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Chassis Battery Explosion
Coach is at a park for the winter. I start it up about once every 12-14 days to inflate the air bags for leveling. Today, went to start it, turned ignition to on, dash lights all came on normally, turned to start position and BAM! Loudest noise I’ve heard away from a gun range. I thought the power post blew up or something. Got the whole park to come out and investigate. Finally determined it was two of the four chassis batteries had exploded. They were Interstate 31-MHD’s installed 10/15, just slightly over two years ago. My engine batteries are connected to an onboard trickle charger that plugs in to the 120v outlet in the engine bay. Was this a defect in batteries or is the onboard trickle charger (which has been there for many years; not sure if it was installed by Marathon but they’ve serviced the coach many times and never mentioned it) a bad idea? I’ve had every conceivable battery problem the past 50 years but never an explosion. Anyone else had this happen?
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22 Replies
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They explode if a spark either internally or externally is produced when the batteries oxygen and hydrogen is not relieved by the internal valve and has built pressure above the plates. Doubt your trickle charger had any impact on the explosion. Could be the valve got plugged and couldn’t vent the Pressure. A loose cable will cause a spark.
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Hi Mike,
A couple things, why would you want to put air in every few weeks? If it’s leaking that bad just put it on it’s belly and leave it plugged in. You don’t have to worry about getting it up to operating temp. Also when you turn your key off the air should lock in your air bags so you have leaks between your bags and the norgrens.
Marathon did not start putting in chassis battery tenders until a few years ago because they felt there was nothing on the market that wouldn’t cook the batteries as you just found out. The previous owner had to add your charger. Mine is an 07 and didn’t come with one and I never added one. If your system is up to snuff you don’t need a chassis battery charger.
You could of had a bad battery in the bunch or your tender is bad. If your charger is not a late model 3 stage charger I would get rid of what’s in there.
Later
bv
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Mike, where are your chassis batteries located? Did it damage anything else?
Sorry this happened to you.
Mark
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Marathon has installed 3 – stage battery tender chargers at owners request. Most often for long term parking.
Any type additional charger should be disconnected prior to turning your key to start.
I assume you disconnected your charger.
An old style battery charger will continue to charge not showing much draw and over a period of time cook your batteries dry.
Your very lucky a fire did not start when two batteries blew up.
AL
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Please tell us what kind of trickle charger your coach has. Post a picture of it if possible. Sorry for your misfortune.
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In the curbside engine compartment. Can’t take it al apart until the morning, but don’t think anything was damaged other than the acid that pooleed in the pan under the batteries. Doused it with baking soda; will rinse it tomorrow. The pan and the cover saved most everything else, I think
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I will take some pix in the AM and post them. The charger (that, like I mentioned, has been in place longer than the 5 years I have owned the coach) had been hard wired to the batteries. No instructions to disconnect came with the coach, nor had there been any evident problem in several trips up and down the US. (Including several service trips to Coburg.) The batteries that came with the coach lasted about 3 years, replaced then 2 years ago. No apparent problems until today.
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It’s always better to be lucky than smart. I agree, lucky in a lot of ways – for one, I was at my winter park site rather than on the side of a freeway or the middle of nowhere.
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Instead of ever using a trickle charger continuously it is far better to insure the batteries are not at the end of life or that they have no power robbing phantom loads.
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When the 24 volt and 12 volt chassis battery switches are turned off there is still a direct wire from battery 12V supply that goes to the DDEC . I had trouble with this circuit draining down the starting batteries during Winter storage so I put a switched inline fuse it that circuit , end of problem. Haven’t charged the chassis batteries since October but on checking battery voltages last week the 24V was 27.4V and 12 v was 12.9V . If anyone should do this just remember that the engine will not start until this switch is turned back on, engine will crank but not start.
This is just what I did for your information and thoughts.
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Others have already said it, so this is just my iteration. The trickle charger does not equal a smart charger. Trickle will continue to put voltage into a full battery, say 2 amps. So over time, the batteries get cooked, albeit slowly. If you need a charger, and need to leave it on all the time, it needs to be the smart three stage variety. But as Bernie said you should not need it on all the time by design. For example, I got eight years out of the last set and hardly ever used the charger. That’s why the OEM cooker is still in there.
If the President had an opinion about batteries, he might say that Interstates are s**t batteries. My experience over the years is consistent with that. So it’s surprising to me that so many are still being sold.
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Most lessons get learned the hard way. Had to order Delco batteries, (which is what Prevost had put in them originally); no one local seems to stock more than one. Going to lose the charger altogether. Will consider the DDEC switch if I have to store it in the future. Thanks again all.
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I don’t even trust the latest 3 stage chargers to leave them connected. I have seen too many of them fail.
I do have a marine 3 stage charger in the engine compartment but I only plug it in once every month or so when storing the bus. Two days is all it needs to bring the voltage back up to float.
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Mike,
A few of us run the Napa Group 31 Commercial Grade Batteries with 1150 CCA
# 7234. They are very good batteries. With your Napa card you can get them for about 6000 bucks I believe.
Later
bv
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NAPA batteries four of them can be ordered at one time. As Bernie wrote above #7234 is top of line at 1150 CCA (cold cranking amps) and you have the best.
NAPA offers a national warranty, If you have a problem NAPA has over 6000 stores in North America. You’ll not find that with Delco Batteries.
Side note… to above would be Lifeline AGM but most agree it’s over kill for application.
To order NAPA # 7234’s w/ threaded top post…..ask clerk to order 4 all the same date code from the warehouse overnite ship to store. This is a pretty common request and should have zero push back on this request.
With your PC..NAPA card appox savings are $50 bucks per battery.
AL
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