AC Generator Question

Jackm · 02-17-2008, 02:55 AM

A while ago, I started the generator in our 2004 Brave while the shore power was connected. As soon as the generator started, one of the house batteries exploded. The batteries had been low on fluid and were undoubtedly emitting flammable gasses. Another lesson learned the hard way.

However, my question is why would the generator starting ignite the gasses. In general, is it okay to start the generator when hooked up to shore power? If so, which power source is being used by the RV when both systems are operable? Thanks in advance.

Jack

Jackm · 02-17-2008, 02:55 AM

A while ago, I started the generator in our 2004 Brave while the shore power was connected. As soon as the generator started, one of the house batteries exploded. The batteries had been low on fluid and were undoubtedly emitting flammable gasses. Another lesson learned the hard way.

However, my question is why would the generator starting ignite the gasses. In general, is it okay to start the generator when hooked up to shore power? If so, which power source is being used by the RV when both systems are operable? Thanks in advance.

Jack

NeilV · 02-17-2008, 03:51 AM

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Jackm:
A while ago, I started the generator in our 2004 Brave while the shore power was connected. As soon as the generator started, one of the house batteries exploded. The batteries had been low on fluid and were undoubtedly emitting flammable gasses. Another lesson learned the hard way.

However, my question is why would the generator starting ignite the gasses. In general, is it okay to start the generator when hooked up to shore power? If so, which power source is being used by the RV when both systems are operable? Thanks in advance.

Jack </div></BLOCKQUOTE>

The charging section of your inverter may have switched off and then back on again causing the spark or it could have have been one of the relays under the step cycling or just purely coincidental.

It should be Ok to start the generator while on shore power but there may be a chance that something may be different on your particlar coach. Call Winnebago's support number, give them the serial number of your coach and they should be able to give you a more authoritative answer.

movin-on · 02-17-2008, 04:08 AM

I beleive that in Winnebagos the generator has priority when connected to shore power...
Don't know how close your batteries are to your transfer switch but check the wiring in it for loose connections...Could have sparked at the relay(s) when it switched over...I never trust the transfer switch and always unplug when I start my genny but that's just me..

Wizard · 02-17-2008, 04:51 AM

Being an Electrician all my life and working with a lot of industrial generators, I would never start the generator while plugged into house power. That said, as long as all systems on your coach is operating correctly, there would be no problem. If a problem occured with your transfer switch, you might never know if until you start the generator. If the generator output ever came in contact wit the power line I wouldn't want to be nearby. I just always like to err on the side of safety.

gunny · 02-17-2008, 05:31 AM

They key issue here is that your batteries were low on electrolyte. Plates exposed, presence of hydrogen gas (a result of battery charging) and a spark between exposed plates from either charging or discharging and you noticed right away what can happen.

Doubt it had anything to do with the source you were usung or switching to. Those transfer switches are usually sealed well and if that had been the source of the explosion, it would have shown evidence of some damage. I'm guessing that your battery or batteries just blew up, pieces of battery and acid every where.

Wash everything down real good with water and baking soda to neutralize any acid.

Makes a good point to waer eye protection when in the vicinity of batteries doesn't it?

John Hilley · 02-17-2008, 09:09 AM

I agree with Gunny about it being an internal battery problem. It was probably triggered by the high starting load put on the battery by the generator starting. A lot of gas had probably collected in the cells with low electrolyte and the starting load probably heated things to the point it exploded. It was I think a combination of the battery being charged by the converter/charger on shore power generating the extra gases and then the generator load causing the explosion. The battery solenoids shouldn't have done anything and the transfer switch is a long way from the batteries and in an enclosure.

Jackm · 02-17-2008, 10:54 PM

Thank you for the insight. My understanding is that for a battery to explode, hydrogen sulphide gas (present in this case) has to be ignited by something. While the battery was clearly a time-bomb, something had to trigger it. In this case, it most likely had someting to do with the generator being started.

The coach is a 2004 Brave with a pretty conventional electrical layout. However, I will call Winnebago to see what their take is. I have cleaned up the mess with baking soda and water but have noticed some localized corrosion as a result. Thanks again for the feedback. I'll let you know what Winnebago has to say after I make the call.

Jack