12v battery low voltage disconnect

[dvrdwn]

What do you use to prevent your battery from discharging too low?

[GeorgeRa]

I use the Intellitec main power disconnect relay with remote switch in convenient location at the sliding door. The solar charge controller is still connected but I can turn it off with an easy access CB/switch if parked inside.

[michaelingp]

If you're looking for a manual disconnect then there are a number available. My old Roadtrek had one made by Intellitek. My new van doesn't have a disconnect, but it's easy to turn off all the devices that use power, except for the propane detector, for which you have to pull the fuse.

If you're looking for an automatic way to disconnect the battery when it was discharged too low, I think you may be disappointed. Even if you could get consensus of what "too low" means, it would be an expensive device to build since it would essentially have to determine how much energy you've pulled out of the battery since the last full charge.

[Roadtrek Adventuous RS1]

Originally Posted by dvrdwn

What do you use to prevent your battery from discharging too low?

Yes, that's correct, took our car across the USA this time... learned a lot in the process.

First, we saved about $800 in fuel and you know what....it paid for nearly all of our hotels.
Priceline....my friends....try it once and you'll be amazed at how much you will save.... just book the rooms from the car before arriving....

Second, while it hurts me to say this...the car is a LOT faster than driving the van and we could easily go further without feeling tired...and my wife will help...she doesn't like driving the RV and is not comfortable doing so... hence, makes me uncomfortable when she does.

Third, more agility....car can go anywhere and park in every place, plus it has heated seats which were very helpful in cold weather.

Fourth, we've taken the van on several trips and in 18 months have had three incidents of the dreaded "check engine light".... sometimes more than 150 miles or more from the nearest Mercedes Benz dealership....(not happy about this!)

Had the car for almost 5 years and it's a 2010 Subaru Outback... twice the mileage...and older than the van..... yeah, you guessed it....the check engine light has NEVER come on.
So, in my experience so far...yes, I have more confidence in my Subaru Outback than I do in the Roadtrek RS Adventurous as far as the vehicle drivetrain is.......two of the issues were the emissions system and the other was a glow plugs failure....

Thankfully, I have a brand new updated emissions system, compliments of Mercedes Benz and a brand new set of glow plugs.... other things with the house failed and needed brand new starting battery.....

SO.... I was a little concerned about leaving my RV in the driveway at home for almost two months....

Here's what my RV mechanic said to do.... push the disconnect switch for the batteries in the house, unplug the power cord, turn off the propane, switch off the refrigerator and prop open the door to the fridge....

Well, I return recently and voila, everything is fine.... vehicle starts, turned on the propane, reactivated the house batteries BEFORE plugging it in ( VERY IMPORTANT)... and fired up the generator for exercise.....

I guess it does help that I have a 160 watt ZAMP solar panels system on the roof...works whenever the sun shines.......

The ZAMP solar panels system was one of the best upgrades I ever made on my RV.

Good luck with your system...

[michaelingp]

Originally Posted by Roadtrek Adventuous RS1

First, we saved about $800 in fuel and you know what....it paid for nearly all of our hotels.
Priceline....my friends....try it once and you'll be amazed at how much you will save.... just book the rooms from the car before arriving....

That comes out to about $16 a night for a hotel room. Was this in the U.S.?

[@Michael]

Originally Posted by dvrdwn

What do you use to prevent your battery from discharging too low?

My Crossfit came with this:

http://precisioncircuitsinc.com/product/battery-guard/

It automatically cuts off the load side of the coach at either 12.2 volts, or 10.5 volts, depending on how its wired. Coachmen set it up at 12.2. I'd rather have a 12.0 volt cutoff.

It also has one of these:

http://precisioncircuitsinc.com/prod...ation-manager/

So apparently, either truck or house battery circuit can charge the other.

[Roadtrek Adventuous RS1]

Originally Posted by michaelingp

That comes out to about $16 a night for a hotel room. Was this in the U.S.?

It was in the USA... how did you figure $16 per night..
Just curious??

[booster]

Originally Posted by Roadtrek Adventuous RS1

It was in the USA... how did you figure $16 per night..
Just curious??

Take $800 and divide it by 49 nights.

[GeorgeRa]

Yes, flying could be even cheaper without a battery disconnect debate, for folks who went tangent see the OP’s first post!

[Roadtrek Adventuous RS1]

Originally Posted by booster

Take $800 and divide it by 49 nights.

OK... let me explain something that I failed to explain...my apologies...

.. YES...we were gone for 7 weeks..I get where you got the 49 days.... however, we have a second home in Michigan near the great lakes and we stayed there for over one month.....

SO... our trip to and from one house and the next is about 16 nights in the road ...

I said it paid for a significant portion of the hotels....not everything.... BUT, with the Priceline app on our smart phones we saved more money on this trip than others....

Plus, we went a LOT of places.... round trip from our primary residence to Michigan and back again was a total of 7,746 miles...at an average of 31 MPG....vs. 18 MPG... what's more is that diesel fuel was .75 cents per gallon higher than diesel all the way across the USA.... average price unleased outside of California...2.19 to 2.69...diesel fuel was $1 more in some areas... At least 65 cents per gallon more.

Diesel fuel consumption at 18 MPG..7, 746 miles... more than 430 gallons of fuel...
Gasoline engine consumption. 31 MPG 7,746 miles...250 gallons of fuel...

430 gallons @ 3.19 average per gallon = $1,372
250 gallons @ 2.50 average per gallon= $ 650

Difference of $722

Even if we had taken the van ..16 nights on the road would have added another $25 per night for hook-ups... for another $400

Our average hotel room cost was around $65 to $70..

If you take the cost for the fuel of the RV plus the cost for the hook-ups.. it's closer to $1800...

Ironically...it is $1,690 to $1,770 for the car's total cost even with hotels... almost a tie.

We carried a cooler in the car and only ate out once per day.. breakfast at the hotel was included and we had plenty of food, sandwiches and snacks for lunch...

For all the places we went ..there were places in cities that would have been challenging for the van...

Finally...and I'm sure a lot of you will not believe this .. but in terms of cargo carrying capacity....we can actually carry more in the car than we can in the van....the RS Adventurous is more about carrying people.. not cargo... Sure, there's a lot of cabinets but they are small.... aside from placing things in the aisle..and tripping over them...we could carry larger items in the cavernous large space behind the two front seats in the station wagon.....

[GeorgeRa]

Originally Posted by Roadtrek Adventuous RS1

OK... let me explain something that I failed to explain...my apologies...

.. YES...we were gone for 7 weeks..I get where you got the 49 days.... however, we have a second home in Michigan near the great lakes and we stayed there for over one month.....

SO... our trip to and from one house and the next is about 16 nights in the road ...

I said it paid for a significant portion of the hotels....not everything.... BUT, with the Priceline app on our smart phones we saved more money on this trip than others....

Plus, we went a LOT of places.... round trip from our primary residence to Michigan and back again was a total of 7,746 miles...at an average of 31 MPG....vs. 18 MPG... what's more is that diesel fuel was .75 cents per gallon higher than diesel all the way across the USA.... average price unleased outside of California...2.19 to 2.69...diesel fuel was $1 more in some areas... At least 65 cents per gallon more.

Diesel fuel consumption at 18 MPG..7, 746 miles... more than 430 gallons of fuel...
Gasoline engine consumption. 31 MPG 7,746 miles...250 gallons of fuel...

430 gallons @ 3.19 average per gallon = $1,372
250 gallons @ 2.50 average per gallon= $ 650

Difference of $722

Even if we had taken the van ..16 nights on the road would have added another $25 per night for hook-ups... for another $400

Our average hotel room cost was around $65 to $70..

If you take the cost for the fuel of the RV plus the cost for the hook-ups.. it's closer to $1800...

Ironically...it is $1,690 to $1,770 for the car's total cost even with hotels... almost a tie.

We carried a cooler in the car and only ate out once per day.. breakfast at the hotel was included and we had plenty of food, sandwiches and snacks for lunch...

For all the places we went ..there were places in cities that would have been challenging for the van...

Finally...and I'm sure a lot of you will not believe this .. but in terms of cargo carrying capacity....we can actually carry more in the car than we can in the van....the RS Adventurous is more about carrying people.. not cargo... Sure, there's a lot of cabinets but they are small.... aside from placing things in the aisle..and tripping over them...we could carry larger items in the cavernous large space behind the two front seats in the station wagon.....

Please help to connect your saga with battery disconnect relay, but if it is going to be too many words and ………………………………………… I would prefer to let it go.

[Roadtrek Adventuous RS1]

Originally Posted by GeorgeRa

Please help to connect your saga with battery disconnect relay, but if it is going to be too many words and ………………………………………… I would prefer to let it go.

George....this question required a substantive explanation...

As far as FLYING being less expensive.... that's incorrect.....

YES, we've done this many times... I know what I'm talking about.
I've done the math on this as well....

Sorry.... but, the cost of the airline tickets and rental car is over $1,800 before you even start your trip. Renting a car for over a month gets very expensive... Maybe a little savings on food....

Remember, you can't see anything from the airplane......At least we were able to visit and tour a lot of places.... something you know that is not possible just flying.

One more thing.. I have plenty of trips planned for the RV....I still love my rig... just this trip was better with the car....no drama...

I've had several trips and experienced "drama" with the RV... I think all the issues are behind me for now...a lot of deferred maintenance from the previous owner.... And, my learning curve..of course.....

A lot of people have told me that RV stands for "ruined vacation"... having had more than 3 or four incidents on a various trips....I can understand.

I just have to plan for electric hook up for anything over 3,000 feet, and not go anywhere below 35 degrees.... regardless of what many people say...the RV is NOT a four seasons thing....

Of course... diesel fuel is insanely expensive right now... And the maintenance for the diesel engine is kinda high.... we'll use it until we decide to sell it....

I wonder how many people really keep these vehicles for 15 to 20 years???

---Mark

[GeorgeRa]

Originally Posted by Roadtrek Adventuous RS1

George....this question required a substantive explanation...

As far as FLYING being less expensive.... that's incorrect.....

YES, we've done this many times... I know what I'm talking about.
I've done the math on this as well....

Sorry.... but, the cost of the airline tickets and rental car is over $1,800 before you even start your trip. Renting a car for over a month gets very expensive... Maybe a little savings on food....

Remember, you can't see anything from the airplane......At least we were able to visit and tour a lot of places.... something you know that is not possible just flying.

One more thing.. I have plenty of trips planned for the RV....I still love my rig... just this trip was better with the car....no drama...

I've had several trips and experienced "drama" with the RV... I think all the issues are behind me for now...a lot of deferred maintenance from the previous owner.... And, my learning curve..of course.....

A lot of people have told me that RV stands for "ruined vacation"... having had more than 3 or four incidents on a various trips....I can understand.

I just have to plan for electric hook up for anything over 3,000 feet, and not go anywhere below 35 degrees.... regardless of what many people say...the RV is NOT a four seasons thing....

Of course... diesel fuel is insanely expensive right now... And the maintenance for the diesel engine is kinda high.... we'll use it until we decide to sell it....

I wonder how many people really keep these vehicles for 15 to 20 years???

---Mark

I would suggest starting your own thread titled “My Bad RV saga” or even better write an RV epic book about your extensive Badexperience to make gazillions of monies.

Going back to this thread, what is your specific recommendation for battery disconnect?

George out for your saga, in for a battery disconnect system.

[Nic7320]

Most solar controllers have a switched DC output with a programmable low voltage disconnect. And once you have solar installed, it keeps your batteries charged during storage and the low voltage issue is rarely a problem.

(see, I stayed on topic!)

[Roadtrek Adventuous RS1]

Originally Posted by Nic7320

Most solar controllers have a switched DC output with a programmable low voltage disconnect. And once you have solar installed, it keeps your batteries charged during storage and the low voltage issue is rarely a problem.

(see, I stayed on topic!)

Nic, thanks for this....YES.... that's WHY I had my solar system permanently installed on the roof.... with a solar system controller and battery monitor......see picture.....

I can ONLY control what I do... when I purchased my RS Adventurous with only 26,000 miles and 5 years old in 2017... I thought how many things could go wrong....

Turned out...the batteries, propane sensor, dump hose, and generator were not in as good of shape as I expected...... batteries... both starting and house along with the propane sensor all get cycled out every five years...same for tires... SO....you really have to pay very close attention to these FIVE year cycles.

Sorry George...no plans for writing a book.... I'm sure everything that's been written about this is already out there....and I'm sure a lot of people have had experiences like mine..

I DID NOT purchase the RV for any financial reason.... only to have the experience....

One thing that's GREAT about having the RV...is for EMERGENCIES.... especially with fires and earthquakes......it's your personal emergency shuttle craft for leaving town on a moment's notice....

We keep clothes and supplies on board for this purpose..

In the event we had to evacuate our house... I would just grab my electronics, phone, laptop and tablet and take off for a safe location....

There's no substitute for the safety and security of being able to just get away whenever you want and the self contained RV is perfect for that..... even though it's small and I would never think of making this my full time rig.

[booster]

Originally Posted by Roadtrek Adventuous RS1

Nic, thanks for this....YES.... that's WHY I had my solar system permanently installed on the roof.... with a solar system controller and battery monitor......see picture.....

I can ONLY control what I do... when I purchased my RS Adventurous with only 26,000 miles and 5 years old in 2017... I thought how many things could go wrong....

Turned out...the batteries, propane sensor, dump hose, and generator were not in as good of shape as I expected...... batteries... both starting and house along with the propane sensor all get cycled out every five years...same for tires... SO....you really have to pay very close attention to these FIVE year cycles.

Sorry George...no plans for writing a book.... I'm sure everything that's been written about this is already out there....and I'm sure a lot of people have had experiences like mine..

I DID NOT purchase the RV for any financial reason.... only to have the experience....

One thing that's GREAT about having the RV...is for EMERGENCIES.... especially with fires and earthquakes......it's your personal emergency shuttle craft for leaving town on a moment's notice....

We keep clothes and supplies on board for this purpose..

In the event we had to evacuate our house... I would just grab my electronics, phone, laptop and tablet and take off for a safe location....

There's no substitute for the safety and security of being able to just get away whenever you want and the self contained RV is perfect for that..... even though it's small and I would never think of making this my full time rig.

So are you saying that the Zamp has a low voltage battery cutout and you run the coach loads off it all the time, or was this just another off topic jaunt to talk about whatever of yours?


On topic a bit, I seem to remember a thread a bit ago where someone was wired up through the load side of the solar controller and there were some issues with it that showed up. I don't recall how it was resolved or if they just moved the loads.


Low voltage cutouts based on normal discharge use are very rare, I think, for lead acid systems. Many have a low voltage cutout tied to an inverter, but it just shuts off the inverter.

[GeorgeRa]

My Morningstar MPPT 45 solar charge controller is wired upstream of the Intellitec battery disconnect. I wired it this way so with the low voltage system disconnected I can still charge the batteries with solar.

Morningstar charge controller has self-consumption at 1.3-2.7W, in long term this draw will drain batteries if the van is parked under a roof. Morningstar MPPT 45 will turn itself off but at fixed voltage of about ~7V, way too low. So, if I park under a roof, I disconnect charge controller as well with the 30A CB.

I don’t know if wiring a charge controller between batteries on disconnect relay is common, maybe not, I can see values with both ways:

battery <> solar <> main disconnect > loads
or battery <> main disconnect <> solar / loads.

[booster]

Originally Posted by GeorgeRa

My Morningstar MPPT 45 solar charge controller is wired upstream of the Intellitec battery disconnect. I wired it this way so with the low voltage system disconnected I can still charge the batteries with solar.

Morningstar charge controller has self-consumption at 1.3-2.7W, in long term this draw will drain batteries if the van is parked under a roof. Morningstar MPPT 45 will turn itself off but at fixed voltage of about ~7V, way too low. So, if I park under a roof, I disconnect charge controller as well with the 30A CB.

I don’t know if wiring a charge controller between batteries on disconnect relay is common, maybe not, I can see values with both ways:

battery <> solar <> main disconnect > loads
or battery <> main disconnect <> solar / loads.

It is usually recommended that solar controllers be wired directly to the batteries with no switch in between them. There were several lengthy discussions of it on the forum a few years ago.


Short story is that you never, ever, want solar panels connected to the controller without a battery in the system unless it is dark so no output from the panels. Without the battery to have the controller stabilized, the panels can over voltage the controller and whatever else may be connected to the output of it.



Some of the biggest risk, it appears would be if you had the controller off the battery and drove from the dark garage out into the bright sun, especially if you are wired in series.


Our solar is wired before any disconnect, as we have a manual all power one and the Intellitek after it for just the coach but leave the inverter charger powered plus the monitor. I do have an easy to pull fuse on the controller and also a switch on the panels so they can be shut off as a second check against error.

[GeorgeRa]

I followed the Morningstar manual with switchable CBs on both sides of the charge controller but didn’t use a double pole CBs for simultaneous disconnect as recommended. I disconnect them both in the same time, both are close to each other.

I wasn’t aware of potential issue of overvoltage on the charge controller, thank you, not likely an issue for me as panels are in parallel and the charge controller is up to 150V.

[booster]

Originally Posted by GeorgeRa

I followed the Morningstar manual with switchable CBs on both sides of the charge controller but didn’t use a double pole CBs for simultaneous disconnect as recommended. I disconnect them both in the same time, both are close to each other.

I wasn’t aware of potential issue of overvoltage on the charge controller, thank you, not likely an issue for me as panels are in parallel and the charge controller is up to 150V.

I am not certain the 150v rating would protect you, as it steps that down to run itself, I am sure, and without the voltage control the internals that should see 12v or so could see much higher even parallel, ours will run over 21v open circuit on the panels.