Seneca 35GS
whittier
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When connected to shore power or when the generator is running the converter charges the 'House Batteries'. If the converter is operating correctly and the house batteries are in a fully charged condition what will the voltage be at the batteries?
Normal battery voltage is 12.7 to 12.8 with no shore power connection or the generator is not running.
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Gale Hawkins
Murray, KY
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Joined: 07/22/2007
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If the converter is charging you will read it's output voltage.
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pianotuna
Regina, SK, Canada
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Hi Seneca,
Mine reads 13.9 if the batteries are fully charged--but that number may well be different on different converters.
Seneca 35GS wrote:When connected to shore power or when the generator is running the converter charges the 'House Batteries'. If the converter is operating correctly and the house batteries are in a fully charged condition what will the voltage be at the batteries?
Normal battery voltage is 12.7 to 12.8 with no shore power connection or the generator is not running.
Regards, Don
Kustom Koach Class C 28'5" 256 watts solar, 875 amp hours in two battery banks 12 volt batteries 2500 watt inverter.
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tomlang
Los Angeles area
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You should look to the battery's spec sheet and see what the float voltage range is, then measure the voltage with a digital voltmeter right at the battery terminals when the battery is fully charged and the charger is charging.
I recently looked-up my Optima yellow-top on the internet, and the spec sheet shows a range of 13.2 to 13.8 volts. When I measured the voltage, it was 13.5 volts.
Be aware that many converter/chargers have a tendency to supply too high a voltage in float mode, causing the electrolyte to boil off. My old Winnebago was that way, and I needed to add water at least once a month when plugged in or suffer the consequences of a dry (dead) battery.
Tom and Lynne
Tom is an Electronics Engineer, Lynne a retired teacher.
2003 Foretravel 38' U295
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Bobbo
Memphis, TN
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The voltage supplied by the converter at float is dependant on the make of the converter. Parallax/Magnatek is higher than PD for example. This is good in cold weather, bad in hot weather. What make of converter do you have?
Bobbo, Linda and the furry kids (German Shepherd and German Shepherd mix)
2007 Winnebago Outlook WF331C on a Ford E450 Super Duty Chassis
NRA Life Member
Near N35 12 17 W89 50 57
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RJsfishin
Winston Or.
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The true standing voltage of an unloaded fully charged 12v liquid lead acid battery is 12.6-7. Any voltage higher than that is a surface charge voltage, from recent charging from one source or another. Any voltage lower than that, either the battery still has a load on it, or it is not fully charged, or it is in a sulfated condition, and may be on borrowed time, or may still give good service for a long while yet.
Rich
'98 Flair, 454, Onan Microlite 4k, Intel PD 9155 w/ wizard, Sta-power 1500 watt Inv, 2 6v batts, ammeters, KingDome/sat, Oly Catalytic Heat, hauling 2 Bent Bikes and sometimes towing a Tracker F&S boat.
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smkettner
Southern California
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Joined: 03/21/2005
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Seneca 35GS wrote: If the converter is operating correctly and the house batteries are in a fully charged condition what will the voltage be at the batteries?
Normal battery voltage is 12.7 to 12.8 with no shore power connection or the generator is not running.
Disconnected and rested 24 to 48 hours a reading of 12.7 is considered fully charged.
While charging the voltage goes higher and will reach 13.6 to 14.7 depending on your converter. For a lower fixed 13.6 voltage converter it will need to hold that voltage on the battery for 24 to 48 hours to fully charge a low battery. If you have a multistage converter it will need to hold the voltage in the 14.5 range for four to six hours to be fully charged. You really need an ammeter to know when you reach full charge. 1/2% of capacity in amps is fully charged. So 220 amp hour battery is fully charged when the current drops to 1.1 amps.
2001 F150 SuperCrew
2006 Keystone Springdale 249FWBHLS
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pnichols
Santa Cruz Mountains
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"You really need an ammeter to know when you reach full charge."
Bingo! The first time I've seen anyone else state this.
And when the ammeter shows this very low 1/2 % of capacity current acceptance reading, they're fully charged regardless of how you got them that way. I don't think a 3-stage charger is needed to fully charge RV batteries at all. Because of a 3-stage charger's initial voltage of 14 plus volts, it just gets batteries charged faster. I don't believe I've ever read anywhere that it's impossible to fully charge lead acid batteries if you don't use voltages above 14 volts. My battery manufacturer posts several 13.8 volt charging curves - it just takes more hours to reach full charge according to the graphs.
(FWIW, I use AGM batteries and they almost have a "hard stop" when they are fully charged. When they are fully charged my ammeter shows them as accepting about 100 milliamps or less regardless of the voltage I apply. My 3-place ammeter's resolution is 0.1 amp.)
* This post was
edited 10/26/09 11:15am by pnichols *
Phil, 2005 E450 Itasca 324V Spirit
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John339
Clyde Ca. USA
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Joined: 01/24/2002
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Since an image is worth a hundred words here is an image.
Here is a link to all you ever wanted to know about batteries.
http://www.batteryfaq.org/
John and Cindy and Misty Rain and Senor Paco(Chihuahuas)
1994 Coachmen Catalina 300 MB RD
in sunny Clyde, Calif. KE6IDM
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pnichols
Santa Cruz Mountains
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John,
Charts like you posted should always state battery temperature at which the chart applies. This chart can read very different if your batteries are exposed to the cold or heat ... like they often are if mounted outside the RV.
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