Dead Batteries, Overheating Water Pump, Replaced Shore Power Receptacle Cover, Oh My!

[bradacc]

Hello everyone, perhaps someone might be able to get me closer to the truth on some issues.
I sent my Roo 233S in for some warranty repairs at the beginning of the month -
1) A water pump that would stop working, and when checked would be too hot to touch for more than a second or two.

2) The shore power receptacle cover needed to be replaced because the power light on it went out.
3) A couple other non-related items.


I was told they couldn't recreate the problem with the water pump, and they replaced the cover. When I picked up the trailer the batteries were dead and the CO2 alarm was beeping. They hooked up jumper cables to the batteries so I could raise the jack and hook up to my truck. Got it home, hooked up to shore power and verified the panel was showing a full battery (meaning shore power was coming in, and by association the batteries were being charged I assumed). 4 days later hooked up to truck to go camping. 2 hour drive later and setting up I notice the slide is moving out slower than usual, check power and it's got one light on. Take batteries out of trailer and have them checked at Pep Boys -
Battery 1 - 2CCA, 10.76 volts
Battery 2 - 24CCA, 11.73 volts
And neither one takes a charge.


Buy one replacement battery to get through the weekend. As soon as I hook it up to the trailer it shows 3 lights (2/3 full), and when I turn on the water pump it goes down to 1 light. Water pump overheats again. Hook up to a 1000 watt generator for several hours with only the main overhead lights on and it never went above 3 lights. Pulled the fuse on the radio (parasitic drain) and went to bed. Heater came on occasionally throughout the night. In the morning (~10 hours) the battery was virtually dead. 2 hour return trip home and battery is still basically dead.



So a few questions -
1) Could hooking the shore power receptacle back up incorrectly somehow screw up battery charging through it?
2) If the water pump is overheating, and left switched on, could that have killed my 2 batteries (both under 1 year old)?
3) Would the batteries be killed if they had accidentally left a light or two on while at the shop?


Thanks in advance for reading all of that!

[stephndudb]

Lead acid batteries do not like being completely discharged. It'll damage their ability to take/hold a charge.

[Brother Les]

1) you have/had two batteries that were 'bad'. I believe that both has a cell or two that were bad. Both should have been replaced at the same time. The NEW battery will Always be hampered and PULLED down to the level of the bad battery. Your new battery will never be able to take and keep a full charge because of the bad battery. buy another battery that is new and use it with your other new battery.



2) Do you have a battery shut off/ disconnect? If not, put one on your unit. If your unit sits very long (two weeks?) with no shore power or the batteries are not disconnected, parasite voltage use will drain your batteries.


3) I don't think that your power cord receptacle was wired up wrong.


4) You said that the water pump would not run and was 'hot'. I think that there is a safety switch in rv water pump motors that will shut it off if they get hot because of some reason (example: something in pump and stops motor from turning and will heat up and switch will shut off). I believe the obstruction was 'removed'.



https://www.smithsrvcentre.com/page/...the-water-pump

[Flybob]

Originally Posted by bradacc

Buy one replacement battery to get through the weekend. As soon as I hook it up to the trailer it shows 3 lights (2/3 full), and when I turn on the water pump it goes down to 1 light. Water pump overheats again. Hook up to a 1000 watt generator for several hours with only the main overhead lights on and it never went above 3 lights. Pulled the fuse on the radio (parasitic drain) and went to bed. Heater came on occasionally throughout the night. In the morning (~10 hours) the battery was virtually dead. 2 hour return trip home and battery is still basically dead.

The the last light on the battery gauge means the battery is charging and is not 100% charged. If the new battery you bought was not fully charged the water pump can cause an additional light to go out. You will not get sufficient charge on a very low battery from the TV during a 2 hour trip. Hopefully when you added the new battery, you did not leave one of the bad ones connected. It is possible you have a bad water pump but it appears there are other battery issues. Once the batteries are damaged they are usually not recoverable.

[bradacc]

Originally Posted by Brother Les

1) you have/had two batteries that were 'bad'. I believe that both has a cell or two that were bad. Both should have been replaced at the same time.


2) Do you have a battery shut off/ disconnect?

1) When I added the 2nd battery the 1st battery was still in excellent condition (only 4 months old).


2) Yes, I do have a shutoff.

[bradacc]

Originally Posted by Flybob

You will not get sufficient charge on a very low battery from the TV during a 2 hour trip. Hopefully when you added the new battery, you did not leave one of the bad ones connected.

I wasn't sure if 2 hours would make a noticeable difference, thanks!


I installed the new battery on its own.

[TimVWulp]

Do you have a volt meter to measure the battery voltage before you plug the trailer into 110 volt shore power? Trailer unplugged the battery should be 12.5 to 13. Volts with a fully charged battery. Trailer pluged in the voltage should be 13.2to 14 + volts when charging the battery’s from the RV battery charging system. If there is less than 13 volts with a good charged battery check the charging system. Running the water pump on a dead battery will make it draw high amperage making it over heat. Running any of your RV 12 volt systems with low voltage will or may damage them.

Hope this helps Tim

[camaraderie]

May I suggest you buy an AC/DC clamp meter for about 50 bucks...this will allow you to read both true voltage rather than blinking lights AND to clamp your red battery wire to see what the amp draw is on it and begin to eliminate the source of your problems.
You will also be able to see what your converter is putting IN to the batts so you can get a better feel for how long you need to charge it.

[Larry-NC]

May I suggest you buy an AC/DC clamp meter for about 50 bucks...this will allow you to read both true voltage rather than blinking lights AND to clamp your red battery wire to see what the amp draw is on it and begin to eliminate the source of your problems.
You will also be able to see what your converter is putting IN to the batts so you can get a better feel for how long you need to charge it.

You don't need a $50 clamp-on ammeter for the voltage measurements being proposed. An inexpensive digital volt-ammeter will do the job just fine. This one is $5.99, but they regularly give them away for free. (I usually have six or seven laying around, give them to my kids or other RVers.)

Larry

[camaraderie]

Originally Posted by Larry-NC

You don't need a $50 clamp-on ammeter for the voltage measurements being proposed. An inexpensive digital volt-ammeter will do the job just fine. This one is $5.99, but they regularly give them away for free. (I usually have six or seven laying around, give them to my kids or other RVers.)

Larry

The reasons for the clamp meter recommendation are:
Voltage readings IN USE are worthless in terms of measuring state of charge.
More importantly they won't help the OP determine what kind of parasitic amp drain he has on the batteries that are causing them to go flat...and you can also isolate what is responsible for the load by pulling fuses and watching the amps.
All a simple volt meter can tell you without disconnecting the batt for 24 hours is whether your charger is working (volt reading over 13.2) or weather the battery is flat (Below 11.5). Obviously a true battery monitor like the victron is a better choice for $150 bucks but I was just trying to give the OP a means of tracing his problem down inexpensively and 50 bucks is about as low as AC/DC clamp meters go.

[bradacc]

Thanks for the replies. I'll look into getting a meter like proposed. Thanks!

[5picker]

Originally Posted by bradacc

Thanks for the replies. I'll look into getting a meter like proposed. Thanks!

If you do buy a clamp meter, you can be frugal with your money and still get something reliable enough for R/V use. Many are amp testers AND multimeters.

Check these out at Harbor Freight.

Harbor freight Clamp Meters

While there, also get a FREE multimeter. (as mentioned in a prior post)
Give it to a fellow R/Ver if you'd like! I hand them out often!

[camaraderie]

Originally Posted by 5picker

Check these out at Harbor Freight.

Harbor freight Clamp Meters

Just remember that you need an AC/DC clamp meter...not one with only AC.

The one I pictured earlier works great for 50 bucks...and includes case accessories and how to use manual.
https://www.amazon.com/Mastech-MS210...ghydr-20&psc=1

[clarkbre]

Reading through this thread, the problems make sense but I think we're looking at the wrong suspects.

My guess is, there is a bad connection in the 12v system, not at the batteries, but at the converter or ground to the trailer's 12v system. Or, it's bad battery cables or the converter.

I'm assuming the 120v AC system is working properly when plugged in to shore power? If so, then this is a 12v DC issue. Unfortunately, most everything (water pump, tongue jack, lights, furnace blower, etc) is 12v.

A bad connection in the electrical system can cause high resistance. The high resistance can cause all sorts of electrical gremlins that appear separate but are actually very related.

1. Bad Batteries...probably not. Both batteries not charging and a 3rd battery still not charging. This leads me to think it's not the batteries to start with. However, a bad connection or voltage drop will not charge the batteries all that well. This can cause damage to the batteries.
Example: A failing alternator in a car engine can destroy a battery from inconsistent and "dirty" power supply.
2. Water pump heating up. High resistance will cause motors and other things asking for larger amounts of power to heat up. With the water pump needing to draw power to push and pressurize the plumbing, it takes a lot of power. This will naturally heat up; however, with poor voltage or amperage, this will cause more heat.
3. Slide moving slower - Similar to the water pump. It's moving slow from poor voltage or amperage. Even in normal operating conditions the slides will work better plugged in to shore power over battery only power.

The slide needs the same amount of power to move in and out no matter what...let's say 30 amps. Plugged in to shore power, it's likely getting 13.25v and 30 amps to move 13.25 x 30 = 397.5 watts

Running only on battery at 12.5v and 30 amps, 12.5 x 30 = 375 watts.

Moving the same slide at a lower wattage causes a higher resistance. This is often seen in blowing fuses. The slide is asking for it's 397.5 watts but the 12.5v can only provide 375 on the circuit. So, when it asks for more it wants 397.5/12.5 = 31.8 amps....and the fuse blows.

This all seems crazy but what I am saying is that the trailer's 12v system (furnace, water pump, slide out, tongue jack) is asking for volts and amps that the batteries are having a hard time supplying....not because the batteries are bad, but because the wiring is a choke point and causing high resistance.

I'll close with this example: In 2015, I had a '90 F150. One night I went to the store and while leaving, started my truck...and the starter stayed engaged because the solenoid stuck in a closed position and did not reopen to disengage the starter. Took it to the shop and had a new battery, starter and solenoid put in. Two days later, same thing. The shop replaced the starter, I picked up the truck and within 5 starts, it did the same thing again! After researching quite a bit on the Ford forums, I found that it was likely bad battery cables. The work around was to install a secondary cable from the battery positive to the solenoid or just replace both positive and ground cables. The shop thought I was crazy for requesting them to replace the battery cables as well...turned out, cables were the culprit.

I bet it's a bad connection where the battery cables meet the converter.

[Larry-NC]

Originally Posted by camaraderie

The reasons for the clamp meter recommendation are:
Voltage readings IN USE are worthless in terms of measuring state of charge.
More importantly they won't help the OP determine what kind of parasitic amp drain he has on the batteries that are causing them to go flat...and you can also isolate what is responsible for the load by pulling fuses and watching the amps.
All a simple volt meter can tell you without disconnecting the batt for 24 hours is whether your charger is working (volt reading over 13.2) or weather the battery is flat (Below 11.5). Obviously a true battery monitor like the victron is a better choice for $150 bucks but I was just trying to give the OP a means of tracing his problem down inexpensively and 50 bucks is about as low as AC/DC clamp meters go.

The parasitic draws are usually less than an amp or two. My tactic, using that same inexpensive multimeter is simple. Set the meter on the 10 amp range. Unplug a fuse. Plug the meter in its place--the probes just fit in one "curl" of the FastOns they use for fuse sockets. Record the current. Go to the next fuse and repeat. After you've done all the fuses on the distribution board, go to the battery and test the fuses on wires directly connected there.

Larry