Explain to me how / why the parallel wiring on the right is better than the parallel wiring on the left? For all intensive purposes they are the same right? But some guys are saying the right is better for some reason
Explain to me how?
Explain to me how / why the parallel wiring on the right is better than the parallel wiring on the left? For all intensive purposes they are the same right? But some guys are saying the right is better for some reason
I work on a lot of DC battery driven industrial equipment, and I have never seen a machine wired like the diagram on the right.
i might be wrong, im drunk bear with me
but the right involves the power moving less distance effectively from battery to source, so less transmisssion loss, and the power wont have to float across the battery.
the difference might be niglegible depending on setup though
I guess there could be a higher chance of having a faulty connection causing problems at one of your battery terminal to cable connections due to the fact that the end battery has to go through the other 3 batteries. But really, as long as the cables are appropriately sized and connections are good it shouldn't matter...
on the left there is progressively more current going through the wires as you go up the chain from the bottom. if you pull hundreds of amps and the wires thickness is too low, the voltage drops would be significant and youre not pulling the same amount from each battery. an improvement would be the same setup as left but tapping the output wires between cells 2/3,..and the right side is an ever further improvement on that.
Amperage is going to remain the same based on workload and voltage. Here it's 12 volts. A 1HP motor should pull ~60 to 80 amps.
(figuring 800 watt 1 hp motor @60% )
So it's not going to really matter where you tap the bank from in the illustrated diagram, as the cable going from the banks still has to carry the same amount of energy to the load to do the same amount of work.
I can only guess they're trying to compensate for manufacturing variances in individual batteries in the banks and minimize individual cell issues within those batteries.
I can tell you're missing the point....which is admittedly subtle. If you really want to understand whats happening model it...except you need to include wire resistance and source impedance of the batteries to see what I'm talking about. I'm an EE and worked on BMS systems for l-ion batteries that have far more series/parallel connections than this and you really have to think about what you're doing. If you're powering a home off solar/batteries and want them to last as long as possible maybe it's worth it...but probably doesn't matter tbh.
Like I said earlier, I've worked on a lot of DC industrial equipment, and it's always resembled what's on the left. I'm no EE, just a field service mechanic
>but probably doesn't matter tbh.
Like I said, I was just guessing as to why, cause it looked like a bunch of mental masturbation for a simple four cell 12V bank.
As is illustrated in
, the total current may be the same, but the amount of current each segment of wire carries is going to be different. The lowest battery in the stack has to push current through four segments of wire, plus the leads to whatever it's powering, while the top only has to deal with the leads. Since real wire has a small resistance, this means that there is effectively a larger resistance in series with the lower batteries than the higher ones. If the voltage of all of the batteries is the same, this means that current each one delivers will be different, with the exact difference being dependent on how much current is being drawn.
Strictly speaking, the drawing on the right isn't as "perfectly balanced" as it says. In order for that to be true, you'd need to connect the batteries in a star arrangement, with each battery having its own lead to the same connection point.
>I've worked on a lot of DC industrial equipment, and it's always resembled what's on the left
I don't doubt it. Assuming a sane conductor thickness and current draw, the actual difference in current between the four batteries will be difficult to even measure. No point in wasting wire and making a rats nest when it won't matter.
>Strictly speaking, the drawing on the right isn't as "perfectly balanced" as it says. In order for that to be true, you'd need to connect the batteries in a star arrangement, with each battery having its own lead to the same connection point.
I get what you're saying, but there is no way in hell JCB, JLG or Terex is going to do that.
Maybe on some huge residential system I could see that, but even the big ~80+ volt stuff is still stupidly simple.
Right, most smaller (common) equipment is running 24 volts from two banks of 6 volt batteries, 36 volts of 6 6 volt batteries, or one bank of four 12 volt.
Really tiny stuff like one man lifts will use four 6 volt, two 12 volt or on really cheap stuff, just on 12 volt deepcycle.
None of those will be pulling the wattage you're describing. That's way outside of my field.
>I'm no EE,
>like a bunch of mental masturbation for a simple four cell 12V bank.
A simple 12v bank is really the type of setup where these wiring minutia become the most problematic.
If you're using 12v, then with any substantial power usage you start to see pretty large currents flowing. Something like a 2000w inverter (at ~85% efficiency) would be pulling just shy of 200 amps. That's enough current that small differences in resistance at each terminal connection or small resistances in the connecting wires will add up to a meaningful imbalance. And most of the time, people don't like to use 4/0 copper for a setup like this because of the expense
and just replying to myself here...i dont quite see how a star connection to each battery wouldn't be the "best" in this case...maybe uses more wire and its messier...interesting if somebody can clarify that further
For anyone that needs spoonfeeding: https://www.windynation.com/jzv/inf/how-configure-battery-bank
Correct. In truth, you can still run into issues when you have really large current rates because, aside from wiring losses, even very small resistance differences in a single terminal connection can lead to imbalances and issues. Then complicated BMS with lots of active balancing enters the picture and it gets more and more messy
I dont really think that a 12V 4 ganged battery is going to experience the losses they claim in the article. That to me would seem like an indication of a poor choice of materials, either in wiring or battery chemistry. If they are using only sealed deep cycle batteries, because acid is scary, then boohoo for them. Lead/sulfur acid is a well studied, predictable system. If ganging lead batteries in series was that bad, we would have blown up enough things that this would be a settled matter, and taught in school. In the real world, considerations like mechanical resistance, thermal expansion, galvanic corrosion, etc., are the more important concerns. If you designed and built it perfectly, the left one is surely more predictable, testable, repairable, and understandable. Which is why thats what we see irl.
I think the only real loss would be 2-5%, from induction. In the left battery setup, the load that is continuing through the terminal junctions would create a significant field, that current leaving the field, would have to overcome. However, at 12V, its almost negligible. And having it sunk into a chemical battery instead of a load may be doing something else entirely.
Thats a wrap. Electric car batteries? Those have to be engineered from the ground up to be excellent in weight, durability, and performance. Using these arcane tricks to steal back 2-3% of your potential is the difference between the EPA passing your design, and failing it. Those things handle enough load, that runaway effects of thermal expansion, induction, and more have to be minimized or it just cooks itself.
It's gonna make a difference when you have a battery bank on solar that cycles every day over many years.
>It's gonna make a difference when you have a battery bank on solar that cycles every day over many years.
But is that worth doing if the battery bank resembles OP's diagram?
Like the kind of stuff you might find in an RV with a small solar system, and it only has 2~8 off the shelf 6 or 12 volt golf cart batteries.
Or is that just something you have to do with really expansive banks, with dozens of batteries?
Maybe you don't give a shit and don't care about spending the money...frick it then. Maybe they don't cycle often...in that case the degradation might be slower than the lifetime of the battery. The batteries will not "wear" evenly. Let's say the batteries last 4 years if you balance them correctly. You buy 4 batteries every 4 years. If you don't wire them balanced you're replacing 1 after 2 years, another 2 on the 3rd year, etc...it's all out of sync a lot quicker...a lot more maintenance. Also in this example, the minute you replace the first battery...you now have an even bigger imbalance and youre fricking up that battery even quicker. It probably won't last 2 years the next time.
Also...you could be so moronic at wiring, that any benefit you gain from the more complicated wiring isn't worth the risk of fricking something up. It's all a trade off.
I used to do a little work on solar panel charging systems for remote job sites. Most of it was heavy diesel engines, but I worked on the solar stuff too. Take that as you will.
I asked the service manager why this arrangement is used on the solar light system. He couldn't answer me, just said "that's how the engineers did it, don't change it," so, on a very boring day, I wrote a sheet of math working out why it's theoretically superior.
I don't have the sheet anymore, I left it with the manual. Basically, the voltage drop across individual cables eventually leads to very small imbalances in the charge/discharge cycles of each battery. This is especially true if one of the cables or terminals begins corroding. It's one of those things where a handful of seemingly tiny variables will compound over very long uptimes to create problems.
NORMALLY this doesn't matter. If it's a system that isn't under 24 hour service conditions then you'll never see the downstream effects unless something genuinely goes wrong (eg massive corrosion of battery cables). But it does matter for systems with massive uptimes.
"That's the way we've always done it" is a common phrase in my industry as well.
On the equipment I deal with, we just replace all the batteries in a bank/machine if one is misbehaving, simply because we can't keep making repeat service calls to individually replace failing batteries.
But I also deal with shit like this, so....
Yeah, we kind of have to replace in sets.
>all intensive purposes
all intents and purposes
>Explain
the batteries closer to the load/source will see more amps than those farther away, this affects charging and discharging rates and depth
it might help to think in terms of bucket and hoses siphoning between one another
>better
that arguable
your no doubles advocate
2 Resons.
1 Drain. When discharging your batteries the top section of wire on the left is going to be pashing 8 amps across is. The resistance of that peace of wire is going to also increase, and if it's not girthy enough it will definitely get hot.
Second reason, charging and resistance.
In the fist diagram the path to get to the last batter is going to be 3 times bigger then the first one. So the first battery is going to be putting in a lot more work.
The differences are minor, but can stack up.
If optimizing is what your going for, I would swap the terminals on the second diagram on the top and second battery around, it'll save you on wire.
>LOL this moron took a screenshot, added the shitty MS paint drawings on it instead of just saving the original image and editing that
LOL what a moron.
only gays screenshot
t. gay
>For all intensive purposes
you deserve a hall of cost
The dress is white and gold.
Ill just put a copper bus bar on it
>bus bar
Where you attach the circuit to the bar "matters."
The wiring on the right carries half the current compaired to the left, excluding the leads going to the load. And frick these captchas
I can see two single points of failure on the left diagram that will put the whole load on a single battery. Left diagram will always have at least two batteries connected after any failure.
Aren't they both. Perfectly balanced anyway? If every joint is one ohm or miliohm or what ever the left batteriesnhave 3 ohms resistance and the right is 2. Is that what they're saying? Wiring them up with all this shit is worth it because of it saved one unit of connection?
I'll tell you.how my offices are setup. They have a special bus bar exactly the size of the terminals for the while string and the connections are greased and checked for torque annually.