Parasitic drain on house batteries?

I searched and read all the other threads where this issue was discussed and checked all the possible sources of drain, but could not identify the source. It is at the point that even when the house batteries are fully charged, they are discharging overnight even though no obvious 12V source is on. I bought this 2007 PC 2350 back in March and it is possible the house batteries are old and need to be replaced (though they read ok when tested with my meter under load; I need to check and see if they have a date code), but of course I'd like to put that off as long as possible. I will turn off the "disconnect" switch tonight and see if they still discharge; I suppose if they do then the problem is with the batteries and not the result of parasitic drain.  Though I am a decent mechanic, I'm not great with electrical stuff so any help with this issue is appreciated! 

Yes, the parasitic drain on my 2007 2350 was also quite serious.  That is until I switched from two 12V batteries in parallel, to two 6V AGM batteries in series.  Maybe they can handle the drain a lot better.  It has been so much better since the change in battery technology done 5 years ago, that I don't have to disconnect the batteries any longer like I used to.

I can't explain how or why.  I can only explain that it has been so much better this past 5 years with two 6V AGM batteries.  I still charge them about every other month, but I feel I could go 4 months between charges.

I wonder if the parasitic drain is worse for us with a 2006 to 2010 model year (or so) who have the whole house 2000 watt Tripp-Lite inverter/converter.

Customer complaint: "" when the house batteries are fully charged, they are discharging overnight even though no obvious 12V source is on""

Possible issues: Bad batteries, or unknown current drain from the camper.

Specialty tools needed -  Battery charger and multimeter.


Correct diagnosis of the problem relies on getting things isolated.

1) Disconnect the house batteries from the camper, and each other. Unless needed for access, you dont need to remove the batteries.
 
2) fully charge the batteries using an external charger. If they are 12V,  charge each separately. If they are (2) 6V batteries, and you dont have a 6V charger, you can connect the two together for charging.

3) When fully charged, disconnect all wires. Check the battery voltage soon after.. 6V battery should be ~6.5V and a 12V should be ~13V right after charging.  Write down the voltage.

4) now its up to you.. you can check the batteries every hour, every 4 hrs, whatever works. If it is a battery 'self discharge' problem, and 'dead' after 24 hrs,you should easily see discharge during one day.



At this point, you will know if the batteries are good, at least to the level that they hold charge overnight. If they are past their service life, new ones are in order.

Lets start there. Finding drains in the coach is a little more involved, but lucky for you there are a few people here with 2350's of that 'vintage' and we can work through it.

But #1 - are the batteries good? You now know how to check them.


(Just saw Rons comment - I have had NO discharge issues using (2) 12V group 31 AGM.  BUT... I do NOT have the "the whole house 2000 watt Tripp-Lite inverter/converter"  so maybe thats a 2007+ addition? I will check, the coach has been unplugged for ~3 weeks, and the 12V left on.  We are planning on using it soon, so I will check voltage BEFORE i plug anything in. )

Volkemon,

I recall hearing long ago from someone at Phoenix around the time we bought our 2007 PC, two batteries and the Tripp-Lite was a late introduction in 2006, either as standard equipment or as an option.  Though I never seen a 2006 with them, I assume there are a rare few out there.

Yes, turn off the 12v battery switch.  With it on, your battery draws some power all the time via the inverter (even if the inverter is turned off), lights in storage compartments or wardrobe if inadvertently left on and a few other low power items such as the TV signal amplifier.

Volkemon's posting should let you know if the batteries are still able to hold a charge.

Don

OK, my coach is being a good example.     

We got back from the last trip in early June, I left it plugged in until early July, weekend of the 11-12th. 

I unplugged it and rolled the cord inside. But.....


* I did not remember to turn off the 12V battery switch in the coach area. 

*I have a manual connection to connect the house and engine batteries. I did not disconnect this. 

(In my defense, I was having a medical procedure done on the 13th, and looking at 3 weeks in bed, so my mind was elsewhere... EVIDENTLY.   )

I do not have solar, or any other charging method enabled.     And all batteries combined to all parasitic loads. 

Expecting the worst...   I tried the 'factory meter' above the stove. All green! So it is at least 11V.. 

Then I used the 12V power outlet to check voltage.  12.4.      It should be low, if not dead.  Checked AGM's in back - 12.3V , I did not bother to undo cables for a quick check.

Well then....  I am now a BIGGER fan of Trojan batteries, their AGM in particular.  Outstanding. These batteries are... 2 years old?  LOL... have to look.  (AGM self discharges at ~25% the rate of Flooded Lead Acid batteries)  Evidently I dont have much for parasitic draw in my camper either.




BUT...for the OP... I am sure you are happy for my good fortune  , but here's hoping we can get your coach to the same state.     

Check your batteries and report back. 

There are a number of possible reasons for self discharge.  A couple of reasons that might contribute to this because of the earlier Phoenix design.


1.  As I understand the earlier units used two twelve volt batteries in parallel.  In this configuration both batteries when connected are at the same potential.  If these batteries are not identical and at the same voltage in isolation then the weaker battery draws down the stronger battery.  The greater the difference in the two batteries the greater the discharge.  Whereas six volt batteries are connected in series.  Each battery maintains it own voltage.  The current passing through one must be the same as the other.  The voltages are additive in this arrangement.  This series configuration is not as prone to self discharge through the other as in parallel.


2.  I remember reading that earlier units used a push button battery disconnect switch.  This is achieved with a solenoid thus consuming battery energy.  The newer Phoenix models use a rotary mechanical switch to isolate the batteries thus no power draw when disconnected.  Others here that are familiar with the older solenoid disconnect switch may have a comment on if and how much this contributes to self discharge.


Volkemon’s method will allow you determine the condition of each battery.  This will provide needed information to determine how much the parallel arrangement contributes to bank self discharge.


When purchasing our unit I was very cognizant of power usage as I wanted to Boondock without electrical hookup. I installed a Victron battery power monitor that allowed for continuous monitoring of power, current, and voltage going into or coming out of the battery bank.  I found with the battery bank connected there was about a 0.35 amp draw with all electrical units that could be switched were turned off.  This was being consumed by the propane detector and the solenoid that energizes the macerator.


For refererence we are still using our original wet cell 6 volt Interstate batteries installed by PC.  I typically disconnect by turning the rotary switch off when returning from trips.  I usually bump up my charge every 4 - 6 weeks when in storage.  Typical battery voltage stays about 12.73 and may drop as low as 12.67 volts before recharging.  This drop is typical of self discharge for this type battery.  I always want to make sure the batteries are at 100% SOC (State of Charge) or as close to that as practical.

The older solenoid style only drew current when "on" which was/is another reason to turn the 12v off when in storage.   I don't know the particular solenoid used by PC but a typical solenoid of that type uses about 10 to 15 watts for the coil to engage the contacts or about 1 amp.

Since the coach battery(s) are typically rated about 200 amp hours so 6 to 8 days without any charge before they are totally discharged which is always a bad thing.

Donc13,  thanks for the info on the solenoid actuated battery disconnect.  I am not sure the capacity of the 12 volt batteries installed but if we assume two 12 volt units connected in parallel have a capacity of 200 amp hours then at the normal usable 50% the solenoid at 1 amp would consume about 1/4th of the useable power per day.


This is not the primary draw causing the OP an overnight discharge but something to consider when boondocking and trying to conserve power. 

Thanks to all of you above for all your knowledge and good advice.

I checked the date on my batteries and, believe it or not, they are dated 2010! I'm pretty sure they were installed by my PC's first owners who purchased the PC new from the factory and owned it until 2018. Do you think it might be time to replace them, lol?!?!  Pretty good run for the two 12V wet cells I'd say! May they rest in peace.   

I'll replace them with some 12V AGM batteries this week. (I'm aware there are better batteries and methods (e.g., two 6 Volts) but time before we hit the road is tight and we are on a strict budget right now) which, given our needs and our 100W solar charger, ought to suffice for a while.

Though I still have some concerns about parasitic drain, I'll pursue that if it appears to still be an issue with the new batteries.

Thanks to all of you above for all your knowledge and good advice.

I checked the date on my batteries and, believe it or not, they are dated 2010! I'm pretty sure they were installed by my PC's first owners who purchased the PC new from the factory and owned it until 2018. Do you think it might be time to replace them, lol?!?!  Pretty good run for the two 12V wet cells I'd say! May they rest in peace.   

I'll replace them with some 12V AGM batteries this week. (I'm aware there are better batteries and methods (e.g., two 6 Volts) but time before we hit the road is tight and we are on a strict budget right now) which, given our needs and our 100W solar charger, ought to suffice for a while.

Though I still have some concerns about parasitic drain, I'll pursue that if it appears to still be an issue with the new batteries.

   Found it!     

There are 3 parasitic drains.
1. CO/Propane on even if System is shutoff
2. Antenna amplifier, turn off if not using tv
3. Inverter, lower if off but still draws power

6V wet batteries do not need much maintenance, every 2-3 months, and easy to access. Much cheaper and easier to find everywhere, but these must be true Deep  Cycle (Golf Cart) batteries.
It's simple to changes cables, you may have to buy one new one.

The 100 w solar is the best solution but there is even a bigger parasitic drain on the engine battery. So turn on the little switch on the left of the steering wheel, (Change the switch to an off on switch, a new one is identical ans requires no wiring expertise, just slide wires on to the terminals,).That way all batteries will be fully charged..

The older solenoid style only drew current when "on" which was/is another reason to turn the 12v off when in storage.   I don't know the particular solenoid used by PC but a typical solenoid of that type uses about 10 to 15 watts for the coil to engage the contacts or about 1 amp.

Since the coach battery(s) are typically rated about 200 amp hours so 6 to 8 days without any charge before they are totally discharged which is always a bad thing.

The relay/solenoid operated switch we are talking about..... is the relay that is switching the 12V system in the coach? Operated by the switch by the coach door step?

If so, I am guessing the relay in mine is some sort of 'latching' relay, (c2006)  by the sound it makes.

That, and I went ~6 weeks and the batteries were not even discharged.    Still pleasantly amazed. They are at 13.4V now plugged in.



The 12V relay that connects the motor battery and the coach batteries IS a solenoid style, but not factory switchable on my old coach. Engages automatically when the motor is running. (or used to... I have added a workaround now)