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Date Posted |
Forum
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RE: Fridge goes off while driving
Here's something that Marks RV wrote up....maybe this will help..
Marks RV fridge venting
Jim
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bigfootford
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06/05/08 08:47am |
Truck Campers
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RE: Are campers supposed to flex?
Too_Tall_Ford, congrats on your new camper.....
If you think your getting some movement because the camper bottom is not flat or your Truck bed is slightly out go to your local Home Depot etc and get you a sheet of high density insulation foam, not styrofoam. You may have to cut a small square out of the center of the sheet to use for matching the footprint of your camper bottom. If there is a little difference the foam will compress in the area and support your camper fully all the way around. I did this and was surprised that one corner was more compressed than the other 3. My camper seemed to be moving / rocking more than it should..
Several guys on the forum use the high density foam.
Keep us informed....
Jim
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bigfootford
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06/05/08 08:28am |
Truck Campers
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RE: Charging/Converter Question
So, in summary after all this it all boils down to the following:
1. A drop of .2-.3 volts from the converter to the battery is a marginal situation for a converter to perform properly. A loss of .3 or greater and your in deep POO. We've known this for several years but it still comes up at least once a month.
This alone is the biggest battery charging problem we have with making multi stage converters perform to spec.
2. AGM batteries resting voltage is .15 or greater for a given State Of Charge. This is the same thing as if you have voltage drop as stated in #1. So if you have wire problems, even .1-.2 volts drop and an AGM battery you are not going to see some converters perform to spec. I have known of this issue for about 2 years.
In reference to my charts......
#2 performance is acceptable. The XADC replaced 21.4 amps in 2 hrs and had 5.1 AH to go for 100% SOC This was with the average JOE's install with 24' (12' one way) of 4 ga wire and several connections.
Note the resting voltage at 75%SOC =12.78 VDC. if this was a wet cell at 75%SOC it would be at about 12.4VDC
#3 performance is acceptable. The XADC replaced 18.8 AH's in 2 hrs.
This was with short 4 ga wires. The battery was colder in this test by 5 deg.
Note the resting voltage was 12.83vdc at 75% SOC
#1 performance is not acceptable although it replaced 43 AH in 2 hrs. It still had 20 AH to go. The Temp of the battery was at 61 deg F.
If I would have reset the XADC and started another cycle as I did in Chart #3 the battery would have reached +90% SOC in about a total of 3 hrs....I will live with that for the time being.
AGM batteries have been around for several years. The converter folks have disregarded them in the lower ended units that many of us use.
The converters perform great for Wet Cells and ok for AGM's.
Hopefully the next generation of converters will address minimum wire losses, battery differences and Temperature compensation with simple switches, adjustments,software and sensors. We are not talking about a major redesign nor a big cost here folks.
Jim
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bigfootford
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06/03/08 02:50pm |
Tech Issues
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RE: Charging/Converter Question
Now you understand the issue. There are adjustments inside the XADC. My goal was to test AS_IS first. It is my feeling that if the MFG sells something it should work as advertised with AGM or WET Cell.
I have the skills to modify circuits and tweak voltages but many on this forum and others that purchase these units don't. And if they run into certain issues they are stuck....Randy at BestConverter and the tech's at PD etc beat their heads against the wall dealing with this issue all the time.
Cal, check your PM's, I sent you one a couple of days ago.
Jim
Jim-
I don't believe it's bad advertisement by the converter manufacturers. The problem is with the consumers who buy agm batteries.
http://www.mkbattery.com/images/MK_AGM_LG_v2_r4.pdf
This link states agm batteries must be charged to at least 14.4V. The XADC60 clearly states it charges to 14.2V. Obviously this charger is not designed for agm batteries and should not be used with them. The sales people who sell these batteries should be telling their customers they need a new charger when purchasing agm batteries.
I now got the PM. Not used to this forum.
Cal
Lifeline battery charge voltage.
As you can see by the link to Lifeline, the voltage for charge is 14.2-14.4 which is ok for XADC etc......The problem lies in the SOC voltages difference from Wet Cells and AGM's.
Note though the Universal battery has a higher minimum charge voltage.
Jim
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bigfootford
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06/03/08 01:06pm |
Tech Issues
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RE: Charging/Converter Question
I don't understand the voltage issue, what difference does the at rest voltage make? If anything AGMs recommend a lower charging voltage not higher. I also do not understand the complaint that the charger was not functioning as advertised when the graphs you posted clearly show it is, please clarify.
Sam
Lifeline battery spec source
100% SOC 12.80 volts or greater
75% SOC 12.55 volts
50% SOC 12.20 volts
25% SOC 11.75 volts
0% SOC 10.50 volts
Flooded Wet Cell
SOC 12 Volt battery Volts per Cell
100% 12.7 2.12
90% 12.5 2.08
80% 12.42 2.07
70% 12.32 2.05
60% 12.20 2.03
50% 12.06 2.01
40% 11.9 1.98
30% 11.75 1.96
20% 11.58 1.93
10% 11.31 1.89
0 10.5 1.75
http://pic20.picturetrail.com/VOL1437/6215710/19809392/319925286.jpg height=640 width=400
http://pic20.picturetrail.com/VOL1437/6215710/19809392/319926685.jpg
This should answer your questions.
Jim
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bigfootford
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06/03/08 12:48pm |
Tech Issues
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RE: Charging/Converter Question
Keep in mind that my agm battery in this test has a higher resting voltage than a flooded wet cell. +.2 to +.3 Thus the Xadc is already in trouble because it's just like voltage drop caused by wire size and connection issues.
I don't see a cure for this other than something like the truecharger Xantrex or others which has settings for AGM's. Several guys have had good success with the PD charging AGM's.
Blue Sky solar charge controllers have an adjustment to compensate for this issue of AGM's.
Jim
Jim-
Sounds like we're getting to the bottom of this. Your Xantrex isn't setup of agm batteries. I also don't believe you discharged the battery far enough to reach 50% discharge state. I consider 12V the 50% discharge point for a standard battery. What is that level for agm batteries?
BTW, you may want to open up the XADC 60 converter and look for a voltage adjustment pot on the circuit board. You may be able to increase your output voltage by 0.3V to match the agm batteries. I have a pot on my Parallax 7345 converter that I needed to re-adjust after modifying the voltage feedback loop.
Cal
Now you understand the issue. There are adjustments inside the XADC. My goal was to test AS_IS first. It is my feeling that if the MFG sells something it should work as advertised with AGM or WET Cell.
I have the skills to modify circuits and tweak voltages but many on this forum and others that purchase these units don't. And if they run into certain issues they are stuck....Randy at BestConverter and the tech's at PD etc beat their heads against the wall dealing with this issue all the time.
Cal, check your PM's, I sent you one a couple of days ago.
Jim
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bigfootford
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06/03/08 10:44am |
Tech Issues
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RE: Charging/Converter Question
Jim, do you have Optima batteries? They have a very high at rest voltage and arn't exactly a true AGM battery.
Sam
It's a Universal AGM gp 30 110 AH battery.
Wayne (Reddog1) has a Lifeline gp 31 100 AH and it's resting voltage is the same as mine.
Jim
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bigfootford
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06/03/08 10:33am |
Tech Issues
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RE: Charging/Converter Question
Jim, The converter didn't go into current limit with just one battery discharged to 50%. We may not see 60A with 2 batteries. However, if you turn on extra loads in the MH (perhaps power the fridge on 120V inverter) you will go into 60A current limit.
The battery voltage needs to be below 13.45V for the converter to supply 60A. Your graph shows the charging voltage starts at about 13.9V (@ the 4 minute mark). The converter will not go into current limit as the battery voltage is already too high.
Cal
Cal, we don't expect a converter to charge at current limit unless our battery banks can handle it. We just don't want it to stop like the XADC did in chart 1.
What we want is for the converter to charge at the highest rate possible, raising the voltage to 14.X and then after a timed duration go into a preset absorb stage and then to a float voltage. That applies to a small bank 75 ah or a hugh bank of 400+.
Even a small 20 amp smart converter can perform this task, it will just take longer.
If a smart converter was hooked to a battery and there was a 1 + volt drop in the wiring the battery would finally reach the charge voltage of 14.x if you left the voltage at 14.x long enough.
Keep in mind that my agm battery in this test has a higher resting voltage than a flooded wet cell. +.2 to +.3 Thus the Xadc is already in trouble because it's just like voltage drop caused by wire size and connection issues.
I don't see a cure for this other than something like the truecharger Xantrex or others which has settings for AGM's. Several guys have had good success with the PD charging AGM's.
Blue Sky solar charge controllers have an adjustment to compensate for this issue of AGM's.
Jim
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bigfootford
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06/02/08 08:20pm |
Tech Issues
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RE: Charging/Converter Question
Jim-
You state: "Note from the beginning of the charge the voltage climbs and the amps go down. That wouldn't be constant anything would it?"
You never get into constant current mode (which would be ~60A), but you are in constant voltage mode (~14.35V). You don't get into constant current mode because you just don't have enough load. The converter has the potential to deliver more than the battery can accept. There's just one battery, right?
Looking at your second chart, we can determine your line resistance. When the converter delivers 25A the battery is at ~13.98V. When at 10A, the battery is ~14.2V.
resistance = - delta Vbat/ delta I
resistance = - (13.98 - 14.2) / (25 - 10)
resistance = 15 mohm
During the phase where battery voltage is rising and current is dropping the output of the converter maintains a constant output voltage. This voltage is:
Vconv = I * resistance + Vbat
Vconv = 25A * 15 mohm + 13.98 = 14.35V
Cal
Salvo, Yes in the chart examples they were obtained with one AGM 110ah battery. I do have others derived from 2 group 24's.
The math shows a .37 volt drop.....actual measurements during initial charging showed less than .3 measured at the converter and then at the battery. (200 mv of that from 2 100 mv shunts). I was attempting to keep under .3 for my actual system.
The 3rd chart was derived with the short cables. The resistance with the math then is about 5 Milli ohms and a drop of .1 vdc. That equates to the value of the 100 mv shunt I use for testing.
My system was installed to represent the average Joe's installation.
Shunt for the trimetric, cutoff switch, disaster fuse (85 amp) and a magnetek converter modification to incorp. a multi-stage converter. There is going to be drops in voltage in all our systems.
Despite all this discussion.....
If I was to put a 20 ah battery that was down 50% SOC and I put the XADC 60 on it to charge I would expect it to do the bulk mode and give the battery what ever it can accept, It wouldn't be much but still it should be bulk mode, then after bulk mode It should switch to absorb mode and do that for 2 hrs or so. in theory get the battery close to 100%. Then drop into Float of 13.5. I have not seen the XADC perform that way.
Same applies to the others PD, WFCO etc. Do they perform exactly as specified???? No. But the PD is the one that does the best in my book.
We've heard now of 2 different PD users modifying the electronics to compensate for performance.
Maybe this has hijacked the OP's post and I apologize for that.
His problem is not resolved, although early on we all said his wiring was probably to fault. I hope we haven't scared him off.
Jim
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bigfootford
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06/02/08 02:20pm |
Tech Issues
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RE: Charging/Converter Question
Jim, I suspect you have more line drop than you think. You are not maintaining a constant 60A of charging current. Your voltage measurement location is probably at the battery. If you place the voltmeter directly at the converter, you will see a different story. The voltage at the converter is where the converter 'thinks' the battery is at. Your charts show that the converter is hardly ever (less than a minute) in constant current mode.
A simple way to measure line drop is to place your voltmeter between the positive output terminal of the converter and the positive terminal of the battery. Now charge your battery while recording charging current and line drop voltage. To avoid measurement errors, I would disconnect all MH 12V loads.
Line resistance = line drop voltage/charging current
Do the same measurement for the ground side.
Cal
Look carefully at the charts I posted.....Your explanation is from text (what you have read). My charts pose a similar situation as the OP. Short cables with no voltage drop or long cables with less than .15 drop, 50% discharged battery and 25% discharged batteries. The XADC does not perform like you described or from the MFG. White papers.
Note from the beginning of the charge the voltage climbs and the amps go down. That wouldn't be constant anything would it?
Jim
The charts show both long cables actual application and short cables bench testing.
Short cables 6 ft total with crimped and soldered...= no drop.
Jim
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bigfootford
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06/01/08 09:43pm |
Tech Issues
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RE: Mileage decrease on mandated 10% Ethanol.
118 gallons/21 lbs = 314 gallons/bushel. If I figure 175 bu/acre corn, which is close to the average yield in Iowa, that is 55,000 gallons/acre. or 1.26 gallons/square feet. Or .008 inches of rain. Iowa gets 40 inches of rain a year. Most of the land is not irrigated.
Each bushel of corn will make 2.5 gallons of ethanol and it will take about 3 1/2 gallons of additional water to process a gallon of ethanol.
All in all, not much water.
Guess it is up in the Dakota's etc....This is a following quote from page 7 of this thread----
"Nebraska, at the present time, is the fourth largest ethanol producer in the United States behind 1. Iowa, 2. Illinois and 3. Minnesota.
At the present there is also a debate about the water needed for these plants in Nebraska. Nebraska is on top of the Ogallala Aquifer, one of the biggest fresh water sources in the United States, and it is being depleted. This is mostly due to over pumping by the farmers to irrigate. New irrigation wells are on hold and some water restrictions now exist. Water may be abundant on the planet, but where a lot of corn is being grown it is becoming a depleted resource. There is great concern that many large ethanol plants may further hasten the depletion."
Guess what we need to do is build a pipe line for water to ship that extra water you have over here so we can make LOT'S of ethanol....
We haven't built a new dam here in over 30 years.
Jim
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bigfootford
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05/30/08 08:32am |
Truck Campers
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RE: Mileage decrease on mandated 10% Ethanol.
After reading some of the gvt reports regarding ethanol and Aviation Gas, they say......
"The FAA has strict regulations in place that require only aviation grade fuels be used in certificated aircraft. There are supplemental type certificates (STC) in use that allow some "properly altered" aircraft to utilize automotive grade fuels that meet certain STM standards.
The pilots/owners of the aircraft where automotive fuel STCs are incorporated have the responsibility to ensure the automotive fuel they use meets those STM standards. Compliance with this requirement is mandatory.
It should be noted that there are several aircraft operating in Hawaii that operate under 14 CFR 103 regulations (ultralight aircraft) and aircraft that have been issued experimental airworthiness certificates (homebuilts).
Hawaii's local FAA safety officer has presented information at General Aviation Safety Meetings (WINGS) that Hawaii's automotive fuels are likely not to meet the required STM standards.
All airmen are reminded that it is their responsibility to ensure the grade of fuel they use in their aircraft meets the regulatory standards specified for their aircraft.
Airmen may direct their queries to the local FAA safety office, (808) 837-8335, and may view pertinent FAA Advisory Circulars and regulations at the FAA website, faa.gov, for example:
* CE 07-06.pdf, "Alcohol (ethanol or methanol) present in the automobile gasoline," dated 10/27/2006
* AC 91-33A.pdf, "Use of Alternate Grades of Aviation Gasoline for Grade 80/87, and Use of Automotive Gasoline," dated 7/18/1984
* AC 21-21.pdf, "Use of Automotive Gasoline in Agricultural Aircraft," dated 8/24/1984
* AC 20-43c.pdf, "Aircraft Fuel Control," dated 10/20/1976
Now I understand......If the stuff were to kill people because of engine failure in an aircraft the GVT wants to make sure they told the pilots not to use this stuff!!!!!
The GVT knows there will be problems.
GEEZZZZ
Jim
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bigfootford
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05/29/08 09:07am |
Truck Campers
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RE: Mileage decrease on mandated 10% Ethanol.
A search for e10 boats
Ummmm blenders get an exemption from the 18.4 cent tax.....
This is another of those biased researched projects.
MTBE (oop's it gets in the wells.water table, kills fish)
Strange, if E10 causes a 10% reduction in mileage what have we really gained besides consuming 90 % amount of gas....That means we still burn the same amount of gasoline because you need 10% more.
Yet the story we are being sold is that we are using less gasoline, 100% stuff, which, if you are in-fact getting a drop in mileage of 10% we are still using the same amount of gasoline, only now we are subsidizing the Farmers and Blenders.....I think that's the story!!
If it's pollution we are dealing with then we shouldn't oxygenate during the summer ( add ethanol). That was the original goal...Reduce polution, not create another subsidization.
Jim
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bigfootford
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05/29/08 08:58am |
Truck Campers
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RE: furnace blower won't shut off
rich&suehr03dbd, here is where you can get parts and read about the operation of your furnace. If you can look at the diagrams etc and have the ability you can fix it your self.
Bryantsrv home page
Bryant's rv write up on furnace problem
Bryantsrv furnace service doc's
Parts for your 8535
Diagrams and operation of Atwood furnaces
Hope this helps.
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bigfootford
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05/28/08 09:16am |
Tech Issues
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RE: Loosen tie downs when camping?
Now I have a tie down question. Why do the tie downs have to be "4 point"? Why wouldn't "2 point" tie downs angled forward work as well when fastened to the center of the main body of the TC? If the tie downs are to just hold the TC down in the truck bed, why 4 instead of just 2? Curious.
Frank
It's my opinion that if you were to perform a harsh maneuver the camper may raise up and create more trouble, otherwise it would work just fine.
Jim
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bigfootford
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05/27/08 09:38pm |
Truck Campers
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RE: Loosen tie downs when camping?
I level with the levelor blocks and try to make the rear a little high. I can tilt and drop the rear with my air bags. I drop the jacks for fine tune and stabilization and I'm done. When needed I will raise the camper with the jacks. I watch the tiedowns and make sure that there is no pressure on them. The camper is still supported by the truck bed. Maybe I have put a couple of hundred pounds of weight on the jack/jacks.
Jim
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bigfootford
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05/27/08 09:33pm |
Truck Campers
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RE: Charging/Converter Question
I suggest you reread my previous post and check Xantrex literature. The charger CAN be in constant current mode until it reaches 14.2V. This can only happen if there is enough load on the charger which happens when there are enough batteries discharged enough and poor wiring is not limiting the charging current. When charger is under heavy load (of constant current) its output voltage is bellow 14.2V due to the internal resistance of the charger. When the load is reduced as batteries charge the output voltage slowly rise and when the voltage reaches 14.2V the charger switches to CONSTANT VOLTAGE and the charging current will keep diminishing until the batteries are fully charged. After fixed time determined by the software the charger switches to lower CONSTANT voltage of 13.5V or so. The exact voltages may slightly differ with temperature and is taken care of by software when optional temperature sensor is used.
libroko,
This topic is regarding the XADC-60. It does not have an external temp sensor option.
A switcher supply (charger) is regulated by preset (maximum) pulsewidths in the primary circuit not by internal resistance. Software controls the various output voltages by controlling the PRF (pulsewidths) and sampling the voltage on the charge output.
Look carefully at the charts I posted.....Your explanation is from text (what you have read). My charts pose a similar situation as the OP. Short cables with no voltage drop or long cables with less than .15 drop, 50% discharged battery and 25% discharged batteries. The XADC does not perform like you described or from the MFG. White papers.
Note from the beginning of the charge the voltage climbs and the amps go down. That wouldn't be constant anything would it?
Read the OP's question. Can you answer his question or only tell us what you've read.
Jim
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bigfootford
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05/27/08 03:05pm |
Tech Issues
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RE: battery replacement
I too do the 2-3 day thing. Seldom run the gen.
Here is the approx amp hours required by things we use.....
Fridge and lp/co parasitic load- about .3 to .4 amp per hr avg X 24hr= 10 amps
Laptop- 4-5 ah so, 3 hrs on per day=15 A
Lights- 1 regular 1-2 amps(non led)X 3 hrs per day+= <6 A
Water pump.....I don't count it
Furnace= gobble gobble....when running 6-7 amps..Mine runs about 15 min every hour so every 4 hrs of heat = 6-7 amps used
Add the amps less the furnace and you will use about 31 amps/day.
You can push 2 days at this rate with the trojan. Cutting back on the Laptop/movie would get you 3 days.
You wouldn't be able to use the heater though. If you did use the heater you would need to charge every day for 2-3 hrs if you have a good converter.
Hope this helps you in deciding your direction you will go to properly equip your rig for what you want to do.
Jim
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bigfootford
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05/27/08 01:32pm |
Truck Campers
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RE: battery replacement
The AGM type battery is a great choice if you have the $. Here is a link to the size and spec of the Universal battery gp 31 that Bestconverter offers.
Best Converter Universal battery
You would loose about 20 AH but gain no maintenance and will still give you 55 ah before recharge. I have one and have pushed it pretty hard in testing and use. Life Line is another AGM mfg. You can check them out at Bestconverter too.
Let us know what you decide.
The trimetric battery monitor is really a great add on too. Once programed you don't have to guess the status of your battery.
Is you converter a multi-stage charger....I don't know what the 01 lances came with?
Jim
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bigfootford
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05/27/08 01:09pm |
Truck Campers
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RE: Mileage decrease on mandated 10% Ethanol.
Thanks for the head's up....Mathewb
What are things like this coming to???
I can't even describe what I'm thinking and feeling right now regarding this subject along with all the other blunders our legislators and media have so scientifically and intelligently produced.....
Jim
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bigfootford
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05/26/08 09:01pm |
Truck Campers
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