OK folks. I have been trying to diagnose a problem that I ***think*** I have. My battery bank is 8 golf cart batteries (new within the year). My inverter is a full sine wave Trace model SW2512MC. I am measuring SOC (state of charge) with a Bogart TriMetric 2020.
My problem is that it seems like it takes a very long time for the battery bank to reach 80-85% SOC and days to reach 100% SOC.
Over the weekend, I worked a vintage sports car race and Pat was in the bus. She ran the generator for about 6-8 hours each day (very hot outside). At the end of one day, the SOC was 70% (starting from about 60%). I finally figured out that I had the input current set to 10 amps (from visiting the relatives). Today we are back home and in about 6 hours the SOC went from 64 to 70% on 50 amp house service (Trace input set at 45 amps).
It seems to me that part of the issue is the switch from bulk to float. I have tried setting the bulk to a fairly high time (don't have notes in front of me, but it was well over an hour.
I have done all sorts of testing/setting and nothing seems to jump out at me.
It seems to me like this whole issue started when I replaced the batteries. I checked the settings on the Trace and TriMetric and I think I have them set for the battery bank I have.
I have tried shutting down the power supply to force the inverter back into bulk charge but the inverter switches to float in a fairly short period of time.
I have done a ton of documentation of playing with the settings, and now I have myself thoroughly confused.
I think I have a problem, but even there I am not sure.
Help :-[ :-[ :-[
Jim
A wiring connection probably Jim check the AC and DC side have you checked for AC reverse polarity that one drove me nuts for 2 days still to this day I do not know how it happen.
There is a good inverter guy in CO/Springs I forgot his name Jim Smith knows it if you need help he is a factory service center and very reasonable on prices if you do need repairs
Jim, please post the make and model of your batteries and all the settings under menu #10.
Sent from my SPH-D700 using Tapatalk
Sean, I will get the Trace information tomorrow - probably late as we have quite a bit going during the day. The batteries are standard issue Sam's 6V golf cart. I will see what the label says.
I started playing with this whole issue back in June. I tried to chart time, SOC, specific gravity, etc. One of my data sheets is almost toast due to battery acid ;D
I would have to look at my notes, but it looks like I have settings in the TriMetric that are a bit conservative. However, I am not impressed with the quality of my hydrometer. The readings do not seem to agree with typical tables for SOC, but the relative numbers look somewhat realistic.
Jim
This morning, after 12 hours, it is up to 76% :'( >:(
The menu 10 main items are set at:
Bulk volts: 14.6
Absorption time 2:00
Float Volts: 13.5
Max charge amps AC: 20
I did not include the equalize and it does not appear that the temp comp is set.
When I was playing with the system in June, I moved the temp. sensor out of the battery box to make sure it was not limiting the charge (the batteries were not at all hot at the time).
It looks like the settings are almost factory settings. I do recall playing with them in June.
I wonder about the 20 amp AC limit should be increased. I have not played with that setting. As I noted, I do use the input amperage quite a bit to reflect marginal 15 amp house circuits when we stay at relatives houses.
Jim
Quote from: rv_safetyman on September 04, 2012, 07:00:26 AM(snip) I do use the input amperage quite a bit to reflect marginal 15 amp house circuits when we stay at relatives houses.
Jim, what are your usual loads. If you're pulling say 10 amps most of the time and you have the input limit set at 15, that wouldn't leave a lot for charging. And if you consider you have efficiency losses, maybe a considerable fewer amp are actually through as charge.
Your bulk and float voltages are actually a couple of tenths higher than mine and mine works OK, so I don't think that that's a big part of the problem. Are you sure that all the batts are OK?
(I don't have a Trace and my inverter/charger is a bit different - just some thoughts, I hope it's not a dumm-@ss distraction.)
BH NC USA
Jim-20amps isn't much. When I had 2-8D deep cycles, I just kept increasing my input amperage until I got a fault code on the inverter. I then backed it off and that's where I had it for years-I believe it was around 50amps (12vdc). With as many golf cart batteries as you have (the equal of 4-8D's) I would think you could increase your charge amperage to 80-100amps (12vdc). This also sounds very elementary-but is all terminals clean? Especially if you have watered batteries.
This is one good example of why I like AGM batteries. In this case, Jim could still have the 8-6V batteries (even increase to the 400amp/hr/battery L16's if he has 18" height) and he could just increase the charge amperage up to the top of what the inverter puts out. Just make sure the charge is not above 14.1 volts, and away you go! Good Luck, TomC
Quote from: rv_safetyman on September 04, 2012, 07:00:26 AM
...
Bulk volts: 14.6
Absorption time 2:00
Float Volts: 13.5
Max charge amps AC: 20
...
Jim, without the detailed battery information I can't say whether these settings are optimal. There is a great deal of difference among GC2 batteries -- Sam's Club alone has at least three different models. That said, I suspect your bulk setting is a bit low for flooded traction batteries.
One of the disadvantages of flooded golf car batteries is the charge acceptance rate. Typical flooded GC2 batteries will be around 230 AH (20-hr rate), so your bank of eight would be around 920 AH. Flooded batteries can typically be charged at C
20/5, which would be ~180 amps at 12vdc, or right around 20 amps of 120VAC at the charger, so that setting is likely correct. Switching to AGM would let you charge at the maximum rate available from the Trace charger.
Frankly, I suspect your Tri-metric is wrong, rather than any problem with the batteries. How often does the meter reset to "full"? If it never gets there, the meter will accumulate more and more error over time. This happens with our Link-10, even though we've dialed the settings in nearly perfectly. In order to zero the meter error, we need to charge overnight on a shore service, causing the meter to reset.
-Sean
http://OurOdyssey.BlogSpot.com (http://ourodyssey.blogspot.com)
Quote from: TomC on September 04, 2012, 08:14:57 AM
Jim-20amps isn't much. ... I would think you could increase your charge amperage to 80-100amps (12vdc).
Tom, the SW series sets charge amperage at 120VAC. So his "20 amp" setting is really around 180 amps at 12 VDC (after accounting for efficiency loss).
-Sean
http://OurOdyssey.BlogSpot.com (http://ourodyssey.blogspot.com)
I'm confused if the 20 amps is input to the batteries or 120VAC input to the inverter. If it's to the inverter, that implies around 180 amps available to go to the batteries. I have US-2200 batteries, so I have this generic charging instruction for all their batteries. They are fairly typical golf cart batteries, and I suspect these all follow a somewhat similar pattern.
http://www.wholesalesolar.com/pdf.folder/battery-folder/charging_instruction_2011_2.pdf (http://www.wholesalesolar.com/pdf.folder/battery-folder/charging_instruction_2011_2.pdf)
They would have a bulk charge up to 14.4 volts at constant current with current equal to 10% of the 20 hour AH rating, then an absorption charge at 14.4 volts for 3 to 4 hours, then a finish charge for 2 - 3 hours at 15.3 volts current limited to 3% of the 20 hour AH rating, then going to the float charge at 13v forever.
Your bulk voltage sounds OK but one hour seems low, it would probably be closer to half the total time so 6 hours. What is the absorption voltage? The absorpion time could be longer. And you have no finish charge - they call for slightly higher voltages and times with no finish charge. Following these instructions the batteries are supposed to recharge in 12 hours or so. Your original post suggests that you are programmed for a 1 hour bulk followed by 2 hours absorption, and then flip to float charge.
Brian
Quote from: bevans6 on September 04, 2012, 09:07:50 AM
... Your bulk voltage sounds OK but one hour seems low, it would probably be closer to half the total time so 6 hours. ... Your original post suggests that you are programmed for a 1 hour bulk followed by 2 hours absorption, and then flip to float charge.
Brian, the SW does not have a bulk timer. Bulk is a voltage setting, and the charger supplies the set current until the bulk voltage is reached. At that point the absorption phase begins, where the bulk voltage is maintained for a set time. This would be the one hour he mentions, although most deep cycle batteries really need two hours or so. After that the charger switches to float. More modern inverter/chargers have more sophisticated charge profiles.
-Sean
http://OurOdyssey.BlogSpot.com (http://ourodyssey.blogspot.com)
Hi Jim,
Based on the information in my Magnum Inverter manual, your absorb time should be 2 1/2 to 3 hours if the capacity of your batteries is in the 900 amp hrs range. Also that size battery bank can accept a lot more than 45 amps if your inverter will put out more than that. The voltage settings agree, within a 1/10 amp, so they should be OK. I think that if you increase both the absorb time and charger amps you will have much better results. Have you checked the voltage at the batteries when the charger is in absorb and float to see if they agree with the TriMetric readout? Have you tried resetting the TriMetric to see if the SOC reading changes?
Good luck, Sam
Lots of confusion about the amp/volt relationship I mentioned. Both the 20 and 45 amp settings are at 120 V.
Prior to this trip the bus sat on inverter charge and reached 100%. I tried to find my TriMetric folder before I left this morning to verify the settings. Will also check battery info when I get home.
I am not concerned about the batteries or the inverter, just trying to get my head around what is going on.
In the past I have observed charge rates over 100 amps at 12V. I will verify that later today by pulling the AC for a while and get the inverter back in bulk.
Thanks everyone for jumping in.
Jim
Hi Jim,
Sorry I misunderstood that the 45 amps was the input to the inverter. I think I was confused because I don't think it is possible for your inverter/charger to draw that much with 12 volt output. I could be wrong. Are you sure you can set the bulk charge time? I can't with my Magnum. I can however set the absorb time according to the rating of the battery bank amp hrs. I think you should check the absorb time setting and increase it if your battery bank is rated at 900 amp hrs and the setting is 2 hrs as indicated. All bets are off if your batteries are not wired correctly. I suspect they are. Do you have a DC clamp on amp meter to verify that the TriMetric is reading correctly? Do you have a large 12 volt load on the batteries at the time you are trying to charge them? It seems to me that something is wrong since you're only getting from 64% SOC to 70% in 6 hours and then only to 76% after another 12 hours. I'm thinking that your charger isn't putting out it's rated capacity.
My thought is base on that I plugged in my inverter/charger this morning since the SOC on my batteries was 53%. I watched the gauge on the remote to see how long the charger stayed in bulk. It was only a minute or so before it went to absorb and the amps climbed to just over 90. About an hour and a half later the SOC was 76%. In 3 hours it was, in float, charging 10 amps and SOC was 83%. Now after 5 hrs the batteries are at full charge. I have a Magnum 4000 watt, 24 volt inverter and 6 group 27 deep cycle batteries that are 3 years old. The bank had 285 amp hrs rating at 24 volts when new. I realize that I have a smaller bank and it's capacity is somewhat less now I would guess.
Good luck, Sam
First, thanks to all for jumping in and giving me some new thoughts. This is driving me crazy (or as Pat would say, crazier :o).
I think I misspoke earlier (did not go back). The bulk charge is not a time function, but the absorption is (two hours current setting). One of the problems is that the Trace only shows LEDs for Bulk and Float. Here is what the manual says about the bulk LED:
QuoteBULK (Yellow)
This indicator will be on to indicate the inverter is in the Bulk or Absorption charge stage. This indicator will
go off and the FLOAT indicator will illuminate when the battery voltage has been held near the SET BULK
VOLTS DC setting for the time period determined by the SET ABSORPTION TIME setting from the
BATTERY CHARGING (10) menu heading.
That explanation confuses me. Almost sounds like Bulk and Absorption is the same thing (?). In any case, the absorption is set for 2 hours and I know that the yellow light does not stay on anywhere near that long.
Sam, your description of your charge rate is somewhat close to what I remember in the past. It only took a few hours to get to 80-85% and then, of course, longer to finish out the full charge.
Here is where I am now. At 4:00 PM (more than 24 hours) I was at 76%. I checked the amperage and it was essentially a net 2 amps in and 13.3 volts (data per TriMetric). I shut off the AC and with the fridge running (house type) the current was about 14 amps out. I will leave the power off for a few hours and then turn on the AC and see what the charge rate is. I will try to monitor it for a few hours to see how fast the charge amperage drops off. Sam, your suggestion of a second DC ammeter is good. I have a great clamp-on ammeter, but it is AC. I found my 40+ year old ammeter that you use to straddle the cable. It has two sizes of notches and two scales. One is 75 amps and the other is a few hundred amps. Not a lab quality meter, but it should validate the TriMetric.
I suspect the TriMetric measures amperage pretty well. It uses a shunt (should be reliable) and the amperage is a simple conversion of the voltage across the shunt. Also, the draw for the fridge seems reasonable.
Will report tonight's testing later. Tomorrow, I will add some testing with the hydrometer to see if I can correlate it to the TriMetric. I did that in June, but have not had a chance to review my notes. At the same time I will get better information on the batteries.
Jim
As thorough as you are, I'm sure you checked the batteries individually. Would one bad one or even one bad cell cause such a problem?
Lin, in June, I checked each cell with a hydrometer. I will repeat that tomorrow. With the same clothes that now have holes in them ::) :-\
Sorry to say this, but hearing about the acid holes in your cloths made me feel good. I way convinced that I was the only one to continually ruin clothing whenever I get near a battery. Hence, another plus for the AGM.
Quote from: Lin on September 04, 2012, 06:43:08 PM(snip) I way convinced that I was the only one to continually ruin clothing whenever I get near a battery.
OK, that's three of us, then.
Quote from: rv_safetyman on September 04, 2012, 04:22:42 PM
...
That explanation confuses me. Almost sounds like Bulk and Absorption is the same thing (?). In any case, the absorption is set for 2 hours and I know that the yellow light does not stay on anywhere near that long.
...
Jim,
First, let me say you are getting a lot of advice here from people who are clearly not familiar with the SW series and its byzantine settings. At the risk of offending well-meaning folks who are just trying to help, guessing at inverter settings or trouble symptoms without a thorough understanding of these units and their peculiarities is ill-advised.
In the SW series, Bulk and Absorption are most definitely not the same. However, as you note, the yellow LED, which is confusingly labeled simply "Bulk," does not necessarily mean the unit is in the Bulk phase. In fact, this LED is used for Bulk, Absorption, and Equalize phases. In Bulk and Absorption, the LED is a steady yellow, whereas in Equalize it blinks.
On a Trace SW, the only way to tell if the unit is in Bulk or Absorption when the LED is on steady is to look at the voltage. If the temperature-compensated voltage is
below the Set Bulk Volts DC setting, then the unit is in Bulk. If the voltage is
at or above this voltage, then the unit is in Absorption.
If you do a full charge cycle starting from, say, 50% SOC (for real, not necessarily what the Tri-Metric says), then you would see nearly a full two hours (if that's what you set for Absorption time) in the absorption phase. The only way to time this, though, is to be watching the temp-comp voltage reading closely, and start your timer at the instant the voltage ticks over from a tenth of a volt below the setpoint, to the setpoint voltage. Also, the timer is "sloppy" in the first 20 minutes.
If you are seeing the LED illuminated for less than the set time before the unit goes to Float it is because the absorption timer is cumulative. This is described on page 47, under the detail for Set Absorption Time. If AC power is applied before the batteries have depleted to the point of requiring a bulk cycle, the amount of absorption time will be only what the timer has accumulated. Note that temperature compensation and load can both affect the perceived battery voltage, to the point where the unit does not enter the Bulk phase and instead goes straight to absorption.
Having batteries that are nearly full when AC power is applied will lead to this type of short cycle. Note also that certain types of battery problems can present the appearance of a bank that fills rapidly and does not initiate the expected Bulk charge cycle.
The behavior of your system sounds perfectly normal to me, although I suspect two things. One is that your batteries are not accepting a complete charge, probably due to insufficient gassing. I would expect a good equalization will help with this a great deal. The second is that your SOC meter needs tweaking. This is just an educated guess, of course -- without closer inspection and more testing, the possibility of a bad charger control circuit can not be ruled out. I think, however, it is the least likely probability.
The only way to know for sure what is going on is to do a fully controlled load/discharge test and a couple of full charge cycles.
Quote
I suspect the TriMetric measures amperage pretty well. It uses a shunt (should be reliable) and the amperage is a simple conversion of the voltage across the shunt
Actually, this type of shunt system, while good, is only as accurate as its calibration, which must be done in the field. Out-of-the-box I would estimate these meters to be no more than about 98% accurate for voltage and current (the meter itself is more accurate than that, but the shunt and cables introduce more error). When it comes to SOC, the accuracy is a good deal less, because many factors such as Peukert exponent and Charge Efficiency are estimates, and if the meter over- or under-estimates charge in either direction even by a little bit, over time this can accumulate into large errors.
Most meters compensate for this by "resetting" to zero (or full, depending on POV) under a well-defined set of conditions. Getting those condition settings correct is part engineering, part trial-and-error, and part voodoo. Get them wrong in one direction, and the meter will reset prematurely, giving the impression the batteries are full when perhaps they are not. Get them wrong in the other direction, and the meter will never reset, leading to ever-lower SOC readings when the batteries are, in fact, full. You are better off with the former, because that error is not cumulative.
FWIW, our SOC meter, even adjusted as accurately as possible, will accumulate negative error over many generator cycles. We don't ever go to 100% full charge on the generator, because that is very inefficient (three hours of extra run time while putting only about 90 amp-hours in, just 10% of capacity). So the only time our SOC meter resets to "full" is when we have a solid shore power connection with enough extra power to run the charger all night. After a couple of weeks of boondocking in one spot, our meter will be reading perhaps 80% of actual. IOTW, at 50% SOC, the meter would read around 40% SOC. The more charge cycles we run, the worse the error gets.
Also FWIW, I've been doing this for eight years full-time and I'm still tweaking the charge and generator settings on the Trace and the parameters on the SOC meter. I'm on my third set of batteries, and each set requires careful readjustment of all the settings, part of which can only be done with direct load-cycle experience with that particular bank.
HTH,
-Sean
http://OurOdyssey.BlogSpot.com (http://ourodyssey.blogspot.com)
Yeah, what Sean said.
if I understood what you said about your current readings at around 2 amps, then you are fully charged. The problem is not your Trace. It's your Bogart settings. BTDT.
Hi Jim,
I concur exactly and totally with what Sean said. That should take care of it!
OK Folks, it does, indeed, look like the TriMetric is out of whack.
First of all, the batteries are labeled "Energizer" and are made by Johnson Controls (like most batteries). I do recall reading that Sam's sells three different Golf Cart batteries, depending on the part of the country. Mine were purchased in Denver.
My plans (dreams?) for this battery change was to go to L16 AGM batteries. However, I did not hit the lotto, so it was back to golf carts. The last set served me pretty well for well over 6 years.
Last nights testing was interesting. After 3 hours without AC input, the SOC dropped from 76 to 73%. That is about normal with all the AC and DC loads I have. The discharge current without the fridge showed 3.7 amps and 5.8 amps with the fridge (both at 12V). I have quite a bit of electronics running in the background. Those currents suggest I don't have a big draw.
As soon as I turned on the AC input, the charge current in bulk went to 84 amps @12V (sort of confirmed with my cheap straddle type DC ammeter). It decreased to about 35 amps in a few minutes. I did some looking at the Trace meters and they suggested about the same values (converting 120V current to 12V current in my head). I unplugged the temp sensor to see if that made a difference (didn't).
About a half hour into the test, I took one quick hydrometer reading and it showed in the middle of the green area. The green area has number values from 1.275 to 1.300 and the level was between the two. That sure suggests that the SOC meter is off (it read 77%)
The bulk yellow light (includes absorption) stayed on for close to 2 hours.
As I think about it, I may has messed up the SOC integration process. Two or three times over the past few months, I have taken the lazy approach to maintaining the charge of the start batteries. I simply connect the house and start batteries and let the inverter charge both. The current to the start batteries does not go through the SOC shunt.
During the testing process, I used my infrared temperature gun to check all connections and battery temperatures. All were in the ambient temperature range (about 80* F).
Today I will do a full hydrometer study of all cells and start working on the TriMetric settings. That will be a challenge, as the manual seems to have been written by a monkey. Almost like it was written off shore, but I am pretty sure it is made by a small company in the US.
Again, I am amazed by the great help from this group. I should not be surprised since it happens every time I have an "issue".
Jim
Jim not that this is any help but my six golf cart batteries were also purchased at Sam's and my friend John Silver who owns central florida bus is always ragging on me about switching them out because the date on mine is 2004 which makes them 8 years old! Im the type that if it isnt broke dont mess with it and they are still working great! The inventor charges them automatically and heck I think i put water in them twice since installing them which reminds me I have to go...
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Well, I have nailed it down to my TriMetric SOC gauge needing to be reset. I had set it up to reset itself after every full charge, but apparently that did not work.
So, let's catch up. A couple of days ago after at least 24 hours of charge on the inverter, I reset the TriMetric. That night I removed the AC source. The next day I had to run a bunch of stuff to get the meter down to 55%. I checked all of the cells with the hydrometer. They were all pretty close (a bit operator sensitive ;)) and all indicated to be at mid-range. That seemed to verify that the SOC meter was close.
I then applied the AC. I turned off most of the loads that I had fired up to get the battery down to 55% and the inverter was charging the batteries at 122 amps (12V). That slowly tapered off to a bit over 60 amps after close to 2 hours. At that point, the SOC was 80%. At the end of 2 hours, the inverter went into float. All of that looked like the process I had been used to in the past.
This morning the SOC was 92%. I reset the meter again.
I think I am good to go. Sure glad that I did not have an Inverter problem!!
Again, thanks for all the help!!
Jim
Quote from: rv_safetyman on September 07, 2012, 06:15:41 AM
Well, I have nailed it down to my TriMetric SOC gauge needing to be reset. I had set it up to reset itself after every full charge, but apparently that did not work. ...
As I said, "voodoo." Getting these meters to correctly detect completion of a full charge cycle is a challenge; I would estimate that I've spent nearly a half dozen hours fiddling with mine to dial it in, and dozens of charge/discharge cycles.
I don't have a Bogart, so it's harder for me to give you precise advice, but often the problem is the finishing current setting.
For us, the optimal settings lead to a situation where the meter never resets while we are boondocking with the generator, but always resets when a finishing charge has been applied by shore power. We typically find a power outlet at least once a month, so the meter is usually accurate enough for most purposes.
A bigger issue for us on a daily basis is that the generator auto-start system is based on voltage and not SOC. Even the less-than-fully-accurate SOC reading would be a better metric, considering the voltage is so widely variable depending on load. Where we are parked right now, running the air conditioner full time when we are home, the generator starts after fewer than six hours, even though I know we can go for eight. I don't dare lower the voltage setting, though, because it would then be too low for the scenario where there are no major loads present. Still, not a big enough problem for me to want to replace my "free" autostart system with something else.
-Sean
http://OurOdyssey.BlogSpot.com (http://ourodyssey.blogspot.com)
I am certainly not presuming to be any kind of expert, but I also have a Trace SW4024 and a Trimetric 2025 monitor. I have had several conversations w/ Ralph at Bogart Eng. and he has been very helpful, informative and patient. If you are having a problem getting the settings correct on the Trimetric, give him a call. I was also a little confused by the text in the Trimetric docs, but after a few discussions with Bogart, I realized that I was the weak link in the chain - not the docs.