DIY Power Station Wiring - Help Needed

[DividedSky]

My kids recently grew out of one of those little sit-on powered vehicles and I want to use the battery in it to make a small portable power station.

The idea is to use a small case to hold the battery and electronic components and to connect a 12V cigarette plug so I can re-charge it from the rig while I drive.

Here are the parts I have planned...
Case from Harbor Feright
DC Auto Plug
USB Plug-in Panel



Is the wiring I will need as simple as this, or am I missing something?



Also, will the Amp rating of the cigarette plug affect the way the battery charges? I've seen some rated at 5 amp, 8.5 amp, 15 amp etc. I know that there is supposed to be a balance in the way you charge these batteries. Trickle charge takes the longest but charges the "fullest", High Amp charges charge fast, but not always to max capacity. So where should I go with this setup, and will the plug I get limit the amount of juice the battery can draw, or will the battery draw as much as it can and blow fuses left and right? Do I need something between the plug and the battery to regulate the charge rate?

 

[DividedSky]

BUmping to the top...

Hopefully someone with a little electrical knowledge can help me out?

 

[El Solis]

Not an expert but have done a lot of wiring of multiple systems on my truck. I’m pretty sure you don’t want to wire the usb and the cig charger together if you want one to charge and the other to power the USB ports. I’m sure it will work but may not be the best way. Also, there should be some fuses in there. I’m not able to draw a pic now but here’s what I’d do:

1. Cig charger to battery
2. Battery to fuse block
3. Fuse block to USB ports
I use blue sea products but this looks good
ONLINE LED STORE 10-Way Blade Fuse Box [LED Indicator for Blown Fuse] [Protection Cover] [100 Amps] - Fuse Block for Automotive
4. If you want to get fancy add a volt meter to the box connected to the battery so you can monitor the capacity.

MICTUNING MIC-VM-BLUE DC 12V LED Display Voltmeter Waterproof for Boat Marine Vehicle Motorcycle Truck Atv Utv Car Camper Caravan Digital Round Panel

 

[DividedSky]

This is the battery. Right now it’s two in series for 24v 7AH. I plan to rewire it in parallel for 12v 14AH. As you can see it has an inline fuse. It’s 30 amp but I’ll change to 5 maybe. When I rewire it I’ll be sure to have the fuse between the battery and usb hub. Really like the idea of the volt readings btw. Thanks.
Oh..
I don’t plan on charging it and using at the same time.

So given that it already has a fuse, do you think I need a separate fuse for each outlet?
Or will one master fuse suffice?

 

[El Solis]

If your just planing on charging phones etc, the one master fuse should be fine. And the 5 amp fuse should be plenty.

 

[DignTRDoffRoad]

I see this is an older thread, and you've probable already tried it, but the safety issue I see is potentially over charge, just be careful, that can be dangerous, no system monitoring, your truck charging system will just keep right on giving until a fuse blows or even worse, unless you use the original charging system and plugged it into a inverter while you drive, just match up the amp draw on the charger vs inverter or a little over on the inverter so it'll handle it.

 

[DividedSky]

Actually, I haven't tried it. Won't the battery kinda self regulate?
My (uneducated) theory was that the cig lighter will only apply a max voltage of about 13-14V (what comes out of the alternator/main battery), and when the power pack batteries are charged up to that voltage, they will no longer draw current.
Is that not correct?

The issue with the original charger was that it was set up to charge these batteries in series (24V), so wouldn't that wreck this system? Plus I don't have an inverter...

 

[DignTRDoffRoad]

Yea, on cheap battery chargers like a wall wort type one of the cautions is not to over charge the battery they have no type monitoring circuit and generally only want left on for a short period of time usually 1 to 3 hrs. , over charge will damage the battery, that's why a monitored system senses the battery is up to the right voltage and will back off the amp/volts to either float charge or shut off all together. I have seen batteries that have been over charged and the acid boil over and for sealed batteries they generally swell and burst. Where I work we have to do maintenance on large battery banks and Over charge is a battery killer but we have certificated battery chargers , and each type of battery is different, example gell cell, lead acid, glass mat ect. and each require a different way of correct charging, amp/volts/time, after a battery reaches it's full charge it's like OK I'm full and I don't need anymore. and the rigged up system is like I don't see it you need more, then the plates start to heat up and thing get warm then hot and reaction starts happening then next thing bang the side blows out. Those type you have are common in ride toys, home alarm systems, and checking the voltage, and putting on a charge for say 30 min. to 1 hr then checking again to see if charge is taking place, feeling of the battery to make sure its not getting hot, probable will not hurt, but again if it's not monitored there is no way of knowing if somethings not right internally, most good battery chargers have a battery check system and while charging something goes wrong internally while charging it's safety circuit detects and shuts down, and yea, don't take apart and use 24v charge on a 12v battery. I have charged those batteries with a car battery charger on 2amp slow charge and got good results, currently have on 2 of my alarm systems with a schumacher battery mantainer. keeps and maintains them very well one of the batteries thats on my shop/alarm is probable 10yrs old and still going strong.

 

[DignTRDoffRoad]

One other thing and I'll hush gotta go to work, even your car/truck has a monitoring system, when the battery needs charged the alternator charges at a different volt/amp rate to bring battery up to a level, with a healthy battery when it reaches that level the alternator backs off that higher volt/amp charge and just maintains, phones, computers, tablets all have their on monitoring system when they've had enough they shut off the charge and just maintain, that what happens when you plug into a cigarette lighter plug or usb port, adding another battery that small may possibly look like just a load to the car system and if left on could potentially over charge, probable want hurt for short period but keeping an eye on is key here, with no such monitoring circuit bad things could happen. Have a good day.

 

[DividedSky]

Thanks. I’ll try charging it in short bursts like my morning commute and feel it occasionally. I do have a volt meter on the pack. At what voltage should I consider it pretty much full? Even if it’s only really at 75%-80% that’s fine. It would still last me a few nights.

 

[DignTRDoffRoad]

The one's I have for the alarm at full charge usually run 12vdc to 12.6vdc, on my voltmeter.

 

[DividedSky]

Perfect, thanks