12 volt battery

Drago wrote:
Back for more, question will a single 12 volt battery charge it's self if used to start a Oman 5000 genorater?
Thanks

:B It looks like the way you worded your question has people confused.

The one way for you to answer your own question is to get a multi-meter and read the voltage with the electrodes touching the "POS" and "NEG" posts of the battery before starting the generator. The reading should be around 12.6 to 12.7 volts for a good battery.

Now start the generator and test the battery again while the generator is running. The battery voltage should rise to 13.6 volts, or more, to show it is being charged while the generator is running.

Now if that original voltage of the battery (before starting the generator) is found to be 12.2 volts or lower when wanting to use the generator your battery is most likely getting old, or sulfated from insufficient charging. This could easily be the case if you are talking about a portable generator with a built-in battery for starting.

I think the original poster is asking if the Onan will charge the start battery without any additional chargers attached to it. Sounds like they want to keep the Onan starting battery isolated from the house battery so that the generator will start when the house battery is dead.

The battery that starts the onan will be either the chassis batt or the house batt. If it is the chassis battery, it very likely will not get charged when the onan is running. On my previous class A Flair, the onan started from the chassis batt. On my existing Rexall, it starts from the house batt.
So to answer the question, maybe !

I don't understand what he's asking???

I too agree the best way to charge your deep cycle batteries when using the generator is to use the generator to operate your on-board converter which will charge the batteries. ALot of our smaller portable generatoes like the 2KW HONDA does a +BATT 12VDC SOURCE at a small 6-8AMPS DC which could trickle charge a battery when the generator was running but not does not have a good regulated DC VOLTAGE source to support any smart mode charging.

I am not up to speed on the larger wattage built-in RV ONAN GENERATOR but it may be the generator has an internal charging alternator type source to charge its CONNECTED START BATTERY when running. My SEARS LT1000 LAWN MOWER even does that ???

A quick test would be to measure the DC VOLTAGE with a multimeter on the start battery terminals before the generator is running and after the generator is running. The start battery terminals should read 12.6-7VDC if fully charged and after the generator starts up it should read around 13.6VDC...

Without smart mode charging techniques it will take 12 hours or so to charge up a deep cycle battery if it has been discharged to the 50% charge level.

Roy Ken

As answered the answer is NO, no battery will ever charge itself. They must be recharged by an eternal source.

Now, if you are in an RV, the ONAN should power the house same as shore power would, (possibly beyond what shore power does, but that's another thread)

This includes powering the CONVERTER which is the device that charges the battery.

So yes, the converter SHOULD charge the battery when the ONAN is running.

What is the make and model of your converter.

Oh, and electronically, no matter if you have a single Group 24, or multiple 4D or say half a dozen six volt in series/parallel.. It's all 1 12 volt battery, though usually with multiple "Jars" we say Battery Bank.

No the battery cannot re-charge itself....:S

It will re-charge only if it is also connected to a 12 volt charging system, such as a converter powered by the generator or shore power. Also a 12volt supply like solar or RV engine will work.:B