I have another battery related question

[BBQ Warren]

We had our final walk thru on a new NoBo travel trailer. I decided to go with 2 group 27 batteries. When we got to the battery disconnect switch he said we should disconnect the batteries if we are on shore power or towing the camper. His reasoning was we don’t want to over charge the battery. Being on shore power seems reasonable but when I’m towing shouldn’t I keep them connected so I have a full battery charge when I get to my destination? In all my previous trailers or motor homes I never disconnected the battery until I was done with my trip.

[xrated]

Originally Posted by BBQ Warren

We had our final walk thru on a new NoBo travel trailer. I decided to go with 2 group 27 batteries. When we got to the battery disconnect switch he said we should disconnect the batteries if we are on shore power or towing the camper. His reasoning was we don’t want to over charge the battery. Being on shore power seems reasonable but when I’m towing shouldn’t I keep them connected so I have a full battery charge when I get to my destination? In all my previous trailers or motor homes I never disconnected the battery until I was done with my trip.

Never take electrical advice, or pretty much ANY advice...from a salesman! Their job is to sell a trailer and make a handsome profit for both themselves and the dealership. How much electrical knowledge do you think a medical doctor has....vs...someone that actually knows electrical stuff.

Every modern day trailer will have a converter/charger onboard and the job of that C/C is to provide 12VDC power to the trailer AND to provide a proper charge to the onboard battery or batteries. Almost every modern day C/C will have at least 3 stage charging built into them.....Bulk/Boost stage, then it goes into absorption stage, then finally a float charge.

Like I said in my first statement...Never take electrical advice from a salesman.......except maybe in my case. I spent 30 years as a Journeyman Electrician and when I retired, I sold new Ford cars and trucks, then another few years selling motorcycles, so I WAS a salesman with electrical knowledge.

[Mark_K5LXP]

The response from me would be what is the converter in this thing and why would it over charge? Modern converters should not be overcharging batteries. I would take that advice with a grain of salt until I knew what converter it had and if there was any chance of overcharging. Even less of a chance of that when connected to the vehicle, so I would go with your experience over what is likely faulty advice.

I'm a proponent of disconnecting for storage, not so much for overcharging but loss of mains power and subsequent battery drain.

Mark B.
Albuquerque, NM

[sahively]

Never trust a single thing an RV or vehicle salesman says. I really want to know how this guy thinks batteries get charged if not when connected to shore or vehicle power.

[Intothewild]

Just so you know. It really important to have the trailer battery on when towing. If there was an issue and the trailer came unhooked from the tow vehicle. The trailer brakes need that trailer battery to make them work

[xrated]

Originally Posted by Intothewild

Just so you know. It really important to have the trailer battery on when towing. If there was an issue and the trailer came unhooked from the tow vehicle. The trailer brakes need that trailer battery to make them work

I don't think that would an issue. As far as I know (could be wrong), the power that is fed to the break-away switch comes directly from the battery terminals of the onboard battery. The Battery disconnect switch is electrically located between the converter/charger and the battery itself. If the leads for the break-away switch is connected directly to the battery, as most....maybe all of them are, turning off the battery switch would NOT affect the break-away switch from activating the trailer brakes during an accidental disconnect from the tow vehicle.

[Mudfrog]

Originally Posted by BBQ Warren

We had our final walk thru on a new NoBo travel trailer. I decided to go with 2 group 27 batteries. When we got to the battery disconnect switch he said we should disconnect the batteries if we are on shore power or towing the camper. His reasoning was we don’t want to over charge the battery. Being on shore power seems reasonable but when I’m towing shouldn’t I keep them connected so I have a full battery charge when I get to my destination? In all my previous trailers or motor homes I never disconnected the battery until I was done with my trip.

BBQ Warren, you might ask,, How would the batteries ever get charged if the advice of the salesman was followed?

A solar panel might help but it's not meant to be the primary charging source. Leave the battery disconnect on when using the rig. Depending on how long, you might turn it off when in storage to help slow battery discharge, if the rig isn't plugged into electricity.

[Persistent]

Originally Posted by BBQ Warren

We had our final walk thru on a new NoBo travel trailer. I decided to go with 2 group 27 batteries. When we got to the battery disconnect switch he said we should disconnect the batteries if we are on shore power or towing the camper. His reasoning was we don’t want to over charge the battery. Being on shore power seems reasonable but when I’m towing shouldn’t I keep them connected so I have a full battery charge when I get to my destination? In all my previous trailers or motor homes I never disconnected the battery until I was done with my trip.

Lots of good advice posted above.

Some battery disconnect switches disconnect the charger from the battery. Some do not. Most leave certain "always on" appliances connected. Often the only way to know is to measure the voltage on the battery terminals.

Plug in to shore power. Measure the battery terminal voltage. If the charger is working, voltage will slowly rise to 13.2, 13.6, or 14.4 volts. Staying at less than 13.0 volts means not charging.

It may take hours for voltage to reach 13.2 volts in deeply discharged batteries when using a low capacity charger.

Make and model of the converter/charger is necessary for better advice.

Measure the voltage on the battery terminals under different conditions. Voltage will slowly rise to the maximum programmed voltage.

Most chargers use 14.4 volts as maximum. This is good for fast charging deeply discharged batteries. This phase should not last for more than a few hours. My WFCO charger allows a maximum of 4 hours.

Next the voltage should drop to 13.6 volts. My WFCO charger will hold 13.6 indefinitely while trailer is occupied.

Finally voltage should drop to 13.2 volts. This voltage is good for long term storage. If you as much as turn a light "on", voltage will jump up to 13.6 again.

Monitor water level in the batteries periodically until you know how much your system consumes. Charging consumes water.

I wish you good luck and happy trails ahead!

12 volt Side of Life part 1
The 12volt Side of Life (Part 1)

12 volt Side of Life part 2
The 12volt Side of Life Part 2
Some of the information is a little dated, but it is still pretty good.

How does the Lead Acid Battery Work?
https://batteryuniversity.com/articl...d-battery-work

How do battery chargers work
https://batteryuniversity.com/articl...-chargers-work

How to Charge and When to Charge?
https://batteryuniversity.com/articl...when-to-charge

[BBQ Warren]

Thanks for the replies. That helps. Oddly it wasn’t the salesman who told me but the tech who does walk throughs

[xrated]

Originally Posted by BBQ Warren

Thanks for the replies. That helps. Oddly it wasn’t the salesman who told me but the tech who does walk throughs

LOL....."Tech" seems to be, in this case with you, a guy with a title, not an actual tech....someone that really knows what they are talking about.

[Tomahawk]

Originally Posted by xrated

I don't think that would an issue. As far as I know (could be wrong), the power that is fed to the break-away switch comes directly from the battery terminals of the onboard battery. The Battery disconnect switch is electrically located between the converter/charger and the battery itself. If the leads for the break-away switch is connected directly to the battery, as most....maybe all of them are, turning off the battery switch would NOT affect the break-away switch from activating the trailer brakes during an accidental disconnect from the tow vehicle.

Not the case on my 2015 trailer. When I got my TT, a single wire went from the Battery positive terminal to the 100 AMP breaker 2 feet away. You flip the breaker off, no power to anything, including the emergency brakes.

I have been running my Group 29 and Group 24 in parallel for 4 years with no issues. When I get home I plug into shore power and leave everything connected. I check the water level every other month. I end up adding water about every 6 months. If I was worried about my converter over charging, I would connect to shore power for a few days, flip the breaker off for about 3 months, flip it back on for a few days, and repeat. So far that hasn't seemed necessary. These are two of the cheapest batteries you can buy. The G24 came with the TT and the G29 is a Walmart Ever Start that costs less than $100. For the last two years I have told my DW I am going to upgrade the batteries soon as they show any sign of performing poorly. Still no issues...

[dustyone]

NEVER NEVER disconnect the battery when towing!!! Doing so may disconnect the emergency braking system. That's the lanyard generally a cable that you attach to your vehicle. It is there to apply the brakes if you get disconnected from the trailer. It uses the battery on the trailer to activate the brakes. It keeps the trailer from running on down the road uncontrolled hitting some one.

[Atlee]

Originally Posted by BBQ Warren

Thanks for the replies. That helps. Oddly it wasn’t the salesman who told me but the tech who does walk throughs

Then hope this "Tech" never works on your RV.

[Winemaker2]

Originally Posted by dustyone

NEVER NEVER disconnect the battery when towing!!! Doing so may disconnect the emergency braking system. That's the lanyard generally a cable that you attach to your vehicle. It is there to apply the brakes if you get disconnected from the trailer. It uses the battery on the trailer to activate the brakes. It keeps the trailer from running on down the road uncontrolled hitting some one.

I certainly agree with all the responses.
The one above us a particularly important one and worth verifying how your break-away is powered. You might consider contacting the dealer manager... top dog... and inform him/her that you feel you were given some very bad info by the "tech" and some that could cause a very dangerous situation. You might go so far as to request a repeat walk thru with someone more competent so you have a thorough and safe understanding of the TT and its use.
If he/She blows you off I'd consider filing a BBB complaint citing serious ( potentially life threatening to others) safety related misinformation.