Isn't it strange that after a bombing, everyone blames the bomber, his upbringing, his environment, his culture, his mental state but … after a shooting, the problem is the gun?
My Uncle Frank was a staunch Conservative and voted straight Republican until the day he died in Chicago. Since then he has voted Democrat. Shrug
Under light loads and normal use, where deep discharge doesn't take place, it isn't much of an issue, but if the battery pack gets down a lot, it really causes problems during recharge. Wouldn't be a big problem during recharge, except in the tye application being discussed, there is also almost always a current draw at the same time the batteries are being recharged--engine is running, lights on, refrigerator on, inverter on etc.
"I think I am right in saying that this is the only example I have ever come across where doing something the correct way actually looks less elegant than doing it incorrectly."
So they both do the same thing it is just a matter of balance in the discharge of individual battery, never heard of that. Individual battery's draw differently that I knew but if they are all the same, made at the same time I see no reason for that different battery draw rate.
From the SmartGuage Electronics link: (pretend there are only two 12v batteries here instead of 4) Example: drawing 100amps from the battery pack: Method 1. The bottom battery provides 35.9 amps of this. The next battery up provides 26.2 amps. The next battery up provides 20.4 amps. The top battery provides 17.8 amps. So the bottom battery provides over twice the current of the top battery.
Method 2
All that has changed in this diagram is that the main feeds to the rest of the installation are now taken from diagonally opposite posts. It is simple to achieve but the difference in the results are truly astounding for such a simple modification. The connecting leads, in fact, everything else in the installation remains identical. Also, it doesn't matter which lead (positive or negative) is moved, Whichever is easiest is the correct one to move. The results of this modification, when compared to the original diagram are shown below. Only that one single connection has been moved. After this simple modification, with the same 100 amp load.... The bottom battery provides 26.7 amps of this. The next battery up provides 23.2 amps. The next battery up provides 23.2 amps. The top battery provides 26.7 amps. This is quite clearly a massive improvement over the first method. The batteries are much closer to being correctly balanced.
So they both do the same thing it is just a matter of balance in the discharge of individual battery, never heard of that. Individual battery's draw differently that I knew but if they are all the same, made at the same time I see no reason for that different battery draw rate.
Steve
It has to do with electron flow and resistance to that flow Steve. The battery in a parallel circuit, closest to load will ALWAYS provide more power to the load than the battery(s) behind it, thus it will do more 'work', require more charging and will fail earlier, IF both +/- cables are directly connected to that battery.
If you disregard the electrical resistance of the cables (i.e. assume zero ohms), then any way of connecting two or more batteries in parallel is as good as any other. But in the real world you can't ignore resistance, because it's always present ... that is, until one of you manages to come up with a practical room-temperature superconductor.
Don, very interesting diagram. I learned something today.
Roger, my inverter shuts down at 11.5 v. I think they did so to allow batteries to go through more charge, discharge cycles. There are charts available that show life expectancy of a battery based on how deeply the battery was discharged. The deeper you discharge, the shorter the life expectancy.
If you disregard the electrical resistance of the cables (i.e. assume zero ohms), then any way of connecting two or more batteries in parallel is as good as any other. But in the real world you can't ignore resistance, because it's always present ... that is, until one of you manages to come up with a practical room-temperature superconductor.
Please expand on that, because to me it sounds like you are saying the first one is better than the second one with longer wires because there is more cable to go threw in the second one.
It has to do with electron flow and resistance to that flow Steve. The battery in a parallel circuit, closest to load will ALWAYS provide more power to the load than the battery(s) behind it, thus it will do more 'work', require more charging and will fail earlier, IF both +/- cables are directly connected to that battery.
Don I beg to differ, remember the GM 80s diesel cars. They had a bad habit in the beginning because the SOOO CALLED GM engineers forgot to put a battery isolator in between the 2. I had one, if one battery went dead, they were both dead. Great engineering. one battery was just for the glow plugs and the other for the starter if I remember right, my memory is shot.
Edit to add link about that setup and as anyone who has ever owned a camper knows if you don't isolate the starter battery from the power battery they all go down and can prevent starting.
Please expand on that, because to me it sounds like you are saying the first one is better than the second one ...
What matters here is the electrical resistance of the links between the batteries. In either case, count the number of such links the current has to flow through between each battery and the load.
In the first case, the number of links is (2 x (p - 1)) ... where p is the position of the battery in the array: 1, 2, 3, etc. The key point is that the number of links is different for each battery.
In the second case, though, the number of links is always (n - 1) ... where n is the total number of batteries; the number of links is always the same for each battery.
[This message has been edited by Marvin McInnis (edited 12-21-2015).]
What matters here is the electrical resistance of the links between the batteries. In either case, count the number of such links the current has to flow through between each battery and the load.
In the first case, the number of links is (2 x (p - 1)) ... where p is the position of the battery in the array: 1, 2, 3, etc. The key point is that the number of links is different for each battery.
In the second case, though, the number of links is always (n - 1) ... where n is the total number of batteries; the number of links is always the same for each battery.
English Marv, English. I hate algebra. What one is better? You obviously have a preference as to what one is better. I say the first because there is less wire to go threw. others say the second because it keeps the battery discharge the same in all battery's. I know they both will do the same thing from when I looked into solar/wind/hydro power battery banks and back ups for those systems and that the longer the run the thicker the wire needs to be. I have looked into this quite a bit years ago, hell I think I even started a thread on it.
Steve
[This message has been edited by 84fiero123 (edited 12-21-2015).]
Isn't it strange that after a bombing, everyone blames the bomber, his upbringing, his environment, his culture, his mental state but … after a shooting, the problem is the gun?
My Uncle Frank was a staunch Conservative and voted straight Republican until the day he died in Chicago. Since then he has voted Democrat. Shrug
After this simple modification, with the same 100 amp load.... The bottom battery provides 26.7 amps of this. The next battery up provides 23.2 amps. The next battery up provides 23.2 amps. The top battery provides 26.7 amps. This is quite clearly a massive improvement over the first method. The batteries are much closer to being correctly balanced.
[This message has been edited by maryjane (edited 12-21-2015).]
Seeing I haven't ever used but 2 algebraic formulas since high school why would I remember it? And to be honest I don't care. Both of those have been in the building fields and I used those rarely compared to balancing my check book monthly. Remember I also have short term memory loss as well so even if I could remember algebra as soon as I read something or even say something I forget it. Nice to know that so many here are so understanding of people with disabilities, not everyone is a rocket scientist or ever wanted to be.
And if you think I am dumb maybe you should look at the latest generation who can't tell you who the first president was, and some of those are college graduates, I know I have worked with some of those who are interns here with Melanie for Animal Assisted Therapy. As well as the professors who are teaching them and more professors in other fields.
Don't forget the very first line in the very first post was also asked by a college graduate.
quote
Originally posted by blackrams:
OK, folks. Here I'm going to prove that having an degree doesn't do you a damn bit of good if it's not in the area of expertise you're delving into. IOWs, I have no idea what the answer to my problem is.
Sorry if my ignorance of something that was taught to me over 40 years ago that I rarely used has slipped my mind.
Don I beg to differ, remember the GM 80s diesel cars. They had a bad habit in the beginning because the SOOO CALLED GM engineers forgot to put a battery isolator in between the 2. I had one, if one battery went dead, they were both dead. Great engineering. one battery was just for the glow plugs and the other for the starter if I remember right, my memory is shot.
Edit to add link about that setup and as anyone who has ever owned a camper knows if you don't isolate the starter battery from the power battery they all go down and can prevent starting.
(self propelled motorhome home only) Yes Steve, there are both coach (rv 'house' battery(s), and chassis battery. House battery is for the RV part, chassis is for vehicle itself only. Both systems have completely different battery set ups. On most, when driving the alternator charges ALL batteries, house and chassis, generator charges both. When the engine is not running, an isolator disconnects the chassis battery from the coach, so even if you run the coach batteries dead the chassis battery remains charged. Most also have a 'jump' switch that bypasses the isolator either way when held. That works if you do accidently discharge the chassis battery, or the generator starter operates off the coach battery and you run them down. It runs power from whichever good battery to the dead one so you can restart the vehicle or start the generator.
[This message has been edited by rogergarrison (edited 12-22-2015).]
