Coach and Engine Batteries

Topic: Coach and Engine Batteries (Read 972 times) previous topic - next topic

Coach and Engine Batteries

June 18, 2016, 03:03:45 pm

I went out to the coach today to turn on the refrigerator to get ready for our trip to Prescott Arizona at the end of the June and thought I should check the batteries.

With everything still hooked to the batteries this is what I came across:

Lifelines all read 13.13 vdc
Redtops all red 5.36 vdc

I thought that my in dash radio ran off of the engine batteries for some reason but it was playing just fine.
I removed the hardware for the first Redtop battery and cleaned everything real good and took another reading and it still read 5.36 vdc.
I then turned on the generator and it started just fine. I put on the boost switch and the lifelines now read 14.00 vdc and the Redtops read 13.09 vdc.

The coach has been sitting for about 8 months in the driveway hooked up to 30 amp electric and every month I start the genny and the aquahot. Run the air conditioners and other stuff to exercise the genny.

Can I charge the Redtops this way or do you all "like myself" think that the Redtops are toast?

Thank you for any and all help on this.
Greg Kemper

Re: Coach and Engine Batteries

Reply #1 – June 18, 2016, 03:16:36 pm

I suspect they are toast with the voltage so low. For storage you need to disconnect the chassis batteries if they aren't getting charged. Parasitic loads otherwise drain them.

You could try charging them through the main charger and boost switch and see if they recover.

The alternative to disconnecting is adding a battery tender or battery minder to keep them trickle charged.

Re: Coach and Engine Batteries

Reply #2 – June 18, 2016, 03:20:54 pm

Be sure to use a smart multi-stage battery minder sort of charger. Much better for the batteries. It is possible that they may recover but I doubt it. The only way to know for sure us to try to charge them and have battery load test done on each battery.

Re: Coach and Engine Batteries

Reply #3 – June 18, 2016, 03:26:09 pm

Agree with Tom and Roger. From what I have read, a battery at that low state of charge for an extended time will be permanently damaged.

Re: Coach and Engine Batteries

Reply #4 – June 18, 2016, 04:14:22 pm

The only things that run on the start battery are your head/running lights and the cigarette lighter. If you have 2 lighters, only 1 is wired to the start battery.

If 1 battery loses a cell it will pull all the batteries down. What I would do is put a charge on the red tops for a day, then disconnect the charge source for 4 hours. Read the voltage at that time (hopefully it will be 12.6'ish or the batteries are toast) and if it is 12.6'ish turn the headlights on for a couple of minutes. Turn them off, wait 10 minutes and measure the voltage again. It it goes back to 12.6'ish, the batteries are fine. If not then they will not hold a charge.

Re: Coach and Engine Batteries

Reply #5 – June 18, 2016, 04:27:53 pm

Twig

That's a good plan. I also think a heavy load test is recommended (1/2 CCA draw for 15 seconds).

Re: Coach and Engine Batteries

Reply #6 – June 18, 2016, 04:53:25 pm

Thank you all for your help on this subject. I don't have a battery charger available at this time so I'm using the boost switch and the generator. I've been running about 2 hrs now and the redtops are at 13.76 with the boost switch on and 12.52 with it off.

Re: Coach and Engine Batteries

Reply #7 – June 18, 2016, 05:09:35 pm

Greg

Your inverter/charger, on shore power, should charge all batteries with the boost on, so you can save diesel and not run your generator. Either way will work.

You will want to leave the boost on for 6-8 hours to get through the absorb phase and make sure the red tops are fully charged.

A quick way to test after charging is to crank the engine. If it spins up fast like normal, maybe you dodged the bullet...

Re: Coach and Engine Batteries

Reply #8 – June 18, 2016, 05:21:22 pm

Peter,
Thank you for the info. I wasn't sure which would be better having only 30 amp service. But we are having a little heat wave in Southern California so I'm enjoying the air conditioning right now. I will plug in as the sun goes down and charge using the shore power.

Re: Coach and Engine Batteries

Reply #9 – June 18, 2016, 06:24:10 pm

Quote from: Twig – June 18, 2016, 04:14:22 pm

The only things that run on the start battery are your head/running lights and the cigarette lighter. If you have 2 lighters, only 1 is wired to the start battery.

If 1 battery loses a cell it will pull all the batteries down. What I would do is put a charge on the red tops for a day, then disconnect the charge source for 4 hours. Read the voltage at that time (hopefully it will be 12.6'ish or the batteries are toast) and if it is 12.6'ish turn the headlights on for a couple of minutes. Turn them off, wait 10 minutes and measure the voltage again. It it goes back to 12.6'ish, the batteries are fine. If not then they will not hold a charge.

Actually, the start battery is continually drained by computers and memory in your engine and transmission computers and radio. There may be more parasitical.

After charging the batteries, you can disconnect them and measure individual voltages to see if all are equally bad. It might be just one with a shorted cell, which you can leave disconnect and probably get by with only two batteries. I did that one time, then replaces the bad one with a blue top I had laying around. I got another three years out of that set.

Re: Coach and Engine Batteries

Reply #10 – June 18, 2016, 06:39:05 pm

Tom,
Thank you for your input. I've turned off the genny for now and hooked back up to shore power 30 amp with the boost switch still on. The Lifelines are at 14.02 and the Redtops are at 13.86. I will leave it on for another 5 hrs or so then recheck.

Thanks again to all that have help out on this. This forum is truly awesome!

Greg

Re: Coach and Engine Batteries

Reply #11 – June 19, 2016, 12:16:19 am

ALL coaches need a common inexpensive device to keep start battery bank under charge when house batteries are being charged. The most popular, simple & reliable unit is Trik-L-Start.
Ultra TRIK-L-START Starting Battery Charger/Maintainer Just a waste to have a coach pugged in and only charge one battery bank.

Re: Coach and Engine Batteries

Reply #12 – June 19, 2016, 02:25:08 am

Barry,
Thank you for the link to the Trik-L-Start unit. I does look like the way to go for us.

Re: Coach and Engine Batteries

Reply #13 – June 19, 2016, 03:16:59 pm

Update: I turned off the boost switch last night around 9:30 pm and the Redtops were reading 12.61 vdc just as Twig had said above. This morning at about 10:00 am the Redtops were reading 12.25 vdc. I turned on the head lights for a couple of minutes and the voltage went down to 11.96 vdc. After turning them off the voltage went back up 12.25 vdc.
I did notice earlier before turning off the boost switch that both the Lifelines and the Redtops voltage reading had dropped down to 13.03 vdc.

Should I put them back on the charge through the boost switch and if so how long can I keep that on?

Thank you again

Greg

Re: Coach and Engine Batteries

Reply #14 – June 19, 2016, 03:37:31 pm

Greg,

Those voltage drops, absent an extraordinary parasitic load (need to verify) is a pretty good indicator of a failed battery bank.

You could also fully charge them (boost switch on) and then have them load tested by any store that sells batteries (usually free).

Re: Coach and Engine Batteries

Reply #15 – June 19, 2016, 04:54:57 pm

Yes. 12.2 would indicate a shorted cell, especially if they dropped with no load.

Shop around for red tops. I've found them online for $145 delivered.

Re: Coach and Engine Batteries

Reply #16 – June 19, 2016, 06:21:15 pm

Several months ago, I replaced my two yellow tops with three red tops. When I took the yellows out, I charged them individually and left them sitting, except for some occasional LED testing,

Today I measured their voltages; one read 12.99, and the other 12.93.

From this, I can draw a couple of conclusions:

1) These batteries were not at death's door, which was one of the reasons I replaced them.

1A) The symptoms that caused me to think they needed replaced have not yet been addressed (e,g, significant drop in voltage while cranking, and the need to use the boost switch at times; although three new red tops should help).

2} We have discussed parasitic loads from time to time, but the fact that these are *not* draining, means that the parasitic loads are much higher than I had imagined.

3) If I install these as a third battery bank via the isolator, without attaching any load, will that cost me much more in maintenance than my existing two battery banks do? I still have the original Foretravel wiring harness, so I could keep them charged as a backup or reserve when needed. Since I have the chassis batteries installed via busbars, it would be easy to put them online by attaching two more wires to the busbars.

Any thoughts or observations from my more experienced brethren?

Thanks,

Trent

Re: Coach and Engine Batteries

Reply #17 – June 19, 2016, 07:22:25 pm

Quote from: TulsaTrent – June 19, 2016, 06:21:15 pm

Today I measured their voltages; one read 12.99, and the other 12.93.

1A) The symptoms that caused me to think they needed replaced have not yet been addressed (e,g, significant drop in voltage while cranking, and the need to use the boost switch at times; although three new red tops should help).

]

YellowTops will hold voltage for a long time. 12.9's are pretty good. Hang on to them, keep them on a smart charger.

Significant voltage drop is not unexpected under big loads. What did they bounce back to after the load? Using the boost switch is not a bad thing but your ISC350 ahould turn over pretty well with two batteries. I would be looking at every terminal and every connection. There are probably two cable posts, one positive, one negative. They need to be clean and tight. Check the cables to the starter, clean and tight? Bad or dirty or loose connections can easily rob you of a volt or two and really disrupt starting performance. Be sure you disconnect the negative cables first and reconnect last. Use CorrosionX or an anti corrosion grease on every connection. This is not too hard to do but a must do. Make sure you take care of the basics before moving to more complicated and expensive actions.

Re: Coach and Engine Batteries

Reply #18 – June 20, 2016, 11:54:37 am

Roger is right on.

Back to Trent conclusions:
1) Confirm battery health with load test as Roger suggested
1A) As Roger's advices
2) 12V Aux AirPump also operate from the chassis batteries
3) Third bank battery only sounds good now because you have 2 spare yellow top batteries. In the long run, they will need to be replaced with age. Putting 2 brand new in its place just to have peace in mind and may never need make me think twice about it.

Thanks,
Michael

Re: Coach and Engine Batteries

Reply #19 – July 10, 2016, 12:55:06 pm

Is 5amp trik-l-start enough for 3 red tops..?? they do offer amp-l-start with 15amp output. Or is 15amp overkill.

Thx

Hans

Re: Coach and Engine Batteries

Reply #20 – July 10, 2016, 01:17:45 pm

Quote from: Hans&Marjet – July 10, 2016, 12:55:06 pm

Is 5amp trik-l-start enough for 3 red tops..?? they do offer amp-l-start with 15amp output. Or is 15amp overkill.

Hans,

We have the 5 amp and it keeps up with the parasite draws on our coach just fine. We were going to upgrade to the 15 when ours just quit but trik-l-start warranted the dead one with another 5 amp and it is still going strong.

Pamela & Mike

Re: Coach and Engine Batteries

Reply #21 – July 10, 2016, 01:22:14 pm

I agree. It's sized for the parasitic drain, not the number of batteries.

Re: Coach and Engine Batteries

Reply #22 – July 10, 2016, 01:42:55 pm

The red tops are agm batteries,get a charger designed for agm batteries,if you look at the optima site that's what they suggest.

Re: Coach and Engine Batteries

Reply #23 – July 10, 2016, 02:01:00 pm

I am using the Optima Red Tops along with their "Model 400" maintainer. I route the wire up into the bedroom with the control. mounted it on the side of the bed. FT in their infinite wisdom knew to install an outlet there. Everything is hidden under the bed skirt. I plug in my shoreline and confirm the the maintainer is set properly and I am done. Sorry I cannot post pics as my coach in at FOT having the refrigerator (Samsung) conversion done along with the usual list of other items. Picking her up at the end of next week.
Then going somewhere for a week or so.

Re: Coach and Engine Batteries

Reply #24 – July 10, 2016, 02:45:07 pm

My batteryMinder set for AGMs at 8 amps max will put my three yellowtops at float in just a few hours. If they haven't been plugged in for a couple weeks, maybe a day.

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