Help for a Newbe

[MWARREN]

I bought a Itasca Impulse 31J about 4 months ago. I am trying to understand the electrical and charging of the house batteries and the engine battery.

I keep the unit plugged in to a 30A plug 24/7

Back in August the unit had sit at home for 3 weeks without use, when I went to crank it, the battery was not strong enough to crank it. I used the battery boost and it cranked. I have not had an issue since. Just wondering why it would go dead that quick and been great ever since.

Yesterday I went into the unit and attempted to crank the generator and it acted as though a battery was dead. I crank the motorhome itself and tried the generator again and it cranked fine.

It does have the house battery disconnect switch as you enter the door. What is the point of that and when should that be used?

Just want some knowledge and advice from those who are experienced with this.

[Morich]

Looks like you almost got lost in the rush of things.
Your issue is a semi-common complaint and has some logic to it once we get a bit of experience. Some difference in different RV but this sounds common.
Let me start and maybe act like you know nothing and you ignore things you already knew?? Not meant to insult, just want to be more complete.

Motorhomes have three electrical systems that are only loosely connected. There is the 110 AC from shore power or gen, The coach portion and it works off the coach batteries, then the chassis which works off the start/chassis battery and that is often the parts like a car might have. Where things get confused is that these systems are separated at times and connected other times.
Car starting is pretty much the same on RV EXCEPT that there is often a battery mode solenoid. We have a switch called boost or Aux and we can push it to connect the start and coach batteries together kind of like a temporary jump start. But when we start the engine, that mode solenoid also jumps up to connect them together so that we can get some charge from the engine alternator put into the coach batteries as we move to the next campsite!
BUT that connection is only temporary and drops off when we are not running the engine.
When we are on shore power or generator, there is often a converter which charges the coach batteries, but not the start battery unless we make sure. There are some RV which come with equipment to do both but many do not unless we add something. A very common one is the Trik-L-Start which runs about $50-60 and is easy to install. It connects the two battery strings together so that when the start battery gets down to a certain level like 12.3?? the electronics "borrow" a little from the coach batteries and that keeps both charged while plugged in.
The coach battery disconnect cuts off most but not all the coach stuff like lights, pumps, etc. but the dirty secret is that it still leaves a few things like CO detector, propane alarm, and such still doing a little drain on the coach battery.
On the start battery, there are still things that are draining that battery also. Some are the radio preset, ignition, any auto stuff like door locks, etc. and they will run that battery down over time. How long varies with different RV.
Sounds like you've done it while not using the RV!
So some tricks to learn?
Do open the coach disconnect when not going to be using the RV for a while but it can't fully protect the battery unless you add some form of charging OR actually remove or disconnect one battery cable on the coach batteries.
The same goes for the start battery only there are fewer that have a switch to do the disconnect.
But be aware that letting a battery go flat is hard on them and doing it very often or for very long is going to shorten the life a whole bunch!
Always best when starting the generator or moving slideouts or jacks to have the engine running to make sure to get the best voltage from the alternator! Normal float voltage for the best battery will be around 15. 6, while the alternator will be putting out closer to 14!

[MWARREN]

I don't know very much! I have only owned a travel trailer up to this point. I appreciate your time and answer. I have been cranking the unit weekly and allowing it to run for about 20 minutes or so. When not using the unit should I keep it plugged in to the 30 amp plug or not? What is the best way to manage batteries and electrical when I am home and its not in use?

[Morich]

That's a bit of differing opinion, so this is my way.
I worked on large batteries for a major phone company and base a lot of what I do on that experience, even though I change it a bit as one small battery that costs a hundred dollars gets different treatment than a string of 24 cells that cost hundreds of thousands!
How much time you spend on watching and cleaning and topping off the water changes the answer of how long they last and and how we treat them. I do far less than when working on them.
The far best is to have equipment that keeps all the cells at the ideal voltage of 13.5 volts. But that is where we are often not as well setup as ideal, so we have to learn what our charging does and do the amount of work we feel right for the way we use the batteries and do the rest of our life on where we want to spend time and money.
This is a really good read on lots of small points on batteries, if you want a really indepth look for background:
https://batteryuniversity.com/learn/...C%20(85%C2%B0F).
The idea is to get enough charge put in to keep them from going down but it comes with letting them get too warm and evaporate off too much water if our charge system is not really good and then most of us also have weather changes that affect the temperature, so I back off from ideal as it's never going to happen here!
Watching the voltage while looking at the water is the way I go.
When stored here at the house, I go out about every 2-3 months, pull the lids and top off each cell just to the point where there is a ring down in each cell as that makes a "dimple" in the water surface when it reaches that point.
Since I have power and the converter on the RV does a pretty good but not ideal job, I go with using that and try not to let the water ever begin getting too hot so that I find spray around the vents. When it really gets hot here, I back off a bit on the time spent charging.
to avoid driving myself too hard, I keep the RV plugged in but have two simple timers, one plugged into the other, so that I can set them to do a charge about one a week! On my RV, full time charging gets too hot but that may be because I live pretty close to the Devil himself during the summer!
If you don't fry eggs on the sidewalk every summer, you can back off a bit!
Basic idea is to keep them as close to 13.5 for maximum power capacity while also not using so much water it boils dry or drives you crazy watching them.
Going totally flat is bad, out of water is a killer and too much work is not good, so find a middle ground to enjoy!

[MWARREN]

How do you feel about a 1 amp trickle charger with automatic shut off?

[Morich]

Originally Posted by MWARREN

How do you feel about a 1 amp trickle charger with automatic shut off?

I think it certainly worth a try if on hand but bears some watching until you get an idea of how good it may be. The question can be, at what point it shuts off and if it is going high enough to boil off too much water, etc.
I used one for quite a while but then it takes a bit of knowing if you are only charging one or both strings of battery. Newer electronics for charging are better at doing the first part higher to speed the process and then moving to lower voltage to finish off and hold or "float". Once I found only the coach batteries were charged by the converter and we knew we were not moving the RV for a long time, I went with the lesser work option.
I had the question of adding a second charger to do both strings or adding the the trik-l-start and only use the onboard converter, so it seemed right for me to add and not deal with two chargers.
Kind of how spoiled we want to get and what we have on hand!

[MWARREN]

I think for now it might be best to crank once a week when not in use and at least run it long enough to charge the batteries and burn the moisture out of the exhaust system. Thank so much for your knowledge!

[Morich]

Always good to wait a bit and get a better feel for what we each need to do---as long as we can stay away from the big binds we can get into. Sounds like a good plan and you can always spent that money on "stuff" later!
Enjoy !

[pobstlmo]

You want an “AMP-l-Start“ To charger the engine batteries when the RV is not being driven.

My response from an earlier post on a similar subject.

Solar panels need Sun light to work

If a coach is not use (ie/ storage) then the coach batteries should be turned off, Unless you have them plugged into 110v to keep them charged.

Batteries under charge need to have the water level checked every 3 months.

Coach batteries and engine batteries are not connected together to charge In storage unless an owner did it.

[Pdest]

Normally the chassis battery is charged by the engine running. The house batteries are charged by shore power when you’re plugged in. However there are devices that will charge both regardless of engine being or the shore power connected. My Meridian comes with that device but you can buy one called trik-l-start.

[jipper]

There is another thing to look at. The 2019 Navion that I have came with the converter/charger wired to the house side of the battery shut off switch.
This means if you have the battery shut off (salesman switch) shut off and you are connected to 120v ac power, you do not charge the batteries.



John

2019 Navion J

[Pdest]

Correct. On mine, both battery switches must be on for the charging crossover device to work.