Battery Corrosion or Leak?

[akadeadeye]

I have 4 six volt deep cycle Interstate batteries that are 5 years old. I am very good at keeping distilled water in them. I check them every month on the first day of the month. They always have a trickle charge on them in our RV garage from the on-board inverter/converter charger. It shows about 13.5 to 13.9 volts on the control panel when "float charging" and I notice there are periods where the read out shows "fully charged". Recently I noticed some evidence of leakage on the garage floor (photo attached....the batteries are up front directly above the leak spots..that's a piece of cardboard to the right). The tops of the batteries show no corrosion at all. I keep them clean and spray red stuff on the terminals to prevent corrosion.

So, what do you think is going on? I have not crawled underneath to try to look at the battery tray. It is very hard to see from below. Comments are appreciated.


Don

[Melmoses]

If your batteries are directly above then I would be pulling them out to check. If your setup is like mine they are so tight together that you can't see the bottoms or more than the edge of the tray. Only way is to remove the batteries.

[dennis45]

Not that it will solve your problem, but, the previous owner of my coach used these cut-down battery boxes to hold each battery. I have nat had any corrosion issues with my battery tray as a result.
I use the 4oz per cell Mineral Oil treatment in my house batteries and find I add much less water and the top of the batteries and cables stay clean.
I also have my coach plugged in to shore power at all times when parked.

In looking at your photo, I would suggest removing the batteries to find the source of the leak. It certainly is not going to improve without attention.

My apologies for the upside down pic. It's an iPad thing that drives me nuts.

[mel s]

Originally Posted by akadeadeye

So, what do you think is going on? I have not crawled underneath to try to look at the battery tray. It is very hard to see from below. Comments are appreciated.
Don

Don
My batteries will overflow like that if I fill them when they are not fully charged.
If the batteries are low, (on both charge and electrolyte), when you check them, add only enough distilled water to cover the plates... allow them to charge fully... and then top them off.
Mel
'96 Safari,
On the 3rd set of batteries...(both of my 1st 2 sets lasted 9 years).

[akadeadeye]

Originally Posted by mel s

Don
My batteries will overflow like that if I fill them when they are not fully charged.
If the batteries are low, (on both charge and electrolyte), when you check them, add only enough distilled water to cover the plates... allow them to charge fully... and then top them off.
Mel
'96 Safari,
On the 3rd set of batteries...(both of my 1st 2 sets lasted 9 years).

Mel,

I think overfilling could be my issue. I fill them to the bottom of the plastic, if you know what I mean. Your reasoning makes sense. I just never know when they are fully charged. Only by accident do I look in on the control panel and read "fully charged". It almost always reads "float charging".

Don

[akadeadeye]

To Dennis and (other) Mel,

Thanks. I have never removed a battery from my motorhome. Besides unplugging shore power do you flip the "battery disconnect" switch?

You are correct. Unless it is just an overfill problem, they will not heal themselves.

Don

[TQ60]

Calibrate your meter!

Float charge should be 13.5 volts ish...

Data sheet will specify preferred voltage but 13.5 will usually be in the allowed range.

This is the voltage AT THE BATTERY not at the charger.

There are many connector, wire and other voltage drops between the battery terminals and the points inside the mh.

Get a good accurate meter and with unit plugged in and charging measure voltage at battery and compare to your inside meter.

Float charge is critical and is usually 0.1% C so a tenth of a volt can be difference between needing to add water often or not often.

[dennis45]

Originally Posted by akadeadeye

To Dennis and (other) Mel,

Thanks. I have never removed a battery from my motorhome. Besides unplugging shore power do you flip the "battery disconnect" switch?

You are correct. Unless it is just an overfill problem, they will not heal themselves.

Don

Don,
If you decide to remove the batteries to clean up the tray, take a photo of the connections before you start so you have a reference putting them back.
Unplug your shore power and turn off the house batteries inside.
Now, remove the Negative Cables first and then the Positive Cables. That way you won't accidentally cause a short to ground while removing the cables.
I wrap each connector once removed with a bit of tape while I'm working just as a precaution.

You can do your clean up using a Baking Soda/Water solution and rinse throughly with water. CAUTION! when using the Baking Soda solution that you don't get any near the battery caps. Baking Soda in the battery will neutralize the Electrolyte and ruin the battery. If you can, simply rinse the batteries with a hose to avoid any problem with the soda.
If the tray is corroded, you will want to sand, prime and paint. Use the same solution and a wire brush to clean the cables.
Good contact between cables and terminals is critical for a good operating electrical system.

Once you have everything cleaned up and ready to install, install the cables in the reverse order. Positive Cables first, then the Negative. This is where your photo is going to come into play.

I use a Dielectric Grease smeared on all the cable connections as I assemble them as opposed to the Spray-on stuff. I personally feel it lasts longer. You can get small tubes of this at any Auto Parts Store.

As mentioned, I have added 4oz per cell of Mineral Oil (Wally World Pharmacy) to mine. Keeps the area clean and extends the interval I need to add water. There are numerous threads on this subject if you want to look further.

Feel free to PM me if you have any questions. Good Luck.

[akadeadeye]

Originally Posted by TQ60

Calibrate your meter!

Float charge should be 13.5 volts ish...

Data sheet will specify preferred voltage but 13.5 will usually be in the allowed range.

This is the voltage AT THE BATTERY not at the charger.

There are many connector, wire and other voltage drops between the battery terminals and the points inside the mh.

Get a good accurate meter and with unit plugged in and charging measure voltage at battery and compare to your inside meter.

Float charge is critical and is usually 0.1% C so a tenth of a volt can be difference between needing to add water often or not often.

Impressed with your knowledge. But, how do I calibrate the meter? What meter? Where? Calibrate with what?

Don

[akadeadeye]

Originally Posted by dennis45

Don,
If you decide to remove the batteries to clean up the tray, take a photo of the connections before you start so you have a reference putting them back.
Unplug your shore power and turn off the house batteries inside.
Now, remove the Negative Cables first and then the Positive Cables. That way you won't accidentally cause a short to ground while removing the cables.
I wrap each connector once removed with a bit of tape while I'm working just as a precaution.

You can do your clean up using a Baking Soda/Water solution and rinse throughly with water. CAUTION! when using the Baking Soda solution that you don't get any near the battery caps. Baking Soda in the battery will neutralize the Electrolyte and ruin the battery. If you can, simply rinse the batteries with a hose to avoid any problem with the soda.
If the tray is corroded, you will want to sand, prime and paint. Use the same solution and a wire brush to clean the cables.
Good contact between cables and terminals is critical for a good operating electrical system.

Once you have everything cleaned up and ready to install, install the cables in the reverse order. Positive Cables first, then the Negative. This is where your photo is going to come into play.

I use a Dielectric Grease smeared on all the cable connections as I assemble them as opposed to the Spray-on stuff. I personally feel it lasts longer. You can get small tubes of this at any Auto Parts Store.

As mentioned, I have added 4oz per cell of Mineral Oil (Wally World Pharmacy) to mine. Keeps the area clean and extends the interval I need to add water. There are numerous threads on this subject if you want to look further.

Feel free to PM me if you have any questions. Good Luck.

Dennis,

Good, instructive information. Thank you very much.

Don

[Elictrix]

The electrolyte only needs to cover the plates.
Putting excess water in only dilutes the electrolyte and runs the risk of overflowing.

[TQ60]

You do not calibrate your meter exactly but you calibrate yiur readings.

Say your battery post reading is 12.5 vdc with your hand held meter and same meter reads 13.0 volts connected to where your inside meter is connected and inside meter reads 12.5.

This indicates 0.5 volts difference in actual voltage and that the meter reads 0.5 low.

Also be sure your meter is accurate...harbor freight and other low buck ones only are good for indicating voltage but not suitable for adjusting charging voltsge as they can be off...we know this...

Just made up numbers but you get the idea.

You need to know what the inside meter should indicate when the correct voltage is at battery.

Also use a reamer type battery cleaner to make battery post to connector great match.

[dennis45]

Originally Posted by Elictrix

The electrolyte only needs to cover the plates.
Putting excess water in only dilutes the electrolyte and runs the risk of overflowing.

Excess water "will not" dilute the electrolyte. See excerpt below from Battery Stuff link that is also attached. Some good Bedtime Reading for you on how batteries work.

During the charging process Hydrogen Gas and Oxygen are discharged out of the cell caps. The Sulphur (see below) returns to the Electrolyte.
So, as time passes, the Hydrogen and Oxygen need to be replaced. Hence adding the H20, Hydrogen and Oxygen..Water..


The Lead Acid battery is made up of plates, lead, and lead oxide (various other elements are used to change density, hardness, porosity, etc.) with a 35% sulfuric acid and 65% water solution. This solution is called electrolyte, which causes a chemical reaction that produce electrons. When you test a battery with a hydrometer, you are measuring the amount of sulfuric acid in the electrolyte. If your reading is low, that means the chemistry that makes electrons is lacking. So where did the sulfur go? It is resting on the battery plates and when you recharge the battery, the sulfur returns to the electrolyte.

http://www.batterystuff.com/kb/artic...ry-basics.html


Sent from my iPad using iRV2 - RV Forum

[mel s]

Originally Posted by akadeadeye

Mel,
I think overfilling could be my issue. I fill them to the bottom of the plastic, if you know what I mean. Your reasoning makes sense. I just never know when they are fully charged. Only by accident do I look in on the control panel and read "fully charged". It almost always reads "float charging".
Don

Don
For 18 years I've always filled my batteries to the bottom of the plastic split rings, although some "experts?" will insist that is overfilled... and that the proper level is 1/8" above the plates.

I believe that "float charging" on your panel indicates that your batteries are fully charged and are automatic being maintained at 13.4 volts by your 3 stage charger...(IF the charge parameters of your inverter/charger are set correctly).
The "charge settings" will be explained in your inverter/charger owner's manual.

BTW, I check the electrolyte level in my flooded lead acid batteries every 3-4 months and find I that they only need water every 6-8 months.

Good luck.

Mel
'96 Safari