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Old 05-16-2019, 11:12 PM   #1
BillandAnn
 
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Question Expected battery life

We bought a used RS Adventurous recently, and took it out for its first extended dry camping last weekend. We had the refrigerator on propane, turned off the water pump, and had nothing plugged in except for our cell phones (the inverter was left on). Each morning, the battery was nearly drained (I didn't have a voltmeter, but the panel showed only the bottom red light, and there was a blinking red light in the inverter). Some mornings, the voltage was so low, that the only way I could get the generator to start was to start the van engine. The batteries had been replaced in Oct 2017, and are not sealed (they are Interstate batteries). I would run the generator between 15 and 30 minutes two or three times a day (the panel showed full charge each time). After two or three nights of this, I began turning off the inverter as well, but still the battery was drained by morning. Are my batteries needing to be replaced already, or am I missing something in my electrical setup that is draining them abnormally? Any thoughts or suggestions?
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Old 05-16-2019, 11:24 PM   #2
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Default Re: Expected battery life

There will be a powered propane monitor somewhere in there (and there's a thread about it).

Beyond that, it just requires tedious dog-work to locate the drains ... it helps to have a clamp-on ammeter (or battery monitor) so that you can measure the current without having to undo wiring.
Then turn off ALL of the loads (via the breaker panel) and see if the monitor/ammeter agree that you've reached zero amps.
If it doesn't, you've got more hunting to do.

For that matter, what does the monitor/ammeter say when known loads are running (fridge, etc).
What does the inverter draw if nothing is plugged into it (or its output breakers are off)?

Multiply any amps you read by (let's say) 12 hours for "overnight" to get an approximation of expected draw.
If you have oodles of USB sockets sprinkled around the van, each of those has some loss, even when nothing's plugged in.

Like i said: tedious.

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Old 05-16-2019, 11:56 PM   #3
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Default Re: Expected battery life

Quote:
Originally Posted by BillandAnn View Post
I would run the generator between 15 and 30 minutes two or three times a day (the panel showed full charge each time).
I have no idea how large of a battery your rig has, or whether it's wired to charge from the alternator while you're driving as well as from the generator and shore power.

That said, at first glance 15-30 minutes of charging time seems wholly inadequate, particularly so for a lead acid battery. Time to reach a full charge is measured in hours not minutes. The rating of the charger is not the limiting factor here; the battery itself simply cannot accept charge any faster.

A voltmeter is not a reliable indication of charge state.
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Old 05-17-2019, 01:06 AM   #4
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Default Re: Expected battery life

You may have killed the new batteries already when they discharged too low several times in a row. Leaving inverter on is definitely a big no-no as it consumes a lot of power in standby.
Otherwise I would suggest taking one of those clamp-in ampermeters and looking at the current flowing out of each fuse. That should quickly identify the line that is sucking the power and hopefully, the culprit.


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Old 05-17-2019, 01:45 AM   #5
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Default Re: Expected battery life

Bill&Ann, 15/30 minutes 3 times a day is not sufficient to bring a depleted battery up to capacity. Except for leaving the inverter on it sounds like you are doing fine at power conservation. If you look at the link below it will help to understand how batteries are charged and how long it takes. There are two sets of graphs.....

https://www.progressivedyn.com/rv/charge-wizard/

In Crow speak, the battery bank is like a swimming pool. You take electricity (water) out, discharging, and you need to refill it by charging. You can drain the water out much faster (high discharge rate over short time or low rate over long time) than you can refill it. Sort of like draining the pool about halfway and then refilling it with a garden hose. The reason is that chargers are designed to bring the state of charge quickly up to 90% with a high charge rate over several hours. They then taper off the current to protect the battery from damage. Then it is low charge rate over a much longer time to complete the charge cycle. Like taking that garden hose and crimping it to slow the flow of water when the pool is 90% full.

At this point, I'd suggest getting at least 90% (or as close as possible) when you recharge. They don't need 100% every time. Try not to go below 50% if you can.

You probably have not seriously damaged the batteries at this point. They can take a lot of abuse except for being flattened and not quickly recharged.
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Old 05-17-2019, 03:03 PM   #6
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Default Re: Expected battery life

The temperature plays a large role in the life and charge of those batteries. We just moved from Florida to the mountains and the January cold really sucked the life out of them overnight. You didnít mention where you were or the temp so could that have been a factor?

Also, if you are checking the battery lights while the generator is running or the van is plugged into shore power all four lights will be lit because it is reading the eXisting power supply not just the batteries.

I doubt those Exide batteries are deep cycle. Maybe the seller just put the cheaper one in to sell it.
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Old 05-17-2019, 07:33 PM   #7
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Default Re: Expected battery life

Thanks for all your comments and suggestions.
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Old 05-21-2019, 01:33 PM   #8
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Default Re: Expected battery life

You need to fully charge the batteries in order to adequately troubleshoot this.

1) Charge the batteries for a day using the shore power cable, or if your drive home is more than 6 hours that should do it.

2) After they are charged, check the cells to insure that they are topped off with water.

3) Turn off all load in the van. Use the battery disconnect switch. Using a digital voltmeter, measure the voltage at each battery and at both batteries (at the terminals). Fully charged should be 12.8, and each 6 volt battery should be half that. Both batteries should have the same voltage reading within 0.1-0.2. If not, then you have a bad battery(s).

4) Wait a day, then check the voltage again. If it has dropped significantly, then you have bad batteries. Should be at least 12.6. If you are down to the elevens or less, then they are discharged. Good batteries should hold a charge (assuming there is no load, but even if you have a small load, they shouldn't change much in 24 hours).
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Old 05-27-2019, 07:42 PM   #9
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Default Re: Expected battery life

IT COULD BE YOUR BATTERIES HAVE GONE BAD FOR SOME RESON BUT THE INVERTER LEFT ON WILL DRAIN BATTERIES SO I LEAVE MINE OFF WHEN NOT USING THE AC IT GENERATES. THE LIGHT PANEL JUST SHOWS VOLTAGE AND DOES NOT TRULY REFLECT THE CHARGED CONDITION OF YOUR BATTERY. I DO NOT BELIEVE 15-30 MINUTES OF CHARGING BY THE GENERATOR IS ENOUGH TO FULLY CHARGE YOUR BATTERIES. EVEN IF THE GENERATOR IS SUPPLYING 20 AMPS FOR 30 MINUTES THIS IS ONLY 10 AMP HOURS AND YOUR BATTERIES MAY HAVE A CAPACITY OF 200 AMP HOURS OR MORE.
YOUR MAY ALREADY KNOW THIS, BUT TO VERIFY YOUR GENERATOR OR ENGINE ALTERNATOR ARE ACTUALLY CHARGING YOUR BATTERIES YOU CAN USE A VOLTMETER TO CHECK THE VOLTAGE ON THE BATTERIES BEFORE RUNING THE GENERATOR OR THE ENGINE AND THEN WHILE RUNNING THE GENERATOR OR ENGINE. YOU SHOULD SEE A LARGER VOLTAGE WHILE CHARGING. FOR DEEP CYCLE BATTERIES THE ONLY REAL TEST I KNOW, UNLESS YOU HAVE A CHARGE MONITOR SYSTEM, IS TO MAKE CERTAIN THE BATTERIES ARE FULLY CHARGED AND THEN SEE HOW THEY PERFORM IN USE. IF YOU CANNOT MAKE IT OVERNIGHT WITH A LITTLE TV OR OTHER LOW POWER DEVICES THEN THEY MAY BE BAD.
I HAVE FULL RIVER 224 AMP HOUR COACH BATTERIES AND WE USUALLY DRIVE SOME EVERY DAY. WE HAVE A COMPRESSOR FRIDGE WHICH DRAWS ABOUT FOUR AMPS WHEN RUNNING AND WITH SOME TV, OUR PARASITIC DRAIN OF 1.5 AMPS, WATER PUMP, AND OTHER LOW POWER DRAIN WE EASILY MAKE IT THROUGH A NIGHT OF CAMPING WITHOUT SHORE POWER.
I HOPE THIS HELPS
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Old 05-28-2019, 08:05 PM   #10
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Default Re: Expected battery life

What year is your RS? The electrical setup changes from year to year. Assuming yours is the same as mine....

When the generator is running, or shore power is plugged in, the battery light in the panel over the door will quickly turn green. This only means the voltage is high enough to start charging the battery. It does not mean the battery is fully charged.

You can get a better indication from the lights on the charger/inverter that is under the driver's seat. Again, assuming yours is like mine, you can see these lights through the slots in the panel below the seat while the generator is running. The light on the left is the one were are interested in.
IMG_7832c.jpg

Here is a view without the panel.
IMG_7830.jpg

Below the green light, there are yellow and red lights that are not lit in the above photos. As the battery charges the color of the lights changes as show in this table.
Tripp Lite charging lights crop.jpg

These lights will only operate when the generator is running or shore power is plugged in. They will all be off when running on the battery.

Bottom line: Run the generator until the green light is lit and the yellow and red are not.
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File Type: jpg IMG_7832cd.jpg (75.3 KB, 21 views)
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