Which is correct method?
Diagram A or Diagram 2?
Click on image to enlarge.
Diagram 2.
Number 2 if not it over charges the first 2 batteries
I think is one of those trick questions. Other than visual, electrically they are the same.
Both are parallel.
Only way you might have some measurable difference is if each battery had it's own + and - cable ran to the inverter. You'd get less line resistance, but those would essentially be giant post extensions.
This is not a trick question. The difference is in how they are hooked to the Inverter/Charger.
Ok, I see it now.
It balances the differences resistance to charge, so it's negative and positive loads are at opposite ends of the bank. I'll need to keep this in mind when I add more 24v banks. Right now I run a single 4x6v arrangement in series.
Diagram 2.
Electricity is lazy, takes the easiest route.
It has to be forced, like a kids' gym class, to go the whole route.
In diagram 1, the closest battery does most of the work, the furthest battery does less, and when charging, the closest gets all the charge, the furthest gets under charged.
Highway tractors are notorious for being wired like diagram 1. Three or 4 batteries in parallel, the furthest battery is first to die.
Often to save a foot or two of heavy cable...
Gary, is the Trace equipped with the optional battery charger?
happy coaching!
buswarrior
More pertinent wisdom from SmartGauge: http://www.smartgauge.co.uk/batt_con.html (http://www.smartgauge.co.uk/batt_con.html) (And no, I don't have shares in their company!)
John
I also like the Balmar Smart Gauge.
Idiot proof, no shunts, stays accurate over time, just attach wires and away you go.
There is a marine how-to site / vendor who sells them at good price.
edit (newer link, site is moving: https://shop.marinehowto.com/products/balmar-smart-guage (https://shop.marinehowto.com/products/balmar-smart-guage) )
http://www.pbase.com/mainecruising/balmar_smart_gauge (http://www.pbase.com/mainecruising/balmar_smart_gauge)
Lots of helpful electrical articles on there for a busnut too.
happy coaching!
buswarrior
How does that differ from the trace remote monitor if you are familiar with it? Curious if Trace one is same, since I have the 2512 with charge and remote monitor.
The Trace remotes I am familiar with are just remote controls for the Inverter/charger, some with simple multi-meter functions built in.
A State of Charge (SOC) meter acts like a fuel gauge for the battery bank by monitoring the energy leaving and returning to the battery bank.
A voltmeter alone cannot readily tell you how "full" or "empty" the battery bank is.
A SOC meter takes all the guess work out.
These questions have immediate answers, that without one, you have no idea:
How much battery capacity did I use overnight last night?
How much battery charging did I do while running the generator this morning for breakfast?
How did the solar panels perform in today's cloudy sunshine?
Am I getting enough charge during my 50 mile drive today?
Should I think about spending more/less on a bigger/smaller battery bank?
When was the last time I am sure that the battery bank reached full charge?
The accompanying article on the Compass Marine site https://marinehowto.com/smart-gauge-battery-monitoring-unit/ goes into great technical detail as to why the Smart Gauge is the latest greatest, having to do with the changes in batteries as they are used, and how older style SOC meters drift in their measurements due to it, without periodic load testing and calibration that none of us want to do $$$.
FWIW, the military are users of this Balmar technology.
No matter which way you want to spend your money, living off a battery bank gets unnecessarily expensive if you can't "see" how much power is going in and out. Put the SOC meter of your choice into your system.
Imagine a world where every busnut gets a decade out of a battery bank?
happy coaching!
buswarrior
Trace monitor uses a shunt so it is completely different. This is the first I've heard of the Balmar product. The referenced website does a good job of sounding like snake oil but coming from Balmar that is unlikely. Balmar makes really good stuff. The pluses I see are that it would be dead simple to install and requires no setup. Setting up a shunt meter requires some indepth understanding of what you are doing. The only negative I can see is that the Balmar unit doesn't display amps. That probably doesn't matter in the long run as long as the SOC information is accurate. However having owned several monitors that did display amps I would - at least initially - miss that feature.
Diagram 2 is the best way to connect. It is the best method of the 2 choices to balance the charge and discharge among the batteries in the bank. It makes allowance for variables which may include the slight resistance in each wire that interconnects the batteries.
Electricity takes ALL paths to ground.....that's why you can plug in multiple devices to many outlets connected to the same circuit breaker in your home, and they will ALL power up. If electricity took only the easiest or shortest path, just the device closest to the electric panel would power up.
I hope you get the boiling issue under control. I would be looking for a shorted battery.
I need your help and suggestions, please. I have an unusual sized and shaped battery storage box (my bus has no bays under the floor). I was able to purchase some AGM batteries that would have cost me about $250 each, delivered but my price was $12 each - they are cell-tower "takeouts". My problem is that with the limited space I have, there appears only one way to fit the 9 battery units into the space available. I am trying to figure out a way to do the "balanced resistance" battery cable arrangement.
It appears that the only way to link negative poles is with a copper bar ground bus -- which is fine with me, they seem to work very well and many heavy trucks use them for severe service. So, my sketch shows the ground bar bus between the two rows of batteries. The only area of concern with this is that it sort of groups adjacent cells into a single negative path resistance. So, the real problem is to arrange the positive linkage so that the resistance on the positive side is balanced with the resistance through the ground bar to the chassis ground. My first proposed layout would have had a single cable into the battery at lower right in the sketch but that would have left the upper right battery with a very long positive resistance path and a fairly short negative resistance path. Not good, the batteries on the lower line would be getting a stronger charge and a stronger power draw than the ones on the top. So, my real question is:
"Is it possible and good practice to make the positive feed to/from the inverter set up as a Y-connector, making the positive connection into the parallel battery setup a loop with low resistance into the right side of each bank, with ground being taken from the collective ground bar at the left side of the battery group?"
Here is the sketch of the way I propose to fit positive cables and the ground bar to the battery bank:
https://photos.google.com/search/_tra_/photo/AF1QipPH-B3uDXn-2FCd8lMUE9p_B3V2dATAazaqZRM
Bruce, your link does not work. Here is what comes up:
404. That's an error.
The requested URL was not found on this server. That's all we know.
The lowest price I have found for the Balmar Smartgauge is $240 from West Marine.
I bought one because it is simpler to hook up but more importantly, doesn't appear to need constant attention to provide accurate information.
But I haven't hooked it up yet so can't comment on its use.
Quote from: usbusin on December 28, 2017, 09:08:07 AM
Bruce, your link does not work. Here is what comes up:
404. That's an error.
The requested URL was not found on this server. That's all we know.
Thanks. Try again.
https://photos.app.goo.gl/BjhAyZrBQgl55Omj2
I was told to always have your cables the same length = + and _ so looking at your drawing it looks like you will have way more length on the + side then the _ side
dave
The first sketch ( battery bank) is generally considered to be the best way to connect multiple batteries for a bank.
The second sketch ( battery bank 2 ) with the fuses between + and - posts of adjacent batteries provides protection for the rest of the battery bank, should one of the batteries short internally. If that happens, an excessive amount of current will be diverted to the defective battery to recharge it, causing the fuse to fail, which in turn protects the rest of the battery bank.
Each fuse should likely be rated at 100amps or greater. A fuse of lesser rating may fail when you draw maximum power out of your inverter.
Also, a catastrophe fuse should be wired on the circuit somewhere, designed to fail in case of (you guessed it) catastrophic failure of the bank.
YMMV.
Mark
Quote from: Stormcloud on December 28, 2017, 11:49:07 AMThe first sketch ( battery bank) is generally considered to be the best way to connect multiple batteries for a bank. ...
Mark
Thanks, Mark. Your sketch shows a 24V battery bank, right? Thanks, BH
Quote from: sledhead on December 28, 2017, 11:07:36 AMI was told to always have your cables the same length = + and _ so looking at your drawing it looks like you will have way more length on the + side then the _ side
dave
Thanks, Dave. I think that you're right but I don't have a way to measure resistance of the cables and ground straps yet. What I was trying to do was to make each battery see a similar resistance. So if a battery has a short positive path and a long negative path, it should be balanced to a similar resistance as a battery that has a long positive path and a short negative path. This is the detail factor that has me stumped. If it makes any difference, here's another scheme that separates out the ground path for each section of batteries. Does that matter?
https://photos.app.goo.gl/b7WOsLeENDANdE9A2
Quote from: Oonrahnjay on December 28, 2017, 01:32:29 PM
Thanks, Mark. Your sketch shows a 24V battery bank, right? Thanks, BH
Hi.
The battery banks in my sketches could be either 12 volt or 24 volt, depending on the batteries installed in the bank.
If the batteries are 6 volt, then it's a 12 volt bank. Similarly, if 12 volt batteries are used, then the bank is 24 volt.
If Gary had a shorted battery in his bank configuration, the blown fuse would tell him which is the bad battery.
YMMV
Quote from: Stormcloud on December 28, 2017, 04:45:51 PM... If Gary had a shorted battery in his bank configuration, the blown fuse would tell him which is the bad battery.
YMMV
Thanks for the voltage info.
Oh, yes, I hadn't thought of the way that might work but - sure - Ohm's law, if it starts sucking watts, the amps go way up (to make the heat) and it either starts a fire or overheat condition or it blows the fuse. Nice. Thanks for that info.
Thanks for all of the help. I will do some more testing before I replace my old batteries.
I talked to my battery guy this morning and he convinced me to replace my six 4D Interstate deep-cycle 12V batteries with eight Trojan T105 6V batteries. He said they have more duty cycles and should last longer. The eight 6V batteries will also give me more Amp Hours as well. Not only that but they are much lighter than the 4D batteries that are about the same size as 8D batteries and more readily available.
Quote from: Stormcloud on December 28, 2017, 11:49:07 AM
The first sketch ( battery bank) is generally considered to be the best way to connect multiple batteries for a bank.
The second sketch ( battery bank 2 ) with the fuses between + and - posts of adjacent batteries provides protection for the rest of the battery bank, should one of the batteries short internally. If that happens, an excessive amount of current will be diverted to the defective battery to recharge it, causing the fuse to fail, which in turn protects the rest of the battery bank.
Each fuse should likely be rated at 100amps or greater. A fuse of lesser rating may fail when you draw maximum power out of your inverter.
Also, a catastrophe fuse should be wired on the circuit somewhere, designed to fail in case of (you guessed it) catastrophic failure of the bank.
YMMV.
Mark
A few years ago Sean Welsh recommended putting the catastrophe fuse on the negative, so I've done exactly that with my system: http://www.busconversions.com/bbs/index.php?topic=22290.msg244760#msg244760 He knows way more about such matters than I ever will, so I'm happy to defer to his wisdom! Actually I have two separate battery banks in parallel, so I have a 300 amp Class T fuse for each bank's negative. The positives will still get their own load fuses.
John
Looking a bit more. I realized that I had put two rows of batteries "long side along" because there was not room for two columns of batteries turned the other way. But (I'm pretty sure, not at the bus now and I'll have to go measure for sure) there appears to be enough to have two unmatching sets of batteries, as shown in the photo link.
This new setup has a lot of advantages -- the upper set is the traditional ladder-arrangement and the lower set is electrically the same but with a slightly different physical layout. It makes installation and battery tiedowns easier and gives the simplest *positive at one corner and negative at the other* to balance the charging. It also allows me to add two more batteries to the parallel setup at a later date.
About the only disadvantage is that my battery box has a metal lip at the top and bottom edge; that's to seal the compartment covers and this layout puts more of the batteries under the lips and that would mean a slightly more fiddly installation and make checking and maintenance a little harder (but that's a less important factor since my batteries are AGMs). Oh, I also found a large-capacity battery cut-off switch from a racing supply store -- not shown on the sketch is that I'll have the switch on the positive cable with a main fuse near the first positive connection.
Finally, don't worry about what looks like large arcs in the positive cables. That comes from showing the separation between positive and negative connections. It appears that I can get a dependable separation of the cables and ground bar with very slight bends in the positive cables so extra length of the positive cables is not a factor in real life.
Comments appreciated.
https://photos.app.goo.gl/G6CWTl9XTWIyITnv2
Oonrahnjay,
I have two battery slides one upper and one lower so my plan is to go with double 6V batteries, one behind the other and there will still be plenty of room to slide them out to water them monthly. But your idea is an interesting set up.
Gary