Battery Disconnect: Bad Design, Warranty Issue, or Just live with it?

[TankerIP]

A few weeks ago we returned home from a trip. Batteries were fully charged and I put the BattSw in "store". 15 days later I went out to check battery and it indicated only 9.7 volts. I plugged trailer in to shore power and discovered a number of suprises which could deplete the battery.

- The battery will charge even in "store" mode. In my previous Airstream the battery was completely taken offline in the "store" mode, but now it is still connected to some "bus" that could possibly cause a drain. Is this correct or a defect?

- I searched for other connections and found the electric jack and light on front are directly connected to battery in even in "store". is this correct or a defect?

- I noted that inverter can be powered even in the "store" mode. Is this correct?

- I have learned that the propane detector is directly connected and drains the battery constantly.

Are there any other items directly wired to battery bus that I should watch for that would drain battery?

I charged the battery for about 5 hours. By that time the converter fan had moved down from a fast speed to silent - I suppose it had moved down to the lowest charge rate. Meter indicated 13.4v on final charge. I disconnected shore power and monitored battery voltage. The next day it was 12.6 - 12.5 volts. On the 3rd day it was at 12.3. On the 4th day: 12.2. And so it appears my voltage drop is about .1v/day.

Is this drop a normal parasitic drain, or some warrantable defect? The trailer is only 7 months old to us. So not sure what I should be demanding from the Airstream company. How have other new owners handled this kind of issue?

[DKB_SATX]

Well, there are 2 things going on here.

1) Your chief complaint, that the Store/Use switch doesn't fully isolate the battery. That's well covered, properly described in documentation, and (IMHO) poorly designed. I put a physical disconnect on the main positive line to the 12V buss, and the other positive line that feeds the inverter. And with those disconnected, I can leave the trailer for months and not have a problem when I reconnect them.

2) You did not fully recharge the battery. If you pulled it down to under 10V, you needed something on the order of 20+ hours on shore power to fully recover the battery, and you describe a 5-ish hour charge cycle, just past the end of the "constant current" initial phase of charging, probably 1/3 or less of the time required for a full charging cycle for a flooded battery.

[nvestysly]

+1 to DKB_SATX's comments. To further elaborate, here's a picture of a battery disconnect switch. This type of switch (there are other switches with other form factors) will make and break the contact of the positive lead from the batteries. To install this switch takes a bit of re-routing of the positive wire, adding a new wire, etc. but it's relatively straightforward.

To further beat a dead horse, our 1992 Classic trailer has such a battery disconnect switch and we do not experience dead batteries when we put the unit in storage for months at a time. Our 2010 Interstate was wired from the factory much like your trailer and we did experience dead batteries. We installed a battery disconnect switch and no more battery problems for weeks and months at a time in storage. Prior to installing the battery disconnect switch the batteries would be dead in less than week.

Another very useful diagnosis tool to add to your trailer is a true battery monitor system. Don't rely on the LED's or some gimicky readout that indicates 25/50/75/100%. A true Battery Monitor System is what you want. There are a variety of them out there, most of them good, do some searching to find one that you like and has the features you want. One of the least expensive and easiest to install is the Expion360 sold by BestConverter.com - I'm sure there are better BMS systems but this one installed in our Interstate in less than 30 minutes with no extra cables needed. YMMV

[BayouBiker]

Although the previous posts mentioned these, I'll go back to your specific questions and elaborate on them.

1. Depending on the model of converter installed, most are full time connected to the battery bus by design. the late model Airstream wiring diagrams show the converters wired this way. Most, operating properly will have no parasitic affect on the battery. Some have "intelligent charge controllers" which continuously detect battery voltage connected to shore power or not and do have a very, very small parasitic load. As the other posters noted, many people don't care for this arrangement.

2. As noted the electric Jack and the inverter are both full time connected to the Batteries through separate leads. Neither have parasitic loads when operating properly and the light switch is off. Again the AS wiring diagrams show this is by design.

3. For safety and liability reasons, AS directly connects the LPG detector to the battery bus. It has a parasitic load of about 0.07 Amps

4. There are no other direct battery connections except the towing connector.

As DKB_SATX indicated, you did not fully recover full battery capacity so your short run of 5 days should be taken with a grain of salt.

However, it is also possible your parasitic load is high or your batteries are damaged because you should safely get about 25-30 days on parasitic load and leakage and still have about 40-50% DOD left (with two 80AH batteries, I presume you have two), whereas you got less than half of that and yours was completely discharged, similar to your 5 day experience. If I were to go out on a limb, I'd bet the batteries are weak and damaged.

It is possible and somewhat common for batteries to get damaged at dealerships if the trailer sits for more than 40 days because dealerships often fail to keep the batteries charged. Perhaps yours were damaged when you took delivery. Also the fact you found your batteries at 9.7 is not good, that in itself is very hard on them and may have caused some permanent damage.

[OTRA15]

Great feedback.

As part of your planning for improvements to the 12v electrical infrastructure, you should probably get fresh batteries IMO. This opens up a new can of worms [of course ] including possible dual 6v golf cart batteries, AGM, lithium, converter options, solar and so forth.



At a minimum, for the new camping season which is just over the horizon, replacement batteries would be advisable IMO.

Happy trails,

Peter

[Mollysdad]

Originally Posted by TankerIP

- I searched for other connections and found the electric jack and light on front are directly connected to battery in even in "store". is this correct or a defect?

In theory the jack doesn't draw power when idle, and the light is off.

- I have learned that the propane detector is directly connected and drains the battery constantly.

True. By law it's illegal to put a on/off switch in the path of the propane detector.

Are there any other items directly wired to battery bus that I should watch for that would drain battery?

Maybe. Things on my suspect list are: Radio memory, subwoofer standby, the converter itself, CO detector, the inverter. [/QUOTE]

IMO, the "use/store" switch is one of the most misunderstood things on the AS. Even to me. I'm not going to try to explain it, but it's not a battery disconnect.
I got tired of dealing with it while stored, so I made a real Battery Disconnect. You can go simple as a switch on a battery post, or all out, like I did.
Here's mine.
https://www.airforums.com/forums/blo...sconnect-3036/
Now, when I leave for a while, I simply switch the disconnect to "off". I wired the converter to "1" and the inverter to "2" so if I only use the converter, I just select 1.
I find it's better to switch the batteries off, then connect a small charger with a "float" mode directly to the battery terminals.

[OTRA15]

Originally Posted by Mollysdad

. . .
IMO, the "use/store" switch is one of the most misunderstood things on the AS.
. . .

. . . plus . . . on top of all the vagaries, there are many different switch makers and designs, even within the same year and model of Airstream . . . such that a comment here -- which may be accurate for the poster's trailer -- is misleading or wrong about the OP's situation.

[Atomic_13]

It’s likely you’ve already considered this but if you opt to install a disconnect switch for the batteries be certain the wire that supplies power to the trailer breakaway switch on the A frame remains “hot” even with the switch set to off. Otherwise you or the next owner of the trailer will need to remember to turn the battery switch on before towing. While unlikely, if the trailer would become unattached from the tow vehicle, no power would be applied to the trailer brakes from the house battery unless this wire is “hot”.

Regarding the LP/CO gas monitor, I have mine wired to be always on per code but struggle with it being capable of draining my 400Ah LiFePO4 battery bank below 20% if I were to leave the trailer unattended for six months.

[kscherzi]

I added solar panels to my camper. Mainly for off grid camping, but a side benefit is that they are always on and keep the batteries fully charged year round.

[Al and Missy]

Originally Posted by Atomic_13

It’s likely you’ve already considered this but if you opt to install a disconnect switch for the batteries be certain the wire that supplies power to the trailer breakaway switch on the A frame remains “hot” even with the switch set to off. Otherwise you or the next owner of the trailer will need to remember to turn the battery switch on before towing. While unlikely, if the trailer would become unattached from the tow vehicle, no power would be applied to the trailer brakes from the house battery unless this wire is “hot”.

Regarding the LP/CO gas monitor, I have mine wired to be always on per code but struggle with it being capable of draining my 400Ah LiFePO4 battery bank below 20% if I were to leave the trailer unattended for six months.

My trailer has the simple “kill switch” in line with the batteries, which are always connected to the converter. Everything that draws current is disconnected when that switch is off. Since the jack cannot be operated with the switch off and I can’t tow without using the Jack, I see no issue with the switch also killing the breakaway switch. This also applies to the propane detector as I will not occupy the trailer unless battery power is on.

Al

[jnm30327]

Battery kill switch is a must. The "store" switch is pretty useless for any storage over a week.

Re the propane detector: It is true that there is little reason to keep it powered when the trailer is being stored. But, it is also a good idea to close valves on the propane tank when trailer is stored.

[jeffmc306]

Originally Posted by TankerIP

A few weeks ago we returned home from a trip. Batteries were fully charged and I put the BattSw in "store". 15 days later I went out to check battery and it indicated only 9.7 volts. I plugged trailer in to shore power and discovered a number of suprises which could deplete the battery.
....
Is this drop a normal parasitic drain, or some warrantable defect? The trailer is only 7 months old to us. So not sure what I should be demanding from the Airstream company. How have other new owners handled this kind of issue?

TankerIP, get yourself a hydrometer from an auto parts store and check each battery cell. Specific gravity is the best indicator of battery charge and it will tell you if one or more cells are different from the rest. That can be the reason your batteries are not holding a charge.

We had both Interstate batteries replaced on our 2018 FC23FB after I found cells that would not charge after 12 hours.

You can install a disconnect switch but it won’t help if your batteries have issues.

Good luck!
Jeff

[Adventure.AS]

Originally Posted by jeffmc306

TankerIP, get yourself a hydrometer from an auto parts store and check each battery cell. Specific gravity is the best indicator of battery charge and it will tell you if one or more cells are different from the rest. That can be the reason your batteries are not holding a charge.

We had both Interstate batteries replaced on our 2018 FC23FB after I found cells that would not charge after 12 hours.

You can install a disconnect switch but it won’t help if your batteries have issues.

Good luck!
Jeff

Unfortunately a hydrometer doesn't work with AGM batteries.

[Al and Missy]

Originally Posted by jnm30327

Battery kill switch is a must. The "store" switch is pretty useless for any storage over a week.

Re the propane detector: It is true that there is little reason to keep it powered when the trailer is being stored. But, it is also a good idea to close valves on the propane tank when trailer is stored.

I do turn off the propane when the trailer is in storage. While it is unlikely that any gas will leak, if it does the amount will be limited to that which is in the lines.

Al

[hhendrix]

For long term storage I close the propane valves and disconnect the negative side of the battery connection.. It takes about one minute.

[drbrick]

I agree with all above - since we store our TT outdoors our 200w solar maintains charge no worries. We did discover the radio was never off in store so we put a "kill switch" on the radio. If we didn't have solar we would add a kill or disconnect the batteries when in storage.

[BayouBiker]

Just to be devil's advocate and so you can consider all sides, remember that lead acid batteries self discharge. After six or so months, they need a charge anyway. Instead of a kill switch or disconnecting them at the terminals, consider connecting a high quality charger that properly maintains the batteries when the camper is not in use. I realize some do both so there is that option as well. In general, batteries will have their longest useful life when discharged as little as practical and properly maintained fully charged but not overcharged. One disadvantage is flooded cell batteries will consume some water while on a charger and will consume a lot of water if overcharged.

[TankerIP]

Thanks to everyone for the replies. I immediately plugged the trailer in to shore power to start a long charging period. I will now look for a hydrometer. I want to be able know the condition of my 2 Interstate batteries before I call the dealer and start complaining about whatever.

After the batteries charge for a full day, then I can start my study again.

I'll also look for a battery disconnect system.

[PKI]

Battery disconnect - remove negative battery cables before storage.

You will learn more by reading the threads on batteries, power monitoring, AS electrical systems, solar, generators and power management. Consider establishing a power budget that will support your RVing life style. It makes a good starting point.

Hope to see you down the road with a smile. Pat

[jeffmc306]

Originally Posted by TankerIP

Thanks to everyone for the replies. I immediately plugged the trailer in to shore power to start a long charging period. I will now look for a hydrometer. I want to be able know the condition of my 2 Interstate batteries before I call the dealer and start complaining about whatever.

After the batteries charge for a full day, then I can start my study again.

I'll also look for a battery disconnect system.

TankerIP, you can directly to any Interstate dealer if you find low cells after charging. We had the first battery replaced by the dealer (they took it to Interstate).

For the second, I found an Interstate dealer 15 minutes from home. I was in and out in 10 minutes with a brand new battery - no paperwork! Great service.

Good luck!