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Battery Charging Problem ***UPDATE***

whizbang
Explorer
Explorer
While dry camping in freezing weather, the charging system died for the dual type 24 house batteries (2002 Winnebago Mini).

It appears to be a solenoid system. It failed two years ago and the RV shop ran a new replacement wire "to tell it to charge".

I am going to fix it myself this time. (I am a ham radio operator and licensed general contractor, Tinkering are us). However, I have zero expertise in automotive charging systems.

My inclination too, is to remove the solenoid system and run a battery isolator instead. I had an isolator in my F350 twenty years ago and it worked great.

Comments or suggestions? I have no clue where to start, other than doing lots of homework...
Whizbang
2002 Winnebago Minnie
http://www.raincityhome.com/RAWH/index.htm
77 REPLIES 77

pianotuna
Nomad II
Nomad II
Log,

I gave up on you when you insulted me. I won't be replying to you again. Thanks.
Regards, Don
My ride is a 28 foot Class C, 256 watts solar, 556 amp-hours of Telcom jars, 3000 watt Magnum hybrid inverter, Sola Basic Autoformer, Microair Easy Start.

LOG
Explorer
Explorer
pianotuna wrote:
Log,

Why do you think I'm attempting to teach you anything? I don't see your name in any of my recent posts on the thread.


Maybe you need to go back and read your posts about "hydrometers" and "dancing on the head of needles", and how I determine fully charged.
LOG
2005 Chinook Glacier

time2roll
Explorer II
Explorer II
OK so measure what the alternator is putting on the house battery terminals after two hours. If you are less than 14.2 volts maybe the DC-DC booster would help to get a faster charge if desired. Until the issue is quantified there is nothing to resolve.

pianotuna
Nomad II
Nomad II
Log,

Why do you think I'm attempting to teach you anything? I don't see your name in any of my recent posts on the thread.
Regards, Don
My ride is a 28 foot Class C, 256 watts solar, 556 amp-hours of Telcom jars, 3000 watt Magnum hybrid inverter, Sola Basic Autoformer, Microair Easy Start.

LOG
Explorer
Explorer
Pianotuna,

When I purchased our Foretravel diesel pusher in 2013. It had the identical 12 volt system as our boat. Even the isolators were from the same company. The only difference was that it had a lot less batteries and one alternator.
LOG
2005 Chinook Glacier

LOG
Explorer
Explorer
Pianatuna.

Before RVing, I had a boat. From 2002 until 2013 I spent months and months anchored in the Bahamas and Exumas. The boat had a single 6 cylinder inline diesel engine. It had two alternators (one 70 amp and one 120 amp), two smart battery chargers (one 40 amp and one 60 amp). The 60 amp was fully field repairable. It had a 2500 watt inverter and a 8 kilowatt diesel generator. It had ten group 31 Lifeline AGM batteries. Five banks, three banks with one battery, one bank with three batteries, and one bank with four batteries. Are you reading? In 2002 it had ten Lifeline AGM batteries.
Do you really believe there is something you can teach me about 12 volt batteries and charging systems?
Really?
LOG
2005 Chinook Glacier

pianotuna
Nomad II
Nomad II
This article is pretty good.

https://deepcyclebatterystore.com/the-battery-blog/how-to-charge-12-volt-6-volt-batteries/

"You have to force more electricity into a battery than it would like to accept or it won’t be fully charged. To charge a standard 12-volt battery, you have to bring it up to above 14 volts (amount varies with the type of battery)"

"The most accurate method of measurement is using a hydrometer to measure specific gravity"

For sealed batteries:

Use a D.C. voltmeter to get the battery voltage
Regards, Don
My ride is a 28 foot Class C, 256 watts solar, 556 amp-hours of Telcom jars, 3000 watt Magnum hybrid inverter, Sola Basic Autoformer, Microair Easy Start.

fourthclassC
Explorer
Explorer
Just had to chime in here as I have the same model RV just 2003. I had to change my trombetta solenoid right after I got the RV. It was hard fitting into the area where the solenoid resides. Replaced it with a NAPA continuous duty unit which has worked fine for 4 -5 years. The magnatek converter has a built in dumb charger function which works ok but I want to upgrade it one day. Originally wanted to change to solid state isolator, but the solenoid works ok. PM me if you want to discuss details of the Mini 24v. I know some interesting stuff about its construction.....

pnichols
Explorer II
Explorer II
LOG wrote:
pianotuna wrote:
LOG wrote:
It appears that your motorhome has the voltage drop problem that DrewE was explaining. And has nothing to do with a "smart" charging system.
Maybe you need a better battery isolation manager or combiner.


LOG,

I have dual charging paths with #8 wire (rating 50 amps) with dual solenoids, each rated at 200 amps continuous. I have manual control of the solenoids and charging from the alternator. Each charging path is protected by a 50 amp automatic circuit breaker.

If the house batteries are "hungry", then I see more than 75 amps of charging. (my meter only reads to 75 amps). On occasion I've observed at least one of the circuit breakers flipping off and then on.

On normal use, because my starting battery is given a maintenance charge when ever the sun is shining, I see little charging after the starter battery is full from the ecm's point of view.

I can "force" charging of the house bank by using the inverter and running the 1400 watt water heater. However this does, after about 20 minutes, cause the starter battery to go down to 12.3 volts. At that point, I use my manual control to stop the charging, and I disconnect the water heater. The reason for doing so, is the 1/3:2/3 duty cycle on the alternator which I do not wish to burn out.

After 40 minutes of highway driving, I can repeat the above process. The last hour of driving I use to return some charge to the house bank.

I can "see" one of the breakers flipping in and out if I run the engine and use the microwave (170 amps draw) and the induction cooker (70 to 130 amps) at the same time.

These observations are from 2013 when I had 8 identical marine jars, one of which was used as a starter battery, and the house banks were configured as 3 and 4. Both banks were wired in a balanced manner. The "house" bank was 875 amp-hours @ 12 volts.


It appears that your motorhome is not the typical motorhome that one would expect to see in a later model motorhome with a "smart" charging system as was explained in one of the first post in this thread by Theoldwizard1.
Would you provide an example of a newer motorhome that would not fully charge the house bank with the engine alternator.
My older 2005 motorhome does not have that problem.
I simply start the engine, drive to my destination, and when I arrive my engine battery and house bank are both fully charged, without my having done anything other than driving and listening to then radio.


What you say is exactly what I find with our 2005 Itasca Class C motorhome.

For traveling I have two (four place - xx.xx) voltmeters mounted on the cab dash right where I can watch them: One shows the chassis battery voltage, and the other other one shows the coach battery bank voltage (two 115AH 12V batteries in parallel). I also have an ammeter on the dash that gets it's input from a shunt in the main line of the coach battery bank right close to the coach battery bank.

Both voltmeters read nearly the same whenever traveling down the road because a heavy duty solenoid connects the coach battery bank and the chassis battery together in direct parallel whenever the ignition key is turned on.

After drycamping long enough to the draw the coach batteries down to around 50% discharged (a rest voltage of ~12.1 volts) and then hitting the road, the voltmeters at first read above 14 volts for awhile and then they slowly settle down to 13.X volts - depending upon the outside ambient temperature.

At first the ammeter can spike up to as high as around 80 amps for a bit before beginning to taper. After driving 3-4 hours, the ammeter will taper down to 2 amps or less - indicating nearly full coach batteries.

The original OEM Ford 130 amp alternator (a "G4" or "G5" or "GX" type?) has been charging all three batteries this way for about 14 years. The alternator is connected to the coach batteries (via the solenoid) by maybe 10 feet of 8 gauge cabling.

Somehow the Ford alternator and it's regulator and/or or engine ECM are doing something just right - with no sophisticated circuitry (i.e. isolaton diodes, etc.) added by Winnebago that I know of - per the Winnebago wiring diagrams.

The coach only has a good old Parallax 45 amp fixed voltage converter in it, and the coach batteries are deep cycle AGM with low internal resistance - which makes them charge much faster than liquid acid batteries - at all applied charging voltages. Lately when drycamped, I've been skipping long generator runs for charging via only this converter and instead merely idling the V10 engine for awhile to let the alternator do the heavy charging.

All this seems to play very well together ... if and only if the solenoid that connects the chassis and coach batteries together works and has "no" resistance in it's contacts when they're closed. If the two voltmeters that I mention above are reading very close to the same, then this solenoid is OK and hence passing charging current to the coach batteries without loss of voltage across the solenoid's contacts due to corrosion.
2005 E450 Itasca 24V Class C

pianotuna
Nomad II
Nomad II
Log,

I designed the system in 2005. It works well and meets my needs.

So you think that if new technology becomes available I should not recommend it?

And you believe that Trojan's suggestions for charging voltages should be ignored?

I guess I will have to start using a Tardis.
Regards, Don
My ride is a 28 foot Class C, 256 watts solar, 556 amp-hours of Telcom jars, 3000 watt Magnum hybrid inverter, Sola Basic Autoformer, Microair Easy Start.

pianotuna
Nomad II
Nomad II
Hi whizbang,

Glad it was something simple!

whizbang wrote:
***UPDATE*** 3/30/20

The center solenoid was loose so it was not turning on. The center wire had been installed without a lock nut. I tightened it up using a plit lock washer as well as a nyloc lock nut.

The Intellitec latching relay (battery disconnect)was a rat's nest of rusted and corroded wires and crimp terminals. I replaced it and crimped and soldered new connectors all around.

It works. We are back in biz.
Regards, Don
My ride is a 28 foot Class C, 256 watts solar, 556 amp-hours of Telcom jars, 3000 watt Magnum hybrid inverter, Sola Basic Autoformer, Microair Easy Start.

LOG
Explorer
Explorer
Whizbang,
I apologize for hijacking your thread. I was simply trying to get Theoldwizard1 and Pianotuna to admit that you did not need one. I was unsuccessful.
LOG
2005 Chinook Glacier

time2roll
Explorer II
Explorer II
Very nice.

Good time to also review your converter to get the most charge from running the generator.

whizbang
Explorer
Explorer
***UPDATE*** 3/30/20

The center solenoid was loose so it was not turning on. The center wire had been installed without a lock nut. I tightened it up using a plit lock washer as well as a nyloc lock nut.

The Intellitec latching relay (battery disconnect)was a rat's nest of rusted and corroded wires and crimp terminals. I replaced it and crimped and soldered new connectors all around.

It works. We are back in biz.
Whizbang
2002 Winnebago Minnie
http://www.raincityhome.com/RAWH/index.htm