Auto leveling - voltage drop

[Ranger431]

Wanted to see if this makes sense to anyone. I took my 2020 355MBQS in for some minor warranty work. One of the things on the list was sometimes when running off of just the batteries on the fifth wheel (no shore power and not connected to the truck) and I’m using the auto leveling system it will fault and the error code is something related to a voltage drop. He said everything checked out, and it had something to do with the residential fridge (even though it happens when the cooling is turned off). It has two batteries, but he said adding more wouldn’t help, because it doesn’t raise the voltage.

I won’t auto level with the truck under the nose of course, but I have pulled my truck next to the trailer and used the cord.

Thoughts?

[75462]

Originally Posted by Ranger431

Wanted to see if this makes sense to anyone. I took my 2020 355MBQS in for some minor warranty work. One of the things on the list was sometimes when running off of just the batteries on the fifth wheel (no shore power and not connected to the truck) and I’m using the auto leveling system it will fault and the error code is something related to a voltage drop. He said everything checked out, and it had something to do with the residential fridge (even though it happens when the cooling is turned off). It has two batteries, but he said adding more wouldn’t help, because it doesn’t raise the voltage.

I won’t auto level with the truck under the nose of course, but I have pulled my truck next to the trailer and used the cord.

Thoughts?

How good is the battery ground attached?
On my 2020, the main house battery ground was attached to painted metal with a #10 self tapping screw.

[Ranger431]

I’ll have to look when I pick it up. I didn’t see anything that looked lose. When it happens it usually in the second half of the sequence.

[Scottenj]

Originally Posted by Ranger431

Wanted to see if this makes sense to anyone. I took my 2020 355MBQS in for some minor warranty work. One of the things on the list was sometimes when running off of just the batteries on the fifth wheel (no shore power and not connected to the truck) and I’m using the auto leveling system it will fault and the error code is something related to a voltage drop. He said everything checked out, and it had something to do with the residential fridge (even though it happens when the cooling is turned off). It has two batteries, but he said adding more wouldn’t help, because it doesn’t raise the voltage.

I won’t auto level with the truck under the nose of course, but I have pulled my truck next to the trailer and used the cord.

Thoughts?

What do you have for batteries, you said you have two but what are they?

Adding another battery won’t raise the voltage with no load but it may reduce the voltage drop under load.

It should be easy to put a meter on the system and see what happens to the voltage during leveling. Maybe your batteries aren’t fully charged or don’t have enough Ah capacity.

[Radar57]

Do you have a residential fridge with an inverter? If they are on they could be a drain source on the battery (not sure what you meant by it happens with the cooling off). Check all you connections not only at the batteries but also at the jacks and the grounds. Is there a reason you do not hook to shore power? I will hook and unhook from the truck using the battery, if no shore 8s available, but I always use shore power to auto level. Unless you're boondocking I would recommend hooking to shore power.

[EBCTrekker]

There is always a voltage drop when a load is placed on a circuit. Definitely check the circuit grounds. You can never have too good a ground connection, especially when using batteries! That helps minimize the drop assuming the batteries are in good shape. I concur with the person above that suggests hooking up to shore power before opening everything up when possible.

[JimD]

Measure once, cut twice. Oops, wrong thought.

Voltage drop is caused by resistance in the line whether it is the wire size, poor connection, bad inline component, etc.

Hook up your voltmeter across the battery(s) and watch it while you operate the leveler. It will drop some but should still be able to hold in the 12s. If the voltage drops dramatically you probably have bad batteries possibly from draining them too far. Then measure as close as you can to the leveler. It will be lower there because of inherent resistance in the circuit.

The first areas to check in any event will be the grounds. Both grounds - the battery and the leveler. I personally would pull the ground and sand the surfaces of both the connector and the frame so they are bare metal. It is very easy to overlook the ground and instead focus on the 12 volt positive side.

When I get to a site I always fire up my generator before leveling and extending the slide. I do this so my batteries aren't immediately drawn down from the high current during setup. I then shut it off after everything is in place.

[Rayco]

I have had similar experiences - usually when picking up at the dealer. Especially if it's cold weather, the batteries just don't last that long if they aren't plugged in to shore power. The leveling system seems to draw a lot of current, I've even had it blow a fuse if the battery voltage is low. If not plugged in to shore power, I try to remember to hook up to the truck first. And I also discovered that if the battery voltage is too low, the 'smarts' in the truck prevent it from supplying current to charge the batteries in order to prevent possible damage to the truck electronics!!!

So, my plan is to bring the generator along with me in case the camper isn't on shore power when I pick it up.

[Ranger431]

Originally Posted by Radar57

Do you have a residential fridge with an inverter? If they are on they could be a drain source on the battery (not sure what you meant by it happens with the cooling off). Check all you connections not only at the batteries but also at the jacks and the grounds. Is there a reason you do not hook to shore power? I will hook and unhook from the truck using the battery, if no shore 8s available, but I always use shore power to auto level. Unless you're boondocking I would recommend hooking to shore power.

Yes, it has the inverter / residential fridge. You can turn the cooling on the fridge off, so it isn’t pulling inverter power when not in use.

I always use short power when available, but before I take a trip I bring it to the house for a couple of days to get ready. No real shore power, but I can plug it into a standard 110v using adapters, and this does the trick. I can work around the issue, but it seems like this shouldn’t be an issue.

Like another poster said, I’ve used my portable generator as well.

[Scottenj]

Originally Posted by Ranger431

Yes, it has the inverter / residential fridge. You can turn the cooling on the fridge off, so it isn’t pulling inverter power when not in use.

I always use short power when available, but before I take a trip I bring it to the house for a couple of days to get ready. No real shore power, but I can plug it into a standard 110v using adapters, and this does the trick. I can work around the issue, but it seems like this shouldn’t be an issue.

Like another poster said, I’ve used my portable generator as well.

I level on batteries all the time, never had a problem, I even run my fridge on my inverter when traveling and then level as soon as I get where I am going. I do have 300Ah of lithium batteries. I would fix the problem as opposed to relying on shore power or a generator, you should be able to level on batteries.

[Ranger431]

Originally Posted by Scottenj

I level on batteries all the time, never had a problem, I even run my fridge on my inverter when traveling and then level as soon as I get where I am going. I do have 300Ah of lithium batteries. I would fix the problem as opposed to relying on shore power or a generator, you should be able to level on batteries.

Thanks - do you mind sharing the details of your batteries? I’m wondering how much bigger I can go without it causing an issue?

[Scottenj]

Originally Posted by Ranger431

Thanks - do you mind sharing the details of your batteries? I’m wondering how much bigger I can go without it causing an issue?

I don't really understand your question, you can put in as many batteries as you can afford, fit into the space and handle the weight of, there is no electrical limit.

As I already mentioned, I have 3 - 100Ah (Amp-Hour) lithium batteries, I am considering adding a 4th.

When you build a battery bank with 12 volt batteries you just put them all in parallel, you still get 12 volts but add Ah capacity. The larger total Ah rating of your bank the longer it takes to draw down and typically the higher the peak current it can supply.

You said you have two batteries now, what are they?

[Scottenj]

Originally Posted by Ranger431

Yes, it has the inverter / residential fridge. You can turn the cooling on the fridge off, so it isn’t pulling inverter power when not in use.

I always use short power when available, but before I take a trip I bring it to the house for a couple of days to get ready. No real shore power, but I can plug it into a standard 110v using adapters, and this does the trick. I can work around the issue, but it seems like this shouldn’t be an issue.

Like another poster said, I’ve used my portable generator as well.

Another thing to be aware of, inverters draw power any time they are on even if there is no load on them, some inverters pull a lot of power even when idle. You said you can turn off the refrigerator cooling but you should really shut off the inverter.

[Ranger431]

Whatever was in them when I bought it. Unfortunately, it’s in storage and I don’t recall. I wasn’t sure if you upgraded into deep cycle batteries or something different. I’m not much of a battery guy....

[Scottenj]

Originally Posted by Ranger431

Whatever was in them when I bought it. Unfortunately, it’s in storage and I don’t recall. I wasn’t sure if you upgraded into deep cycle batteries or something different. I’m not much of a battery guy....

For an RV you should only put in deep cycle batteries, hopefully your dealer did that, if they put in starting batteries they won't last long.

My dealer was going to put in a single Interstate battery deep cycle battery with about 75Ah of capacity, I told them not to bother and I bought 2 - 125Ah AGM batteries and had them put them in. I boondock a lot and wanted more capacity.

I later upgraded to 3 - 100Ah lithium's.

With the 2 - 125Ah AGM batteries they weighed 150 pounds and only had 125Ah of usable power. Also with lead acid batteries (AGMs are a type of lead acid batteries) they charge at full speed up to 80% and then the charging speed slows down by about 5x.

The 3 - 100Ah lithium batteries weigh 90 pounds, can be discharged a lot further without damage giving a lot more usable power and charge at full speed until full. With lead acid batteries and solar you end up wasting a lot of power while trying to charge the last 20%. But to change over to lithium's you would have to replace your converter and they are around $800 each.

Lead acid should work and either you have a bad connection, not enough Ah or the wrong type of batteries.

[billcf7]

Originally Posted by Scottenj

What do you have for batteries, you said you have two but what are they?

Adding another battery won’t raise the voltage with no load but it may reduce the voltage drop under load.

It should be easy to put a meter on the system and see what happens to the voltage during leveling. Maybe your batteries aren’t fully charged or don’t have enough Ah capacity.

The voltage also doesnt drop with current draw on lithium like it does with lead acid, stays around 13.2v

[Scottenj]

Originally Posted by billcf7

The voltage also doesnt drop with current draw on lithium like it does with lead acid, stays around 13.2v

Agreed, but I never had a problem leveling on my two AGM batteries before I upgraded to lithium.

[poohbear]

Just went thru this low voltage problem. My Equalizer Hydraulic system didn't want to work the other day. I checked standing volts & ok but hit button leveler would start raising legs but stop quick with low volt fault light. Checked batteries unhooked for 30 min, gnd , etc. pulled them & went to Autozone for load test. Of course its bad batteries but it's what I figured as they were about 5 yrs old.

[Ranger431]

I hadn’t thought to have them checked since they’re only a year old, but you never know. Thanks.

[poohbear]

Originally Posted by Ranger431

I hadn’t thought to have them checked since they’re only a year old, but you never know. Thanks.

If they were the rv dealers install probably cheapest made battery on the planet