Hello all. Thought I understood batteries but I don't. I have a 2018 redhawk 26 xd with 2 new group 27, 12 volt lead acid batteries, 3 months old, wired in parallel, with 80 amp hours each (80 usable). I recharge daily with a 200 watt renogy suitcase. It stays at 14.7 during the day and when it gets dark, it drops to 12.89. During the night I have nothing turned on except the frig on gas and whatever usual parasitic stuff is on. In the morning I'm down to 12.24 which I don't understand. Is that normal? Is 12.06 the lowest I should safely go down to? I'm not well versed in batteries so "answers for dummies" would be appreciated! Thanks for the help.
Are these deep cycle batteries? 80 seems low for a group 27. 14.2 is that while still on charge? If so take off charge and read volts about a hour later. Most inverters will operate till volts get down to 10.5 with a load before shutting down with low voltage error message.
12.24, depending on whose chart you're looking at, is about 75% charged. It could be worse.
I would want to know if you're ever getting your batteries as charged as they can be. Taking a voltmeter reading while they being charged, or soon after they've been charged will give an optimistic/erroneous reading, as the batteries will still have a "surface charge". Depending on the ambient temperature, getting rid of the surface charge can take hours or days. I would check them with a hydrometer to determine their true state of charge. A hydrometer isn't effected by a surface charge. It's an inexpensive piece of equipment that I keep in my trailer.
IMO, you'll need to verify that, "... nothing turned on except the frig on gas and whatever usual parasitic stuff is on."
What about your inverter stand-by power? furnace fan? television(s)? Laptop? Something could be drawing more 12v power than you realize.
And, like already mentioned, you'll need to verify that your batteries are being fully charged during the day. 14.7volts is the 'boost' voltage where most of the battery charging occurs. Others may have a better idea of your solar system, but as batteries approach full charge, the controller reduces voltage and current flow.
Maybe 200 watts of solar is not sufficient to replace the power you use over night. If you don't fully charge your batteries during the day, you lose some capacity every day.
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Quote:
Originally Posted by jdux999
During the night I have nothing turned on except the frig on gas and whatever usual parasitic stuff is on. In the morning I'm down to 12.24 which I don't understand. .
Quote:
Originally Posted by Siamese
12.24, depending on whose chart you're looking at, is about 75% charged. It could be worse.
I would want to know if you're ever getting your batteries as charged as they can be. Taking a voltmeter reading while they being charged, or soon after they've been charged will give an optimistic/erroneous reading, as the batteries will still have a "surface charge". Depending on the ambient temperature, getting rid of the surface charge can take hours or days. I would check them with a hydrometer to determine their true state of charge. A hydrometer isn't effected by a surface charge. It's an inexpensive piece of equipment that I keep in my trailer.
When you are measuring 12.24 in the morning... Is the fridge and other items in the motorhome still connected to the batteries?
If they are - you are not getting a true "resting voltage" you are getting a measurement with a load still being applied to the batteries. If so, you are actually better than 75% charge since you still have a load drawing down the voltage from what would be at rest.
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Steve & Stacy with Jasper (Australian Cattle dog)
2015 Seneca 36FK
Custom 27' flatbed trailer hauling:
07 Toyota FJC & Yamaha Kodiak 400 ATV
More information on the type of batteries ( brand - type ) what charge controller are you using and did you set its charging perimeters as per the battery manufacturers recommendation
There are many people on here that can really help you if they have more useful information Les
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2016 Seneca HJ - Scangauge D - Truma Comfort
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Hello all. Thought I understood batteries but I don't. I have a 2018 redhawk 26 xd with 2 new group 27, 12 volt lead acid batteries, 3 months old, wired in parallel, with 80 amp hours each (80 usable). I recharge daily with a 200 watt renogy suitcase. It stays at 14.7 during the day and when it gets dark, it drops to 12.89. During the night I have nothing turned on except the frig on gas and whatever usual parasitic stuff is on. In the morning I'm down to 12.24 which I don't understand. Is that normal? Is 12.06 the lowest I should safely go down to? I'm not well versed in batteries so "answers for dummies" would be appreciated! Thanks for the help.
Check the mfr dates on the batteries. The code conversion is on the Interstate site. Both batteries should be the same dates if they were purchased together and should not be older than 6 months at the most. Are the batteries water levels all topped off. Have any individual cells needed more water than the others?
Based on your Ah's, it sounds like you have the Interstate batteries that are rated at I believe 85Ah's, which will give you around 80 useable Ah's (for the 2 batteries combined).
When you will be at home again, for a good test, give your batteries a full charge plugged in to a shore power source for 24 hours. Disconnect all the cables on the batteries and let them sit for 24 hours, with nothing connected to them. Then take the voltage reading of each battery. The voltage of each batter (not connected to each other) should be around 12.8 volts or higher. If one battery is lower than the other, it may be something to investigate.
Question, are ALL your loads connected to the same 12Volt battery Positive post, or are there loads on both batteries? For the best wiring connections for 2 12Volt batteries in parallel is below. Ignore the battery disconnect switch or add one. Make sure ALL the loads are connected to the same connection that the RV load wire is connected to.
Oh, the worst thing is to have the inverter automatically shut down, as mentioned in another post, because a DEAD 12 Volt battery is 10.5VDC that is when the specific gravity of the batteries is "0". A few automatic shut downs and your battery could be toast, your Ah's will be reduced, that happens each time you mistreat your batteries.
I would recommend adding an inexpensive Digital Amp meter like the one below. It will give you a basic idea as to how much your battery is putting out. If you buy 2 meters, your can see how the current going in both directions. Just a thought. There is a wiring diagram for 2 meters on the "RVing with SOLAR" social group.
Do you have a inline blade fuse between your batteries and the loads?
Just something to think about, solar is DRAMATICALLY affected by shade. Shading even one your cell of a solar panel will cut the output by over half. You might want to check out this video.
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