House Battery Explodes

[Bill Borden]

Having trouble with understanding what happened, I will try to explain.

After 5 days of not being plugged in, the batteries were low the motor barely turn over.  I stopped trying to start the Coach, then I notice the Propane detector in the front room beeping, indicating low Voltage.

I removed the Chassis batteries to charge them overnight.  At the same time with the Chassis batteries out of the coach & the Chassis battery disconnect in the OFF position, then I plugged in the coach to charge the House batteries.  This is where I think I made a mistake.

Testing the Chassis Batteries at the Napa store the next day, the first test said they were OK, so I asked for a test of available Cranking Amps.

1st Battery had 237 CCA available, the other one 35 CCA, both batteries were bad.  The load test said they were OK, Cranking amp test show them bad, replace.

So both were covered under warranty, less than a year old, Class 31, 950 CCA, commercial batteries.  Good, new ones coming home.

The next day, I went to install the new batteries and found a BIG surprise, one of the House batteries blew up.

I believe the house batteries had overcharged.  Recently I topped off the batteries with Distilled water.  Now they were all low.

The question is did I cause this by disconnecting the Chassis batteries?

Because the Chassis batteries were not present, did it cause the House batteries to overcharge?

Or is it because one of the House batteries was bad and the voltage didn't reach the charge level shutdown of 13.1v? 

Then the one that blew had shorted and set off the Hydrogen gas inside, blew the top of the battery off.

I noticed the Echo's LED was solid Red, Thermal shutdown?

The House batteries are Trojan T105's, close to 5 years old.

I plan on replacing all of the House batteries.  What testing shall I do to ensure everything is working as it should?

I read a post here about the Propane detector should not have two Voltage feeds, just should run off the House, so I will check that.  I replaced that about 2 years ago, since I have been having battery troubles, maybe related?

Lots of questions and concerns as to why this happens.

Any help and comments would be appreciated.  Also, testing procedure if there is one.

Thank you.
 




 

[Bill Borden]

Here is a picture of the Battery

[Fred Brooks]

  Bill,
 From reading your post, I don't think you did anything wrong. You state the 105's are 5 years old but did not state what was the voltage when you plugged them in. What type of inverter/charger do you have? Typically the charger will start to charge if the voltage is around 9-10 volts and go into "bulk charge" (80 to 100 amps) charge rate if below 12 volts. If one of the plates inside the battery became shorted in the bulk charging process, that could cause the explosion. If you can, replace the Trojans (very good batteries) with some fresh ones. Sorry about the mess, no joy cleaning that up. The Echo charger sensed what was about to happen and went into thermal shut down, should be ok. Check the 20amp slo-blow fuses inside the yellow fuse holders. The red wire with the yellow stripe is the chassis battery feed. Hope this helps, Fred

[Carl Boger]

I am not sure exactly how your coach charges the batteries, but on my 1998 Patriot Savannah the house batteries are charged first by the inverter.  When they reach a full charge, 13.1 volts the echo charger then charges the chassis batteries.  Before I installed my echo charger the house batteries would remain fully charged, but the chassis batteries would get weak in a week or so since they were not being charged and the Cat engine has a continual parasitic drain.

If yours is the same I would think that you had a bad cell when you charged your house batteries and that is what caused the battery to explode.

[Steve Huber Co-Admin]

Bill,
Charging the house batteries with the chassis batteries removed and the disconnect switch off should not be a problem. The Echo charger monitors house battery voltage and will attempt to charge the chassis units when the house voltage reaches 13v+. I think one of 3 things happened. 1. The battery charger in the inverter overcharged the house units, boiling off the battery water, exposing the plates on the failed battery resulting in an internal spark that ignited the hydrogen gas. 2. The failed battery would not take a charge but rather drew significant current and sparked internally. 3.The wire from the Echo charger to the chassis batteries sparked against a grounded source when the house batteries reached 13v. This is doubtful though as I’d expect more than one battery affected.  If I was pressed to guess as to the cause, my choice would be 2 above.
In any case I’d recommend a thorough cleaning of all battery connections and the battery tray before reinstalling and powering the system. I’d also check the fuses on the isolator board. They should be OK but check anyway.
Steve

[Bill Borden]

Thank you for your comments, I am thinking along the same lines.  One or more of the house batteries were bad.

After the removal of the old batteries and cleaning up the mess.  I checked the voltage on each of the old batteries, only one had 6 + volts, the rest were 4.5, 4.2 & 2.5 volts.  The one with 6+V looks like it may have been the next to lose its top.

I have the Xantrex inverter/charger & the Echo charger.   On a side note, I have lost the signal or reading from the Chassis batteries on the Heart Interface.  I am wondering if I have a wire crossed or in the wrong position on the batteries, or an open circuit.  Chassis voltage does show up on the VMSpc and the dash meter.  Does anyone know where the Heart Interface gets the Chassis voltage from?

Fred mentioned in another post about the Propane Detector in the main room, I replaced it over 2 to 3 years ago, after re-installing all the new batteries, I will check the connections.  I remember installing with a little confusion over the two wires.  So now it should only be the House supply connected not the Chassis, right?

I have added over the years Blue Sea Disconnects on both battery banks, but even with the instruction to turn them off while in storage, I am not confident that it happens.

So the next project is a Beaver House at home.

Thanks again for your input.

[Steve Huber Co-Admin]

Bill,
For wiring hookup, suggest you go to Coach Assist (BAC website, Technical tab) and bring up the 2002-2003 Patriot wiring diagrams. Should be same as yours. Check page 41 of 47 which shows the isolator board wiring. It shows the Echo Charger and other wiring you are concerned about.
Steve

[George Harwell]

Bill, just a reminder to cover the solar panel if you have one.

[Fred Brooks]

   Hi Bill,
  Just to clarify what I said about the original propane detector on some models. They had 2 red wires and a ground wire. The original engineering was to give the detector 2- 12 volt energy sources in case one of them went dead the unit would still operate and offer protection. The issue is one red wire is the house batteries and the other is the chassis batteries. The newer replacement detector only has one red wire. If you combine the 2 red wires and attach it to the one red wire of the detector, you have now inadvertently connected the 2 battery banks to each other.
   The Xantrex inverter/charger is not attached to the chassis batteries. The Echo charger is the only source to charge the chassis batteries (other than solar) when plugged into shore power or on generator. As Steve stated, once the Echo charger senses 13.2 volts from the house batteries, it then "latches" onto the chassis batteries to trickle charge them. When the coach is unplugged and the house batteries return to 12.8 volts and drop below the 13.2 volts threshold, the Echo charger unlatches from the chassis batteries.
   Another indicator that the house batteries are approaching the end of their life is this. If the batteries are starting to sulfate they now have more internal resistance to being charged. The inverter/charger tries to "overpower" that resistance and forces them to charge. The batteries now start to smell like "rotten eggs" and get really hot to the touch. In that event, unplug the coach and test the batteries if that is in your wheel house or seek professional assistance.
   Hope this helps, or call me at 520-309-1260. Blessings, Fred

[Bill Borden]

Thanks, Fred your explanation cleared up some of my questions, with the help of the wiring diagram.  I should be good.

But I do have a question regarding the Freedom Inverter connections.  The Temperature Sensing Charging wire, connected to the Positive of the House Batteries.  If it has a bad or broken connection, could the Inverter overcharge the batteries?   The manual says it would default to battery type. 

I think I will check the TSC connection, make sure it's good.

Today I will finish prepping the tray for a coating to protect it, I settled on a heavy coating, used for underbody protection.  Hopefully, it will resist rust for a few more years than the last epoxy I used.

It may take a day or two to dry, temps in the 60's right now.

Thanks again,

[Fred Brooks]

   Bill,
The thermal sensing device attached to the batteries is for communicating the battery temperature back to the inverter/charger. If the batteries get too hot from charging, that device tells the charger to back off and slow down the charging sequence. If the wire was broken that may have contributed to this event. I think the 5 year old batteries had expired and the worst one was the culprit. Good idea with the undercoating! Fred

[Bill Borden]

Update,  Sunday AM

All the New batteries are installed, and the steps I have taken are.

Repainted the battery tray, cleaned all cables, re-organized the cable routing, check fuses (ok), replaced TSC cable.  (I had a spare cable that I had not used, replaced the Freedom that failed about 7 years ago)

I have been monitoring the charging rate on the house batteries, it seems to be in line with normal charging.  The Inverter has been charging for 24 hrs, but Echo has not come on.  This morning the current draw is 4 Amps on the AC connection, down from last nights 9 Amps.  House batteries voltage is presently at 13.76 v, the Chassis is at 13.34 v.

The Inverter is still charging, in Float condition, Echo is off, Solar is 4.3 amps (per the Heart interface) but the Led on the AGM solar charger is off.

Question?  When or what voltage does the Inverter turn off?  When does the Echo charger take over?   

Here are two things that are a concern.

When I checked the Fuses on the Echo charger, (both wires are Red, the Chassis Batteries have a Yellow broken line on Red, the two were crossed.  The last time someone checked the fuses (could have been me) they were crossed.   It is hard to see.  Corrected now.

The Coach Monitor Panel (CMP II) is not showing the correct Chassis Battery status, it is displaying 0.3 volts.  This concerns me.  (Corrected misstated this originally as a problem with the Heart system.  It is the CMP II.)

Can anyone tell me this measurement source?

This has been going on for a while, but the dash gauge and the Silverleaf VMSpc are working.  But I know that is from a different source.

My goal here is to ensure all systems are working correctly, not just accept it is working.

Comments?

[Steve Huber Co-Admin]

Bill,
Suggest you either access the Echo Charger manual in Coach Assist or read "Batteries Not Charging " in Common Problems. Both describe how the echo Charger works (your isn't) and the correct hookup.
Steve

[Fred Brooks]

   Bill,
If the echo charger wiring was reversed it would not work. The solid red wire is the sense wire from the house batteries that tells the echo charger that it is above 13 volts and to latch onto the chassis batteries. (red wire with the yellow stripe).
   Hope this helps, Fred

[Bill Borden]

Hi Fred,

I have bench tested the Echo, and it seems to be working properly.  When 13.4 v applied to the solid Red wire, the Red wire with yellow splashed on it, provided a 13.5v output.

The one thing that lent to the confusion was the manual referred to a Green solid led, a blinking green, and a solid Red for thermal overload.  The Echo on this Coach (2000) PAT only has a Red led.  No green led.

The Echo manual on the Coach Assist page is for a newer model.  And the Electrical diagram for a 2002 PAT is also not the same as the 2000 PAT.  But it helped.

Everything seems to be back in working order.  So far.

Thanks for your help, I do appreciate all the assistance from the members of the Forum.