Thread Tools Display Modes
Old 01-14-2015, 02:15 PM   #1
Junior Member
Join Date: Dec 2013
Posts: 11
Trilogy 38RE Battery charging question

My apologies if this has been covered before, I've searched and can't find the answer that I need. I need to know how I should be charging my batteries.

2013 Trilogy 38RE

1)My unit is inside a pole barn, no electricity available. I'm in Nebraska, temps have routinely gotten to zero and will again more than likely.

2)Even though I turn the master battery switch to OFF, there are still phantom loads that drain my 2 deep cycle batteries to the point that even the door keypad won't operate.

3)I've been taking my Honda 2000i out to the storage shed, hooking it up to the shore power line, and letting the generator run until the gas runs out. I turned the battery cutoff ON. Unfortunately, I just checked on the unit a week later, and discovered that I left a light on inside, so even if the generator fully charged the batteries, that light drained them over the past week.

4)I filled the generator back up, turned off the lights (idiot!), kept the battery disconnect ON, and left it running through another tank of gas. Approximately 8-9 hours of runtime I believe.

Here are my questions:

A)Am I doing this the right way? If so, will the onboard battery charger still charge the batteries if the disconnect switch is turned to OFF?

B)Would I be better off taking my 200amp rolling battery charger out there, and connecting the generator to the battery charger at 20amps, and the charger to the batteries? If so, I assume that I'd connect the positive to one battery, and the negative to another? I assume that if I connect the charger directly to the batteries, I can keep the master cutoff switch to OFF.

C)Can I save myself the hassle of dragging out my rolling charger, and just use the battery charging cables that came with the Honda generator? Since there are no charging settings to set, I'm afraid that the quality of charge directly from the generator is poor.

Last winter I removed the batteries and just topped them off individually in my garage. Since I'll be taking it out for a trip in a month, I didn't want to have to reinstall them in the dead of winter this year, so I kept them in place. I'd prefer to avoid doing that now, but it might save me time over driving 20 minutes each way just to add fuel to the generator at this point.

One last question. Since the batteries have already been run fully dead more than once, should I just forget about it right now, and deal with it when I bring it home in 1 month to prep for my trip? It'll be in my driveway, hooked up to shore power for a week before I leave, so I'll have time to either realize that the batteries are totally shot and replace them, or fully charge them. I'll only need to go 10 or 12 hours between being hooked up to either my generator or shore power while on my trip...
Thanks in advance, sorry for the long post....

Attached Thumbnails
Click image for larger version

Name:	IMG_3915.jpg
Views:	74
Size:	237.1 KB
ID:	68431  

Arcosanti is offline   Reply With Quote
Old 01-14-2015, 03:28 PM   #2
Senior Member
Join Date: Apr 2012
Location: South Carolina
Posts: 1,077
Don't leave the batteries dead. In your area, they could freeze, split the cases and leak acid. Here's a table from a Trojan Battery web page. Notice that the freezing point for acid at 40% charge is +5 F.

Electrolyte Freezing Point at Various States of Charge
Specific Gravity State of Charge Freezing Temperature

1.280 100 -92.0 F

1.265 92 -71.3 F

1.250 85 -62.0 F

1.200 62 -16.0 F

1.150 40 + 5.0 F

1.100 20 +19.0 F

Source: BCI Battery Service Manual 1995

2011 Sunseeker 3100
1997 Pathfinder Toad
RamblerGuy is online now   Reply With Quote
Old 01-14-2015, 08:21 PM   #3
Senior Member
camaraderie's Avatar
Join Date: Feb 2014
Posts: 1,329
Arcosanti....based on your comments you have ALREADY done significant damage to your batteries since they've been fully discharged to dead more than once. Don't be surprised if they give you significantly reduced life and show a loss of capacity.
It looks like you have Optima Blue Tops which are DUAL PURPOSE AGM's and are not really suitable if you boondock a lot ...but are fine if you plug in almost always when you camp.
The good news with AGM's is that they self discharge at 1/10th the rate of Flooded batts so once you have them fully charged...if you DISCONNECT the negative wire...the parasitic loads cannot drain them and they will last 6 months or more in freezing weather way below zero without being damaged and will start right up in the spring.
Now as to charging in the barn....since you have AGM's ... you want to use a quality 3 stage charger which I assume you have installed IN the Trilogy. I would plug that directly into your Honda with an extension cord and turn your battery switch to ON while making sure loads like lights are off.
BUT...before you do that....take a reading on your battery terminals with a multimeter and make sure you're getting over 11.5 volts. Anything less...and it's time to take em out and head to the battery shop to do load testing AND/OR replacement.

Assuming you get a decent reading, but below are gonna probably need more than one tank of generator gas to 100% charge the batts. Do one tank and take another reading at the battery terminals. Should read between 12.6 and 13.4.
If so...disconnect the negative terminal and wait 24 hours. Take another reading.
If it is less than 12.6 ...reconnect the negative...and run another tank through the Honda. Then measure, disconnect and re-measure 24 hours later. If you are 12.6 or over have a full battery bank and you are good for months WITH the NEGATIVE disconnected.
If you are reading below have capacity loss....below 12.4 and your should probably get them load tested at the auto store...below 12.2 and you should shop for new ones and avoid the blue tops & get real deep cycle AGM's.

Hope this helps...good luck!
2015 Georgetown 280DS
2014 Vespa LX150 2014 StellaAuto 125
camaraderie is offline   Reply With Quote
Old 01-16-2015, 09:05 AM   #4
Junior Member
Join Date: Dec 2013
Posts: 11
Thanks Cam, that's exactly what I was looking for. I'm just going to bite the bullet and bring the batteries home so that I can monitor them and find out if they are already totally shot or not.
I have a leased campsite from April to October, so it's plugged in most of the year. I go on 1 or 2 trips down south in the winter, so I boondock overnight in a parking lot with my Honda 2000 hooked up. The Trilogy has a residential fridge in it, so it takes a fair amount of juice to keep that sucker running for the 12-14 hours that I typically drive per day when traveling. I also hooked up a solar panel to hopefully help charge while I'm driving long days, but I haven't had a chance to test it out yet to see if and how well it works.
I was really anal about keeping an eye on the batteries, but I had to drop my unit off at the dealer twice in November and December, and each time that I came to pick it back up, the batteries were completely dead, so I haven't been too particular about them since then. I figured that I'd be buying new ones in the Spring anyways.
Arcosanti is offline   Reply With Quote
Old 01-16-2015, 09:38 AM   #5
Senior Member
camaraderie's Avatar
Join Date: Feb 2014
Posts: 1,329
You're welcome Arco...based on the additional info on the residential fridge, I'd look at getting the biggest 12V's you can fit....suggest group 31 if you can fit 'em. Three would even be better since you don't want to HAVE to go below 50% charge on any battery bank. If you don't have a lot of base space but do have extra room for height the Trojan Reliant J185 AGM is 15x7 base and 14 inches high and has more amp hours (200) than the two batts you have in there now. If you can't fit 2 group 31' gives the same amp hours in 1 battery (118 lbs!). Two of those is the rough equivalent of 4 6V batts. So there's a few choices for you once you take your compartment measurements. All best....
2015 Georgetown 280DS
2014 Vespa LX150 2014 StellaAuto 125
camaraderie is offline   Reply With Quote

battery, charging

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

» Virginia Campgrounds

Reviews provided by is not in any way associated with Forest River, Inc. or its associated RV manufacturing divisions.

Our Communities

Our communities encompass many different hobbies and interests, but each one is built on friendly, intelligent membership.

» More about our Communities

Automotive Communities

Our Automotive communities encompass many different makes and models. From U.S. domestics to European Saloons.

» More about our Automotive Communities

Marine Communities

Our Marine websites focus on Cruising and Sailing Vessels, including forums and the largest cruising Wiki project on the web today.

» More about our Marine Communities

Copyright 2002-2015 Social Knowledge, LLC All Rights Reserved.

All times are GMT -5. The time now is 11:05 AM.