2018 Vista batteries not charging when on shore power

[mitchpadl]

Hoping someone can help. I have a 2018 Vista 27n. My house batteries are not charging when I am using shore power. This is something that never used to be a problem. I checked the voltage coming into the house batteries and with the engine running it's 14.5v, with the generator on its 13.2v and when plugged into shore power it's 0v. I have a xantrex pro m1000 inverter and a FFCO converter under the bed which I think is also the charger. after reading the directions for the converter I checked the output on the 12v side of the converter and it said 13.5 v when the rv is plugged in so it seems to me that the problem is somewhere between the converter and the batteries. I checked as many fuses I could find including the one on the bottom of the inverter that pops out and it seemed fine. I'm not really sure if the inverter has anything to do with charging the batteries. I also make sure that the disconnect rocker switch for the coach is in the "on" position when I'm plugged in. My 2 house batteries are a year old and my chassis battery is brand new.
Any help would be greatly appreciated since I am supposed to be leaving town a a few days. Thanks!

 

[Bnystrom]

Since you have a converter and a separate inverter, the former charges your batteries and the latter only provides AC from your batteries. That's assuming that they're both original equipment. Check that the inverter only has inputs from the batteries and not from shore power. If so, you can ignore the inverter for now.



There should be a positive lead from the converter directly to your batteries, or to a positive bus bar that your batteries connect to. Check that the connections are tight at both ends and not corroded. Measure the converter output at the connection for this lead; it should be the same as you saw previously. If not, the converter is probably defective.

 

[mitchpadl]

Thanks, I've been looking and can't figure out where the positive lead connects to the batteries. If there is a positive bus bar I haven't been able to find it. I'll keep looking.

 

[Bnystrom]

I'm not sure how your rig is wired, but in ours the positive lead from the converter to the batteries was green, not red as you would expect.

 

[Morich]

Mind if I throw in an alternate thought as I don't see this as a converter problem but possibly a transfer switch problem?

I sometimes use the lights on the microwave as an easy point to check for AC getting past the load center and to RV users.
If you have lights on the microwave, they are 110AC. Do they work when on generator as well as when on cord?
If they fail when on cord, it may be they are stuck and only feeding from the generator!
Once it passes the load center the wiring, etc. to the converter doesn't change whether on cord or generator.

 

[powercat_ras]

I'm assuming you still have Lead Acid house batteries. In order to bulk charge them the converter charger should be putting out it's max current output (probally <= 45 amps) until it senses that the house batteries state of charge reaches 80%. Depending on the battery state of charge the will be no more than 14.4 but could be less, but much more than 13.5, if the converter is putting out max current. I believe if the converter is only putting out 13.5 when you first apply AC power to it, it has failed internally is not going into bulk charge mode. 13.5 would indicate that is in trickle charge mode and is only adding 1-3 amp-hours per hour to the house batteries state of charge. If two batteries under the step, you will have somewhere between 100 (if OEM, if several yaars old) and 210 (if you replaced with 2 new intertate GC2 6V golf cart in series) amp-hours capacity Bottom line is at 13.5 charge voltage it will take well over a full day plugged in to charge the batteries.

The fact the battery voltage jumps to 13.5 when you apply AC to the converter charger tells me that it is not a wiring problem or a fuse problem. It also tells me that the AC is reaching the converter charger. Another way to tell that it is not the AC transfer switch is to see if the microwave clock display comes on when you plug into shore power (assuming you have the inverter off and no display before plugging in).

All that said if you have replaced your house batteries with lithium iron add to the thread and say that. It is very likely that your 2018 Vista does not have a converter charger designed to charge lithium iron, it has one that is desighed to charge either flooded lead acid or AGM lead acid batteries only.

 

[Morich]

Too many things wrong with the report to actually figure! If they are actually reading the battery voltage at 13+ on generator but zero when on the cord, they are not likely to actually be reading the battery voltage!
A reading of zero when the only change is from generator to cord is almost impossible to get IF the reading is actual/factual battery voltage!
Even a bad dead battery rarely reads zero! Especially hard to get zero when it has just been reading above 13!
I suspect there is a major error in the works somewhere! Possibly using a monitor panel rather than an actual reading?
At that point I would want to check how and where the reading is gone and then start at the start to see that there is actually AC getting into the RV from the transfer switch.

 

[mitchpadl]

Thanks, yes the microwave lights come on when hooked to shore power or Gen.

 

[mitchpadl]

Update, after driving for 4 days the batteries seem to be at least not running down when plugged into AC. The inverter display says the batteries have been steady at 13.6v while plugged in. The battery level seems to drop really fast when the engine is off and not plugged into AC or running generator. I believe my 1 yr old AGM batteries may be bad. Thanks for everyone's input.

 

[Morich]

A small point to keep in mind when looking at batteries may be in play here.
Are you familiar with what they call surface charge on batteries?
It can lead to missing what the actual battery is doing if we don't keep it in mind, so thought to mention it.
A battery is a slow moving chemical process and charging or discharge takes time that can't be rushed to far.
Different types do it at different rates but if we are speaking of lead acid, it takes hours to get from really run down back to fully charged. Like maybe 6 hours!
What we can miss if not alert, is when we look at a battery on charge and see the voltage from the charger.
It should always be higher than the normal battery can hold as that is what makes the current flow into the battery.
One way it is explained in schools is charging batteries and testing voltage is somewhat like pouring something thick like syrup in a hole in a barrel! Goofy sounding but works to explain some of the problems!
If we test voltage of a battery while charging, it may be something like looking at the syrup running in the hole of a barrel we are filling. It looks like the barrel is full as we see syrup, but if we looked a bit further down in the barrel we might find it nearly empty down where we can't see! Same with battery voltage!

When we test voltage, we can only see what is at the posts and if we are pouring power in, we see lots, even though the rest of the battery may be near empty!
But when we stop charging and test voltage too soon, the syrup/power has not had time to spread out all through the chemicals in the battery and we may not get the real idea of how well charged the battery until we wait for it to settle and become stable after we take the charge off.
This an trick us if we are not really alert. If you saw 13+, that will be the charge voltage as the normal really good new lead acid can only hold a charge of near 12.8 at best!
If you put a battery on charge for long enough to get it fully charged and just have it setting not connected to anything, you will first see the 13+ but it will soon go down to 12.8 or so, even if not connected to anything!
But if there is a problem with the battery, it may keep on going and get really down, like 10 volts if it is not in good enough shape to take and hold a charge!

Something that sounds like what you might have?
When driving for a 4 hours, the alternator should be connected to ALL the RV batteries and try to charge them to around 13+. So you get to a campsite and check voltage and you may see 13+ for a few hours until it settles? You plug in and see the 13+ from the shore power and converter feeding the coach batteries. All normal there, but if you unplug from shore power and charging stops, the voltage may go down really too fast if the batteries are not in good enough shape to actually take and hold that charge.

Kind of like the syrup and barrel, we can only look at the hole or post and the battery may actually only be half full down where we can't see!

A stop by an auto parts place where they put a load on a battery to test can be free and get some good info on the battery condition.

They can be so simple but still be so tricky, that we have to look really close at times.
Hope that's not a bunch of boring stuff you already knew but I have to keep reminding myself at times.

Good luck on the chase!

 

[mitchpadl]

Thanks Richard, very infomative
!