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Discussion Starter #1
Thanks to information on this forum, I recently purchased a fancy battery box (https://www.arkportablepower.com/arkpak) and a 100 Amp-hour battery.


The battery box has a 50 amp Anderson plug that can be used to charge the battery. (It also has an isolator switch).

I recently discovered that I do have the upfitter electrical interface module in my door post.

Can I wire (what size wire?) from the electrical interface module to the anderson plug on the battery box? When is the isolator switch important?

I am using power for recharging a computer battery lights and a fan.
 

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110V Mains recharging:
Simply plug your ArkPak into the mains power socket at home and Arkpak's built in charger will recharge most 12V batteries (up to 130ah / Group 31) overnight in 12-16 hours. Plus when you are not using it, leave your ArkPak plugged in so that the battery receives a constant charge and hence the full benefit of the 7 stage smart charger . This will maintain, condition and prolong the life of your 12V battery.
In-Vehicle recharging:
There are two ways you can recharge your ArkPak in your vehicle:

(a) Simply by plugging it into the 12V socket in your vehicle, via the optional DC-DC car charger adaptor (sold separately) – giving you 6 amps of charge per driving hour.

(b) Via the ArkPak’s built-in 50 amp Anderson Plug, giving you a potential 50amp charge per hour directly off your vehicle’s alternator.

You're going to need a very heavy duty wire (like #6), correctly connected to the alternator, and protected from rubs, etc. Length may be an issue. I would be looking for an RV type dealer to install.

On the other hand, using the 12V to 12V charger adapter, you can connect that directly to the upfitter feed, by just adding a connector to the optional adapter.

I haven't decided on a "house battery or not" yet, but I am setting up a 120V feed from outside the van to inside that will connect to an outdoor outlet at the house. This sounds like the best charge method, if you have house AC access, because it sounds like the most precise way to charge, and it will happen overnight. In addition, the 6 amp charge adapter would supplement the charging on the road.

Ed
 

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Discussion Starter #3 (Edited)
Thanks, Eddie. but that doesn't quite answer my question.

Charging the battery from 110v from my house is useful but limited to when I have access to 110v. I am planning a month long trip to remote places- so plugging into 110v will be rare.

I have the 12v DC to DC cigarette lighter charger but it is so slow. It will take more hours to recharge what I use than I will be driving and I am not planning to drive very much per day on this trip. 1 hour on the 12v DC charger only recharges 6 amps.

So that is why I want to use that big old 220 Amp alternator to charge the house battery. An hour of driving will recharge 50 Amps.

So my question is whether I can hook up the house battery via the Anderson plug to the upfitter connector box? Or does it need to go directly to the alternator?
 

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.....cut......

So my question is whether I can hook up the house battery via the Anderson plug to the upfitter connector box? Or does it need to go directly to the alternator?
I suggest looking in owner's manual to see if they list a fuse dedicated to the upfitter connector box. If it's not at least 50 Amps (unlikely in my opinion) I personally wouldn't hook it up directly to upfitter connector box because the chance of blowing the fuse when the house battery is low is too great.

Regarding wire size, 50 Amps may sound like a lot but it's not really, so I wouldn't let that deter me. 50 Amps is just about what a small 500 watt inverter would require on the 12 Volt side. And the wires out of your alternator that handle a steady 200 Amps aren't huge.

To your previous question, an isolator switch is important to make sure the batteries are not connected in parallel when you are parked and drawing current to power devices. During that time you want electrical power to come from the house battery only. That way your vehicle starting battery won't get run down due to house loads. I can't really tell from description if the isolation switch is manual or automatic. If manual I'd make sure to disconnect house battery from vehicle battery/alternator when not driving.

And for what it's worth, I agree with you that a 6-Amp circuit for charging a 100 Amp-hour battery is not enough. Even if you drove 6 to 8 hours a day it would be marginal at best.
 

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Discussion Starter #5 (Edited)
Thanks, Chance. I always enjoy reading your posts.


Notes: the isolator switch on the battery box is manual.

The link below is the upfitter connector and it does have a 50 amp fuse But it may stay on independent of the key. which might drain my starter battery. Unless the isolator takes care of that.

https://flic.kr/p/oXcFoP
 

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Thanks, Chance. I always enjoy reading your posts.

This is the upfitter connector with a 50 amp fuse! But it may stay on independently of the key. which might drain my starter battery.

https://flic.kr/p/oXcFoP
On my Promaster, the 50A upfitter connection is ON when the van is OFF. Or, to put it your way, it does stay on independently of the key. which might drain the starter battery.

I do think the best method is a direct connection to the alternator, but then I wonder what would limit the charging rate to the battery pack. Wish I had a better answer!

Ed
 

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....cut......


Notes: the isolator switch on the battery box is manual.

The link below is the upfitter connector and it does have a 50 amp fuse But it may stay on independent of the key. which might drain my starter battery. Unless the isolator takes care of that.

https://flic.kr/p/oXcFoP
Thanks for sharing this information. And also on the portable battery unit. I had looked at a similar unit in the past to run a 1000 watt inverter for small microwave.

Anyway, a few random thoughts:

Where are you going to place the house battery? I ask only because the upfitter connector box is by the sliding door, which may not be the best place for battery. Depending on where you place it, it may be easier to tie to power at vehicle battery.

Because connector is reportedly always hot (has power), you definitely don't want to forget to disconnect the house battery while dry camping regardless of how you get power to it. Personally I'd even go one step further and initially check with volt meter and/or conductivity meter to make sure than when isolation switch is open that the house battery is completely disconnected from vehicle.

The specs you linked show minimum cable size as 10 mm^2. That answers your question about cable size for 50 Amps. It does not hurt much to go bigger except for cost, weight, and over current protection in case of accidental grounding. These are all next to trivial factors.

Regarding the maximum current that may possibly flow to house battery during charging, that's a tough one to answer -- more like guess at. If you park for long period and your house battery gets fairly low, while your vehicle battery remains fully charged, then when you start the van and close the isolation switch a lot of current (as in Amps) can flow from alternator to house battery. The larger the house battery the lower it's resistance and the greater the chance you could exceed 50 Amps. The alternator could be trying to maintain 14V while the depleted house battery is at 11 Volts. Without restrictions of some type I can see going over 50 Amps under some conditions.

It's possible your house battery box may limit current somehow since the connector is rated at 50 Amps. Or you may be able to find a simple gadget to limit battery-charging current (an inline resistor would do it but it's highly inefficient -- but may be included in the house battery box).

You can always try calling the house battery box manufacturer and ask them what the maximum charging current may be. And while at it, I'd ask them if it prevents current from flowing back to vehicle.

One final thought -- house batteries often have a direct connection switch to bypass automated isolators. This is used in case your vehicle battery is dead (like you left vehicle lights on) and you want to use the house battery to jump start the van. Since your isolation switch is manual, just closing it will likely do the same unless RAM or battery box prevents current from flowing backwards. What can easily happen when you forget to open the switch every single time is that if your starting battery is weak at all then the house battery will help in starting the van. And that can easily exceed 50 Amps.

I mention all this because most of the time it all works out fine, but occasionally unexpected things can happen that are hard to figure out. What you have is a simple system yet I can see potential problems if everything is not compatible.

Sorry for the length, just sharing some food for thought.
 

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Electric systems can be so confusing. When I was working on the electric system on a pop-up camper I found this website:

http://www.marxrv.com/12volt/12volt.htm

Lots of good info and it's spelled out so folks other than electricians can understand it...
 

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Discussion Starter #9
Nope. I appreciate it. Just trying to avoid this:

Jesse Pinkman: Battery's dead.
Walter H. White: Jesse. Back when I asked you to put the keys in a safe place, where did you put them?
Jesse Pinkman: I left them right here. In the, um... the ignition.
Walter H. White: Son of a bitch!
Jesse Pinkman: Whoa whoa. No, this is not my fault, alright? The buzzer didn't buzz.
Walter H. White: The WHAT?
Jesse Pinkman: The buzzer! The buzzer that buzzes when you put the keys in. To like let you know that the battery's on. I know that! It didn't buzz. Look, I didn't turn the key or anything, alright? I'm not stupid. Did you hear the buzzer buzz? I did not... It's faulty, it's a faulty mechanism.
Walter H. White: Is this just a genetic thing with you? Is it congenital? Did your, did your mother drop you on your head when you were a baby?
Jesse Pinkman: THE BUZZER DID NOT BUZZ and you were the one that made me move the keys in the first place, REMEMBER?
Walter H. White: Yes, I see your point. Your imbecility being what it is, I should have known to say JESSE, DON'T LEAVE THE KEYS IN THE IGNITION THE ENTIRE TWO DAYS.
Jesse Pinkman: I wanted to leave them on the counter. BITCH. Oh, I'm sorry, oh, the "work station". Jesus.
Walter H. White: Okay, just... Alright so, we need to jump the battery somehow.
Jesse Pinkman: Okay. How?
 

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Hi,
I would be careful about high charging rates.

I'm using two golf cart batteries rated at 200 amp-hrs for my house battery. When I called Trojan batteries to find out the reccommended charging current, they said that they do not want more than 30 amps charging current for these 200 ah batteries. They said that rates higher than 30 amps will shorten battery life and will increase out gassing of the batteries.

I'm using a battery isolater in the line from the van battery to the house battery that is basically a relay that only connects the two when the ignition is on. The isolater relay needs to be connected to a 12 V source in the van that is only on when the ignition is on -- I used the 12 V power outlet at the back of the van.
Also have a 50 amp circuit breaker in the line from the van battery to the house battery. I'm using #8 wire, which is good for the 50 amps.

I plan to measure the charging current to the house battery, and if its more than 30 amps, I'll introduce some voltage drop (added resistance?) to get it down to 30 amps.

If Trojan sells a battery similar to what you have, they have a very helpful tech support department that actually answers the phone and has people who seem to know what they are talking about. Might be worth calling them?

Gary
 

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I was researching to see how others have handled this possible high-charging-current issue when on a simple and cheap DIY basis and found this exchange between engineers both informative and funny. I say funny because some of the comments show that while some of the writers knew about electrical systems they appear to know very little about batteries or camping use of house batteries. Based on bad assumptions some recommendations are poor. Eventually they mostly get on the same page.

http://www.eng-tips.com/viewthread.cfm?qid=130882


In fairness they did bring up some valid issues I questioned above, like what will happen if the vehicle battery is dead or weak and you try to start the van with the house battery online. Maybe a set of old fashion jumper cables could come in handy!
 

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What are you using for an isolator?

Hi,
I used this PAC-200 one:
[ame]http://www.amazon.com/PAC-PAC-200-200-Amp-Battery-Isolator/dp/B000CEBXRS/ref=sr_1_2?ie=UTF8&qid=1410882882&sr=8-2&keywords=200+amp+battery+isolator[/ame]

I think that the 200 amps is overkill -- I bought back when I was thinking that it should have a rating about like the alternator (180 amp) and before realizing that you don't want to charge at anything like that rate. I have a 50 amp breaker in line with the battery isolator, so I'd guess that anything over 50 amps for the isolator would be OK. That said it does appear to be a well built unit.

By the way, I finished the windows yesterday using your flat window technique -- came out really nice.

Gary
 

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Hi,
I used this PAC-200 one:
http://www.amazon.com/PAC-PAC-200-200-Amp-Battery-Isolator/dp/B000CEBXRS/ref=sr_1_2?ie=UTF8&qid=1410882882&sr=8-2&keywords=200+amp+battery+isolator

I think that the 200 amps is overkill -- I bought back when I was thinking that it should have a rating about like the alternator (180 amp) and before realizing that you don't want to charge at anything like that rate. I have a 50 amp breaker in line with the battery isolator, so I'd guess that anything over 50 amps for the isolator would be OK. That said it does appear to be a well built unit.

By the way, I finished the windows yesterday using your flat window technique -- came out really nice.

Gary
Glad the windows worked. I used this isolator. [ame]http://www.amazon.com/gp/product/B000OTIPDQ/ref=oh_aui_detailpage_o04_s00?ie=UTF8&psc=1[/ame]
It seems very good. I added the extra led to it and mounted it up front with a digital voltmeter so I can monitor the house battery voltage and see when the combiner/isolator is on. It works well but I do want to add a disconnect before the combiner just in case I want to totally disconnect it.
 

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I think you are being a bit over cautious. That's a good thing. But consider that you aren't trying to take a totally dead battery (in the Arkpak) and zap it to fully charged as fast as the alternator will make juice. What you are in fact doing is taking a 100% charged Akrpak, running some measly lights and a fan and a computer on it, and if you do that long enough the Arkpak will tell you it's down to 11v or 10v or 60% or whatever (assuming I'm reading the Arkpak literature right). So now you start the engine, hit the isolator, and the alternator starts recharging everything at a measured rate as determined by the computer. The alternator isn't a full on/full off device, it's controlled.

For years and years I have run dual battery systems in motor homes and truck sleepers. Just junker car batteries, a big switch, and regular Autozone battery cabling. Not rocket science. The hardest part of all this is either remembering to use the switch, or rigging up a relay or a timer or some such to operate the switch.

You'll find that anything you are running on 12v will pretty much quit working by the time the battery is down to 9v. An interverter would certainly have kicked itself to off by that point as well. So in the broadest strokes, you are only ever charging from 75-100%, not from 0-100%.
 
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