Battery Depletion Question

[Airhills]

Newbies here, trying to make sense of the battery usage in our '17 25fb fc. Took it on its maiden voyage for a couple days this weekend and the batteries seemed to deplete rather quickly.

Got home, plugged her in for 24 hours, unplugged from the house and the meter read 13.0. To test, we turned on the radio and the main lights, which caused the meter to immediately drop to 12.9. A few minutes later the meter showed 12.6. Left the trailer (radio and lights still on) for three hours and the meter was at 12.3, which I understand to be 70%.

Does this rate of depletion align to expectations?

I appreciate feedback and advice!

Chris

[DKB_SATX]

If I were a gambling man, I'd bet that you never really got to the point at which your batteries were at 100%. I'm going through the same thing right now with our new Flying Cloud... the voltage dropped faster than I expected given use, and having disconnected the batteries, topped off with distilled water and put them on a battery tender-reconditioner for a few days I'll be more likely to believe the results on our next trip. I'd lay even odds that one of mine is a bit ill, but it doesn't read like a dead cell, just lower than the other.

The 13v-to-12.6v drop is just from you drawing off what's called the "surface charge" from the batteries, 12.6 v or MAYBE 12.7v is where they'll sit on their own if they're healthy flooded lead-acid batteries with no load. After the drop to 12.3v, turn everything off and recheck in a few hours. Also, don't put TOO much stock in what the SeeLevel says, get a real multimeter and measure at the battery terminals as your source of truth.

If you don't want to fiddle with it personally but don't mind removing the batteries, take a photo of the cabling (for ease of reassembly), remove the batteries and haul them to your nearest Interstate dealer that can test them properly (call around and confirm that they'll do this.) Then you'll know if you're working with a phantom draw in the trailer or an issue with one or both batteries.

[Airhills]

Originally Posted by DKB_SATX

If I were a gambling man, I'd bet that you never really got to the point at which your batteries were at 100%. I'm going through the same thing right now with our new Flying Cloud... the voltage dropped faster than I expected given use, and having disconnected the batteries, topped off with distilled water and put them on a battery tender-reconditioner for a few days I'll be more likely to believe the results on our next trip. I'd lay even odds that one of mine is a bit ill, but it doesn't read like a dead cell, just lower than the other.

The 13v-to-12.6v drop is just from you drawing off what's called the "surface charge" from the batteries, 12.6 v or MAYBE 12.7v is where they'll sit on their own if they're healthy flooded lead-acid batteries with no load. After the drop to 12.3v, turn everything off and recheck in a few hours. Also, don't put TOO much stock in what the SeeLevel says, get a real multimeter and measure at the battery terminals as your source of truth.

If you don't want to fiddle with it personally but don't mind removing the batteries, take a photo of the cabling (for ease of reassembly), remove the batteries and haul them to your nearest Interstate dealer that can test them properly (call around and confirm that they'll do this.) Then you'll know if you're working with a phantom draw in the trailer or an issue with one or both batteries.

Thank you for the speedy response! I went to shut off radio/lights and now we're at 12.1 (little more than an hour later since the 12.3 reading). Turned off the radio/lights and now seeing 12.3. I will check back in a few hours.

Is there a multimeter you recommend?

Thanks again,
Chris

[DKB_SATX]

As I said, I like a Fluke. Mine has more bells and whistles, but this is a good basic one and as far as I know is as good as fancier ones.

Fluke 101 basic "pocket" multimeter

[DKB_SATX]

I apologize... I was just writing about my Fluke, but it was on another thread. Oops!

So, some differences between the Fluke I recommended and mine. My Fluke that cost about 4x that 15 yrs ago has a few more bells and whistles and was made in the US, and I can theoretically send it in for service (though I've never had to do so.) I think the leads that came with mine are a little nicer than the ones on the cheaper new ones, but a) you can buy fancier leads if you want, they're plug-and-play, and b) you probably don't need the fancier soft-touch leads anyway.

There are decent meters for $20 if you like. I'm weak for nice tools, though, and like to keep stuff forever. Basically you want a fairly-accurate auto-ranging meter that reads DC voltage and AC voltage and continuity. The basic meter I linked doesn't have the capability to read current, that'll cost you more and is a bit of a fiddly thing to do, but it's useful on occasion. Accurately reading DC current will likely require a bit of rewiring so it qualifies as nerdy stuff. AC current is easy to read with a clamp-on accessory if the meter has the option, but less of an issue with an Airstream. Maybe if you're troubleshooting the air conditioner...

[OTRA15]

Chris,

For a more deliberate pace of diagnosis, IMO it would make sense to keep things simple at first, and plug in your trailer's shore power for 2-3 days, in order to charge the batteries fully. First, make sure the cells are all full with distilled water [using safety goggles and gloves] per your owner's manual. [A 24-hour charge after a trip is not enough.]

Then unplug from shore power, wait an hour, and see what the battery voltage is on your monitor panel. All of your 12-volt functions should be off: furnace, lights, radio etc.. [Reading the voltage without waiting an hour gives an inaccurate reading.]

Put the Use/Store switch on Store, wait 24 hours, put the switch on Use, and report on the battery voltage again. Go back to Store.

Repeat the above for another day and check the voltage.

From the above simple steps, further steps can be recommended. Your batteries may have "lot rot" from improper care at the dealer, but this will become apparent soon if so.

Yes, if you have the time and inclination to take the batteries to the store for testing that will be quicker.

Good luck!

Peter

PS -- One of many RV battery primers for background FYI:

http://www.batteriesnorthwest.com/batteryschool.cfm

[Airhills]

Thanks for all of the great info... ordered a multimeter and have the batteries charging.... looks like patience is a virtue. In the meantime I will be going to Battery School!

I hope to report back with good info in a few days.

Chris

[DKB_SATX]

I need to add to what I wrote earlier... I've found a relatively affordable meter that, under the right conditions, does a good job of measuring DC current with a clamp. I knew there were some Flukes that do so, but a) I already have 2 Flukes, and b) the Flukes that have this feature don't seem to be the more-affordable ones. I decided to try out a lesser meter that claims this functionality and I have to say the results were pretty good.

I bought a Southwire 21050T True RMS Clamp Meter from Lowe's for $85 from Lowe's. It seems that most of the clamp meters in the half-that-or-less price range only measure AC current. It's actually got some nice features... in addition to the amp-clamp, it has a temperature sensor that can be useful in certain situations, contactless voltage detection and normal voltage and resistance measurement. It comes with a nylon carrying bag to keep all the parts together and clean, and now it lives in the front locker of our Flying Cloud.

It is *NOT* the best multimeter from an ergonomic point of view. I never find myself having to "fiddle" much with a Fluke to get it into the mode I want, but the Southwire is less well thought-out, or perhaps designed by someone who thinks differently than I do. One often needs to adjust 3 different controls to get it set to do what you want, but once set it does the job and now I have a way to measure DC current that'll do nicely until I rewire things for a Tri-Metric someday.

[ITSNO60]

Originally Posted by Airhills

In the meantime I will be going to Battery School!

Chris

You mean Battery "U" right? This is a great place to learn, probably more info than the average Joe needs.



http://batteryuniversity.com/

[Spinonedad]

Make sure all your lights are turned off
I left the awning lights on the first three days I went out

Also ,unplug your sub woofer when not using,,,it draws current just setting

[dmbecke]

I'll bet those batteries sat around a while prior to your ownership and thus are in great need of tending
As mentioned, check cell levels and using a good charger let them go 2-3 days and recheck
I'll bet you will be fine after that

[Airhills]

Originally Posted by DKB_SATX

I need to add to what I wrote earlier... I've found a relatively affordable meter that, under the right conditions, does a good job of measuring DC current with a clamp. I knew there were some Flukes that do so, but a) I already have 2 Flukes, and b) the Flukes that have this feature don't seem to be the more-affordable ones. I decided to try out a lesser meter that claims this functionality and I have to say the results were pretty good.

I bought a Southwire 21050T True RMS Clamp Meter from Lowe's for $85 from Lowe's. It seems that most of the clamp meters in the half-that-or-less price range only measure AC current. It's actually got some nice features... in addition to the amp-clamp, it has a temperature sensor that can be useful in certain situations, contactless voltage detection and normal voltage and resistance measurement. It comes with a nylon carrying bag to keep all the parts together and clean, and now it lives in the front locker of our Flying Cloud.

It is *NOT* the best multimeter from an ergonomic point of view. I never find myself having to "fiddle" much with a Fluke to get it into the mode I want, but the Southwire is less well thought-out, or perhaps designed by someone who thinks differently than I do. One often needs to adjust 3 different controls to get it set to do what you want, but once set it does the job and now I have a way to measure DC current that'll do nicely until I rewire things for a Tri-Metric someday.

Thank you for the info on the multimeter and following up! Our trailer is in with service for due bill and warranty work. I requested they check out batteries of which they claim they would send to interstate (takes a week). I'm very curious to see the results.

[OTRA15]

Originally Posted by Airhills

Thank you for the info on the multimeter and following up! Our trailer is in with service for due bill and warranty work. I requested they check out batteries of which they claim they would send to interstate (takes a week). I'm very curious to see the results.

Thanks for the update. Looking forward to hearing what the dealer says.

[OTRA15]

Originally Posted by Airhills

Thank you for the info on the multimeter and following up! Our trailer is in with service for due bill and warranty work. I requested they check out batteries of which they claim they would send to interstate (takes a week). I'm very curious to see the results.

Wondering what the dealer said about the batteries?

Thanks,

Peter

[Airhills]

They still have the trailer, but when I asked the question when I spoke to them on the phone and they had zero information. Told me they are just replacing them with brand new batteries. The pessimism in me immediately came out... How would I know if they actually replaced them?

I guess I’ll know when I get it home and if the batteries are working as expected, then all is good. :-|

[jcanavera]

One of the things to realize is the amount of power that is being drawn from the batteries when you aren't using the trailer. I borrowed a test meter to measure the draw from the batteries when the disconnect switch was in the store or off position and when it was in the use or on position with all appliances turned off. It was enlightening to say the least and gave me some inside as to what my battery conditions are when the trailer is in storage. I'd also note that this is from a 2004 Classic and most likely your results might be different dependent upon your model trailer.

I measured the amp hour draw on my batteries when the battery switch was set to on or the use position. All appliances and lights were turned off. The draw was .1 amp. I flipped the switch to disconnect and the draw was .01 amp. After talking to the dealer about this I found out that the draw when in the on position was from the propane detector, the electronics in the refrigerator (even though it was turned off), and the electronics in the water heater. The draw with the switch in the off position is from the propane detector which is not wired through the switch.

So I sat down and found the amp hour ratings for my batteries when fully charged. Once doing the math with a .1 amp draw per hour, I pretty much figured out why the batteries were almost dead after allowing the trailer to sit several weeks with the disconnect switch in the on position. At .01 amp draw you can also make the same calculation as to how long the batteries will last with the switch in the off position. So understand that the batteries will continue to discharge on some trailers even if that switch is off and you may need some auxiliary charging if the trailer is going to sit for a while, or you need to disconnect the batteries.

Jack

[OTRA15]

Originally Posted by Airhills

They still have the trailer, but when I asked the question when I spoke to them on the phone and they had zero information. Told me they are just replacing them with brand new batteries. The pessimism in me immediately came out... How would I know if they actually replaced them?

I guess I’ll know when I get it home and if the batteries are working as expected, then all is good. :-|

New batteries should have a manufacturer's date sticker on them, which should indicate the install date. Also make sure your dealer receipt has the battery replacement listed, even if there is no charge. Also, the batteries should look shiny and new!

Thanks for the update.

Peter

[jcanavera]

Originally Posted by Airhills

They still have the trailer, but when I asked the question when I spoke to them on the phone and they had zero information. Told me they are just replacing them with brand new batteries. The pessimism in me immediately came out... How would I know if they actually replaced them?

I guess I’ll know when I get it home and if the batteries are working as expected, then all is good. :-|

You might see a manufactured date on the batteries. Typically the OEM batteries have a manufactured date that is prior to the manufactured date of the trailer. If the batteries are dated after the date of the trailer manufacture then you know you had a replacement. Obviously that isn't absolutely the bottom line since you don't know how long the dealer has had the batteries he is using to replace yours, nor how long his supplier has had them on their shelves. In a crunch I've even see a dealer pull batteries out of another unsold trailer sitting on the lot to get a customer out in a timely manner.

Jack