Sound like a converter problem?

[Moonkitty]

We are new owners of a 2008 FB International. Unfortunately no documentation came with trailer as it was a repo. We camped for a month in February, sometimes turning on lights made a humming noise but had no problems other than an occasional humming which went away within 30 seconds.

Just got back from a 2 week trip. Humming more pronounced and some clicking noises that seemed to come form the dinette but not sure. If we flipped the Store/Use switch it seemed to help until the last few days. Lights went dim.

Checked with a voltmeter and someone more knowledgeable than us checked and thought it was the converter. Plugged into shore power, all outlets work but lights made noise and dimmed and he said it was because they run off of 12 volt. I thought with shore power lights run from there but he said no.

While camping we used a battery jump box connected to shore power and battery to keep things going until we got home.

The converter is a Parallax 7300 and the one battery (should have 2 which we will replace eventually) is a Deka Marine Master.

Before we replace the converter does this sound like its actually the problem? Reading posts it sounds like someone had problems with the Store/Use switch which could also be our problem.

Any ideas and thank you for any input.
Beth

[Shaggy1970]

I think you should put two brand new batteries in there and see if that does not solve your problems before you go throwing whole bunch of money trying to trouble shoot this problem.

[nickmeloy]

Originally Posted by shaggy1970AS

I think you should put two brand new batteries in there and see if that does not solve your problems before you go throwing whole bunch of money trying to trouble shoot this problem.

While I agree with the above statement, if you plan to keep the trailer for a while, then an upgrade to a three stage converter is a good place to start. This will help on the battery life of the new batteries that you are about to install.

[Shaggy1970]

Originally Posted by nickmeloy

While I agree with the above statement, if you plan to keep the trailer for a while, then an upgrade to a three stage converter is a good place to start. This will help on the battery life of the new batteries that you are about to install.

Nick,
I am new to this Airstream thing too. So these A/S have a two stage converter installed right, the three stage helps with charging the batteries when on shore power, kinda like a trickle charger?

[idroba]

The original Airstream converter/charger is a single stage, that it it puts out 13.6 volts at all times. As the battery becomes fully charged, that voltage is too high and gassing of the electrolyte can occur over a longer period of time, basically an overcharge situation.

A three stage converter/charger starts out at a voltage in the 14.5 range which dumps a lot of power into the battery fast (called the bulk charge stage). That brings the battery up to about 80 to 85% charge. After that relatively rapid charge is finished, it goes into an absorption stage, at a lower voltage (in the range of 13.6 volts), which brings the batteries to almost full charge (95 to 98%). This can take 15 to 20 hours to complete. At that point the voltage across the battery is reduced again (to about 13.2 volts) which is the maintenance voltage or float voltage, and keeps them there. That does the last few % of charge, up to 100%. Virtually no electrolyte evaporation takes place at that voltage, so the batteries can be left there continuously.

I hope no one nitpicks my specific numbers, they are approximate and each manufacturer uses some different numbers. Some also measure the temp of the battery and adjust to that. I am just trying to give you an idea of how they work.

[Shaggy1970]

Originally Posted by idroba

The original Airstream converter/charger is a single stage, that it it puts out 13.6 volts at all times. As the battery becomes fully charged, that voltage is too high and gassing of the electrolyte can occur over a longer period of time, basically an overcharge situation.

A three stage converter/charger starts out at a voltage in the 14.5 range which dumps a lot of power into the battery fast (called the bulk charge stage). That brings the battery up to about 80 to 85% charge. After that relatively rapid charge is finished, it goes into an absorption stage, at a lower voltage (in the range of 13.6 volts), which brings the batteries to almost full charge (95 to 98%). This can take 15 to 20 hours to complete. At that point the voltage across the battery is reduced again (to about 13.2 volts) which is the maintenance voltage or float voltage, and keeps them there. That does the last few % of charge, up to 100%. Virtually no electrolyte evaporation takes place at that voltage, so the batteries can be left there continuously.

I hope no one nitpicks my specific numbers, they are approximate and each manufacturer uses some different numbers. Some also measure the temp of the battery and adjust to that. I am just trying to give you an idea of how they work.

Thank you, I am going to have to upgrade my converter since majority of my time is going to be spent on shore power and don't want to "cook" the batteries. Can you recommend a good four stage converter?

[lewster]

Originally Posted by shaggy1970AS

Thank you, I am going to have to upgrade my converter since majority of my time is going to be spent on shore power and don't want to "cook" the batteries. Can you recommend a good four stage converter?

There really are no '4 stage converters' To get a true 4 stage battery charger, you have to upgrade to an inverter/charger like a Magnum, which produces a bulk, absorption and float charge and will then power down either for 4 hours or until it sees a drain on the batteries, when it will run thru the entire charge cycle for an abbreviated period to ensure that the batteries remain fully charged and in float mode.

Every battery requires a different 'charging profile' and certain converter/chargers or inverter/chargers are better than others for what your battery manufacturer specifies. For example: Lifeline AGM batteries require a float and absorption charge of 14.2-14.3VDC and a float charge charge of 13.3VDC.

During the bulk charging phase for a Lifeline, both the voltage and amperage increase until they reach the required voltage (14.2 in this example) and let's say 50 amps if we were using a Magnum MMS-1012 inverter/charger. Once both set points are reached, the charger section then begins the ' absorption phase' where the majority of the charging happens.

During this absorption phase (also referred to as the 'taper' phase) the voltage remains at 14.2 VDC and as the battery fills up, the amperage starts do decrease.....hence the 'taper' name. When the battery is is almost full and the amperage has reduced to almost zero, the charger then enters the 'float' phase.

During the float stage, the voltage is reduced to 13.2 VDC and the amperage is also reduced to a minimum.....the exact amount is dictated by the batteries and the draw being placed on the battery bank.

Please note that all of these numbers are for 'standard' conditions of 77ºF. As the battery temperatures vary, the battery's needs for charging voltage also vary dramatically.....lower in hot temps and higher in low temps. This is why every quality charger has temperature compensation which tracks this temperature and varies the charging voltage accordingly.

Unfortunately, there is only one popularly priced RV converter/charger with temperature compensation, and they have reliability problems. That leaves the job to a quality inverter/charger.

Questions?

[Shaggy1970]

Lewster,
So for my current setup, two interstate deep cycle batteries mostly used with shore power on days and weekends at a time will the factory installed converter cook the batteries? Or is a upgrade to a two/three stage converter required? Whats the best course to take? If the original is a single stage and constantly providing 13.6 amp will it not eventually overcharge both batteries?

[lewster]

Originally Posted by shaggy1970AS

Lewster,
So for my current setup, two interstate deep cycle batteries mostly used with shore power on days and weekends at a time will the factory installed converter cook the batteries? Or is a upgrade to a two/three stage converter required? Whats the best course to take? If the original is a single stage and constantly providing 13.6 amp will it not eventually overcharge both batteries?

Shaggy,

Yes and no. I am no fan of Interstate batteries, as this is the brand that I replace most frequently, but even they will benefit from proper charging. There is nothing worse than to give a battery a constant voltage somewhere in the middle of what they require; it becomes either too much (overcharge) or too little (undercharge). Your stock Parallax converter WILL destroy your batteries in short order if left constantly connected to shore power!

When batteries are undercharged, the sulfur in the sulfuric acid electrolyte forms crystals on the plates, which are generally broken back down and driven back into the acid solution when the higher voltages of a proper bulk and absorption charge are applied. This does NOT happen at 13.6 VDC, and you will see your battery's charge retention capacity rapidly decreasing because of it.

You will benefit most from a better quality converter with 3-stage charging like the 9200 series or 4600 series from Progressive Dynamics. There are some others out there, but the PD products are still made in the USA. The voltage profile of a PD is still not ideal (you need an adjustable inverter/charger for that) but better than most.

Another life-extending practice is to refrain from deeply discharging your batteries on a regular basis. By this I mean below 50% depth of discharge (DoD, which is about 12.2 VDC). Batteries retain their maximum number of charge cycles when the DoD is kept above this level. In fact, the less deeply you draw down your batteries, the greater number of charge cycles will be available.

Hope this helps!

[AtomicNo13]

Believe it or not, Walmart carries batteries mfd by Johnson Controls. It is branded Maxx Everstart. The group 29 is a really nice battery for the money. People laugh at Walmart but there is a nice thing about a 3 year warranty at 20000 locations everywhere in the us!

I have used the Iota brand converters with great success.
I lime the DLS55 with built in IQ4.

[Moonkitty]

If I understand this correctly, we should buy 2 new batteries and replace the converter. I've been reading on here that Parallax will fry your batteries so I figured this is a good time to replace it. We can do all of this, I just didn't want to needlessly buy something if that was not the problem.

[AtomicNo13]

Batteries are a necessary evil... Consumables!
The converter it the heart of your electrical system. The multistage converters can make your new batteries last 6-7-8 years. It is what should have been installed during manufacture.
You will not regret the investment.
No one here will talk you into keeping what you have presently!

[Captain Hank]

I have a 2007 Safari 27' and replaced my two batteries with AutoZone deep cycle batteries.
I replaced my converter my a 4 stage "Boondocker" converter from Best Converters. Randy at Best will help you with your selection. Other Airstream friends have used this converter and have been happy. It does require some small modifications to your converter box. I have all my pictures, but Randy from Best can also help.

[Moonkitty]

Thank you all for your great suggestions. As we plan to keep this AS for a long time I need to get shopping and get this done!

[Rrroberts40]

I installed a Progressive Dynamics 4655 to replace the original Paralax and am happy as a clam...better in every way and won't cook the batteries...this converter takes about 1 hour to change out 2 hrs if you are careful to a fault and pretty much anyone can do this job...minimum tools and a little common sense and you are good to go...I would put a pair of batteries in to when you get the funds...

http://www.airforums.com/forums/f37/...er-114099.html
This link should help you with the install.

[damonbeals]

Just FYI but you can get the Airstream docs for your trailer from the airstream website.

http://www.airstream.com/files/libra...e4b8b27ee7.pdf

Damon
#4827

Originally Posted by Moonkitty

We are new owners of a 2008 FB International. Unfortunately no documentation came with trailer as it was a repo. We camped for a month in February, sometimes turning on lights made a humming noise but had no problems other than an occasional humming which went away within 30 seconds.

Any ideas and thank you for any input.
Beth

[Moonkitty]

We have taken the battery out. I bought new ones but they were too big so I need to exchange and will do so. We connected shore power to test.
But, when you turn the lights on a clicking is still heard through the speaker system (or that is where it sounds like it is coming from). Switching the use/store button seems to help but still have a loud hum through speaker which then stops.
Would this rule out the battery and it could be a bad use/store solenoid?

[AtomicNo13]

The popular opinion is that the OEM supplied converter is crap. Change it. The solenoid either works or it doesn't. The system is not really designed to work IR be used without a buffer (viable battery) installed.
The humming is most likely unfilteted ripple voltage straight from the converter. These use a very sloppy switching circuit which will introduce "AC noise" to your audio equipment without a battery in place.
Change your converter and battery then post your success.

[Moonkitty]

I ordered the Progressive Dynamics 4655 from Bestconverters. They recommended I wait to replace batteries until after the new converter is installed to make sure that was the problem.
Will let you know outcome after I install next week.
Thank you for all your suggestions!

[AtomicNo13]

Good plan, good start! It is always wise to throw money one bucket at a time...