Community Forums

Crankshaft · 09-17-2017, 11:55 AM

Haven't started the RV in a few weeks. The chassis battery (Motorcraft BXT-65-750) is dead even though it's been on a battery tender. I tired the battery boost button but that did nothing, I didn't want to boost too long, afraid of what it might do to the house batteries. Unplugged the battery tender, waited 5 minutes and checked the battery with a meter. It had 11.2 volts. Toast I assume?

The RV is a 2015, the chassis is a 2014 but I can't believe a battery lasted 3 years.

If it's really the battery and not something else, should I stick with a Motorcraft battery or something else. The search I ran lead me to believe that almost anything will be good because they are all basically made by 2 companies.

Lastly, the negative terminal clamp was corroded but cleaned at the beginning of the summer. Now it's bolt is rusted and that clamp isn't budging. Any ideas to get it off?

Thanks

Fred

ladagobago · 09-17-2017, 12:01 PM

Quote:

Originally Posted by Crankshaft

Haven't started the RV in a few weeks. The chassis battery (Motorcraft BXT-65-750) is dead even though it's been on a battery tender. I tired the battery boost button but that did nothing, I didn't want to boost too long, afraid of what it might do to the house batteries. Unplugged the battery tender, waited 5 minutes and checked the battery with a meter. It had 11.2 volts. Toast I assume?

The RV is a 2015, the chassis is a 2014 but I can't believe a battery lasted 3 years.

If it's really the battery and not something else, should I stick with a Motorcraft battery or something else. The search I ran lead me to believe that almost anything will be good because they are all basically made by 2 companies.

Lastly, the negative terminal clamp was corroded but cleaned at the beginning of the summer. Now it's bolt is rusted and that clamp isn't budging. Any ideas to get it off?

Thanks

Fred

any battery can crap out at any time. in your case i would replace with an AGM for quick starts. If you have corrosion and rust it would indicate to me anyway that you should improve the maintenance of the battery connection with a can of battery protector spray (red) sold in auto section of stores.

You could have an overcharging condition too. check the charge voltage with a meter

Arch Hoagland · 09-17-2017, 01:10 PM

How much water was in the cells?

MCJones · 09-17-2017, 01:24 PM

I wouldn't automatically toss the batteries. I've brought my starting batteries back from a 9v state over a 4 day period using a 2 amp charger. I had left the seat heater on and for some reason, it is powered by the chassis bats. So, I don't do that anymore and the bats are fine again. Something drew your batteries down I bet..jmo mark

twinboat · 09-17-2017, 01:30 PM

Did you test the battery at the posts or the terminals.

If you test volts on the terminals and they are corroded, you don't see the battery volts. You see the resistance thru the corrosion.

Go directly to the actually battery posts.

Crankshaft · 09-17-2017, 02:00 PM

Quote:

Originally Posted by ladagobago

any battery can crap out at any time. in your case i would replace with an AGM for quick starts. If you have corrosion and rust it would indicate to me anyway that you should improve the maintenance of the battery connection with a can of battery protector spray (red) sold in auto section of stores.

You could have an overcharging condition too. check the charge voltage with a meter

When it is running, the alternator is putting out 14.5 volts and then settles down to 13.8 volts.

Crankshaft · 09-17-2017, 02:01 PM

Quote:

Originally Posted by Arch Hoagland

How much water was in the cells?

It's a sealed chassis battery

Crankshaft · 09-17-2017, 02:04 PM

Quote:

Originally Posted by twinboat

Did you test the battery at the posts or the terminals.

If you test volts on the terminals and they are corroded, you don't see the battery volts. You see the resistance thru the corrosion.

Go directly to the actually battery posts.

Right on the battery posts. In fact, I have to go check it again after restarting the battery tender. It won't bring a battery back from the dead but maybe resetting might have done something.

Stay tuned.

bluepill · 09-17-2017, 02:06 PM

Lastly, the negative terminal clamp was corroded but cleaned at the beginning of the summer. Now it's bolt is rusted and that clamp isn't budging. Any ideas to get it off?

Soak in in rust penetrant overnight. Might take a second treatment if really bad.

Winemaker2 · 09-17-2017, 02:57 PM

In general I've seen the following explanation re terminal corrosion...

In addition to the comments from others, there is a seal surrounding the battery post where it enters the battery. If any previous person applied too much force to the terminal when removing or replacing the battery cable, the seal can become compromised. A compromised seal will allow moisture from the battery to seep up cause accelerated corrosion on the terminal.

If that happens, I've found that those felt red/green battery terminal pads can help slow down the corrosion.

If you are having corrosion w/ a sealed batty I would suspect a bad seal at the post - maybe due to previous difficulty getting connection off??
A batty terminal puller might be worth having - less stress on seal - definitely coat it after cleaning & interconnecting - either vaseline of the specialty spray for battys

I noticed you metioned the negative terminal and interestingly I have also seen a distinction re which terminal is showing the corrosion...

Generally, if the corrosion is occurring on the negative terminal, your system is probably undercharging. If on the positive side, it is probably overcharging. Most often it will be seen on the negative side because the battery is usually in an undercharged situation.

Crankshaft · 09-17-2017, 02:58 PM

Battery is toast, still can't imagine why after 3 years.

I rechecked the battery on the posts, the battery tender got it up to 11.5 volts. I plugged the tender back in to make sure it was working and I had 14 volts at the posts.

So, I said lets try it one more time. Turned the key, hit the boost button and it spun like it was in frozen molasses. It started.

The voltmeter I have in the dash went to 14.5 volts which means the house batteries were getting charged.

The ScanGauge showed 14.2 at start and settled to 13.8 while running. I left it running for a while. Shut it down and it wouldn't restart without a boost. The ScanGauge showed 13.8 volts before shutdown, once off it went to 12.9, then 11.1.

Safe to assume it's toast.

What's the recommended replacement considering winter is coming and it will be sitting on the battery tender for about 5 months.

Thanks

Crankshaft · 09-17-2017, 03:25 PM

Quote:

Originally Posted by Winemaker2

In general I've seen the following explanation re terminal corrosion...

In addition to the comments from others, there is a seal surrounding the battery post where it enters the battery. If any previous person applied too much force to the terminal when removing or replacing the battery cable, the seal can become compromised. A compromised seal will allow moisture from the battery to seep up cause accelerated corrosion on the terminal.

If that happens, I've found that those felt red/green battery terminal pads can help slow down the corrosion.

If you are having corrosion w/ a sealed batty I would suspect a bad seal at the post - maybe due to previous difficulty getting connection off??
A batty terminal puller might be worth having - less stress on seal - definitely coat it after cleaning & interconnecting - either vaseline of the specialty spray for battys

I noticed you metioned the negative terminal and interestingly I have also seen a distinction re which terminal is showing the corrosion...

Generally, if the corrosion is occurring on the negative terminal, your system is probably undercharging. If on the positive side, it is probably overcharging. Most often it will be seen on the negative side because the battery is usually in an undercharged situation.

I haven't had the cables off yet, this will be my first attempt. I have get a puller, the negative cable isn't coming off too easily. They wedged the battery in there pretty good so getting it out and a new one in will be a challenge.

Based on your information it would seem like the battery may have a post seal issue. However, what I'm more interested in is what is the correct charging voltage? What is considered too low and too high?

Thanks

John Wayne · 09-17-2017, 03:35 PM

My last one I got at Costco they are all over the place and if I need to replace under warranty I can find another Costco

OLYLEN · 09-17-2017, 04:07 PM

when I replace a start battery I get the biggest baddest that will fit the space. An xtra $10-$20 means a stronger start. crossing fingers I have never been left without a start, I also replace at the first sign of a battery going south. I have been running Interstates in all my rigs, except for the deep cycles, but am running the interstate 12 volt deep cycles in the C and seem to be as good as the trojans 6 volt I had in A's.

LEN