How many amps can I put through a 12v power socket? "Poor Man's Goal Zero"

Martinjmpr

Wiffleball Batter
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If you don't care about cost, a 10a MPPT might be the way to get the most into the aux battery while not quite overloading the cig plug:
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https://www.solar-electric.com/12vo10ampmpc.html
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But I wouldn't bother. The voltage differential from the engine battery to the house battery isn't large enough to make MPPT worth the cost. PWM is fine for this sort of thing.


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I'd say go with a 10a SunSaver. 10a is enough to make a (slight) difference in charge time (drive time), but small enough it probably won't blow a fuse or melt a socket.
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The solar charge controller is powered by the aux battery, so you'll have to mount it in the portable battery box so it stays connected to the aux battery. Plugging/unplugging from the cig socket will be like the sun going up/down.
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And an additional benefit of using a PWM controller is that I could also plug my 100w solar panel into the box to charge as well, right? :sombrero:
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Thanks for all the input and thought that's gone into your responses.
 

Martinjmpr

Wiffleball Batter
That Wagan jumpstarter has a 10 minute timer. Read the reviews.
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I figured it might. Plus the reviews say it gets very hot - not an ideal situation for something that will be plugged in for hours in the cargo compartment of a vehicle.
 

dwh

Tail-End Charlie
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And an additional benefit of using a PWM controller is that I could also plug my 100w solar panel into the box to charge as well, right? :sombrero:

Sure, as long as the panel's Vmp is in the "12v nominal" range (15v-22v). But you could use the MPPT that way as well, so it's not a specifically PWM benefit.


Thanks for all the input and thought that's gone into your responses.

No worries.
 

Martinjmpr

Wiffleball Batter
Hmmm...OK, I think I'm going to have to shelve this idea for now.
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I did find something interesting on Amazon:
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https://www.amazon.com/Newport-Vess...TF8&qid=1506110212&sr=8-3&keywords=arkpak#Ask
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Basically it is everything I am looking to try and do, EXCEPT that it does not come with a way to charge the battery.
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Reviews also seem to be spotty, though. Some people like the product but others have had issues with durability.
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Still, The more I look into this, the more I'm feeling like I'm at a dead end. Basically I don't think I can build something that's going to work as well as an ArkPak unless I spend close to the cost of an ArkPak. As much as I enjoy hobby-ing around, at some point it just makes sense to pay the money and save my time.
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The Achilles heel seems to be in the recharging. Without a way to send a high amount of current in a reasonably short time to the battery, the power box will only be good until it needs recharging, and at that point it's just extra weight and taking up space. And the only way to charge, it seems, is to either find a way to connect it directly to the alternator/vehicle battery with heavy-gauge cable, or find a 120vAC outlet to plug it into.
 

john61ct

Adventurer
. Not sure if you read through the whole thread or not but using a different sort of connector (Anderson, etc) would defeat the whole purpose of the exercise.
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What I'm trying to build here is, as I said, a kind of "poor man's ArkPak." - That is, something that I can pick up and plug into virtually ANY vehicle with ZERO preparation done to said vehicle. Something that is portable and switchable, that will run the fridge and that can be recharged as I drive.

So don't think that the 12v power port would the the "only" method of charging this up, I just want to have that option if I have no other.
I am pointing out that it is not **safe** to try to put that amount of current through a ciggie port.

Just because you want to do something, doesn't make it possible.

Now if you are driving 18 hours a day, maybe.

And it may be that the difference between what I'm trying to do and an ArkPak is that the ArkPak has some kind of sophisticated computerized charge controller that can regulate the current going to the battery to allow for safe charging no matter what the source. If that's the way it is, then it may be that the $350+ price tag of the ArkPak (plus the battery, which the user supplies) is well worth the cost. I'm absolutely willing to consider that this might be the case.

The more I look into this, the more I'm feeling like I'm at a dead end. Basically I don't think I can build something that's going to work as well as an ArkPak unless I spend close to the cost of an ArkPak. As much as I enjoy hobby-ing around, at some point it just makes sense to pay the money and save my time.
The advantage of DIY is **not** saving money. It is getting the ancillary devices that actually match your desired usage patterns.

For many, the inverter is either not needed at all, or they need a bigger one, or can get by with super cheap ones, etc.

The shore power charger is completely inadequate by any standard in a mobile context, needs to be at least 30-40A just for battery health, not to mention having to wait 16 hours to recharge. Also not compatible with LFP like the Battle Born G31 drop-in, which would otherwise be perfect.

And so on. . .

The Achilles heel seems to be in the recharging. Without a way to send a high amount of current in a reasonably short time to the battery, the power box will only be good until it needs recharging, and at that point it's just extra weight and taking up space. And the only way to charge, it seems, is to either find a way to connect it directly to the alternator/vehicle battery with heavy-gauge cable, or find a 120vAC outlet to plug it into.
Bingo!

A little portable genny matched to the biggest shore power charger it will power, plus a "suitcase style" portable solar panels gives maximum flexibility.

The total charging capacity from an alternator is pretty minimal for most usage patterns, and you still need solar to get the battery to 100% full for longevity.

Of course shore power available overnight makes all these problems go away, but. . .
 

Martinjmpr

Wiffleball Batter
I realize i'm late to this thread. L plug a simple hobby charger into the 12v socket. using a charger allows me to safely control the charge of a depleted house battery. no inverter needed.
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This charger can do many things other then charge pb batteries.
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Turnigy Reaktor 250W 10A 1-6S Balance Charger
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That's a 120vAC charger though right? My whole question was how to recharge a portable battery while I was away from electrical power using the 12v socket in the vehicle.
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EDIT: Just looked at it, I guess I was wrong, looks like input voltage is 10 - 18vDC. So what do you do, just connect the alligator clips to the battery? That would work while stationary but would not work while driving down the road, obviously.
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Which brings me back to my original problem....but from what I've seen here, it seems that routing power through a PWM solar controller would probably work.
 
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Martinjmpr

Wiffleball Batter
How about a 215ah AGM battery, that you just use while out, the recharge with shore power at home and or top off with solar?
I am going this direction with one I picked up second hand for $85 http://resources.fullriverbattery.com/fullriver-battery/spec-sheets/DC215-12.pdf DWH has said a few times that he does not baby his batteries and just plans on replacing them more often, so he draws them below 50%.
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Good thought but at 132 lbs for the battery alone that takes it out of the "portable" category. ;)
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2 x 6v golf cart batteries hooked up in series would give me the same capacity. In fact, that's what I have our travel trailer running on now.
 

gwittman

Adventurer
I have read through all this information and I don't have any advice to help you Martin, but I can share some experience regarding cig lighter/power port usage. I ran my ARB refrigerator off of my power port. It worked fine for many years but I eventually started having a problem with it. After considerable investigating I discovered the power port backside wiring connection was getting warm enough to oxidize the connection and increasing the resistance enough to get even hotter resulting in partially melting the plastic refrigerator plug.
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I looked around for a better power port and plug. Not much information was available on the rating of them but I finally decided on some that at least looked to be of better quality. Once installed everything worked better. I even installed a three port extension and am able to plug my refrigerator and other accessories into it without over loading now. I keep an eye on the port to make sure they are not getting warm and so far so good. I expect with age, oxidation may show its ugly head but at around 10 years it is still working well.
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What I am trying to point out is; even if it appears to work well at a certain amperage, longer term usage at the higher amperage may degrade the port to the point of failure. I am thinking charging a battery would draw enough continuous amps to do to do this.
 

rayra

Expedition Leader
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And an additional benefit of using a PWM controller is that I could also plug my 100w solar panel into the box to charge as well, right? :sombrero:
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Thanks for all the input and thought that's gone into your responses.


Yes, wire all the 12v-17v inputs to the charge controller.
But I am suggesting you add the APP as a connector type, to add that as an optional input connection. You are after all talking about a portable system, so why deliberately exclude the option?

I'm about to relocate the charge controller from my portable panel kit to my built-in power module, as part of creating a roof-deck flat mount for the panel(s). I'll hard wire thru the roof rack to the built in box, as well as convert or add another coupling on the rear face of the module for connecting the solarpanel kit when it is deployed on the ground. And if I need to use the panel kit somewhere else or on another vehicle, I'll just pull the controller out and put it back on the panel kit. I'll be using APP connectors and some velcro to facilitate those options.
eta all that stuff in the module is connected via a 1/0 cable 'bus' to my under-hood Aux battery. I chose to add options so I could power just about anything I encounter.
I'm also planning front and rear bumper mounted APP SB175 couplings, both branching from that Aux battery 1/0 cabling arrangement so I can run a hitch-mounted winch front or rear.
On top of that, I'm planning to retrofit my heavy duty jumper cables wwith an SB175 coupling near on end, so they can be connected to those bumper couplings a la a military vehicle 'slave' cable.
Point being that as long as you are making a portable power box based on such a large battery, you could also add such connections to add 'portable jump box' to the roster of capabilities.

powermodule183.jpg
solarpanelmount04.jpg
 
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trae

Adventurer
I'm after the same thing @Martinjmpr, so I read this thread with some interest. While I feel I could build my own, I"m not sure it's worth the time.. and whether I could do it cleanly (for a really nice example check this one out http://forum.expeditionportal.com/t...erator-Build-in-Progress-Few-questions-though or this one http://forum.expeditionportal.com/t...erator-Build-in-Progress-Few-questions-though) but I recently found a Paxcess Solar generator: https://www.amazon.com/gp/product/B01M3S00H0/ref=ox_sc_act_title_1?smid=A1URT32HDKZE0B&psc=1

Some highlights:

- usb outlets
- cigarette outlet (via an adapter)
- 100w inverter
- battery indicator
- solar ready
- 12Ah @ 12 v

basically it's an all in one unit. It's not a huge capacity, but with decent solar it meets all of the needs (including in car charging) that you outlined. Combined with a smallish panel this would be a great "accessory charging station". Thoughts?
 

Martinjmpr

Wiffleball Batter
I'm after the same thing @Martinjmpr, so I read this thread with some interest. While I feel I could build my own, I"m not sure it's worth the time.. and whether I could do it cleanly (for a really nice example check this one out http://forum.expeditionportal.com/t...erator-Build-in-Progress-Few-questions-though or this one http://forum.expeditionportal.com/t...erator-Build-in-Progress-Few-questions-though) but I recently found a Paxcess Solar generator: https://www.amazon.com/gp/product/B01M3S00H0/ref=ox_sc_act_title_1?smid=A1URT32HDKZE0B&psc=1
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Some highlights:
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- usb outlets
- cigarette outlet (via an adapter)
- 100w inverter
- battery indicator
- solar ready
- 12Ah @ 12 v
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basically it's an all in one unit. It's not a huge capacity, but with decent solar it meets all of the needs (including in car charging) that you outlined. Combined with a smallish panel this would be a great "accessory charging station". Thoughts?
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Eh, I think those "all in one" "power packs" are more for people who want to be able to charge their phones or tablets. And 12ah isn't much - Hell I can go down to HF and get a "portable jump starter" with a 17ah battery for less than $60:
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https://www.harborfreight.com/3-in-1-portable-power-pack-with-jump-starter-62306.html
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Those little "power packs" have deceptively high "mAH" ratings but you have to dig into the details to see that the "40000 mAH battery" is measured at 3.8v. As you pointed out at 12v the battery is more in the 12ah range.
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In fact, when I was at HF a couple weeks ago I came across their solar stuff. Here's a 35ah battery that is small enough to fit into an ammo can:
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https://www.harborfreight.com/12-volt-35-amp-hour-universal-battery-68680.html
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Combine it with a simple PWM controller and the appropriate input/outputs and it would probably do everything I need as well.
 

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