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Old 10-18-2017, 08:58 AM   #21
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You cant trust the built-in charger that keeps your battery up when you're camping on electricity- from the converter. UNLESS, again, it's the "Charge Wizard".

But the Battery Tenders or "smart chargers" will NOT fry your batteries but will GREATLY extend the life of them if they go unused for months. They keep the battery topped off at a safe voltage. It's when the voltage drops (discharge) that allows the battery to start "sulphating" and will cut the capacity (amps) down on the battery and eventually snuff the life out of it at an early age. If you dont trust the Battery Tender or Battery Minder, I cant offer any more suggestions- but I'm 100% positive they work!

Here's a link to my light. The pic actually shows where I removed the stove and replaced it with a chopping board that covers the stove's cavity where the wife stores dish rags etc. I still have the stove in case I sell the Scamp. We dont do internal propane usage. I hate it. Anyway, the light is beside the refrige at the top...actually looks like it's beside the drawer in the pic.
https://www.flickr.com/photos/503516...n/photostream/

I dont have any "tricks"...I do try to exercise good common sense and study up on stuff by searching online and putting it all together then test to see what works for me overall. Going on 8 yrs, I'm happy with all my results.

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Originally Posted by k0wtz View Post
Darrell I don't trust those chargers in the rv good way to burn your battery up. I usually put a battery charger on for a bit before taking off easier on my alternator I think maybe just me!


good ideas


bob
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Old 10-18-2017, 09:18 AM   #22
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Charge Wizard isn't the only safe battery charger on the market. There are a lot of other brands at all price points. I personally like Iona, made in Tucson AZ.

I'm not fond of leaving any charger hooked to the batteries all the time. I prefer to disconnect the ground wire using a heavy duty switch. This will minimize battery loss without the worries of overcharging. Maybe once every two or three months I'll charge if it hasn't been used/charged through normal use.
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Old 10-18-2017, 09:33 AM   #23
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People that do not understand the "Smart chargers" WONT leave them on there. But I've proved it works. When you randomly charge the batteries with any old charger, you have NO idea as to exactly what state the battery is actually in. When you take a "smart" charger off the battery, you're not letting it do its job and potentially doing more damage to the battery.

Batteries Plus convinced me. No, they didnt try and sell me anything but was replacing a battery in a vehicle that sits more than it runs. She asked, "Does this car get much driving?" I said "No". She said if you dont drive a vehicle, the battery will deteriorate and mine was about 1-1/2 yrs. As I said, in 3 yrs now with these chargers, I havent lost another battery since. Brands of batteries didnt matter. They're about like tires now- mostly made in the same "china" factories with different name plates.

For those that will listen, go out and "google", "Youtube" these chargers I mentioned and you will change your mind. The "Battery Tender JR" is about $30. Plug-n-forget. These chargers also have a 5 yrs warranty...that should tell you something.

I also have the Battery Minder (different brand) that desulfates in the process.

Back to the OP's desirous info on "Charging while towing".

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Originally Posted by kingbiscuit View Post
Charge Wizard isn't the only safe battery charger on the market. There are a lot of other brands at all price points. I personally like Iona, made in Tucson AZ.

I'm not fond of leaving any charger hooked to the batteries all the time. I prefer to disconnect the ground wire using a heavy duty switch. This will minimize battery loss without the worries of overcharging. Maybe once every two or three months I'll charge if it hasn't been used/charged through normal use.
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Old 10-18-2017, 10:00 AM   #24
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Name: Dan
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I'm not recommending "non smart" chargers. When charging, I always use a smart chargers. My point is that charge Wizard isn't the only brand and secondly, if properly maintained, it's not necessary to be on a charger all the time.

Battery tenders work great for their purpose. A current model car will drain a battery fairly quickly because of phantom loads. So a battery tender makes perfect sense. Disconnect the battery, removing the load, and the need for constant charging is greatly reduced. Most people, including me, don't want to disconnect their car battery so the tender is used.

On a motor coach, the phantom load can be really high. My old bus was considered "normal" at 4.5 amp phantom load. My buddy's 2003 model, all electric coach has 12.5 amp phantom load. I put disconnect switches on both the house and crank banks. Over the winter in OH, I'd disconnect the batteries for 3 or 4 months. In the spring, no problem. My friend leaves his on a very expensive Xantrex smart charger/inverter and replaced batteries a lot more frequently than I did.

Whatever works best for you is what's best for you.
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Old 10-18-2017, 10:08 AM   #25
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We're talking "Scamp" or "FG" level batteries here. That's all I'm recommending on. I have no clue about the big motor coaches (and their phantom draws) as I'm sure they have their own discussion boards on this that requires more than the small Tenders. But for the sake of the OP's questions/discussions on this topic and their Scamp, the smaller smart chargers (or comparable) will still do the job efficiently and reliably.

Quote:
Originally Posted by kingbiscuit View Post
I'm not recommending "non smart" chargers. When charging, I always use a smart chargers. My point is that charge Wizard isn't the only brand and secondly, if properly maintained, it's not necessary to be on a charger all the time.

Battery tenders work great for their purpose. A current model car will drain a battery fairly quickly because of phantom loads. So a battery tender makes perfect sense. Disconnect the battery, removing the load, and the need for constant charging is greatly reduced. Most people, including me, don't want to disconnect their car battery so the tender is used.

On a motor coach, the phantom load can be really high. My old bus was considered "normal" at 4.5 amp phantom load. My buddy's 2003 model, all electric coach has 12.5 amp phantom load. I put disconnect switches on both the house and crank banks. Over the winter in OH, I'd disconnect the batteries for 3 or 4 months. In the spring, no problem. My friend leaves his on a very expensive Xantrex smart charger/inverter and replaced batteries a lot more frequently than I did.

Whatever works best for you is what's best for you.
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Old 10-18-2017, 10:19 AM   #26
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The best way to make your batteries last and not lose their amp/hour rating is to use a battery tender. Use a "smart" one. These are not old school battery chargers, they are chargers designed to preserve batteries and designed to be connected all the time. They have a multi-level charging program with a float cycle of about 13 volts.

This is a proven design that has been used for years and will not hurt the battery. I've had one on each of my quads for years and they are always ready to go with the touch of a button. I never do any maintenance on my boat battery and it too is always ready to go. My Oliver's onboard charger holds the batteries at a float voltage of 13.2 while plugged in and stored. It will do this even with small loads such as lights or the television, or the water pump.

My Ram even has this feature. At startup it puts out 14 volts to the batteries. Then after a while (bulk and absorption phase) it drops the voltage to 13 during longer run times. So, on trips, I check the voltage while driving and find it sitting at 13.

The seven pin plug is always hot on mine so I disconnect at the campsite. But if I want to charge the trailer batteries when I have no shore power, I run jumper cables from the truck batteries to the trailer batteries and idle the truck for a half hour or so. That cranks in about 100 or more amps or whatever the batteries can accept during their bulk cycle and it's much faster than using a small generator hooked up the the onboard battery charger.

I will never disconnect the batteries and then occasionally charge them. That will lead to sulfation and it requires more work and remembering to charge them. Plus, you can't go into the trailer and turn on a light or anything else.
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Old 10-18-2017, 12:15 PM   #27
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Back in the olden days I used a 7 day time switch and a 2 amp battery charger to keep my battery charged over the Winter. I remember about 12 hours per week kept it fully charged and prevented freezing. Not sure that is as good as a modern 3-4 stage charger, but it worked for me. Now my solar panel and 3 stage charge controller do the job.

Happy Halloween campers! John

Pic of picking up our 13 at Backus in January, 2014.
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Old 10-18-2017, 09:23 PM   #28
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Hey Jeroen,

I just added this American made, very low amp draw, voltage triggered relay, from Atkinson Electronics, part number TBCM-40A. Here is a link to it-

Atkinson Electronics Inc - TBCM-40 TRAILER BATTERY CHARGING MODULE

I copied some other egghead here on the forum.

When it senses 13.5 volts or so, which means things are charging, it connects the tow vehicle current (fed by the black wire on your 7 pin connector from the tow vehicle) to the trailer battery. When the voltage drops below 12.9 it knows things are not charging and it disconnects the two so you'll never drain the tow vehicle battery. I might have those numbers a bit off from memory here but it's something like that.

I installed it on the trailer side of things so that it doesn't matter what tow vehicle I'm using. If the tow vehicle has a relay built in great and if not it's covered.

I never thought there might be a problem with draining the tow vehicle battery and I kind of abuse my systems but once I heard about it I figured I'd throw the relay on and then forget about it.

Those crazy huge solenoids that you see are made for a slightly different situation I think but in any event they draw a lot of power.

On that 7 pin connection odds are probably pretty close to a hundred percent that your tow vehicle is wired properly and the color coding is according to standard. There are lots of color coding diagrams for standard trailer light color codes and I think some of them are even on the etrailer website.

On the other hand it's these RV trailers that always have the colors goofed up for some reason lots of the old manufacturers, from what I've read, didn't follow any standard colors. None of my campers have followed the right colors on the trailer side of things. It makes wiring up the 7 pin connector on the trailer side of things a real exercise in patience.

So on this egg build I'm doing here I ordered a brand new 8 foot 7 pin connector and cable with junction box. I had wired the whole trailer fresh front to back following the standard color codes. I break open the box of the 7 pin connector and cable, look at the instructions and find that the cable does not follow the standard color coding! It just took a little bit of thought as I got that junction box mated up to the trailer wiring I had installed but it's all good.

So anyway I guess it's a long-winded way of saying just take a close look at how your trailer cord is manufactured because the cord itself might not have the standard color coding used.

Whether or not your tow vehicle has a relay for the auxiliary black wire power, it will be a fuse circuit because everything is in a tow vehicle. Probably a 15 amp or 20 amp fuse for that is what you'll find in your fuse box on the tow vehicle.

I know people talk about using the tow vehicle to charge their battery bank while traveling, but I've really never thought of mine as doing much more than floating something across the top of the charge to keep it feeling fresh. Given the long run of wire from your alternator through the tow vehicle through the cords and into your camper by the time the delivery is made there's a whole lot lost to heat or whatever happens in long runs of wires. So I don't think there's ever a massive amount of amps that actually make it through.

There you've got it - a full two cents worth!
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