Solar Systems

[jcussen]

Originally Posted by C.Martin

The Lifeline manual recommends a procedure for calculating capacity...when put into service and then annually. Section 5.7 Capacity Testing. I’m not sure a lot of us are hooking up a 25A load to each battery and counting the time it takes to run from full to 10.5v.

Simply put...SOC is not capacity. This is all I’m trying to point out. The SOC is a simple counter. It makes an assumption that you are at 100% if some parameter is met...beit triggered by time or tail current held at absorption voltage. It sees this and says....Eureka...this is where 100% begins. It displays a change in SOC simply by counting the aH taken thereafter. It does the calculation based on the aH capacity you programmed it with. If you told it you had 800aH...that is how it computes the SOC as a percentage of 800aH...it cannot detect the size of your battery bank or the current true capacity.

Load testing, or using specialize impedance test equipment it the only way to tell what the capacity of the battery is.

Using a voltage graph is a crude way to get a general idea of battery capacity without doing a load run down test or using a sophisticated tester. I’m sure it is inaccurate...but has more validity than solely relying on SOC measurements.

I bring this up simply because it was pointed out that after eight years...the batteries could still charge to 101%... Alone...this really doesn’t mean anything other than there isn’t a shorted cell. Capacity can only be found by further testing...not a SOC reading.

Guess I was saying that even though my monitor was saying 100%, as the batteries aged and developed faults, it never actually got to the 100% of the original 1000 a/hr's I programmed into it, so was not a good indicator of actual battery capacity.

Not sure how it works with lithium now, Thinking monitor will just count amps in and amps out. But I do have the ability to synchronize 0 battery and fully charged battery, but do not see any way to actually calculate battery capacity other than run batteries down to cut off point and look at a/h's disharged.

[C.Martin]

Originally Posted by jcussen

Guess I was saying that even though my monitor was saying 100%, as the batteries aged and developed faults, it never actually got to the 100% of the original 1000 a/hr's I programmed into it, so was not a good indicator of actual battery capacity.

Not sure how it works with lithium now, Thinking monitor will just count amps in and amps out. But I do have the ability to synchronize 0 battery and fully charged battery, but do not see any way to actually calculate battery capacity other than run batteries down to cut off point and look at a/h's disharged.

True...the voltage curve is very flat. If you are top balanced via a BMS...then the battery monitor should detect the voltage stage and recalibrate. The Victron is programmable for the trigger, time...voltage...tail current.., plus has a manual calibration feature. The only way to measure capacity is to count aH on a rundown to cutout voltage. I haven’t even seen any impedance measuring for any of the LiFePO4 chemistries yet. You shouldn’t need to worry for quite some time.

[joes2901]

Originally Posted by C.Martin

True...the voltage curve is very flat. If you are top balanced via a BMS...then the battery monitor should detect the voltage stage and recalibrate. The Victron is programmable for the trigger, time...voltage...tail current.., plus has a manual calibration feature. The only way to measure capacity is to count aH on a rundown to cutout voltage. I haven’t even seen any impedance measuring for any of the LiFePO4 chemistries yet. You shouldn’t need to worry for quite some time.

Thanks C.Martin, you are right that SOC is an approximation.
Being familiar with how the battery bank performs with your normal load helps reinforce the all is well confidence. The Magnum MS2812 AGM-1 setting enables it to behave properly with Lifeline AGMs. I think it needs a 10% discharge to recalculate the 100% SOC based on voltage and amps the battery bank will accept. When the bank is getting full it gets harder to stuff more amps into it (unlike us humans) and the Outback controller reduces the power it produces even though the sun is shining. I have temp sensors on the battery bank for both the Magnum and Outback chargers so when the battery bank is cold charging begins at a higher voltage. Both chargers also record the low and high battery voltage for each day. When I see a a low of 11.7 volts or less it is because I had run both the coffee pot and microwave at the same time. When they shut off and dawn is breaking and the voltage bounces back to about 12.2 to 12.5 volts (no solar power yet).
After Labor Day it is getting cooler when parked at about 6,600' in Wyoming mountain campgrounds. I boondock for up to 5 months a year, propane refilled after Labor Day and holding tanks good for 17 to 19 days. When night temps are below freezing I turn on the 120 volt AC holding tanks heat pad (powered by the inverter) and set the furnace to 55. The heat pad increases the normal 12.4 amp draw from the battery bank to 53 amps and then settles down cycling off and on to maintain the tanks at 40 degrees. I like Fall the best and enjoy the hot pot of coffee and bowl of hot cereal while watching other campers and locals in parkas trying to get thier moose pictures; the TV may also be on so I can hear if it is going to be another 100+ degree day at home.
With the additional load and fewer hours of sunshine I notice the gen starts every other morning versus maybe once or twice a week in the summer and the run time increases to 2 to 2.5 hours. This has been normal from my battery bank since Spring 2012. The bank never is discharged to 50% and totally recharged every day, the batteries never get a rest and I expect a lifetime of 5,000+ recharge cycles. It is really fun around the first snow falls to run about 100 miles to Old Faithful Inn in Yellowstone for breakfast, if I get there early enough, or lunch, watch Old Faithful erupt, and drive back into dark clouds threatening a Winter storm.
Thanks Newmar for the great Bay Star. It did not require me to toss out too much stuff before I could finish it to a level of comfort that satisfied me.

[joes2901]

Originally Posted by Allentc2

There is sooooo much techie stuff that I am not getting. LOL


Well, after thinking about some of the stuff pointed out in the last couple of pages, I started calling Newmar and asking the installer questions. Turns out the 3401 battery bay would not come close to housing the AGMs. Per Newmar, I'd have 4 Interstate 75aH (which seems ridiculous to me) batteries, Interstate SRM-24s, and they "had just enough room". So at least some of the proposed 6 Lifeline AGMs would be occupying space in a cargo bay. The installer said lithiums should not be stored 'open air' and had to go in cargo spaces.


I figured if batteries were going to be in a cargo bay anyway, might as well go with lithium, though I went with 600aH of LifeBlue instead of the Battle Borns. Maybe I can use the free space in the battery bay to store the autoformer.

The photos below during installation shows where and how the 4 Lifeline L-16s (800 AH coach battery bank), Magnum stuff, and Outback controller, plus wiring were installed. A sub-panel for the inverter powered circuits was installed in the bathroom. The control panel over the door modified. I also put a pair of Lifeline 4CTs in front of the radiator for the chassis 12 volt loads. A forklift will help putting the 120 lbs L-16s into the 11" high pass rhrough. Don't compromise on your dream; you will be happier when it is achieved.

[CoreyinWP]

Great thread! Have learned a lot from C Martin and others who generously share info in a constructive fashion! Love the charts!!

[C.Martin]

Originally Posted by joes2901

The photos below during installation shows where and how the 4 Lifeline L-16s ....

Beautiful job! Craftmanship exemplified!!

[C.Martin]

Originally Posted by CoreyinWP

Great thread! Have learned a lot from C Martin and others who generously share info in a constructive fashion! Love the charts!!

My thanks to you! I love the charts too... They inspire thought. Instead of just wondering...it's fun to be able to look at real life data and see how everything works.

[C.Martin]

Originally Posted by joes2901

Thanks C.Martin, you are right that SOC is an approximation.
Being familiar with how the battery bank performs with your normal load helps reinforce the all is well confidence. The Magnum MS2812 AGM-1 setting enables it to behave properly with Lifeline AGMs. I think it needs a 10% discharge to recalculate the 100% SOC based on voltage and amps the battery bank will accept. When the bank is getting full it gets harder to stuff more amps into it (unlike us humans) and the Outback controller reduces the power it produces even though the sun is shining. I have temp sensors on the battery bank for both the Magnum and Outback chargers so when the battery bank is cold charging begins at a higher voltage. Both chargers also record the low and high battery voltage for each day. When I see a a low of 11.7 volts or less it is because I had run both the coffee pot and microwave at the same time. When they shut off and dawn is breaking and the voltage bounces back to about 12.2 to 12.5 volts (no solar power yet).
After Labor Day it is getting cooler when parked at about 6,600' in Wyoming mountain campgrounds. I boondock for up to 5 months a year, propane refilled after Labor Day and holding tanks good for 17 to 19 days. When night temps are below freezing I turn on the 120 volt AC holding tanks heat pad (powered by the inverter) and set the furnace to 55. The heat pad increases the normal 12.4 amp draw from the battery bank to 53 amps and then settles down cycling off and on to maintain the tanks at 40 degrees. I like Fall the best and enjoy the hot pot of coffee and bowl of hot cereal while watching other campers and locals in parkas trying to get thier moose pictures; the TV may also be on so I can hear if it is going to be another 100+ degree day at home.
With the additional load and fewer hours of sunshine I notice the gen starts every other morning versus maybe once or twice a week in the summer and the run time increases to 2 to 2.5 hours. This has been normal from my battery bank since Spring 2012. The bank never is discharged to 50% and totally recharged every day, the batteries never get a rest and I expect a lifetime of 5,000+ recharge cycles. It is really fun around the first snow falls to run about 100 miles to Old Faithful Inn in Yellowstone for breakfast, if I get there early enough, or lunch, watch Old Faithful erupt, and drive back into dark clouds threatening a Winter storm.
Thanks Newmar for the great Bay Star. It did not require me to toss out too much stuff before I could finish it to a level of comfort that satisfied me.

Wow...I can't wait to head out and see those places too.

If that testimony doesn't inspire folks to add some solar...I don't know what will.

I think living with your system, as you have...you have learned it's nuances. There isn't a measurement or tester that can replace that. The most important piece of the equation is that it meets the task you have given it. Brilliantly at that.

I think I'll know when my batteries are ready to retire...when the LBCO makes it's unwelcomed appearance before morning light comes around.

Can't wait to boondock out west...

[757driver]

Originally Posted by joes2901

Thanks C.Martin, you are right that SOC is an approximation.
Being familiar with how the battery bank performs with your normal load helps reinforce the all is well confidence. The Magnum MS2812 AGM-1 setting enables it to behave properly with Lifeline AGMs. I think it needs a 10% discharge to recalculate the 100% SOC based on voltage and amps the battery bank will accept. When the bank is getting full it gets harder to stuff more amps into it (unlike us humans) and the Outback controller reduces the power it produces even though the sun is shining. I have temp sensors on the battery bank for both the Magnum and Outback chargers so when the battery bank is cold charging begins at a higher voltage. Both chargers also record the low and high battery voltage for each day. When I see a a low of 11.7 volts or less it is because I had run both the coffee pot and microwave at the same time. When they shut off and dawn is breaking and the voltage bounces back to about 12.2 to 12.5 volts (no solar power yet).
After Labor Day it is getting cooler when parked at about 6,600' in Wyoming mountain campgrounds. I boondock for up to 5 months a year, propane refilled after Labor Day and holding tanks good for 17 to 19 days. When night temps are below freezing I turn on the 120 volt AC holding tanks heat pad (powered by the inverter) and set the furnace to 55. The heat pad increases the normal 12.4 amp draw from the battery bank to 53 amps and then settles down cycling off and on to maintain the tanks at 40 degrees. I like Fall the best and enjoy the hot pot of coffee and bowl of hot cereal while watching other campers and locals in parkas trying to get thier moose pictures; the TV may also be on so I can hear if it is going to be another 100+ degree day at home.
With the additional load and fewer hours of sunshine I notice the gen starts every other morning versus maybe once or twice a week in the summer and the run time increases to 2 to 2.5 hours. This has been normal from my battery bank since Spring 2012. The bank never is discharged to 50% and totally recharged every day, the batteries never get a rest and I expect a lifetime of 5,000+ recharge cycles. It is really fun around the first snow falls to run about 100 miles to Old Faithful Inn in Yellowstone for breakfast, if I get there early enough, or lunch, watch Old Faithful erupt, and drive back into dark clouds threatening a Winter storm.
Thanks Newmar for the great Bay Star. It did not require me to toss out too much stuff before I could finish it to a level of comfort that satisfied me.

I think that if you check Lifelines recommended charging voltages you will find that Magnum is behind the times. AGM1 will only give a Float voltage of 13.1v and Lifeline has recommended a Float voltage of 13.3v for some time now. An easy fix with custom settings in the Magnum remote.

[allen8106]

Check out Handy Bob. I modeled my 520 watt solar system based on his recommendations and it works flawlessly.

https://handybobsolar.wordpress.com/