Author Topic: Battery expertise  (Read 17357 times)

Adam Hicklin

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Battery expertise
« on: April 12, 2013, 05:52:09 PM »
Having not owned this coach since it was new I'm finding that I just don't know what is as it should be and what is a problem.  So I turn to the BAC forum expertise.  I think I'm having a battery problem.  

The coach sat for a week, not being run and not plugged in.  Only charging source would be the solar panels.  I decided to throw a volt meter on the batteries and this is what I found.  Nothing on, at rest, the two 12V chassis batteries read 12.3V  The 6, 6V batteries read 6.1V individually and 12.3V for the bank.

I started the coach.  Chassis group read 13.3.  House group read 13.3  Interestingly, the volt meter on the dash read just over 16V, which it always reads (thats what made me start to investigate potential problem)

Plugged the coach in.  Chassis group stayed at 12.3V  House group was up at 14.2V

Multiple questions.  Shouldn't the charger, while plugged in, be charging the chassis battery also?  Shouldn't the alternator be charging at a higher rate? (I ran it at 1000 RPM for about 10 minutes, didn't fluctuate.)  Do I just have a bad dash V gauge and is this something to worry about?  Anything else I'm not smart enough to ask?

As always, thanks for your help.

Gerald Farris

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Re: Battery expertise
« Reply #1 on: April 12, 2013, 07:17:48 PM »
Adam,
The first thing that I can tell you is not to worry about the dash gauge as long as you know were it should run. The analog gauges in your dash are famous for inaccuracy. The common phrase is that they are for entertainment purposes only.

The next thing that you need to know is that there is always a drain on your chassis batteries unless you disconnect the cable or add a disconnect at the batteries. The ECM (engine control module) is always powered, even with the factory installed disconnect switches turned off. The normal current draw of the ECM will kill the chassis batteries in about a week on most coaches without the solar panels (stored inside).

The next thing is that the alternator was probably not able to produce any higher voltage with both of the battery banks discharged as much as they were. Your alternator can only produce 160 amps under perfect conditions. If the alternator will not produce more than 13.4 volts with charged batteries, it either needs the adjustable regulator adjusted or replaced.  

The next thing is that the inverter does not charge the chassis batteries. The chassis batteries are charged by the Echo Charger on your coach. If the chassis batteries do not charge up after you are on shore power a few hours while the house batteries are being charged, check the Echo Charger.

Gerald  

Adam Hicklin

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Re: Battery expertise
« Reply #2 on: April 12, 2013, 11:07:27 PM »
That clears some things up.  A fully charged battery should be at what voltage?  Conceivably, once everything is charged, and the coach is started, the alternator should kick out just over 14 volts, correct?  If I understand you correctly, the inverter will charge the house batteries first, then the Echo charger takes over?  Not exactly sure how that works.  Where does the echo charger get its power from.

Thanks Gerald.  I appreciate your expertise.

Gerald Farris

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Re: Battery expertise
« Reply #3 on: April 13, 2013, 02:54:39 AM »
Adam,
The alternator on your coach when cold with fully charged batteries should produce 14.2V to 14.5V. The output voltage for your coach alternator will normally drop about 1/2 of a volt below that reading as the alternator heats up.

The Echo Charger uses the house batteries as a power source when they are being charged. You can go to the Xantrex website to download the Echo Charger operators manual.

At 8o degrees with the battery sitting for 6 hours without being charged or discharged, a fully charged 12V battery will have 12.73 volts. You can find a state of charge chart at; http://www.trojanbattery.com/batterymaintenance/testing.aspx

Gerald

Richard And Babs Ames

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Re: Battery expertise
« Reply #4 on: April 13, 2013, 01:04:36 PM »
On our 1997 Patriot the chassis batteries did not have any charge source from the shore power or Onan generator. We found out the hard after using the Onan for a forced 11 day dry camp after hurricane Charlie. Beaver's reaction "our bad". We added an Echo Charger at about $90 and the problem was solved. BTY the Onan starts off the chassis batteries and has a draw on them when running .

Some owners use a Battery Minder" if they have a nearby 110 power source in the coach.

Adam Hicklin

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Re: Battery expertise
« Reply #5 on: April 16, 2013, 07:12:07 AM »
Ok, this is starting to make some sense.  Let me ask...if the coachis plugged in to shore power, should the charge function on the inverter be on all the time?  I know it has three different level of charge, But does that mean it should always be on while plugged in?  

Joel Ashley

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Re: Battery expertise
« Reply #6 on: April 16, 2013, 07:32:11 AM »
There is always some sort of parasitic load on the battery banks, and the inverter's charger needs to replace it.  Once they are fully charged, float charge maintains them, so it is common to see the charge lamp on when you check it, even after having been plugged in for some time.

Joel
Joel and Lee Rae Ashley
Clackamas, Oregon
36.9 ft. 2006 Monterey Ventura IV, aka"Monty Rae"
C9 400HP Cat

Bill Sprague

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Re: Battery expertise
« Reply #7 on: April 16, 2013, 03:53:46 PM »
Quote from: Adam Hicklin
Ok, this is starting to make some sense.  Let me ask...if the coachis plugged in to shore power, should the charge function on the inverter be on all the time?  I know it has three different level of charge, But does that mean it should always be on while plugged in?  

I think I understand your question, but each coach can be different so I'll explain what I do.  For me it is best to think in terms of two functions, although it is all contained in one box.

First, the three stage charging function was set up to match my batteries a couple years ago.  Except when driving and occasionally dry camping, the motorhome is plugged in and the charging takes place as the charger function sees fit.

Second, the choice of the inverter function being on or off is off no importance when plugged in.  It does not do anything unless the motorhome is unplugged from shore power -- like when driving or dry camping.  That said, I leave my inverter turned on so that when I am driving our computers and cell phones can charge and all the lights work.  Many see that as unnecessary and only and extra load on the engine alternator.

There is one caution.  If you leave the inverter on while driving elect to take a break and run things like the microwave you will be converting battery energy into 120 volt energy.  The house batteries will be in a discharged condition and the relatively small engine alternator will have to replace that energy.  If the amount is significant the engine alternator will have to work pretty hard for an extended time.  It can get hot and have a shorter life!  The solution is, when the house batteries have been discharged, run the Onan.  It has far greater capacity.


Adam Hicklin

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Re: Battery expertise
« Reply #8 on: April 16, 2013, 04:03:19 PM »
Thanks Joel and Bill.  I guess I was expecting the charge light on the panel to always be on when plugged in, assuming at a minimum the float function would always be on.  What I'm hearing is that may or may not be the case.  Correct?

Joel Ashley

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Re: Battery expertise
« Reply #9 on: April 17, 2013, 03:00:26 AM »
Adam, on my rig when fully charged and plugged in, the Magnum screen says float charge or full charge always, but the chg lamp is usually out.  I wouldn't be concerned if it was on or not.  It is mainly for when you manually hit the Charge button so you know it is on, but use of the manual button is rare.

Your inverter/charger may not be a late model Magnum, but the principle idea should be the same.

Joel
« Last Edit: April 24, 2013, 01:13:11 AM by 77 »
Joel and Lee Rae Ashley
Clackamas, Oregon
36.9 ft. 2006 Monterey Ventura IV, aka"Monty Rae"
C9 400HP Cat

Joel Buchan

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Re: Battery expertise
« Reply #10 on: April 18, 2013, 02:30:46 AM »
4 Solar panels with a good controller and all AGM battery's will make life some muck easier. Plus it will solve wear on your alternator and extend its life.  Expensive yes, but well worth it.

Jeff Watt

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Re: Battery expertise
« Reply #11 on: April 22, 2013, 07:08:35 PM »
Tying this thread to my genset starting issue, I am looking for assistance as I try to figure out my battery bank.

It appears that I have 2 Lifeline GPL-4D as chassis batteries. These are AGM, deep cycle but have 1100 CCA.  I also have 2 of these same batteries as part of my house battery bank. There are 4 Lifeline GPL-4CT 6v as well. I believe the GPL-4D are correct and think the 4CT are correct from the dimensions and from the electrical schematic book.

If I change the house batteries (so I can start the genset and have reliable house power) should I stay with these size of batteries. I have physical room to but bigger batteries (not taller) where the 4 small batteries are located. I see from the Lifeline page, these 6V batteries are better than the GPL-4D in discharge rate.

I don't have a Lifeline distributor near me (closest is 2.5 hrs and I'd have to cross into North Dakota and then pay possible duties/fees when import back).

It is somewhat confusing to me that I have 6 and 12 volt batteries in the same bank, although I understand how it is done. Lifeline does suggest equalizing them if they do not hold charge well but given they are 6+ years old I don't know if that makes much sense to try.

I know from past experience the battery store in Winnipeg is a Trojan fan and will likely try to convince me to use Trojan. Good batteries, although I am now partial to the 0 maintenance aspect of the AGM, albeit more considerably more expensive (last year the Trojans were $165 and equivalent AGM was $335 - I know we are gouged in Canada but that seems quite a difference in price.) I will contact the Lifeline dealer in Grand Forks ND and see what their price is for replacements - may make the drive worth it.

I guess I'm not sure what I am asking, just looking for thoughts and suggestions re. batteries.

Jeff

http://www.lifelinebatteries.com/rvdeepcyclebatteries.php

Joel Ashley

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Re: Battery expertise
« Reply #12 on: April 22, 2013, 11:18:51 PM »
I just was reading my solar manual the other day, and not being a fan or owner of AGM's I was newly informed when it said you have to reset the solar controller for AGMs since they aren't ever equalize charged like wet cells.  My solar controller apparently automatically equalize charges once a week or so, but only for wet cells;  which is why you have to reset it if AGMs are used.

I know there is plenty of controversy here, but I would not put out the extra money for AGMs, mostly because having grown up on and run a farm, maintaining wet cells is not a big deal to me - especially if it saves money, and my units are original to our '06 coach and doing just fine.

The fact that you have such a mixed bag of coach batteries is certainly notable.  I'm not sure how you'd set your charge controller for either the solar system or your inverter.  Mine need to know which type they are charging, AGM, Gel, or wet cell - but only one.  I'd consider reconfiguring your coach ones all alike and the same age.

Joel
Joel and Lee Rae Ashley
Clackamas, Oregon
36.9 ft. 2006 Monterey Ventura IV, aka"Monty Rae"
C9 400HP Cat

Adam Hicklin

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Re: Battery expertise
« Reply #13 on: April 23, 2013, 07:22:52 AM »
Where would I find my solar charge controller?  Also, will usine my equalizing feature one my Prosine inverter only equalize the house batteries or both the house and chassis?

Gerald Farris

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Re: Battery expertise
« Reply #14 on: April 23, 2013, 02:46:48 PM »
Adam,
I am not sure where the solar controller is located on your coach, but it is probably either on the rear basement wall or under the bed.

Equalizing the batteries with the inverter on your coach will only equalize the house batteries.

Gerald