Parasitic Drain on House batteries

[Dragonfly-THOR]

Hi,

I am hoping to get some help with my house batteries draining overnight.

Here's some history:
Batteries are 31M AGM Interstate less than 2 years old. I have had them load tested twice now at 2 different Interstate dealers and am told they are fine.

I have a Renogy solar system with 400 watts of panels on the roof with a Renogy Rover 40 controller.

I had my onboard converter replaced over a year ago, so it adjusts charging based on the batteries.

During the spring I dry camped for as long as 10 days with no problem.



Now, if not connected to shore power, I have gone to bed at night with the batteries reading 12.7 volts (either from solar or the alternator).
There should be nothing drawing power except the refrigerator thermostat, CO/propane monitor, possibly the smoke detector and my radio which runs off these batteries and is always in standby mode. (I haven't figured out how to shut that off.)
In the morning, the batteries read 12.4 volts, but as soon as I turn on the water pump OR house lights (7 LED lights in main area), the batteries read 11.4v. When I shut those off, it will jump back up to 12.0v.


Any ideas?

 

[Bonzen]

Batteries are funky and are continually built with crap recycled lead as time goes on. Best guess is you have a bad cell(s) in your AGMs that are turning the batteries into resistors as opposed to capacitors. So even though they may hold a charge, take a charge and test fine, they suck themselves dry as soon as they see an actual load. had this happen to batteries in every RV/boat/truck I've owned.


Sucks to replace them but might be the best bet if you cant figure out another obvious issue.

 

[dkoldman]

Any reason you are doing your load testing at Interstate Dealerships?

What you are doing or have described is proof they fail a load test. The Dealers may get dinged by Interstate based on number of failed load tests under warranty?

The irony is every time you go through the cycle you describe, you are damaging your batteries.

I have my own Load Tester tied to my Innova ODB2 Port. You may try auto parts store and see if they will give you a report. Then take that to a dealer or contact Interstate directly.

But I would find the drain and get it fixed. It may take some rewiring. If my House switch is off, I have nothing, even the CO is off. I did buy two new Victron devices recently and both have bluetooth, but I have not noticed any difference. They connect direct to the batteries.

 

[Scubawise]

Hi,

I am hoping to get some help with my house batteries draining overnight.

Here's some history:
Batteries are 31M AGM Interstate less than 2 years old. I have had them load tested twice now at 2 different Interstate dealers and am told they are fine.

I have a Renogy solar system with 400 watts of panels on the roof with a Renogy Rover 40 controller.

I had my onboard converter replaced over a year ago, so it adjusts charging based on the batteries.

During the spring I dry camped for as long as 10 days with no problem.



Now, if not connected to shore power, I have gone to bed at night with the batteries reading 12.7 volts (either from solar or the alternator).
There should be nothing drawing power except the refrigerator thermostat, CO/propane monitor, possibly the smoke detector and my radio which runs off these batteries and is always in standby mode. (I haven't figured out how to shut that off.)
In the morning, the batteries read 12.4 volts, but as soon as I turn on the water pump OR house lights (7 LED lights in main area), the batteries read 11.4v. When I shut those off, it will jump back up to 12.0v.


Any ideas?

I had interstate replace my LFA after saying they were ok.
Fixed everything

 

[rudyhehn]

Since you're not dropping much voltage overnight, I don't think this is a parasitic load. I think you have a battery which is dying earlier than expected. I would have your battery inspected and load somewhere else and I'll think you'll find it's near the end of its life. I'd recommend replacement with a lithium

 

[stevedarlene]

I checked the load on my 2016 Thor Axis and got a 1 amp draw with everything off and battery use switch in store position. Made it a habit of disconnecting ground from batteries when not in use

 

[Chateau_Nomad]

I checked the load on my 2016 Thor Axis and got a 1 amp draw with everything off and battery use switch in store position. Made it a habit of disconnecting ground from batteries when not in use

Something is wired incorrectly. The use/store switch is supposed to be a battery DISCONNECT... meaning the battery should be COMPLETELY disconnected.

Someone wired a circuit somewhere between the battery and disconnect switch... which defeats the purpose of having a battery disconnect. ALL 12 volt components should be OFF... including propane detector.

It's like having a circuit breaker that doesn't really disconnect ALL power in the circuit.

 

[Beau388]

Something is wired incorrectly. The use/store switch is supposed to be a battery DISCONNECT... meaning the battery should be COMPLETELY disconnected.

Someone wired a circuit somewhere between the battery and disconnect switch... which defeats the purpose of having a battery disconnect. ALL 12 volt components should be OFF... including propane detector.

It's like having a circuit breaker that doesn't really disconnect ALL power in the circuit.

In my coach the use/store latching relay (battery disconnect relay) disconnects the 12 volt fuse panel in the power center. It does not disconnect the inverter, the generator start/jack circuits and the BIRD controller.

 

[dkoldman]

In my coach the use/store latching relay (battery disconnect relay) disconnects the 12 volt fuse panel in the power center. It does not disconnect the inverter, the generator start/jack circuits and the BIRD controller.

My inverter will operate if use/store switch is OFF as well, but if OP has an inverter that draws power when the inverter if off, they may wish to replace it?

IMO and I discount the Mercedes Benz chassis and Tellaro RVs, but I never understood why so many have parasitic draws. It seems to be such an easy fix?

I read where people spends $100s if not $1,000s of dollars with solar systems etc. to counter the draw versus simply eliminate the drains. Again, I get some Chassis are designed that way from mfg, but that is exception.

When I turn off House Battery, I am turning off the CO detector as well. In fact, per my Victron Shunt, if everything in coach is OFF and House battery is in Use mode, I show a draw of 6 watts .1 ah. But is I disconnect the switch it goes to 0 watts and 0ah.

Ironically when I wired by alarm for the Catalytic Converter Theft system, I defied the instructions and put on the Chassis battery. That way if my House battery is off I can still have that alarm if needed. Never had the Chassis battery drain down, but if it did I could use the house battery to restart.

 

[Chateau_Nomad]

In my coach the use/store latching relay (battery disconnect relay) disconnects the 12 volt fuse panel in the power center. It does not disconnect the inverter, the generator start/jack circuits and the BIRD controller.

I can understand the BIRD (or any battery iso relay) as it's function requires being directly connected to both chassis and house batteries.

My inverter powers the entire power center. After my lithium upgrade the jacks, generator start and inverter all are cabled to a main battery bus... which is disconnected by the battery disconnect switch. With that switch off the only live circuit connection to the batteries is the solar charging... which has it's own PV disconnect.

The way Thor cheats with wiring shortcuts is why so many people start posts about mysterious parasitic drains and dead batteries. Just me, but my definition of a "battery disconnect switch" is a device that actually disconnects ALL 12 volt systems from the battery that are potential drains.

I actually leave my "battery disconnect switch" on all year... even during storage. I've verified I have no parasitic drains, and also have solar keeping the batteries topped up.

 

[Dragonfly-THOR]

Thank you all for your replies!

I really appreciate all the replies.

I am inclined to agree that the batteries are failing. So the next question is why?
This is the second set of batteries is less than 3 years! The first set was replaced under warrantee.
I spoke to one of the engineers at Interstate last week. He said that the main reasons these batteries fail is due to charging with too high a voltage (>14.8V) or letting them get below 11.0V. Io the best of my knowledge neither has happened.
I can't say I monitor the Renogy app all the time, but I have never seen charging voltage that high.

My lights start to flicker when the voltage is below 11.8 or 11.9 so I definitely would have known if the voltage went below 11.0.


To clarify, I live in the RV so I am not putting battery in storage mode overnight. And I do not have an inverter, just a converter.



The engineer did say that he would try to get me another "courtesy" replacement under warrantee, but suggested I have the system checked to try to find the cause for the short life cycle.
I'm just not sure what to look for...

 

[dkoldman]

I am no one to argue with a Interstate Engineer, but I would never let my FLA battery operate under 12 volts, 12.2 for AGM and 12.4 for Lithium.

I agree you need to find the source of the drain, I would do so with urgency before you get the new batteries. Having tools that measure the current being drawn but you can eliminate items one by one but just take longer. It is only so many things in the coach and none should draw if it is OFF. Start with what works when disconnect switch is off. Get that fixed.

 

[Chateau_Nomad]

I really appreciate all the replies.

I am inclined to agree that the batteries are failing. So the next question is why?
This is the second set of batteries is less than 3 years! The first set was replaced under warrantee.
I spoke to one of the engineers at Interstate last week. He said that the main reasons these batteries fail is due to charging with too high a voltage (>14.8V) or letting them get below 11.0V. Io the best of my knowledge neither has happened.
I can't say I monitor the Renogy app all the time, but I have never seen charging voltage that high.

My lights start to flicker when the voltage is below 11.8 or 11.9 so I definitely would have known if the voltage went below 11.0.


To clarify, I live in the RV so I am not putting battery in storage mode overnight. And I do not have an inverter, just a converter.



The engineer did say that he would try to get me another "courtesy" replacement under warrantee, but suggested I have the system checked to try to find the cause for the short life cycle.
I'm just not sure what to look for...

If I were you I'd push for a credit on the batteries. Otherwise I think you're going in circles. Then apply the credit to as many amp hours of LiFePO4 batteries as you can afford... I'd recommend minimum 200 amp hours.

That will eliminate the problem of destroying the batteries with over-discharging. Although not ideal, you can completely discharge those batteries with little ill effects.

If you still have an issue, we can start systematically tracking down what's discharging them so quickly.

At this point I think the root of your problem is crappy batteries. You need to eliminate that part first before going further.

 

[Beau388]

If you have FLA batteries, the amount of water you have to add monthly is an indication of battery health. In FLA batteries where the lead-oxide paste is alloyed with antimony will use less than a tea spoon per cell a month. Predictive failure is one cell of the battery will need significantly more water than the others. This can be caused by sulfation o a weak short.


The primary cause of sulfation is the battery being left in a partially discharged state for a week or more or a battery grid being exposed to air (partially exposed plate).


Partial shorts occur when the dendrites form on the paste surface break loose and fall to the bottom of the battery case. If the dendrites build up sufficiently, they can bridge the plates causing a short. Large dendrites form on the plates when a FLA battery is charged or discharged to fast (too high current).


A FLA where the plates are alloyed with calcium (low maintenance FLA batteries) seldom need watering unless they are overcharged. In fact, most LA batteries with calcium alloy lead are sealed valve regulated lead acid batteries (VRLA).


One more note: overcharging can also be caused by too high floating voltage. LA battery charging is temperature dependent (faster when hot and slower when cold). A good three stage converter will have a temperature probe to measure the battery temperature. My PPL charger would vary the float voltage from 13.1 volts on a 100 degree day to 13.7 volts on a below zero day.

 

[Chateau_Nomad]

If you have FLA batteries, the amount of water you have to add monthly is an indication of battery health. In FLA batteries where the lead-oxide paste is alloyed with antimony will use less than a tea spoon per cell a month. Predictive failure is one cell of the battery will need significantly more water than the others. This can be caused by sulfation o a weak short.


The primary cause of sulfation is the battery being left in a partially discharged state for a week or more or a battery grid being exposed to air (partially exposed plate).


Partial shorts occur when the dendrites form on the paste surface break loose and fall to the bottom of the battery case. If the dendrites build up sufficiently, they can bridge the plates causing a short. Large dendrites form on the plates when a FLA battery is charged or discharged to fast (too high current).


A FLA where the plates are alloyed with calcium (low maintenance FLA batteries) seldom need watering unless they are overcharged. In fact, most LA batteries with calcium alloy lead are sealed valve regulated lead acid batteries (VRLA).


One more note: overcharging can also be caused by too high floating voltage. LA battery charging is temperature dependent (faster when hot and slower when cold). A good three stage converter will have a temperature probe to measure the battery temperature. My PPL charger would vary the float voltage from 13.1 volts on a 100 degree day to 13.7 volts on a below zero day.

He said he has AGM batteries in his original post. Short of measuring voltages...
While charging
At rest
Under load

He's at the mercy of what the state of health his current batteries are in. Maybe start by going to an auto parts store for an independent opinion - a good stress test to evaluate their health would tell a lot. I doubt the Interstate engineer will give an unbiased opinion.

 

[dkoldman]

If you have FLA batteries, the amount of water you have to add monthly is an indication of battery health. In FLA batteries where the lead-oxide paste is alloyed with antimony will use less than a tea spoon per cell a month. Predictive failure is one cell of the battery will need significantly more water than the others. This can be caused by sulfation o a weak short.


The primary cause of sulfation is the battery being left in a partially discharged state for a week or more or a battery grid being exposed to air (partially exposed plate).


Partial shorts occur when the dendrites form on the paste surface break loose and fall to the bottom of the battery case. If the dendrites build up sufficiently, they can bridge the plates causing a short. Large dendrites form on the plates when a FLA battery is charged or discharged to fast (too high current).


A FLA where the plates are alloyed with calcium (low maintenance FLA batteries) seldom need watering unless they are overcharged. In fact, most LA batteries with calcium alloy lead are sealed valve regulated lead acid batteries (VRLA).


One more note: overcharging can also be caused by too high floating voltage. LA battery charging is temperature dependent (faster when hot and slower when cold). A good three stage converter will have a temperature probe to measure the battery temperature. My PPL charger would vary the float voltage from 13.1 volts on a 100 degree day to 13.7 volts on a below zero day.

What is the engineering behind the fact that my OEM FLA Motorcraft that is now 6 years old has never had any water added. Worse, I have never popped the tops off to even check :whistling: I took the battery out of RV last week because I simply don't want a 6 year old battery even if it could make 8 - 10 years.

My fascination with refusal to check or add water is simply because I have never done so in any car I have ever own. Of course I will never buy another FLA; although the battery I put in the RV is one I purchased 4 months ago for an older vehicle that I plan to sell soon. I swapped the batteries only because I rather have the 4 month on FLA in RV versus the 6 year old one.

 

[Beau388]

What is the engineering behind the fact that my OEM FLA Motorcraft that is now 6 years old has never had any water added. Worse, I have never popped the tops off to even check :whistling: I took the battery out of RV last week because I simply don't want a 6 year old battery even if it could make 8 - 10 years.

My fascination with refusal to check or add water is simply because I have never done so in any car I have ever own. Of course I will never buy another FLA; although the battery I put in the RV is one I purchased 4 months ago for an older vehicle that I plan to sell soon. I swapped the batteries only because I rather have the 4 month on FLA in RV versus the 6 year old one.

A quote from the Ford Motorcraft battery web site.
"The Motorcraft Battery BXT65-850 requires no water level maintenance. The battery is designed with (BIC) vent caps, which helps prevent electrolyte loss."

 

[dkoldman]

A quote from the Ford Motorcraft battery web site.
"The Motorcraft Battery BXT65-850 requires no water level maintenance. The battery is designed with (BIC) vent caps, which helps prevent electrolyte loss."

You the damn man :bow:

That is exactly what I got. I glad I have not been trying to add water. It will be interesting to see what the Everstart Maxx 65 does. It has a 3 year warranty. If I had known when I bought it that it would ultimately be in the RV, I would have bought the Everstart Platinum 65 AGM.

With that said if the Maxx 65 falters, I will not hesitate to and get the OEM Motorcraft Battery BXT65-850. The battery is 6 years old and still going

 

[Chateau_Nomad]

I still have the original Motorcraft flooded battery in my 2017 F-150... so it's going on 8 years old! I started carrying a jump box this year just in case. I've never pulled the caps off to check water. The truck sometimes sits for a week without being driven... and even with temps in the teens recently the battery STILL cranks like new.

 

[16ACE27]

I still have the original Motorcraft flooded battery in my 2017 F-150... so it's going on 8 years old! I started carrying a jump box this year just in case. I've never pulled the caps off to check water. The truck sometimes sits for a week without being driven... and even with temps in the teens recently the battery STILL cranks like new.

Mine did that until I stopped for gas one day and it wouldn't even turn over when trying to start afterward. Dead cell just like that.