Engine battery drain

Topic: Engine battery drain (Read 1722 times) previous topic - next topic

Re: Engine battery drain

Reply #25 – June 02, 2020, 03:32:23 pm

Thanks Brett. It seems like they always are at about 12.2-12.5 or somewhere around there. Usually below 13v. Except when I put the 110v battery tender on it.

Re: Engine battery drain

Reply #26 – June 02, 2020, 03:40:14 pm

12.8 is a fully charged battery at rest.

Re: Engine battery drain

Reply #27 – June 02, 2020, 03:43:35 pm

50% discharge is damaging them. External solar panel? Or remove the batteries?

Re: Engine battery drain

Reply #28 – June 02, 2020, 04:48:10 pm

Quote from: Caflashbob – June 02, 2020, 03:43:35 pm

50% discharge is damaging them. External solar panel? Or remove the batteries?

I don't have a solar panel. I'll look into one tonight. I wouldn't think one to maintain the batteries in a situation like this would be overly expensive.

Re: Engine battery drain

Reply #29 – June 02, 2020, 04:56:31 pm

Just curious. What would the voltage be at 50 percent discharge?

Re: Engine battery drain

Reply #30 – June 02, 2020, 05:00:52 pm

12.2 VDC is the commonly accepted 50% SOC.

Re: Engine battery drain

Reply #31 – June 02, 2020, 06:23:01 pm

Removing the batteries this time of year will just keep the discharge process going. Rather than me giving a clumsy explanation, read the page here: Battery Basics - Progressive Dynamics

Pierce

Re: Engine battery drain

Reply #32 – June 02, 2020, 09:34:41 pm

I hooked my truck up to it yesterday because it was at 11.1v. I need to get these voltages all squared away and clean all my connections. Then move on to why it doesn't want to start very good.

I really appreciate and value everyone's input on here. We couldn't afford to own one if we had to take it to a shop every time something needed fixed.

Re: Engine battery drain

Reply #33 – June 02, 2020, 09:38:02 pm

Quote from: DJ and Jane – June 02, 2020, 03:10:24 pm

I checked the voltage on the engine batteries. They're at 12.20v. Yesterday when I disconnected them they were at 12.24.

If the voltage keep going down with the battery disconnected, you have an internal short* that is only going to get worse. When you choose to replace the battery depends on you pain tolerance. I met a person on this list who tried to get by with too little battery. He learned just how expensive the starter motor can be to purchase.

*In my personal experience, the lead sponge that makes up the active material in a lead acid battery slowly sifts down to the bottom of the battery cell where it piles up until it touches the bottom of one or more plate. AGM and Gel constructions delay this action.

FWIW I use Battery University as my main on-line source for battery facts and figures. More reliable than my memory.

Re: Engine battery drain

Reply #34 – June 02, 2020, 09:58:39 pm

Quote from: Old Toolmaker – June 02, 2020, 09:38:02 pm

More reliable than my memory.

Same here. I think smart phones have made it worse. I will check out battery university. We've got all AGM's.

Re: Engine battery drain

Reply #35 – June 02, 2020, 10:40:48 pm

Asked my guru buddy today what 50% discharged would be on gels. 12.4. Which equates to 12.2 for agm's.

Re: Engine battery drain

Reply #36 – June 03, 2020, 02:00:43 pm

The reason that a gel battery at 50% discharge reads 12.4 rather than 12.2 (the accepted 50% discharge voltage) is because the internal resistance of a gel battery is lower than the internal resistance of a flooded battery. The fully charged voltage of a gel is also higher than the fully charged voltage of a flooded battery, such that the voltage drop to 50% discharged is circa 0.5 volts for any battery.
On a side note: using a battery desulfator also raises the fully charged and 50% discharged voltages. The previous gel batteries I had actually reached 13.1 volts when fully charged. I have not measured the fully charged voltage of the AGM batteries I currently have.

Re: Engine battery drain

Reply #37 – June 03, 2020, 02:34:48 pm

My Guru buddy yesterday mentioned the resting 13.1 volts for mk gels as well as the 12.4 volts at 50% discharged.

Thank you for the input. I built up three precision test/load bank setups to test all my 7 year old gels at once just for time constraints.

Have not finalized the amount of load I will use as each device is adjustable from zero to 20amps.

Separately powered. Not off the batteries themselves.

Any input Wyatt? You would like the setups. May lend them out after testing

Re: Engine battery drain

Reply #38 – June 03, 2020, 04:23:45 pm

Quote from: Caflashbob – June 03, 2020, 02:34:48 pm

Have not finalized the amount of load I will use as each device is adjustable from zero to 20amps.

Separately powered. Not off the batteries themselves.

Bob, I look forward to your test results. On the following two links from my Dropbox, at the bottom of the screen that pops up, click on continue to wesite.

Found this info from Deca on capacity testing their Gel 8D and record keeping of testing.
https://www.dropbox.com/s/9xmd9hsmzf6o683/8A-8G-IO-Manual-1833%20%281%29.pdf?dl=0

Gel tech manual from East Penn.
https://www.dropbox.com/s/so0pah5514crtug/0139%20%286%29.pdf?dl=0

From MK.
https://youtu.be/vCRDWN_6K8U

From beamalarm.
Load Testing Gell Cell and AGM Batteries

An interesting read from some others that did capacity testing on their 8D.
Lifeline Batteries: Long Term Review and Capacity Test | Expedition Portal

Some history on MK built by East Penn.
MK Battery Celebrates 30 Years of Business - East Penn Manufacturing

Re: Engine battery drain

Reply #39 – June 03, 2020, 07:09:21 pm

Great machine. Can print reports or go to usb. $1070.

My guru buddy yesterday mentioned I was the only rv'er who had ever asked him these type of questions.

Which is a good thing. I think

Especially if you might REALLY. need the coach to work correctly.

I have 3 of these.

12V Electronic Load Battery Capacity Tester Module 0-20A 250W Intelligent...

And three of these

Powerwerx Watt Meter, DC Inline Power Analyzer, 45A Continuous, 12 Gauge,...

And a bunch of Anderson powerpole cables to connect them

And three 12 volt separate power supplies to power the testers

As an Amazon Associate Foretravel Owners' Forum earns from qualifying purchases.

Re: Engine battery drain

Reply #40 – June 13, 2020, 10:51:56 pm

A little update:

Last week I got around to getting the batteries out and brought them home to put a charger on them to run some tests to see how the voltage held up. I had one that didn't seem to want to hold a charge so I took them to O'reillys to get them tested. Out of the three one was bad according to their machine. Another one said that it had 25% life left. The guy didn't seem like he knew what that meant. I didn't get a chance to see what the other was said. They ended up replacing the one that was bad. This morning, I went to the coach to put them in. First I removed all of the cables and cleaned all of the connections including on the starter. I found some conductive grease at Lowes with zinc and added it to the connections before I reconnected them. I hope that will help. Just before I went to put the batteries up in the rack I thought I should check them quick. the new one read 12.6v and the old ones read 12.53v and 11.74v. Both of them had been on the charger within the last two days. I took the 11.74v one with me to get retested. now that I think of it I may go back in the morning and check the other old one to be sure.

Re: Engine battery drain

Reply #41 – June 13, 2020, 11:31:20 pm

If it were me, I'd change all 3.

Re: Engine battery drain

Reply #42 – June 14, 2020, 12:37:38 am

Only a set.

Re: Engine battery drain

Reply #43 – June 14, 2020, 04:09:30 am

Quote from: DJ and Jane – June 13, 2020, 10:51:56 pm

A little update:

....... They ended up replacing the one that was bad.
........Just before I went to put the batteries up in the rack I thought I should check them quick. the new one read 12.6v and the old ones read 12.53v and 11.74v. Both of them had been on the charger within the last two days. I took the 11.74v one with me to get retested. now that I think of it I may go back in the morning and check the other old one to be sure.

You say "they ended up replacing", was it under warranty? Good advice from others to replace all three. Being on charger two days, does not mean they are fully charged. It depends on charge amps, voltage, and battery charge profile. Good agm batteries, when fully charged, will test at rest, and not combined, 12.8 volts or above. That is from the maker of the grey cased, black top AGMs, that East Penn make.

Re: Engine battery drain

Reply #44 – June 14, 2020, 07:36:30 am

Quote from: Jack Lewis – June 14, 2020, 04:09:30 am

You say "they ended up replacing", was it under warranty?

It was under warranty. I replaced them all at the same time. I'm going off of my battery tender with a solid green light which is supposed to mean fully charged.

Re: Engine battery drain

Reply #45 – June 14, 2020, 10:03:54 am

I had a trickl Charger green light on that put out no power,

Re: Engine battery drain

Reply #46 – June 14, 2020, 10:20:03 am

Quote from: Caflashbob – June 14, 2020, 10:03:54 am

I had a trickl Charger green light on that put out no power,

Thanks Bob, This one's working. I make sure to check it. It's been putting out like 13.6v. It got the other one up to 12.5v. The more I think about it the one in the coach is probably working right but the house batteries go below 13v for so long before the gen kicks on it isn't keeping the engine batteries up. The one in the coach stops charging the engine batteries below 13v and it won't charge if there's over 2v difference between them. I'm going to go get the other battery, check it and take it to get it tested again with the other one.

Re: Engine battery drain

Reply #47 – June 14, 2020, 08:14:28 pm

Alright, I got them both tested one was bad. I hoped the other one was but two places couldn't kill it for me. I had a professional That could read/use the DVM properly come over and help me reinstall the batteries and check my voltages all came out good. I turned the boost on just because. The engine turned over and fired right up like it had been running all day.

Re: Engine battery drain

Reply #48 – June 14, 2020, 08:24:15 pm

Also one of the lugs or whatever it's called had a big cut in it when I was cleaning them the other day. I replaced it. I'm not sure where it goes because the label was gone.

Re: Engine battery drain

Reply #49 – June 15, 2020, 01:55:05 pm

Peel the cover back to ensure it's not green and crappy inside.

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