Battery charging off of the converter when plugged in to shore power

**Cya3124** · 10-19-2021, 07:20 PM

I plugged my 2003 3124KB into an outlet for the first time today. The wires at the tongue for the battery had about 15 VDC on them. Does the converter work like a normal charger in that it bulk charges then steps down? I don't have a battery there yet, but I plan to put one from the boat in to test it.

**Bill** · 10-21-2021, 09:26 AM

Yes, you have it exactly right. Go ahead and connect your boat battery,and it will charge properly. One small word of warning. If you put your TM away for storage, don't leave the battery connected - even the thee mode charger tends to over-charge after a while.

Bill

**Cya3124** · 10-21-2021, 02:24 PM

Thanks, Bill. I have heard that even the tender types like to overcharge over long periods so I don't typically leave a battery on a charger for any length of time.

**rickst29** · 10-23-2021, 10:12 AM

The power converter (the "board" in the bottom of the power center, which converts 120-VAC to charge 12v batteries and provide 12v "DC" power) was especially prone to overcharging and burning off the water in your older TM model.

You would do well to leave the Trailer unplugged, and instead use a good "battery tender" to keep your batteries charged over the winter. Otherwise, you'll have a lot of maintenance and checking to do.

In the long term, if you find yourself replacing batteries too often via having them "damaged" by overcharging, you might want to replace that Converter "board" with a better one - but that's about a $200 replacement item, while a great battery maintainer can be had for less than $70.

**Cya3124** · 10-24-2021, 06:47 AM

Thanks Rick. I keep the batteries inside over the winter, so no worry of overcharging them. I'll look into the new board a little in case I decide to change it. I read another thread about them.

MrGallegos · 11-29-2021, 09:53 AM

If I were to pull out the battery during winter and then decide to open the TM to do some work inside or to use it as a temporary guest room, would I be able to operate most of the electrical equipment (not the A/C) with household shore-power or would I still need to re-install the battery?

Does anyone know of a modification for easier access to the battery or of removing it rather than keeping it in the "hole" ? I was thinking of a tray that slides out to make checking water levels and other maintenance easier. Or would it be less hassle to get two 6 volt AGM batteries?

**Bill** · 11-29-2021, 01:20 PM

Quote:

Originally Posted by MrGallegos

If I were to pull out the battery during winter and then decide to open the TM to do some work inside or to use it as a temporary guest room, would I be able to operate most of the electrical equipment (not the A/C) with household shore-power or would I still need to re-install the battery?

All of the AC devices would be fine, but I'm not sure what the result would be for the 12 volt devices. I think that the converter's battery charger might be confused. Remember, the charger tries to determine the proper rate of charge (charge voltage) by sensing the battery voltage, and if there is no battery, I'm not sure what it would do. I think a better solution would be to unplug the TM from AC power, leave the battery in place, and connect a good battery maintainer such as the BatteryTenderJr (there are other maintainers - just avoid a cheap "trickle charger"). Then, when you need AC power in the TM, just plug it in - no need to disconnect the Maintainer.

I set up my TM this way. I actually connect the Maintainer through the Bargman cable up front, where it emulates the charge line from the tow vehicle and keeps the battery voltage at the proper level. Then, just like arriving at a campground, I can plug in the TM's big black AC power cord, and power up all the AC and DC systems.

Bill

MrGallegos · 11-29-2021, 02:02 PM

Quote:

Originally Posted by Bill

All of the AC devices would be fine, but I'm not sure what the result would be for the 12 volt devices. I think that the converter's battery charger might be confused. Remember, the charger tries to determine the proper rate of charge (charge voltage) by sensing the battery voltage, and if there is no battery, I'm not sure what it would do. I think a better solution would be to unplug the TM from AC power, leave the battery in place, and connect a good battery maintainer such as the BatteryTenderJr (there are other maintainers - just avoid a cheap "trickle charger"). Then, when you need AC power in the TM, just plug it in - no need to disconnect the Maintainer.

I set up my TM this way. I actually connect the Maintainer through the Bargman cable up front, where it emulates the charge line from the tow vehicle and keeps the battery voltage at the proper level. Then, just like arriving at a campground, I can plug in the TM's big black AC power cord, and power up all the AC and DC systems.

Bill

Is this the charger you are referring to?

DBT021-0123 Battery Tender Jr. 12V 0.75 Amp Charger

https://www.batteriesplus.com/produc...=All%20Website

mickmanor · 11-29-2021, 08:08 PM

remote on about 10' of wire, and with a solar panel regulator?

Shore power would not be used, and the winter sun would enable
only part-time daily charging. The lights would still work, I think.

Any thoughts, or, maybe someone has tried this method.

**Bill** · 11-29-2021, 10:10 PM

Quote:

Originally Posted by MrGallegos

Is this the charger you are referring to?

DBT021-0123 Battery Tender Jr. 12V 0.75 Amp Charger

That's the one. Remember, there are others that some of our members prefer. You can find their info and comments by doing a forum search on the term MAINTAINER.

Bill