Battery case top explodes

Ron on Meander · Posted: Sun Mar 17, 2013 4:02 pm Post subject: Battery case top explodes

Well maybe explodes is too graphic a word but it did blow off the battery caps and crack and raise the top of the case about 3/16 of an inch pretty much all around the top of the battery. We haven't used Meander since our Jan 1st outing and she has been stored with her storage cover on, and with shore power to her Xantrex 30 amp three stage charger, which in the past has kept the batteries topped up on float. And I expect it is the reason the batteries have lasted so well is that when ever Meander has been parked the charger has been on and has kept the batteries topped up. Meander has 4 wet cell batteries. Two group 21's came with her new and two group 27's I added about a year later. The battery that exploded came with the boat and is 7 years old. It isn't surprising that the battery failed, but I am shocked that the top of the case came off. The other three batteries look fine so far.

Any thoughts as to what would cause that to happen?
Battery acid has always been kept to proper levels.
Batteries strapped down and this is definitely not external damage.
Xantrex charger always on when boat not in use and whenever hooked to shore power while cruising.
It certainly has not been cold enough here to freeze a battery, especially one that is charged.

Has any one heard of a Xantrex charger going hay wire and putting out too high of a charge?

I"m looking forward to some of the C-brats who have more battery knowledge than me letting me know what they think the cause might be.

Thanks
Ron

potter water · Posted: Sun Mar 17, 2013 5:47 pm Post subject:

My first thought with little information, is freezing. If a battery is pretty much fully discharged and you get some low temps, the juice in the battery will freeze and expand and bulge/crack/damage the case.

So, a possible scenario: Battery is bad, won't charge any more. Means the fluid is basically just h2o. Hard freeze will damage case.

It is less likely in my mind that the charger is at fault. But if you are in a storage and location where no freezing happens, then it will obviously not be a problem. Something else happened.

I've had lots of popped caps and bulged cases over all the years I've lived in cold country due to bad and/or discharged batteries.

CaptainChris · Posted: Sun Mar 17, 2013 6:20 pm Post subject:

If you were close by, you'd definitely know it when a battery exploded. The freeze/crack theory is a good one. Generally a battery does not explode unless provoked.

I had heard for many years and read all the warnings of exploding batteries and one day 4 or 5 years ago it happened to me. It was similar to a shotgun blast. I was readying the boat for spring, battery was charged, wing nuts tightened, case closed and strapped down and one turn of the key was all it took. The explosion broke the tie-down strap, blew off case top, split the sides of the case, and split open the actual batter case. I felt a bit of wet spray and immediately hosed everything down...me included. If you aren't hurt by the explosion, washing things down well cannot happen fast enough. So it does happen. My dealer later showed me holes in his steel building roof insulation (14ft above the bench) made by embedded battery caps. Wing nuts can be the bane of an exploding battery and likely was in my case. Use Nylock or some other type of nylon-insert nut.

Let's just hope it was only a battery and no damage made. Many wake up in the Spring to find much more than a battery to have met its fate by a hard winter freeze.
Safe boating...

thataway · Posted: Sun Mar 17, 2013 6:25 pm Post subject:

I have had several car batteries explode--and it was near the end of their useful service life. It occurred when I started the car, and I thought it was probably due to an internal short--and perhaps some gas build up.

A group 21 battery would be unusual to see on a C Dory--are they group 31's? In any case it is probably time to replace those 7 year old batteries.

As for the charger--anything is possible--and I have had a number of chargers fail thru the years. Only one over charged, and that was an older "Charles".

Ron on Meander · Posted: Sun Mar 17, 2013 6:46 pm Post subject:

Thanks for the replies.

There is no chance that it was freezing that caused the battery to break. Temps don't get that cold here.

The batteries are definitely near the max of their life span and could possibly be worn out enough to short out internally.

I'm probably remembering wrong on the battery size. Maybe a group 24? I think its a 85 amp hour battery.

My link 20 monitor is saying the batteries are charging at 12.7 volts and 0 to .2 amps. So I think the charger is just keeping them charged.

Its possible that the battery burst when I last ran the boat in Jan and I just didn't hear or notice anything when it happened.

There is no evidence of shorting on any of the wiring connecting the batteries.

BrentB · Posted: Sun Mar 17, 2013 7:18 pm Post subject:

Over charging can cause a battery to explode.

potter water · Posted: Sun Mar 17, 2013 8:27 pm Post subject:

And over charging would only happen with a defective or really cheap charger.

starcrafttom · Posted: Sun Mar 17, 2013 8:52 pm Post subject:

I found a exploded battery in my camper this year. I dont know when the battery went as I had not used the camper in over a year. It had been on and off a charger at different times. My father beleives that it was due to over charging.

Dad knows a lot about battery's. He has installed racks and rack of them in cell and microwave site all around the country. Over charging a batter is worse then under charging one.

TyBoo · Posted: Sun Mar 17, 2013 9:02 pm Post subject:

Tom - does your dad still insist that it is bad to set a battery on concrete? Mine does.

The only battery explosion I ever saw was one time when I laid a wrench across the terminals to see if it had any spark. It did. Must have been some gas present too. That was many years ago and although prior to that I did it often, I have not done it since.

starcrafttom · Posted: Sun Mar 17, 2013 11:16 pm Post subject:

No hes does not but a lot of folks do.
When I say over charge I don't mean for long amounts of time. I mean to much voltage going in. They are designed to handle a range and you should not over load one for two long.

BrentB · Posted: Mon Mar 18, 2013 10:22 am Post subject:

Ron on Meander · Posted: Mon Mar 18, 2013 5:02 pm Post subject:

This picture shows how the battery looks.

I guess seeing it has been 84 months since installation date I shouldn't expect any warranty! LOL.

I think what probably happened is I've gotten fairly lax in checking the electrolyte level because in the past 7 years the batteries have hardly needed any top ups at all. This batteries mate, the one that isn't damaged is quite low on electrolyte. I'll bet I let them get too low and that is what caused the problems.
Thanks everyone for you ideas.
Cheers
Ron

Bill K · Posted: Mon Mar 18, 2013 5:27 pm Post subject:

I had that same problem and it ended up being that the charger was not cutting back as far as it should.

Bill Kelleher

BrentB · Posted: Mon Mar 18, 2013 7:19 pm Post subject:

Sea Wolf · Posted: Mon Mar 18, 2013 8:07 pm Post subject:

I had a battery explode on me once. I thought it was pretty much dead (discharged), so started the motor manually, and just let the 4-amp charger in the 15 HP Johnson charge it during the day. It blew one cell (only) up after about three hours.

I don know if it was steam pressure (more probable) or a hydrogen-oxygen explosion (less probable- how do you get a spark inside a cell?).

Anyway, it blew it up good, and that was the end of that battery.

Fortunately, it was in the battery box with the strap on, so it didn't blow acid all over me!

Joe. Teeth