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jtwind · 03-24-2015, 03:31 PM

Hi, I assume this has been answered before but can't find it. I have a 2014 Bambi 16 and have a few questions, first how does the battery disconnect switch fit into the system and when should it be off and on. I read somewhere that you should just flip the switch back and forth when hooking to shore power, anything to that. Also if the tow vehicle charges the battery, my bambi battery was dead after towing north from Florida so that doesn't make much sense. The disconnect switch was off so doesn't seem like it should have discharged. Just call me confused about this switch. Jeff T Madison WI

HowieE · 03-24-2015, 04:09 PM

I for one have never seen any reason for the switch to even be there. The best I can figure is it is a hold over from when the old non regulated charging system were used. In that case if you were plugged into shore power for a prolonged period without much use of electricity you would boil the batteries if the switch was not turned off.

Never used it and can't think of a reason to.

idroba · 03-24-2015, 04:15 PM

From the 2013 Airstream FC 20' manual:

When the switch is turned to USe (on) and the trailer is plugged into a 110-volt shoreline, the 12-volt distribution panel will receive power from the converter and the batteries will be charged through the converter charging system.
When the switch is turned to STORe (off) and the trailer is plugged into a 110-volt shoreline, the 12- volt distribution panel will still receive power from the converter, but the batteries are disconnected from the system. The batteries will not be drained with the switch in the store position. The converter will not charge the batteries with the switch in this position.
The charge in the 12-volt batteries is replenished, when towing, from the tow vehicle alternator through the 7-way cord. This charge will flow to the batteries regardless of the battery disconnect switch position. likewise, if on or off, the solar panel is still charging the batteries.

jtwind · 03-24-2015, 04:50 PM

I got that info and it really doesn't tell me much. Like why after towing for 20 hours is the trailer battery dead? That switch was off so the trailer didn't drain the battery, nothing wrong with the TV and it's battery, a bad new battery? I also assuming that whatever is charging the batteries when the switch is on and you are plugged into shore power isn't a battery charger. As a battery charger wouldn't overcharge and wreck batteries.

AWCHIEF · 03-24-2015, 05:06 PM

If the Airstream manual offered a clear explanation of the switch people would stop asking questions about it. At my house the trailer stays plugged in to AC power. I just leave the switch in "use". I asked at the factory when I was there and was to told leave it in the "use" position when not in deep storage.

Al and Missy · 03-24-2015, 05:13 PM

What are you towing with? Did it work before? With my F-150 I had to buy and install a relay to get the charging pin to have any power. I'm told that it came from the factory with a plastic bag containing the relay and a trailer brake adapter cable, but I bought it used and none of that stuff was on there.

Look in your TV manual and find what fuse feeds the trailer charging circuit. Look for a relay with the same function and then check your fuse panel to see if it is installed.

Also, TVs differ as to when the function is enabled. On my F-150 the relay cuts the charging power when the engine is not running. On my Ram 2500, it is energized all the time. With a TV like my RAM, one must be careful not to leave the trailer connected for several days when shore power is not available less the trailer discharge both the trailer and TV batteries.

Re: the store/use switch - the philosophy and wiring must have changed over the years. Mine disconnects the fuse panel from both the batteries and the converter but leaves the converter connected to the batteries. It also leaves the propane detector powered up all the time. After several months, the propane detector will discharge the batteries. It was wired this way and the schematic in my manual confirms this. Leaving my trailer connected to shore power for a long time with the original converter was not good for the batteries. I changed my converter, and re-wired the switch so putting it in store mode disconnects both the fuse panel and the propane detector so there is no drain on the batteries. Now instead of having to disconnect my batteries I just throw the switch when the trailer is in storage.

Al

HowieE · 03-24-2015, 05:14 PM

First off why was the switch OFF while towing?

It is time to get out the volt meter. With the switch on plug the trailer into shore power over night. Record the voltage on the battery while plugged in. Unplug and record the voltage. Now hook up the TV and while the engine is running at about 1500rpm record the voltage on the battery.

After an over night charge with the convertor you should almost have a fully charged battery. The voltage just after pulling the shore power should drop a little but when you start the TV the voltage should go up. This will test the convertor and the TV charging system. Now leave the trailer over night and test the battery voltage again. If it has dropped below 10 volts you have a bad battery or a heavy drain in the trailer.

Are you sure the emergency brake away switch fir the trailer brakes is in place? That will kill your battery in short order.

Len n Jeanne · 03-24-2015, 05:24 PM

jtwind, I'm not sure I get your drift, other than to say we do a lot of boondocking so having a fully charged battery that can keep us camping for several nights is just huge.

1. We have heard conflicting opinions as to whether the main battery switch should be "on" or "store" while driving, but the consensus seems to be "on." Since some of these people are Airstream mechanics, I'd go with that. However, when we are camping we often turn the main switch to store, just to nurse the batteries that much further.

We have also had all of the following problems at various times that prevent the batteries from holding a charge.

2. Bad/dud batteries. They should always be kept at a reading of "12" or above, according to our AS dealer. Letting a battery drop too low shortens its life. We take them out in winter, or whenever we want to charge them with a battery recharger. Sometimes they just have to be replaced.

3. Wiring problems.

4. Low levels of distilled water in the battery. We couldn't figure out why the generator wasn't recharging our batteries after a week in Death Valley. Turned out that 95-degree heat had evaporated the distilled water. Easily refilled.

jtwind · 03-24-2015, 05:28 PM

Quote:

Originally Posted by HowieE

First off why was the switch OFF while towing?

It is time to get out the volt meter. With the switch on plug the trailer into shore power over night. Record the voltage on the battery while plugged in. Unplug and record the voltage. Now hook up the TV and while the engine is running at about 1500rpm record the voltage on the battery.

After an over night charge with the convertor you should almost have a fully charged battery. The voltage just after pulling the shore power should drop a little but when you start the TV the voltage should go up. This will test the convertor and the TV charging system. Now leave the trailer over night and test the battery voltage again. If it has dropped below 10 volts you have a bad battery or a heavy drain in the trailer.

Are you sure the emergency brake away switch fir the trailer brakes is in place? That will kill your battery in short order.

Thanks, I'll do some testing in the morning. The switch was off when towing simply because I never really used the batteries on this trip so never had the switch on. And was never told it should be on when towing.

jtwind · 03-24-2015, 05:33 PM

Quote:

Originally Posted by Al and Missy

What are you towing with? Did it work before? With my F-150 I had to buy and install a relay to get the charging pin to have any power. I'm told that it came from the factory with a plastic bag containing the relay and a trailer brake adapter cable, but I bought it used and none of that stuff was on there.

Look in your TV manual and find what fuse feeds the trailer charging circuit. Look for a relay with the same function and then check your fuse panel to see if it is installed.

Also, TVs differ as to when the function is enabled. On my F-150 the relay cuts the charging power when the engine is not running. On my Ram 2500, it is energized all the time. With a TV like my RAM, one must be careful not to leave the trailer connected for several days when shore power is not available less the trailer discharge both the trailer and TV batteries.

Re: the store/use switch - the philosophy and wiring must have changed over the years. Mine disconnects the fuse panel from both the batteries and the converter but leaves the converter connected to the batteries. It also leaves the propane detector powered up all the time. After several months, the propane detector will discharge the batteries. It was wired this way and the schematic in my manual confirms this. Leaving my trailer connected to shore power for a long time with the original converter was not good for the batteries. I changed my converter, and re-wired the switch so putting it in store mode disconnects both the fuse panel and the propane detector so there is no drain on the batteries. Now instead of having to disconnect my batteries I just throw the switch when the trailer is in storage.

Al

I guess I don't know if it worked before, it's new and this was the first trip. I am towing with a Nissan Frontier crewcab, the trailer plug 12 volt pin is hot all the time.

jtwind · 03-24-2015, 05:38 PM

Quote:

Originally Posted by Len n Jeanne

jtwind, I'm not sure I get your drift, other than to say we do a lot of boondocking so having a fully charged battery that can keep us camping for several nights is just huge.

1. We have heard conflicting opinions as to whether the main battery switch should be "on" or "store" while driving, but the consensus seems to be "on." Since some of these people are Airstream mechanics, I'd go with that. However, when we are camping we often turn the main switch to store, just to nurse the batteries that much further.

We have also had all of the following problems at various times that prevent the batteries from holding a charge.

2. Bad/dud batteries. They should always be kept at a reading of "12" or above, according to our AS dealer. Letting a battery drop too low shortens its life. We take them out in winter, or whenever we want to charge them with a battery recharger. Sometimes they just have to be replaced.

3. Wiring problems.

4. Low levels of distilled water in the battery. We couldn't figure out why the generator wasn't recharging our batteries after a week in Death Valley. Turned out that 95-degree heat had evaporated the distilled water. Easily refilled.

Thanks, I was just surprised that a brand new battery was drained, it was removed after I bought the trailer last fall and kept on a trickle charger. Reinstalled 3 weeks ago and I was gone for 3 weeks, Frankly the battery was never used and the switch was in the off position almost all the time. I and maybe wrongly assumed that you turned the switch on when you needed to use the battery. I figured that the fact the the trailer was moved and towed for 2-6 hours every 3-4 days would have kept the battery charged. Not to mention the drive home. I'll figure it out eventually and it all has to go to the dealer soon for multiple warranty stuff.

Landrum · 03-24-2015, 07:28 PM

The batteries could have been badly damaged when you bought the AS. I think most/some dealerships don't take care of the AS batteries and let them discharge on the lot which drastically shortens their life.

You may already know this, but I ruined a set of batteries before I figured it out. If you are plugged into shore power the battery monitor in the AS will show the batteries as full even if the batteries are only partially charged. I keep my AS plugged in at home. I didn't want to cook the batteries so I used the store mood. I thought my batteries were ok because I kept checking the monitor. They looked perfect (100% charged) until I would get to a campground and notice they were far less the 100%.

Sent from my iPhone using Airstream Forums

richinny · 03-24-2015, 07:51 PM

the use/store relay will not work if the battery voltage drops too low.

the LP gas detector is always drawing power even when in store mode and it has been often reported that this will drain the battery in a week or two.

chect to see if any compartment lights or jack light (if u have one) has been left on.

fth · 03-25-2015, 10:35 AM

And that adds just a little bit more security from being stolen as it would take the thief longer to do it manually.

switz · 03-25-2015, 10:47 AM

The thief would have to have the manual jack wrench which should be stored in the tow vehicle to make it harder to find.

In the for what it is worth column, a cheap bottle jack can raise the Airstream tongue enough to fit onto a high hitch ball on the thief's tow vehicle. Once down the road, a quick torch work job can cut the jack shorter.

Perhaps having the WBCCI numbers on both ends of the trailer would make the thief realize that they are unique and easily seen by anyone on the road including police.....

jtwind · 03-25-2015, 11:05 AM

Quote:

Originally Posted by HowieE

First off why was the switch OFF while towing?

It is time to get out the volt meter. With the switch on plug the trailer into shore power over night. Record the voltage on the battery while plugged in. Unplug and record the voltage. Now hook up the TV and while the engine is running at about 1500rpm record the voltage on the battery.

After an over night charge with the convertor you should almost have a fully charged battery. The voltage just after pulling the shore power should drop a little but when you start the TV the voltage should go up. This will test the convertor and the TV charging system. Now leave the trailer over night and test the battery voltage again. If it has dropped below 10 volts you have a bad battery or a heavy drain in the trailer.

Are you sure the emergency brake away switch fir the trailer brakes is in place? That will kill your battery in short order.

Howie, this is what I had after a nights charging
13.28 volts with trailer still plugged in
11.62 volts after unplugging
12.53 volts plugged into TV and running at 1500rpm
I'll see what the voltage is after sitting overnight, I already sort of suspect it isn't the greatest battery. Thanks again.

FishinHatteras · 03-25-2015, 11:54 AM

JT,
I wouldn't waste another minute of time on that battery. With those results, your TV & TT are indeed charging the battery. Betya ten bucks you have several cells that are dead. If the battery is under warranty, take it back for a replacement.
You don't want to be out in the boonies with a battery that has a pulse like that. It's toast, and won't make toast either in this case!

Gavin

jtwind · 03-25-2015, 12:41 PM

Quote:

Originally Posted by FishinHatteras

JT,
I wouldn't waste another minute of time on that battery. With those results, your TV & TT are indeed charging the battery. Betya ten bucks you have several cells that are dead. If the battery is under warranty, take it back for a replacement.
You don't want to be out in the boonies with a battery that has a pulse like that. It's toast, and won't make toast either in this case!

Gavin

I figured, it's new or still under warrenty. I got the trailer new last Oct. put the battery inside with a trickle charger and "assumed" all was well when I put it back 3 weeks ago but obviously it was probably bad from the dealer. I've never really used it. Thanks for the help

Howard Lefkowitz · 03-25-2015, 02:42 PM

The reason the Airstream mechanics told you to keep the switch on is because it powers a relay that operates to disconnect the batteries from the 50 amp breaker that feeds the main trailer DC supply system. All of the DC breakers are supplied from this line. It is described on page 5-8 of the manual. The purpose of the switch is to disconnect your batteries from the system when in storage. There are lots of electric circuits (called phantom loads) that constantly draw power without you having to switch anything on. This includes radios, propane detectors, fire detectors, 12 volt TV, etc. Leave it on unless you are going to store the trailer.

Charging the batteries from the Tow Vehicle does not always work. You should obviously have the wires checked as well as the 30 amp circuit breaker in the charge line. Assuming this is all OK then your problem could be that you cannot get enough current through the cable wires to bring a highly discharged battery back to life. If your Tow Vehicle batteries are well charged than your alternator will be putting out just over 13 volts. If your Trailer battery just needs to be brought up to full charge this will work fine. If your batteries are really discharged then you will need over 14 volts to bring them back to life. You also get a significant voltage loss in all of the wiring from the Tow Vehicle through the cable harness.

If you are boondocking and cannot use the 110 VAC powered Converter to charge the batteries you could remove the trailer batteries and hook then directly to the TV batteries with jumper cables. Run the TV and put some charge on them. The key is try to not to let your batteries get into a deep cycle discharge. If all else fails remove the batteries and take them to a local garage to have them recharged.

Howard Lefkowitz · 03-25-2015, 02:49 PM

I just saw page two. There is nothing wrong with your battery. A deep cycle discharge level is 12 volts. There is no way your TV can provide enough voltage and current to bring the battery back. A trickle charge will not do anything when the battery is in a deep cycle. You need a charger that can provide over 14 volts at a minimum of 10 amps to charge the battery. Your Trailer Converter should bring the battery up to full charge in about 6 - 8 hours.