So to summarise, more money required and some loss of existing flexibility. Offset by a yet unproven promise of extra life (will I live long enough to benefit?), the ability to use some higher current appliances (that I don't currently use & conditional on buying a bigger inverter) and a valuable reduction in weight. Thanks for the time spent Terry.
Cheers, Peter
We have only been doing this for 7 yrs or so but we do have graphs etc from the longest continuous use set up that returned over 100% capacity under the same test regime used by Winston the cell manufacturer, so that's about as much proven extra life we can offer at the moment. Not quite sure about the loss of existing flexibility you mention but if you want a system to automatically do what you do manually now then you must expect it cost a bit more to set up.
As far as the higher current devices, you do use a bread maker now off the system you have but you have to wait for the right solar conditions.
Basically, the difference between being in charge of what you do and when you do it rather than living life under the control of the battery condition, to me that is added flexibility anyway.
T1 Terry
Peter_n_Margaret said
02:23 PM Aug 7, 2018
No, I will need to manually look after the alternator. Now it can operate full auto.
We can bake bread at any time now, including at night to have it fresh for breakfast, so no change there.
In fact, if the sun does not shine, 400Ah of AGMs will run a compressor fridge drawing 3.5A for longer than 400Ah of lithiums because 400Ah of AGMs can run down to 10.5V and will provide in excess of 400Ah (at that low current draw). The lithiums are typically capped at 90% and you can not flatten them without risk of serious damage, so they will only provide something like 300Ah in real life.
Horses for courses Terry.
Each battery system has its own strengths and weakness and which is right for each individual will depend on their priorities at the time.
Right now, spending an extra $4,000 to change to lithiums is not justified, for me.
Maybe next time, if I live long enough?
Cheers,
Peter
T1 Terry said
03:11 PM Aug 7, 2018
Peter_n_Margaret wrote:
No, I will need to manually look after the alternator. Now it can operate full auto. We can bake bread at any time now, including at night to have it fresh for breakfast, so no change there. In fact, if the sun does not shine, 400Ah of AGMs will run a compressor fridge drawing 3.5A for longer than 400Ah of lithiums because 400Ah of AGMs can run down to 10.5V and will provide in excess of 400Ah (at that low current draw). The lithiums are typically capped at 90% and you can not flatten them without risk of serious damage, so they will only provide something like 300Ah in real life.
Horses for courses Terry. Each battery system has its own strengths and weakness and which is right for each individual will depend on their priorities at the time. Right now, spending an extra $4,000 to change to lithiums is not justified, for me. Maybe next time, if I live long enough?
Cheers, Peter
No idea who fed you that nonsense but it is nonsense none the less. The 400Ah is measured at a 200 amp load, not a 3.5 amp load, you will get a lot more than 400 Ah out of 400Ah of lithium before it drops below 12v or 3v per cell. As far as the 90% cap, more nonsense, the safe discharge limit is measured at cell voltage level not state of charge, do I need to provide a cell logger graph to show the number of hrs a 400 Ah lithium battery can supply 3.5 amps before a cell drops below 3v to prove it to you? I'm happy to do that if you post the graph for 400Ah of AGM batteries before an battery in the bank drops below 12v. You can't show actual cell voltage unfortunately because that is simply not available so the risk of a cell dropping below the lead acid safe threshold is all your responsibility but you are the one who put up the comparison after all.
What price for your 400Ah of AGM you intend to use for this test?
T1 Terry
Peter_n_Margaret said
11:43 AM Aug 8, 2018
So are you are saying that Peukart applies to Lithium?
So how long will 400Ah of Lithium run a fridge drawing 3.5A?
And it is rubbish to suggest that an AGM can not or should not be discharged below 12V.
Cheers,
Peter
T1 Terry said
12:34 PM Aug 8, 2018
Peter_n_Margaret wrote:
So are you are saying that Peukart applies to Lithium? So how long will 400Ah of Lithium run a fridge drawing 3.5A? And it is rubbish to suggest that an AGM can not or should not be discharged below 12V. Cheers, Peter
Peukert's law applies to all batteries developed at the moment, it is just the percentage it effects the advertised capacity that needs to be taken into account. The graph I posted previously shows both chemistry batteries and using a bit of reverse maths to clear up what is hidden in the Full River graph you can see how much of the advertised capacity at a given load will effect how long the battery can supply that load.
As an example, the Full River chart for a 105Ah battery at a 105 amp load shows a 1CA load graph line and following Full Rivers dotted graph line that shows completely discharged it intersects the time line at around 30 mins. 105Ah divided 60 mins = 1.75 amp mins x 30 mins = 52Ah capacity at that load, the Peukert effect displayed in chart fashion , albeit rather disguised in the manner it is presented.
Now let's look at the Winston graph. It doesn't try to hide the Peukert effect but rather clearly shows the effect a high current discharge effects the advertised usable capacity is a percentage graph along the bottom line.
Unfortunately the chart does not show any load less than 0.5CA or 50 amps per 100Ah of battery capacity so there can not be a direct comparison of a 0.05CA or C20 discharge rate as shown in the Full River chart in the line marked 5.3 amp load.
So, neither chemistry battery can give a tested result of the total capacity available under a 3.5 amp load for a 100Ah battery and most certainly not a 3.5 amp load for a 400Ah battery, so that would need to be actually tested and the test repeated a min of 3 times to get an average result ... are you up for it Peter, I can provide the workshop and test equipment if you want to supply the new 400Ah of AGM batteries and the end of test battery voltage, after all, you probably don't want to wreck a brand new set of AGM batteries do you ... but it would answer your second part of the question when the average over the 3 tests were shown and it there was any difference between the first test and the last test as this would show battery damage wouldn't it.
T1 Terry
-- Edited by T1 Terry on Wednesday 8th of August 2018 12:35:59 PM
Again why do I step in ?? Just a masochist I guess But another technical rant that seem to present not much useful information ? but issues a challenge to Peter to test his new batteries to ultimate discharge to prove your point at his expense ?? Hmmmm seriously ?
However my point is the two graphs are not directly comparable, for those who may be interested in the comparison. Peter talked about discharging his batteries at 3.5A The Fullriver graph has a line for 5.3A so that will do for some comparison perhaps.
The Winston graph has a normal linear scale along the bottom so double the distance is double the capacity. As expected ! But the Full River graph is a log scale along the bottom. A common maths trick to compact the information into a shorter graph. So that means that double the distance represents four times the time. So going from full at 105A to discharged at ~30 min (0.5Hr) compared to 5.3A to discharged at ~20 hrs are ratios of current 20/1 and the time is a ratio of 40/1. At a lesser rate of 3.5A it would be about double the time again ~40Hr. I guess that is what Peter was saying about his LA batteries running his fridge !!
You might sensibly choose to end the discharge at the end of the flat line part of the voltage graph which gives the same ratios and roughly halves the times.
Just saying "Lies, damm lies and statistics" is another old saying.
Jaahn
PS what might be of interest from that Full River graph is the reason why a volt meter reading is not useful for determining the state of charge or anything else of much use while the battery is charging or discharging. However with some experience you can "get the feel of what is happening" under the usual charge/discharge cycle.
-- Edited by Jaahn on Wednesday 8th of August 2018 09:32:59 PM
T1 Terry said
10:15 AM Aug 10, 2018
The Winston graph has a normal linear scale along the bottom so double the distance is double the capacity. As expected ! But the Full River graph is a log scale along the bottom. A common maths trick to compact the information into a shorter graph. So that means that double the distance represents four times the time. So going from full at 105A to discharged at ~30 min (0.5Hr) compared to 5.3A to discharged at ~20 hrs are ratios of current 20/1 and the time is a ratio of 40/1. At a lesser rate of 3.5A it would be about double the time again ~40Hr. I guess that is what Peter was saying about his LA batteries running his fridge !!
That is serious assumption there Jaahn and something I would not have expected from you. The Full River graph shows the battery completely discharged in one hr as a 60.9amp load, yet a 105 amp load returns only 30 mins. for your assumption to follow a logical doubling the discharge time by having the load should equally mean doubling load should equal half the discharge time ... but it doesn't does it. If a load of 60.9 amps results in 1hrs supply then a load of twice that, 121.8amps, should give 30 mins of supply, yet only 105 amps can be extracted for 30 mins until the supply is drained.
So, without testing a theory you can't give a definitive result that a 3.5hr load on a 100Ah AGM battery will give a 40hr supply without wrecking the battery during the attempt.
Peter tried to set a trap in the way he worded his post, I answered it in way he didn't want to see because it might have made the post about getting a longer run out of the 400Ah of AGM batteries until fully discharge than he could out the same capacity lithium battery a complete load of uniformed nonsense.
Every time I put up the challenge to test a theory I'm happy to provide my side of the test equipment but those making the unproven claims are never willing to put up their half of the goods to be put to the test.
You quote a few sayings in your post but it really has come down to the well known phase "Put up or shut up" to end this nonsense being put forward as fact. Prove me wrong and I'll be happy to shut up, but the same has to go both ways.
T1 Terry
Jaahn said
04:29 PM Aug 10, 2018
Hi Terry
Actually I made no assumptions Terry, but just pointed out the facts of the graphs as shown on the lableing of the axis of the two graphs. Then for the 3.5A comments I looked at the trend of the discharge amps and times shown by the lines on the Full River graph. I did a quick analysis of the trend and showed the expected result with "approximate ~" as a rider. So I stand by that
As I pointed out a log scale graph does present information that need some interpreting, compared to a normal linear graph. There was no trap in my words and I was not suggesting either graph was good or bad.
I am not justifying everything Peter has said, he can stand by what he wrote himself. He did make an incorrect statement IMHO about the relative merits of the LA Vs Li 400AHr batteries running the 3.5A.
Jaahn
-- Edited by Jaahn on Friday 10th of August 2018 05:30:53 PM
We have only been doing this for 7 yrs or so but we do have graphs etc from the longest continuous use set up that returned over 100% capacity under the same test regime used by Winston the cell manufacturer, so that's about as much proven extra life we can offer at the moment. Not quite sure about the loss of existing flexibility you mention but if you want a system to automatically do what you do manually now then you must expect it cost a bit more to set up.
As far as the higher current devices, you do use a bread maker now off the system you have but you have to wait for the right solar conditions.
Basically, the difference between being in charge of what you do and when you do it rather than living life under the control of the battery condition, to me that is added flexibility anyway.
T1 Terry
We can bake bread at any time now, including at night to have it fresh for breakfast, so no change there.
In fact, if the sun does not shine, 400Ah of AGMs will run a compressor fridge drawing 3.5A for longer than 400Ah of lithiums because 400Ah of AGMs can run down to 10.5V and will provide in excess of 400Ah (at that low current draw). The lithiums are typically capped at 90% and you can not flatten them without risk of serious damage, so they will only provide something like 300Ah in real life.
Horses for courses Terry.
Each battery system has its own strengths and weakness and which is right for each individual will depend on their priorities at the time.
Right now, spending an extra $4,000 to change to lithiums is not justified, for me.
Maybe next time, if I live long enough?
Cheers,
Peter
No idea who fed you that nonsense but it is nonsense none the less. The 400Ah is measured at a 200 amp load, not a 3.5 amp load, you will get a lot more than 400 Ah out of 400Ah of lithium before it drops below 12v or 3v per cell. As far as the 90% cap, more nonsense, the safe discharge limit is measured at cell voltage level not state of charge, do I need to provide a cell logger graph to show the number of hrs a 400 Ah lithium battery can supply 3.5 amps before a cell drops below 3v to prove it to you? I'm happy to do that if you post the graph for 400Ah of AGM batteries before an battery in the bank drops below 12v. You can't show actual cell voltage unfortunately because that is simply not available so the risk of a cell dropping below the lead acid safe threshold is all your responsibility but you are the one who put up the comparison after all.
What price for your 400Ah of AGM you intend to use for this test?
T1 Terry
So how long will 400Ah of Lithium run a fridge drawing 3.5A?
And it is rubbish to suggest that an AGM can not or should not be discharged below 12V.
Cheers,
Peter
Peukert's law applies to all batteries developed at the moment, it is just the percentage it effects the advertised capacity that needs to be taken into account. The graph I posted previously shows both chemistry batteries and using a bit of reverse maths to clear up what is hidden in the Full River graph you can see how much of the advertised capacity at a given load will effect how long the battery can supply that load.
As an example, the Full River chart for a 105Ah battery at a 105 amp load shows a 1CA load graph line and following Full Rivers dotted graph line that shows completely discharged it intersects the time line at around 30 mins. 105Ah divided 60 mins = 1.75 amp mins x 30 mins = 52Ah capacity at that load, the Peukert effect displayed in chart fashion , albeit rather disguised in the manner it is presented.
Now let's look at the Winston graph. It doesn't try to hide the Peukert effect but rather clearly shows the effect a high current discharge effects the advertised usable capacity is a percentage graph along the bottom line.
Unfortunately the chart does not show any load less than 0.5CA or 50 amps per 100Ah of battery capacity so there can not be a direct comparison of a 0.05CA or C20 discharge rate as shown in the Full River chart in the line marked 5.3 amp load.
So, neither chemistry battery can give a tested result of the total capacity available under a 3.5 amp load for a 100Ah battery and most certainly not a 3.5 amp load for a 400Ah battery, so that would need to be actually tested and the test repeated a min of 3 times to get an average result ... are you up for it Peter, I can provide the workshop and test equipment if you want to supply the new 400Ah of AGM batteries and the end of test battery voltage, after all, you probably don't want to wreck a brand new set of AGM batteries do you ... but it would answer your second part of the question when the average over the 3 tests were shown and it there was any difference between the first test and the last test as this would show battery damage wouldn't it.
T1 Terry
-- Edited by T1 Terry on Wednesday 8th of August 2018 12:35:59 PM
Cheers,
Peter
Hi Terry
Again why do I step in ?? Just a masochist I guess
But another technical rant that seem to present not much useful information ? but issues a challenge to Peter to test his new batteries to ultimate discharge to prove your point at his expense ?? Hmmmm seriously ?
However my point is the two graphs are not directly comparable, for those who may be interested in the comparison. Peter talked about discharging his batteries at 3.5A The Fullriver graph has a line for 5.3A so that will do for some comparison perhaps.
The Winston graph has a normal linear scale along the bottom so double the distance is double the capacity. As expected ! But the Full River graph is a log scale along the bottom. A common maths trick to compact the information into a shorter graph. So that means that double the distance represents four times the time. So going from full at 105A to discharged at ~30 min (0.5Hr) compared to 5.3A to discharged at ~20 hrs are ratios of current 20/1 and the time is a ratio of 40/1. At a lesser rate of 3.5A it would be about double the time again ~40Hr. I guess that is what Peter was saying about his LA batteries running his fridge !!
You might sensibly choose to end the discharge at the end of the flat line part of the voltage graph which gives the same ratios and roughly halves the times.
Just saying
"Lies, damm lies and statistics" is another old saying.
PS what might be of interest from that Full River graph is the reason why a volt meter reading is not useful for determining the state of charge or anything else of much use while the battery is charging or discharging. However with some experience you can "get the feel of what is happening" under the usual charge/discharge cycle.
-- Edited by Jaahn on Wednesday 8th of August 2018 09:32:59 PM
The Winston graph has a normal linear scale along the bottom so double the distance is double the capacity. As expected ! But the Full River graph is a log scale along the bottom. A common maths trick to compact the information into a shorter graph. So that means that double the distance represents four times the time. So going from full at 105A to discharged at ~30 min (0.5Hr) compared to 5.3A to discharged at ~20 hrs are ratios of current 20/1 and the time is a ratio of 40/1. At a lesser rate of 3.5A it would be about double the time again ~40Hr. I guess that is what Peter was saying about his LA batteries running his fridge !!
That is serious assumption there Jaahn and something I would not have expected from you. The Full River graph shows the battery completely discharged in one hr as a 60.9amp load, yet a 105 amp load returns only 30 mins. for your assumption to follow a logical doubling the discharge time by having the load should equally mean doubling load should equal half the discharge time ... but it doesn't does it. If a load of 60.9 amps results in 1hrs supply then a load of twice that, 121.8amps, should give 30 mins of supply, yet only 105 amps can be extracted for 30 mins until the supply is drained.
So, without testing a theory you can't give a definitive result that a 3.5hr load on a 100Ah AGM battery will give a 40hr supply without wrecking the battery during the attempt.
Peter tried to set a trap in the way he worded his post, I answered it in way he didn't want to see because it might have made the post about getting a longer run out of the 400Ah of AGM batteries until fully discharge than he could out the same capacity lithium battery a complete load of uniformed nonsense.
Every time I put up the challenge to test a theory I'm happy to provide my side of the test equipment but those making the unproven claims are never willing to put up their half of the goods to be put to the test.
You quote a few sayings in your post but it really has come down to the well known phase "Put up or shut up" to end this nonsense being put forward as fact. Prove me wrong and I'll be happy to shut up, but the same has to go both ways.
T1 Terry
Hi Terry
Actually I made no assumptions Terry, but just pointed out the facts of the graphs as shown on the lableing of the axis of the two graphs. Then for the 3.5A comments I looked at the trend of the discharge amps and times shown by the lines on the Full River graph. I did a quick analysis of the trend and showed the expected result with "approximate ~" as a rider. So I stand by that
As I pointed out a log scale graph does present information that need some interpreting, compared to a normal linear graph. There was no trap in my words and I was not suggesting either graph was good or bad.
I am not justifying everything Peter has said, he can stand by what he wrote himself. He did make an incorrect statement IMHO about the relative merits of the LA Vs Li 400AHr batteries running the 3.5A.
Jaahn
-- Edited by Jaahn on Friday 10th of August 2018 05:30:53 PM