Reply
 
Thread Tools Search this Thread Display Modes
 
Old 01-12-2008, 08:29 AM   #29
2 Rivet Member
 
Surprise , Arizona
Join Date: Dec 2006
Posts: 52
Guy99, your additional info is helpful.

First, your analysis of the batteries and the generator seems sound. But if you have a good voltmeter, (and you understand the hazards and can handle them safely), then I'd measure the output voltage of the generator, just to be sure. As for the batteries, I'll have more to say in a minute. First, a few questions.

You say, “What was happening was I would use the batteries using say 75 amp hours, I would then run the generator and partially recharge the battery replacing say 50 amp hours. The trimetric would give a -25 reading on the AH scale. Repeat this the next day and I would have a -50 reading, repeat I'd have -75. At this point I ran the generator for an extended period but was still unable to achieve a high state of charge.”

Are you saying that every day you “replaced” 50AH of the 75AH you used? If so, then you would have a deficit of 25 AH per day, and it would be normal for the Trimetric to read -25, -50, and -75 on successive days.

But if this were occurring, I’m sure you wouldn’t be alarmed. So obviously I’ve missed your point. Can you please clarify.

You also say, “What I observed was that when I started the generator and the converter started charging the batteries I would see a charge rate of around 40 amps or so but within 15 minutes that rate was down to 20. By a half an hour it was in the 10-12 range. After an hour it was always well under 10 and declined from there.”

I don’t understand this statement, because I don’t know how the Trimetric works. Are you saying that it gives a “real time” reading of charge rate, and that you can observe it dropping from 40A down to 10A in an hour? If so, that is a big clue that probably implicates the batteries more than the converter.

I am very suspicious that your batteries have lost their capacity to store a charge, and so I strongly encourage you to test them again. You could do that by disconnecting them from the WFCO and by charging them directly from a good battery charger.

My concern is motivated by the fact that you’ve been only partially charging the batteries. That’s a common practice, but it is known to be one of the surest fire ways to shorten a battery’s life. Experts strongly recommend that batteries be fully charged before they’re used again. I’m also suspicious of your batteries, because I know so little about them (did you say you got them at Costco?). I’ve had my share of problems with inferior batteries that made extravagant claims about their quality, and I’m afraid you may have ended up with some of the same.

I have a final comment to make about WFCO converters, but I’ll post that separately, since message length on this forum is limited.

Hope these suggestions are helpful! Good luck!

Titus
__________________

__________________
TitusLivy is offline   Reply With Quote
Old 01-12-2008, 08:53 AM   #30
2 Rivet Member
 
Surprise , Arizona
Join Date: Dec 2006
Posts: 52
Back again, Guy99!

I have a final comment about WFCO converters.

Converters and battery chargers are poorly understood. That’s because the manufacturers’ advertising material is sometimes confusing, and their manuals are incomplete and poorly written. Worse, their “support technicians” do not generally understand the issues, and so they inadvertently mislead customers…just as you were apparently misled when you called WFCO for help. But if you carefully cross-check the details, the facts become clear.

Here’s the big misconception: The WFCO (or name almost any other popular 3-stage charger) measures the batteries’ voltage, and if it’s low, then the converter jumps into “bulk charge” mode, during which it applies a voltage of 14.4V. After the battery is suitably charged, the converter then switches into “absorption mode”, during which it applies a voltage of 13.6V. Finally, when everything is neat and tidy, the converter settles into “float mode” with a voltage of 13.2V.

Bottom line: It just ain’t so!

It’s best to think of the WFCO (etc) as a “current limited” device. So if you have a model rated for 55A, then it is limited to providing a maximum of about 55A. Now here’s the point that’s generally not understood: the voltage produced by those 55A will depend on the resistance through which they flow, and the “effective resistance” of batteries depends on their state of charge (and other complex stuff). So even though your WFCO has shifted into “bulk charge mode” and is pouring a full 55A into your batteries, 14.4V usually will not be measured across the batteries’ terminals.

This fact is clear from a graph on page 4 of the WFCO “Installation and User’s Manual”. It shows that a WF-9855 will provide about 55A while raising a battery’s voltage from 12V to about 13.2V. Then the current slowly decreases while raising the voltage higher. And at about 14V, “bulk charging” stops.

Although the WFCO manual is chock full of confusing and semi-indecipherable language, it eventually states this fact explicitly. Bear in mind that “buck mode” means “bulk charging mode” as you read this quote from their manual: “Under Buck mode when the power converter senses that out put voltage is at 14.4VDC, it will change back to absorption mode.”

In other words, bulk mode does not begin with 14.4 VDC. It ENDS there.

So what’s the point? Lots of people have thought their charger wasn’t working properly because it didn’t produce 14.4VDC even though the batteries were very discharged. And so they ask for help because they “…can’t get the converter to switch into bulk mode.” But measuring the voltage across the converter’s terminals while it’s charging is not the proper way to assess its performance.

Even though the voltage across your converter may not be 14.4VDC, the odds are high it’s functioning properly. To be sure, follow “Procedure #3” on page 7 of the WFCO user’s manual: disconnect the output cables from the WFCO, and measure the voltage. It should be 13.6VDC (+/- .3V).

Hope this is helpful.

Titus
__________________

__________________
TitusLivy is offline   Reply With Quote
Old 01-12-2008, 09:44 AM   #31
Rivet Master
 
guy99's Avatar
 
1984 31' Airstream310
Dunsmuir , California
Join Date: May 2004
Posts: 1,336
Images: 16
Quote:
Originally Posted by azflycaster
With all the checking and eliminating you have done, it sounds like your converter thinks the batteries are charged more then they are. Too bad that Randy from bestconvertors has not found this thread yet, he knows this stuff. Didn't you replace the converter last year after you had issues at 29 Palms?
Yes, last year at 29 Palms I had my second Progressive Dynamics PD9180 fail. That is when I replaced it with the 65 amp WFCO.
__________________
If you want others to be happy, practice compassion.
If you want to be happy, practice compassion - The Dalai Lama

1984 310 Limited Motorhome
Courtesy Parking (W/S/E/Wi-Fi) on I-5 in Northern California, 70 miles from Oregon border
guy99 is offline   Reply With Quote
Old 01-13-2008, 12:55 PM   #32
Rivet Master
 
guy99's Avatar
 
1984 31' Airstream310
Dunsmuir , California
Join Date: May 2004
Posts: 1,336
Images: 16
Hello everyone,
Sorry to have not responded to all of the posts here recently. I spent most of yesterday in the ER. Turned out not to be serious but a real time consuming undertaking.

I am working on a post which I hope to send today which will tell you all what else I have observed and learned?

Contrary to a suggestion made in this thread, I do understand that your posts here represent an investment of time and effort.

I appreciate every attempt to help.
__________________
If you want others to be happy, practice compassion.
If you want to be happy, practice compassion - The Dalai Lama

1984 310 Limited Motorhome
Courtesy Parking (W/S/E/Wi-Fi) on I-5 in Northern California, 70 miles from Oregon border
guy99 is offline   Reply With Quote
Old 01-14-2008, 04:00 PM   #33
Rivet Master
Commercial Member
 
New Borockton , Alabama
Join Date: Sep 2002
Posts: 1,288
Images: 21
Quote:
Originally Posted by azflycaster
With all the checking and eliminating you have done, it sounds like your converter thinks the batteries are charged more then they are. Too bad that Randy from bestconvertors has not found this thread yet, he knows this stuff. Didn't you replace the converter last year after you had issues at 29 Palms?
I did just find this thread as I was gone this weekend but have actually been corresponding with Guy for a week or so on this. Titus above has given a pretty fair accessment of how these units work and quite frankly, there is not a lot of difference between manufactures in terms of automatic mode changing.
I understand from Guy this morning that all is well and his unit is working properly but I'll let him elaborate at his leisure.
__________________
Randy...Converters, Inverters, Trimetric, Surge Protectors, Zamp Solar, AGM Batteries
www.bestconverter.com
68 Overlander is offline   Reply With Quote
Old 01-14-2008, 06:41 PM   #34
1 Rivet Member
 
CAMBRIDGE , ONTARIO
Join Date: Apr 2007
Posts: 14
I have had the same conceres re WFCO not charging at expected Amps. This site has an indepth study of the WFCO converter. www.dudesrv.com/wfcothe real dirt Hope this helps. I concluded that I do not have enough battery capacity to ever get the full amperage available.
__________________
Yonner is offline   Reply With Quote
Old 01-15-2008, 12:18 PM   #35
Rivet Master
 
guy99's Avatar
 
1984 31' Airstream310
Dunsmuir , California
Join Date: May 2004
Posts: 1,336
Images: 16
Resolution

Hello everyone. Sorry I am so slow getting this posted. I have had some medical issues that required attention and haven't had a lot of time to compose this.

It occurs to me that some unstated assumptions and some background information which I have not made explicit may be helpful for this discussion.

First let me explain the basic functionality of the Trimeteric 2020. From my point of view the key data which it provides is battery volts and amps. Discharging amps are reported as negative, charging amps as positive. It also tracks cumulative net amps. So if you discharge the battery by 50 amps and then charge it by 40 amps, the cumulative display would read -10. I believe that the volts and amps measurements are accurate within measurement error. The cumulative net depends on what charging efficiency you assume and how you define a fully charged battery. (When the "fully charged" criteria are met, the cumulative net amps is set to 0 and the percent full is set to 100%). The cumulative net amps is kept until the batteries are fully charged.

In summary the Trimetric gives near real time measurements of battery volts and amps (in or out), it also estimates net amps in or out and percent of charge of the battery bank using some assumptions. It also tracks a number of other items thought to be useful in managing a battery bank such as total amp hours ever withdrawn from the battery bank, time since last full recharge, etc. Here is a link to Randy's website: TriMetric Battery Monitor
and here is a link to the manual: http://www.bogartengineering.com/TM2Instrpt1.pdf

What I was expecting

In preparation for this current trip I increased my battery capacity from ~ 230 amp hours (2 group 27 marine deep cycle batteries) to ~ 460 amp hours (4 group 27 marine deep cycle batteries) by buying 4 new batteries moving my chassis battery out of the battery drawer, wiring the drawer to support 4 batteries, and shoe horning the batteries in. I used the group 27 batteries rather than golf cart batteries because there is not enough height to allow the taller batteries to fit.

From prior trips with two batteries I knew that we could get by with just two batteries by running the generator as needed to recharge but I felt the batteries were discharging overnight further than was good for them and my old batteries had been run very low in 29 Palms when my converter failed while I was plugged in and I didn't realize it until the batteries were very discharged. So I figured they should be replaced anyway.

With the new configuration I expected to be able to boondock indefinitely by running the generator enough on a daily basis to bring the batteries up to 90% charge or so and then every week or 10 days running the generator longer so as to fully charge the batteries. This is what the fellow who I am traveling with does with his SOB motorhome. He has approximately the same battery capacity in amp hours although he has golf cart batteries and he has an inverter charger with 100 amp charging capacity (compared to my 65 amp WFCO). I expected that I might need to run my generator a bit longer than he because of the lower charger capacity.

What actually happened was that my WFCO converter was never putting out more than 13.6 volts with the consequence that the rate of charge declined very quickly from around 45-50 amps to 15 amps and less (It took less than 15 minutes for the charge rate to fall to below 15). This is when I started with batteries around 12.3 volts with a very light load of 1.8 amps (approximately 70%).

My research suggested that it was going to take forever to charge my batteries if the charger never put out more than 13.6 volts. For example the article on this link says that a fully dischrged battery can be brought back to a 90% state of charge in 3 hours at at 14.4 volts but that it takes 40 hours to achieve 90% state of charge at 13.6 volts. Charge Wizard

This is when I made the first post in this thread.

Based on suggestions here I decided to connect a battery charger. So, I fired up the generator and then started the converter with the batteries disconnected. I then plugged in the battery charger and hooked it up to my batteries. After about 6 hours of charging the batteries were up to around 12.5 volts and the charger (which unfortunately is automatic) shut off. I noticed however that during the time the generator had been running the converter was supplying 14.4 volts to the rig. Never before had I seen this converter put out more than 13.6 volts! I hypothesize that because the converter powered up with the batteries disconnected, it went into "bulk" mode.

Since I 'tricked' the converter into going into 'bulk' mode, it seems to always start there. So, for example, this morning my batteries were at about 12.3 volts when I started the generator, when the converter came on, the voltage started at 12.8 with a charge rate in the 40's. Over the next 2 hours the voltage climber to 14.4 and the charge rate fell slowly to about 14 amps. It has been an hour since I shut down the generator and the batteries have been supporting a 4 amp load (with briefly higher loads when the water pump or furnace runs). The Trimetric reports battery voltage of 12.8 and amperage of -3.8.

This is the performance I expected from the converter in the first place.

It seems to me that once the WFCO convert gets in to a state (bulk, normal, float) it really tends to stay there until it gets 'reset' somehow. When I first got the WFCO I noticed that once it went into 'float' - 13.2 volts it never came out even when the batteries were discharged to 80%. I spoke to Randy about this and he advised me to disconnect the batteries and shore power for a minute, then reconnect. Sure enough when I did this the converter started up in 'normal' - 13.6 volts mode. I have had to follow this procedure several times when the rig has been plugged in and not in use. It also as happens during extended stays in camp grounds when we were plugged in and not using a lot of power.

The following link documents some extensive testing of the WFCO converter which produced results which are pretty much consistent with what I have experienced. Yonner posted this link earlier but it seems to have a space inserted into the url so it is not complete.

WFCO Testing and results.

Bottom line. I have escaped battery charging hell. I don't really understand why the WFCO acts as it does but I seem to know how to get it to do what I need it to, so I'm OK.

Thank You all for your suggestions and concern. I know that it took an investment of time and effort.

Guy
__________________
If you want others to be happy, practice compassion.
If you want to be happy, practice compassion - The Dalai Lama

1984 310 Limited Motorhome
Courtesy Parking (W/S/E/Wi-Fi) on I-5 in Northern California, 70 miles from Oregon border
guy99 is offline   Reply With Quote
Old 01-15-2008, 06:07 PM   #36
Ready-to-Travel
 
pmclemore's Avatar

 
2012 30' International
Walkerton , Virginia
Join Date: Dec 2003
Posts: 2,494
When you disconnected the batteries, what did you do (how did you do it?)

Pat
__________________
pmclemore is offline   Reply With Quote
Old 01-15-2008, 08:46 PM   #37
Rivet Master
 
guy99's Avatar
 
1984 31' Airstream310
Dunsmuir , California
Join Date: May 2004
Posts: 1,336
Images: 16
Quote:
Originally Posted by pmclemore
When you disconnected the batteries, what did you do (how did you do it?)

Pat
I have two battery disconnect switches on the rear of my battery drawer (I don't know if they are stock). I flipped the switch for the coach batteries. This disconnects the positive line from the battery bank to the coach.
__________________
If you want others to be happy, practice compassion.
If you want to be happy, practice compassion - The Dalai Lama

1984 310 Limited Motorhome
Courtesy Parking (W/S/E/Wi-Fi) on I-5 in Northern California, 70 miles from Oregon border
guy99 is offline   Reply With Quote
Old 03-01-2008, 10:35 PM   #38
2 Rivet Member
 
danesh's Avatar
 
Join Date: Nov 2003
Posts: 57
Images: 6
Hello Everyone.
Today when I was trying to get our AS ready for a trip I noticed that the battery is dead and charger/converter is not working. I cehcked the voltages, battery was 4.3 volts and the charger/converter was 4.3 volts. The system must have been in this condition at least for a few weeks(I checcked the AS two weeks ago when we had a bad freeze). I disconnected the battery and took the converter out. The battery reads 6 volts (I guess it is dead for good!!!) and converter read 4.3 volts. But it seems that the converter is comming back to life. After I pluged it in again the voltage went up to 11.4 volts and now it is at 14.4 volts. By the way i forgot to mention that the converter is a WFCO WF-8855.
My question is: what has happend? Why did the converter voltage went from 4.3 to 11.4 and now 14.4 volts? And, why the voltage without any load is 14.4 volts? I thought the converter voltage without being connected to anything should be around 13.6 volts. Is converter damaged too?
Thanks for any reply.
__________________
85 sovereign
danesh is offline   Reply With Quote
Old 03-01-2008, 10:37 PM   #39
2 Rivet Member
 
danesh's Avatar
 
Join Date: Nov 2003
Posts: 57
Images: 6
Dead Battery and Starnge Converter bahavior

Hello Everyone.
Today when I was trying to get our AS ready for a trip I noticed that the battery is dead and charger/converter is not working . I checked the voltages, battery was 4.3 volts and the charger/converter was 4.3 volts. The system must have been in this condition at least for a few weeks(I checcked the AS two weeks ago when we had a bad freeze). I disconnected the battery and took the converter out. The battery reads 6 volts (I guess it is dead for good!!!) and converter read 4.3 volts. But it seems that the converter is comming back to life. After I pluged it in again the voltage went up to 11.4 volts and now it is at 14.4 volts. By the way i forgot to mention that the converter is a WFCO WF-8855.
My question is: what has happend? Why did the converter voltage went from 4.3 to 11.4 and now 14.4 volts? And, why the voltage without any load is 14.4 volts? I thought the converter voltage without being connected to anything should be around 13.6 volts. Is converter damaged too ?
Thanks for any reply.
__________________
85 sovereign
danesh is offline   Reply With Quote
Old 03-01-2008, 11:31 PM   #40
2 Rivet Member
 
danesh's Avatar
 
Join Date: Nov 2003
Posts: 57
Images: 6
Dead Battery and Starnge Converter bahavior

It is me again.
I just checked the converter once more. It is back to 11.4 volts. I guess I need a new converter . Any comments?
Cheers
__________________
85 sovereign
danesh is offline   Reply With Quote
Old 03-01-2008, 11:56 PM   #41
Rivet Master
 
guy99's Avatar
 
1984 31' Airstream310
Dunsmuir , California
Join Date: May 2004
Posts: 1,336
Images: 16
Sure sounds to me like the converter is dead. I suggest you write/call Randy at Bestconverter.com. He should be able to tell you how to test it definitively. If it dead, he might be able to provide parts to repair it.

It's possible your battery could come to life. (I'm not saying likely, especially if the battery actually froze). I suggest that you charge it with a good battery charger and see how it behaves after being fully charged. Be sure to check water levels.

Good luck.

Guy
__________________

__________________
If you want others to be happy, practice compassion.
If you want to be happy, practice compassion - The Dalai Lama

1984 310 Limited Motorhome
Courtesy Parking (W/S/E/Wi-Fi) on I-5 in Northern California, 70 miles from Oregon border
guy99 is offline   Reply With Quote
Reply


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Battery Charging with Univolt? andoboba Batteries, Univolts, Converters & Inverters 59 10-29-2009 11:22 AM
Battery charging with Honda Cracker Generators & Solar Power 39 04-02-2007 08:53 PM
Charging Chassis Battery guy99 Mechanics Corner - Engines, Transmission & More... 3 11-17-2005 12:55 PM
battery charging w/honda 2k dhe9 1997 - 2004 Bambi 9 10-21-2004 04:01 PM
Solar battery charging Charles Q Treichel Generators & Solar Power 23 10-17-2002 11:22 AM


Virginia Campgrounds

Reviews provided by




Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -6. The time now is 11:45 AM.


Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, Jelsoft Enterprises Ltd.

Airstream is a registered trademark of Airstream Inc. All rights reserved. Airstream trademark used under license to Social Knowledge LLC.