How to Charge House/Coach batteries?

[moonlitcoyote]

I have read through old posts and used the search feature but I am still a bit confused...

How exactly do I charge the house batteries? As far as I know, they are charged right now, (I have it plugged into shore power). From what I understand and I may be totally wrong here, when driving I am supposed to put the battery switch to dual? instead of in the middle? And if I do this, do I have to put the switch back into the center when I'm not driving? Also do the batteries get charged when plugged into shore power? I wouldnt want to overcharge my batteries and have them blow up... I just learned today that my fridge is a 3-way, so I want to be sure my batteries always stay charged.

[ClydesdaleKevin]

When we had a 3 way fridge, we never used it on 12 volts because it draws a LOT of amps that way...would be okay to use it on 12 volts when driving, since it will be charged up by the alternator, but you HAVE to remember to switch it to shore power AC or propane when you stop.

Your converter should charge the batteries whenever you are plugged into shore power...an older converter might not charge them quickly, but it will charge them...just check your battery water once in a while...always keep your batteries topped off with distilled water.

I'm not overly familiar with the MOM switch.  We had one in the Itasca, and if I recall, I always had it set to Dual when driving, but set it back to single when parked.  The HR doesn't have that kind of switch, just a momentary toggle switch for auxiliary starting power...it always charges both coach and chassis batteries while driving.

Kev

[DaveVA78Chieftain]

Dual/Norm/MOM switch - Controls AUX Battery Relay

Dual (AUX Battery Relay energized; B+ from chassis battery) - Allows engine alternator to charge both chassis and house battery when ignition switch is is in ON position (engine running).  AUX Battery Relay is de-energized if ignition switch is OFF.

Norm (AUX Battery Relay de-energized) - Allows engine alternator to only charge chassis battery.

MOM (AUX Battery Relay energized; B+ from house battery) - Allows the house battery to be used to assit in starting the engine if the chasssis battery has been inadvertantly depleted.  Hold MOM switch down for a couple of minutes to partially charge the chassis battery from the house battery, then while still holding the MOM switch down start the engine.

Original converter only charged the house battery.  Chassis battery was not charged by the converter.   Even though you may have a 45 amp converter, only 6 amps was provided to the house battery for charging.  Remaining amperage was only used for house loads.   Many people upgrade to a modern 3 stage converter which provides enhanced house battery charging capabilities.

You can add a device called a Trick-L-Start which allows the converter to also maintain the charge on the chassis battery when the converter is ON.  ON later model rigs this is a absolute need as the computerized engines draw have several parasitic loads that continue to draw power from the chassis battery when the ignition key is OFF.

Dave

[shimmy]

Dave,

Thanks for the explanation.  Now it makes sense to me.

[Lefty]

Good explanation Dave, That darned switch always confused me as well.

[LJ-TJ]

Dido  Thanks Dave  D:oH!

[JDxeper]

What about if you have the gen set running while driving?

[DaveVA78Chieftain]

If you have upgraded to a newer 3 stage converter, I would place the DUAL/NORM/MOM switch in NORM if the generator is on while driving.  If still the older single stage converter, I would use DUAL as the alternator can provide more charge current than what the converter can.  Of course, if the battery is already charged up, NORM would be fine also.

Dave

[Randy_in_Ohio]

Thanks for the explanation on that switch Dave, I had been wondering the same thing. 

I've noticed that my Aux. battery seems to discharge even when plugged into shore power.  Right now I only have one Aux. battery (the one under the drivers seat)  The PO has the  + cable for the second battery(under passenger seat) wrapped up in a sock and black tape. Hm?  I'm wondering if the reason it's not charging is because the second battery is missing? The PO told me that he used a separate battery charger to keep the coach battery charged, which is what I've been doing but there must be a better solution.

I know I should replace both batteries at the same time but if I do that I would want to replace the the charger/converter to maintain the new batteries properly.

[DaveVA78Chieftain]

I've noticed that my Aux. battery seems to discharge even when plugged into shore power.

Either you aux battery is not connected to the house or the converter is not working.

Typical RV electrical system (note: ground a neutral shown connected together inside RV but that is not correct.  Ground and neutral have to be kept seperate in RV)



Both "coach side" batteries should be connected in parallel.

To test converter, connect to shore power and then at the coach DC fuse panel, verify you have at least 13.6VDC at each fuse to ground.  By 84, you would have had a converter that is connected directly to the battery in parallel (no seperate battery tap off).  Acts just like a car alternator does.

Dave

[Randy_in_Ohio]

Thanks for that diagram Dave, I'm going to download that and keep it in my folder for the MH.

I know one of my batteries is connected to house because the lights and such work when unplugged from shore power. Could it be caused by only having one of the batteries?  I should have two, but like I said, the PO had removed one of them and left the second positive battery cable wrapped in a sock and electrical tape. my thinking is maybe the power from the converter may be coming in on the other battery.

[DaveVA78Chieftain]

Just to be sure I am following you correctly:

You have one chassis battery that is used to start the engine (Location?)

You have one coach battery under the drivers seat that is currently connected to the coach system

You have a spot for a 2nd coach battery under the passenger seat that does not currently have a battery installed.

Spots for 3 batteries total (1 chassis, 2 coach).

Dave

[Randy_in_Ohio]

That's exactly right Dave. 1 under the hood, 1 under the drivers seat, and a space for one under the passengers seat but it is missing right now.

I plan on adding a second coach battery, but was hoping I could get by with just one for a little while.  I'm usually going to be hooked up to shore power at home and at camp grounds as we don't intend to do a lot of "boon docking" (correct term?)  I know that you should have all the batteries in a parallel bank at the same age and type and figured it would be best to replace them both at the same time. But there are other things I want to do first...

[DaveVA78Chieftain]

Having just 1 house battery is ok as long as the cabling between the 2 house batteries are connected like this (even though no battery is there):



The 2 batteries in parallel just become one big 12VDC battery

Dave

[moonlitcoyote]

Hey dave can you post a pic like that using say 4 12v batteries? I never did understand how they are supposed to be hooked up

[DaveVA78Chieftain]

As you can see it's just a continuation of above

[Froggy1936]

 Note: The 2 12 V batteries are in parellel  and the 2 6 V batteries are in series  Frank

[moonlitcoyote]

What is the difference between parallel and series? Do you only put them in series if they are 6V?

[Oz]

That is  correct.  You would put them in series with 6 volt batteries in order to create a 12v supply.  When would you have cause to do this?  When using something like large, multiple, 6v golf cart batteries designed for long, constant use.  (Wow, I answered my first, and likely last, electrical question!).

[moonlitcoyote]

.  (Wow, I answered my first, and likely last, electrical question!).

LOL.. Well answer this one, what would be the purpose of using golf cart batteries instead of car batteries, or whatever I am supposed to be using. I dont even know that..lol.. I always used car batteries in my travel trailer

[Oz]

Over the last 10 years or so, regular car batteries (and marine batteries) have come a long way as far as being able to hold a charge for greater demand over longer periods of time. In addition, different technology from the traditional, electrolyte acid based cores such as gel batteries, AGMs, and and who knows what else, now have become the bees knees.  A good article to read about all this is in the Member Area.  Fred's Poop Sheets (no kidding... )  In fact, there's several good RV articles on those "poop sheets".  But, these upgraded batteries can be quite expensive, depending on your needs.  Especially if you're a constant boondocker.

Prior to these improvements and as an alternate solution, golf cart batteries were a good choice since golf carts use a lot of go juice and are used for a long period of time.  In my "Chariot", I had two electric fork lift batteries.  Six volt, heavy buggers but, they lasted a real long time and were much cheaper than equivalent gels at the time.

As for what battery you should use?  An automotive one for your engine and deep cell marine batteries for your coach is good for most campers.  For extended periods of dry camping, you may want to look into gels, golf cart batteries or electric fork lift batteries.  There are topics about battery recommendations here on the forum which are really comprehensive if you want more info.  I have no more answers left.  You've drained the sum total of my electrical knowledge...
D:oH!

 

[DaveVA78Chieftain]

A chassis battery is designed for high amperage (engine start) and fast recovery.  There are more lead plates per cell and they are thinner in design which allows the chemical to electrical transfer to be more aggressive (and vice versa).

Deep cycle battery (your typical 6VDC golf cart battery) is designed for low amerage of an extended time periods.  The lead plates are of heavier construction.  These do last longer (age) due to the heavier construction and are more forgiving if you inadvertantly draw the charge down below 50%.

Marine Batteries are a comprimise between chassis and deep cycle.  They perform deep cycle operations fairly well (i.e a trolling motor) but, by design, also provide the higher current capability needed to start an evinrude outboard motor (ergo the name Marine Deep Cycle).

So, different designs for different applications.  Even so, for lower to mid-range apllications, RV mfg's typically use the 12VDC Marine deep cycle version (cost cutting measure).  For higher end rigs and all diesel rigs, they almost always use true 6VDC deep cycle batteries.

I am using 4 Marine Deep Cycle batteries which gives me 400AH total which gives 200AH at 50%.

Dave

[TommyM]

LOL.. Well answer this one, what would be the purpose of using golf cart batteries instead of car batteries, or whatever I am supposed to be using. I dont even know that..lol.. I always used car batteries in my travel trailer

In addition to Mark's & Dave's replies, look at posts #55 and following in this thread:

http://www.classicwinnebagos.com/forum/index.php?topic=5910.50

In particular, notice the comments by Kevin about the golf cart batteries, and about what I've had to do to fit them into Chieftains like yours and mine.

Tommy