What's a good way to charge my 12v battery box?

[Shokgoblr]

New member/first real post....I have a question:

I built a simple 12v/12Ah lead acid battery box to carry with me on weekend trips. I use it for charging my devices and running LED lights ususally, and it lasts two nights. When I get home after a trip, I have an SAE pigtail wired in, andI plug it into a charger.
I am going to start carrying that on longer trips to power fans in my RTT and I need an easy way to keep it charged for extended periods when I cant get to a power outlet. I am all ears if you have a good option for charging on the go....

 

[RoarinRow]

I'm not electrician, but how about a suit case solar panel with charge controller? My suit case solar panel came with attachments to connect to a battery, at least I think it did. Welcome by the way!

 

[M Rose]

New member/first real post....I have a question:

I built a simple 12v/12Ah lead acid battery box to carry with me on weekend trips. I use it for charging my devices and running LED lights ususally, and it lasts two nights. When I get home after a trip, I have an SAE pigtail wired in, andI plug it into a charger.
I am going to start carrying that on longer trips to power fans in my RTT and I need an easy way to keep it charged for extended periods when I cant get to a power outlet. I am all ears if you have a good option for charging on the go....

Use the SAE pigtail wired directly to your Onboard Battery, and the alternator will charge it for you as you drive down the road... with that, look into adding dual batteries to your rig and what parts are required... for me, I had to upgrade the alternator. Others require battery isolators and switches.

 

[reaver]

The above is a good option, if you have the room. Another option to consider is a DC to DC charger.

Dual battery setups more or less require both batteries to be the same to work properly, which can get expensive quickly. DC to DC systems allow your batteries to be different, and should work without requiring you to upgrade your alternator.

 

[Rolasolar]

Hi, You can not directly charge a small 12v 12Ah battery direct from your vehicle unless a charge controller is fitted inline. An option to consider is a small solar panel (40w max) with solar charge controller. Regards Dave G

 

[Shokgoblr]

Thanks. I was wondering what options I have to charge from the car while driving. I am not going a dual battery route. I have always been wary of the "suitcase" solar panels. I am going to look into a DC-DC charger, and see what they can offer me.

Thanks!

 

[Downs]

I use a dual sided male cigarette lighter cord and charge via my box's 12v outlet, when going down the road via the cargo area 12v port. I don't leave it hooked up in camp as I'm typically using it at that point and I have a larger box (3 7aH batteries) and unless I'm gone for almost a week at a time hooking it up to recharge is basically not needed. Other than airing up my air mattress nearly everything I use anymore is 5V usb driven with a one or 2 12v items which dont' always get used. The 5V usb side gets used a lot.

 

[M Rose]

The above is a good option, if you have the room. Another option to consider is a DC to DC charger.

Dual battery setups more or less require both batteries to be the same to work properly, which can get expensive quickly. DC to DC systems allow your batteries to be different, and should work without requiring you to upgrade your alternator.

Depends on rig, and what the stock alternator is... with some alternators only being 35 amp units stock from the factory (my Bronco), you can’t add even a simple light because there isn’t enough reserve amps... so like I said you still have to look at how many amps the stock alternator puts out... using the battery isolator like I mentioned is the same thing as a dc to dc charger... but old school and doesn’t cost as much.

 

[RJ Howell]

I've left my solar behind, due to not staying anywhere that long.. A good DC/DC unit will service you nicely. As you grow in power needs (which you will), it will still be there for you. I have a 20amp Renogy (Renogy 20a).

Now it does kinda make me think a bit of only a 12ah battery, draw only to 75% (so it will last) and how you get by on 3 amps for two days...

 

[M Rose]

I've left my solar behind, due to not staying anywhere that long.. A good DC/DC unit will service you nicely. As you grow in power needs (which you will), it will still be there for you. I have a 20amp Renogy (Renogy 20a).

Now it does kinda make me think a bit of only a 12ah battery, draw only to 75% (so it will last) and how you get by on 3 amps for two days...

How do you guys get by with only 3 amps for two days? I go through a group 35 deep cycle battery in 3 hours.

 

[RJ Howell]

I've left my solar behind, due to not staying anywhere that long.. A good DC/DC unit will service you nicely. As you grow in power needs (which you will), it will still be there for you. I have a 20amp Renogy (Renogy 20a).

Now it does kinda make me think a bit of only a 12ah battery, draw only to 75% (so it will last) and how you get by on 3 amps for two days...

Mis-read.. My bad.. 3 / 7ah batteries.

 

[4wheelspulling]

The Two ways I would consider is this; wire up a manual or automatic battery Isolation switch, fuse and the right gage wire to your portable battery box and battery, to where you a storing your battery box while traveling. Using the vehicle alternator to charge the battery. This is the cheapest way, and works if you are not camping in one spot for days at a time. You will have to run the vehicle thought every day or other to keep the battery charged. Second; is to look at some portable solar charging systems like the one from Overland solar.com this will work great if you are in one spot camping, but remember you have to put the solar system out in the sun to work!! Best is both ways but cost some coin! Vance.

 

[4wheelspulling]

New member/first real post....I have a question:

I built a simple 12v/12Ah lead acid battery box to carry with me on weekend trips. I use it for charging my devices and running LED lights ususally, and it lasts two nights. When I get home after a trip, I have an SAE pigtail wired in, andI plug it into a charger.
I am going to start carrying that on longer trips to power fans in my RTT and I need an easy way to keep it charged for extended periods when I cant get to a power outlet. I am all ears if you have a good option for charging on the go....

Shokgoblr,
Welcome to our forum! Glad you are asking questions. There is a lot of knowledgeable people here and lots of good information in the posts on our site. Hope to see you around here! Vance.

 

[Shokgoblr]

So about what I run off this- I have only been running fairy light LEDS and charging my phone before bedtime. I am doing nothing serious with it. I dont run a fridge or anything like that. These new 12v fans may prove too much for this battery. I can definetly see myselfy upgrading to a DIY lithium pack or a Jackery in the future. So what i need to find out now is how many amps my stock Subaru alternator is putting out, then I can decide if an isolator or a solar panel is more useful.

 

[M Rose]

So about what I run off this- I have only been running fairy light LEDS and charging my phone before bedtime. I am doing nothing serious with it. I dont run a fridge or anything like that. These new 12v fans may prove too much for this battery. I can definetly see myselfy upgrading to a DIY lithium pack or a Jackery in the future. So what i need to find out now is how many amps my stock Subaru alternator is putting out, then I can decide if an isolator or a solar panel is more useful.

What year, and model of Subaru?

 

[Shokgoblr]

2019 Crosstrek

 

[Downs]

So about what I run off this- I have only been running fairy light LEDS and charging my phone before bedtime. I am doing nothing serious with it. I dont run a fridge or anything like that. These new 12v fans may prove too much for this battery. I can definetly see myselfy upgrading to a DIY lithium pack or a Jackery in the future. So what i need to find out now is how many amps my stock Subaru alternator is putting out, then I can decide if an isolator or a solar panel is more useful.

Check these out. On high they move just as much air as my 12v fans have. Ran one for 3 nights straight on my box. Barely put a dent in the batteries.

 

[Downs]

Rock Auto shows a 200 amp alternator. Not sure what the base requirements are for the car and what kind of reserve you have.

 

[M Rose]

Rock Auto shows a 200 amp alternator. Not sure what the base requirements are for the car and what kind of reserve you have.

Well since the biggest automotive alternator you can possibly get right now is a 240 amp, I would say 200 is pretty healthy.

 

[Downs]

Rock Auto shows a 200 amp alternator. Not
sure what the base requirements are for the car and what kind of reserve you have.

Well since the biggest automotive alternator you can possibly get right now is a 240 amp, I would say 200 is pretty healthy.

This place claims they make a 370amp unit for Imprezas and a few others.