Battery charging at campsite question

[Mustang65]

Originally Posted by Duke4857

... I keep 2 12 volt interstates and 2 6 volt Trojan batteries charged. Batteries are switched with disconnects in two different banks. I never have trusted certain, "under the bench batteries." I have had too many failures with them. I have read that if one battery fails in a bank, it might take out the whole bunch. Every thing you read on the internet may not be true but, why take a chance?

Properly maintained Deep cycle batteries do not just die in one day. Unlike car batteries, that you walk out in the morning and all you get is clicking, because there is no EASY way of properly monitoring them and the car gauges leave a lot to be desired. Even with automotive batteries, you will probably notice a different sound from the starting motor as the battery begins to lose it power, even if it is only a day or 2 before the battery bites the dust.

Properly maintained Deep cycle batteries tend to die a slow death, and they let you know they are heading south. The Voltage of the bank will drop faster than normal when under a load. It will take longer to get to a full charge back into them. When they are supplying power without help, you will notice that the amount of time that they supply power is decreasing.

These are signs that a cell may be going bad, battery age, or could be that the frame ground bolt may be corroding, or a battery terminal. Proper monitoring... maintenance... maintenance... maintenance!
This is where monitoring the battery system is critical. I do not mean just grabbing your multimeter once every 3 or 4 months and doing a voltage check, they need real monitoring. IE... a digital display that monitors your batteries voltage, charging/discharging Ah's or Wh's which ever you prefer.


In the above scenario, a battery bank selector switch is needed for the different battery types. The 12Volt batteries have different charging characteristics than the (2) 6Volt batteries in series. Should someone decide to connect 2 sets of batteries with different Ah ratings, mfr, size, or age, the different batteries will not charge properly. Using Duke4857 battery scenario (thanks Duke..), and IF they were all connected to one load point (12Volt batteries and (2) 6 volt batteries in series), the charge controller is looking at the combined combination as an average IE 12.4VDC and charge accordingly. Since the internal resistances of the 2 types of batteries are different, one set would probably be overcharged and the other set under charged. The same holds true for similar batteries of different ages connected together. Eventually the weaker of the 2 will bring down the stronger one of the 2. Like the "Chain is only as strong as its weakest link"!

If your system consists of (2) 12volt batteries or if your system consists of (4) 6volt battery setup there is no need to have 2 banks of batteries with a regular battery charge controller. IE... switching between the (2) 12 volt batteries... BUT WAIT, some of the newer battery charge controllers allow for the charging of 2 separate banks of batteries, but the load is still spread across both banks.

Switching between two banks does not make it any easier on the charge controller, or get the batteries charged any faster. IE... If you have (2) Interstate 100Ah batteries (total 200Ah, of which you can ONLY use 100Ah's) and you happen to need 100Ah's over night dry-camping, at some point during the night you need to manually switch between the battery bank. Whereas, if you leave the (2) Interstate 100Ah batteries connected together (in parallel), you equalized the 100Ah's across the 2 batteries. It will take the same amount of time to replenish the used 100Ah in both scenarios.

The problem with splitting identical batteries into 2 banks is that you need to charge them independent of each other, since the ODDs of using the same amount of Ah's from each battery is next to impossible without a battery monitoring system that monitors Ah or Wh charging/discharging. If you leave the batteries connected together, no issue. Same time to charge, no need to switch banks, batteries maintain close to the same stats throughout the charge/discharge cycle.

If you are going to lay down some big bucks for Deep Cycle batteries you need to monitor them (Voltage.. Voltage never drops below 12.2Volts) and a good maintenance schedule (water levels, connections...) or it could become expensive replacing the batteries.

Ok you can wake up now, I am finished.

Don


My Registry

RVing with SOLAR

[rockaw]

Originally Posted by Kaliona

Wow. Thanks everyone for the quick and helpful replies. My next question was going to be since I keep my trailer at home, should I plug it in to keep the batteries maintained. Greg&Nancy do what I was hoping would be ok to do by plugging in at home. I will definitely check make and model of my controller and report back. I too would like to know to what type of charge I'm getting from the controller.

Keep in mind most homes run 15 or maybe 20 amp fuses, if you're plugging in a 30amp RV plug, make sure you limit what you are using in the trailer to under the 15 or 20 amps or you could blow a fuse or worse burn up a electrical line in the home (fuses are suppose to prevent that, but as a retired firefighter, things don't always work as planned) Even just running your RV AC might exceed the lines amps.

And yes, I leave mine plugged in all the time when home.

[skids]

Originally Posted by rockaw

(snip)

And yes, I leave mine plugged in all the time when home.

And while doing that do you leave the battery cables connected? I fear overcharging the battery...

[Duke4857]

Originally Posted by Mustang65

Properly maintained Deep cycle batteries do not just die in one day. Unlike car batteries, that you walk out in the morning and all you get is clicking, because there is no EASY way of properly monitoring them and the car gauges leave a lot to be desired. Even with automotive batteries, you will probably notice a different sound from the starting motor as the battery begins to lose it power, even if it is only a day or 2 before the battery bites the dust.

Properly maintained Deep cycle batteries tend to die a slow death, and they let you know they are heading south. The Voltage of the bank will drop faster than normal when under a load. It will take longer to get to a full charge back into them. When they are supplying power without help, you will notice that the amount of time that they supply power is decreasing.

These are signs that a cell may be going bad, battery age, or could be that the frame ground bolt may be corroding, or a battery terminal. Proper monitoring... maintenance... maintenance... maintenance!
This is where monitoring the battery system is critical. I do not mean just grabbing your multimeter once every 3 or 4 months and doing a voltage check, they need real monitoring. IE... a digital display that monitors your batteries voltage, charging/discharging Ah's or Wh's which ever you prefer.


In the above scenario, a battery bank selector switch is needed for the different battery types. The 12Volt batteries have different charging characteristics than the (2) 6Volt batteries in series. Should someone decide to connect 2 sets of batteries with different Ah ratings, mfr, size, or age, the different batteries will not charge properly. Using Duke4857 battery scenario (thanks Duke..), and IF they were all connected to one load point (12Volt batteries and (2) 6 volt batteries in series), the charge controller is looking at the combined combination as an average IE 12.4VDC and charge accordingly. Since the internal resistances of the 2 types of batteries are different, one set would probably be overcharged and the other set under charged. The same holds true for similar batteries of different ages connected together. Eventually the weaker of the 2 will bring down the stronger one of the 2. Like the "Chain is only as strong as its weakest link"!

If your system consists of (2) 12volt batteries or if your system consists of (4) 6volt battery setup there is no need to have 2 banks of batteries with a regular battery charge controller. IE... switching between the (2) 12 volt batteries... BUT WAIT, some of the newer battery charge controllers allow for the charging of 2 separate banks of batteries, but the load is still spread across both banks.

Switching between two banks does not make it any easier on the charge controller, or get the batteries charged any faster. IE... If you have (2) Interstate 100Ah batteries (total 200Ah, of which you can ONLY use 100Ah's) and you happen to need 100Ah's over night dry-camping, at some point during the night you need to manually switch between the battery bank. Whereas, if you leave the (2) Interstate 100Ah batteries connected together (in parallel), you equalized the 100Ah's across the 2 batteries. It will take the same amount of time to replenish the used 100Ah in both scenarios.

The problem with splitting identical batteries into 2 banks is that you need to charge them independent of each other, since the ODDs of using the same amount of Ah's from each battery is next to impossible without a battery monitoring system that monitors Ah or Wh charging/discharging. If you leave the batteries connected together, no issue. Same time to charge, no need to switch banks, batteries maintain close to the same stats throughout the charge/discharge cycle.

If you are going to lay down some big bucks for Deep Cycle batteries you need to monitor them (Voltage.. Voltage never drops below 12.2Volts) and a good maintenance schedule (water levels, connections...) or it could become expensive replacing the batteries.

Ok you can wake up now, I am finished.

Don


My Registry

RVing with SOLAR

Thank you for the info. I will have to read it again after I digest it, but by no means causes me drowsiness. Thanks again!

[rockaw]

Originally Posted by skids

And while doing that do you leave the battery cables connected? I fear overcharging the battery...

Shouldn't, you don't disconnect when you go camping for weeks. I'm at 2.5 with the same battery with no problems..

Anyone else????

[mnaquaman]

Lots of good advice and correct answers. I agree that the charge while driving is slow but it does charge.

At home I keep the TT connected to the house all summer long. It keeps the battery charged and the refrigerator cold. NO need to remove items and its always cold and ready to go. Besides how often do you wish the house fridge was just a bit bigger? Great overflow when you are planning a party and need more fridge or freezer space.

I don't boondock so I am not ever too concerned with my battery life. However in the my last TT I replaced the battery once in 10 years!

Happy Camping

[rockaw]

Originally Posted by mnaquaman

Lots of good advice and correct answers. I agree that the charge while driving is slow but it does charge.

At home I keep the TT connected to the house all summer long. It keeps the battery charged and the refrigerator cold. NO need to remove items and its always cold and ready to go. Besides how often do you wish the house fridge was just a bit bigger? Great overflow when you are planning a party and need more fridge or freezer space.

I don't boondock so I am not ever too concerned with my battery life. However in the my last TT I replaced the battery once in 10 years!

Happy Camping

Or in an emergency, it was ready to go....we got hit by hurricane last year, we moved the TT up against the house and it was on the leeward side (most wind blocked by the house) After it hit, we were without power for 4.5 days. We had a full load of water and generator, we just moved into the TT to live. Easier than trying to do it in the house. (and moved a lot of the food too).

[Morfoot]

Originally Posted by oldmanAZ

I didn't see anyone suggest a digital 12volt meter that plugs into a trailer's 12v port ('cigarette ligher').

I have one in my TT's 12v port all the time. It was inexpensive and lets me know at a glance the voltage at my batteries when boondocking, voltage from my converter or from my truck.

Where did you get that and do you have a photo or a model number so I can find one for myself??

Thank you in advance!

[Bracco]

Yes, as long as all systems are working. You can check the charge going into the batteries once your setup all you need is a meter

[Randy G]

One option during storage is a solar powered charger. If the system is large enough and permanently mounted it will maintain your battery(s) while camping as well.

[Hollander Mutthaulers]

Originally Posted by oldmanAZ

I didn't see anyone suggest a digital 12volt meter that plugs into a trailer's 12v port ('cigarette ligher').

I have one in my TT's 12v port all the time. It was inexpensive and lets me know at a glance the voltage at my batteries when boondocking, voltage from my converter or from my truck.

Yes! Absolutely! We have a 12v (DC) meter with an old coffee pot rocker switch to turn it on and off with wired into a wood panel attached above the electric control panel. We also keep a 120v (AC) meter plugged into a power strip to monitor camp ground power. With a lot of air conditioners going, sometimes camps get low on power. Plan to not use motors or heating elements if volts go below 106.

We stay plugged in at home during summer. When not plugged in we turn off battery with as negative post disconnect switch built into the battery box cover. During winter we bring battery inside and check/charge it about once a month. We also carry our compact charger with us in the camper just in case.

[rhouthoofd]

When I am at home, I do not connect power but rather use a solar charger purchased from Harbor Freight. I also installed a switch to disconnect the battery from the TT.

[JesseS]

Just be aware that most of the converters (especially the older ones) have only single stage chargers, meaning they only have absorption charging at about 13.6-8 vdc constantly, which is not the best for a battery, it will slowly boil the electrolyte away. The better or after market converter/charger (such as Progressive Dynamics) is a three or four stage charger, providing Boost, Absorption, Float, and vacation modes and are fully automatic. These types of chargers will help your battery last much longer than just a single stage charger. The charger built into a converter is generally between a 30-60 amp charger so will charge a flooded battery from 70% to full in about 4-5 hours, where as a trickle charger will take 24-48 hours, if it will charge it at all as trickle chargers are designed to maintain a full battery, not charge it.

[Sbrinson]

Originally Posted by Kaliona

First time TT owner here. Just picked up a 2012 26RLS and want to make sure I understand how and when the batteries get charged. I know they get charged while hooked up to the tow vehicle, but what about when plugged in to shore power? Does the inverter provide a trickle charge to the batteries?
Thanks for any info.

As several others have said, many/most RV Power units operate on nominal 115VAC (Shore Power) and provide fused circuits to feed 115 VAC to items such as Air Conditioners, Microwave, TV sets & Refrigerator etc., while also containing a converter that outputs 12 VDC to Furnace Blower, vent hood, lighting, and onboard battery charging. Modern Dual-fuel refrigerators and hotwater heaters use propane as the alternative fuel but use 12VDC for igniting the burner(s). Whether-or-not the tow vehicle electrical system will charge the RV Battery (ies) depends largely upon the capacity of the vehicles alternator and the gauge of the wiring going to the vehicle's trailer connector. If both are adequate you can certainly charge your RV battery with the vehicle's system. I've outfitted extra batteries with 7-Pin pigtails to facilitate charging them (singly) in the back of the pickup (after dropping the TT) while driving around when we're boondocking. It should also be noted that leaving the TT connected to the tow vehicle for a lengthy time when not underway, can result in the "equalizing" of the batteries in each machine....meaning a weak or undercharged TT battery can deplete your tow vehicle battery.

[JesseS]

A battery isolater installed in the tow vehicle will still charge the TT batteries but will prevent the TT from drawing down the truck's battery.

[Mustang65]

Originally Posted by JesseS

A battery isolater installed in the tow vehicle will still charge the TT batteries but will prevent the TT from drawing down the truck's battery.

If you have a Ford TV, it only supplies power to the trailer if the ignition is on. Not sure about the other mfr's.
Don

My Registry

RVing with SOLAR

[kreid]

Originally Posted by John from Central Florida

Don’t expect much more than a trickle charge when you’re hooked up to your tow vehicle.

Your tow vehicle will do a pretty good job charging if you have the tow package with heavy duty alternator. Just make sure to test the plug on your bumper each time you hook up. Most truck manufacturers dont install the fuse for the 12v :charge line" into the fuse block from the factory but usually do include it in the glove compartment along with a relay if it is a ford

[Tavtracks]

If a low battery and no shore power. If I plug into TV will I be able to operate slide on my trailer?

[oldmanAZ]

Originally Posted by Tavtracks

If a low battery and no shore power. If I plug into TV will I be able to operate slide on my trailer?

Yes, with the TV running; some TVs only supply power to the trailer when the engine is running.

Many of us operate the slide only when plugged into the tow vehicle to not drain the battery unnecessarily.