makes NO sense to me how they can vary so much.  even amongst the 6 volt batteries, or should I say especially!  LOL.  So, give me a few more days of absorbing.  

Yawn, okay, heading off to sleep now.  

Rayne

  On 5/3/2019 at 11:13 AM, Rayne said:

Hi Al, I am in the process still of absorbing all of this.  So far, I have added a Battery monitor to be compatible with my Xantrex Solar Charge controller, and I am now seriously looking at adding batteries.  I'm thinking of two of the 6 volt in addition to my current 12 v ones, but I am thinking that it may not be a good combo, right?  Reason to keep my two current ones is that I was thinking of adding the two more 6 volt ones in the bed of the truck directly below the camper battery compartment in the section between the camper wall and my truck bed wall.  I would of course need a quick disconnect there for when I may someday be able to take my rig off my truck to camp (this is a rear stair issue being worked on by someone for me).  

The info you sent to me via the links was very helpful.  Thank you.  But it still makes me nuts on the batteries and their various Amh hours versus their sizes etc.  Makes NO sense to me how they can vary so much.  even amongst the 6 volt batteries, or should I say especially!  LOL.  So, give me a few more days of absorbing.  

Yawn, okay, heading off to sleep now.  

Rayne

Sorry,  I have been away from my computer since yesterday.

Mixing a pair of group 31 batteries, each with a rated capacity of about 100AH with what would be a third battery (the two 6V Golf Cart batteries, wired in series make 1 large 12V battery) with an amp hour (AH) capacity of about 200-220AH is not a good idea.  The basic problem is the group 31 batteries will fill before the golf cart batteries do, also the discharge parameters will be different.  Basically you won't get the full additional capacity.  

If you want to add more batteries in the bed of the P/U I would go with additional Group 31 batteries, the same make and age of the ones you already have.  If you do you want these additional batteries to be as close to the existing batteries as possible.  No more than 12"-18" of cable between the additional batteries and the existing.  Ideally you want to put all the batteries in the same space, i.e. 1/4" to 1/2" apart and all the cables connecting the batteries basically the same length.  

  On 5/3/2019 at 11:13 AM, Rayne said:

Hi Al, I am in the process still of absorbing all of this.  So far, I have added a Battery monitor to be compatible with my Xantrex Solar Charge controller,...................

Which battery monitor did you add?  

You initial post said you just wanted to know how to read you charge controller to monitor the state of your batteries.  Depending on what additional battery monitor you just installed, you now have the best device for monitoring your batteries, not matter if you are charging from the solar or shore power.  Also this battery monitor will show you how many AH's you are using from your batteries, no matter if it is 120V devices or just the lights, forced air propane furnace (from the fan blowing) or anything else.  It will show you the total of number of AH's used as well as the percentage of charge in the batteries.