Hi, not sure if I'm in the right spot but...
New to the forum and have a few electronics questions. I'm going to be honest here and say upfront the answers I am looking for are the "dummy" answers since I don't know much about this stuff.

I am an amateur astronomer and enjoy taking photos of the night sky.

I would like to make a self contained battery system to power the equipment I need. I realize there's probably a million different ways of doing this, some being easier but I'm trying to keep costs down.

My goal is to have a self contained single battery system that can operate for at least two nights of astrophotography (16 hours at least but more is fine).

My equipment:

My telescope mount can run on a 12 volt battery. In the past, I've used a car battery jump starter with no issues. I'm not sure how long it would power the mount before it would die though.

My laptop, it requires 19.5 volts to run. In the past I built a battery box for the laptop alone. It consisted of four 12v 9ah lead acid batteries connected in parallel. The box had a 12v socket and I have a 12v plug with variable volt settings (one of which is 19.5) to run the laptop. Although I've run my equipment with those power supplies in the past, I never really had a chance to push the limits and see how long each would last. Since then, the lead acid batteries have completely died and the box to run the laptop no longer works.

My idea/question:

A 12v 100ah lifepo4 battery in a battery box with two 12v cigarette type sockets.

Can I use a 12v to 24v stepup converter with it's positive and negative connected to a male 12v plug in one of the boxes 12v sockets to boost just what comes through that one socket to 24v to run my laptop? I already have the variable 12v plug with 19.5 volts to run the laptop should this work. And the second 12v socket on the box remain a 12v socket to run the telescope mount?

Would that work? I'm not good with this stuff so "electricity for dummies" answers would be greatly appreciated!

Battery:
Power Queen 12V 100Ah Group 24 LiFePO4 Battery, 1280Wh Lithium Battery with 100A BMS,Grade A Battery Cell, Perfect for Trailer RV, Marine, Solar Power System https://a.co/d/1bvXjgL

Battery box (box #3):
12V Battery Box Outdoor Portable Multifunction Trolling Motor Battery Tray Cases for Marine Boat RV Camping Travel Lead acid AGM Lithium LiFePO4 Battery Plastic Boxes(Battery not Include) https://a.co/d/hOvDAtC

Boost converter:
SUPERNIGHT DC Boost Converter DC 12V Step Up to 24V 10A 240W Waterproof Voltage Regulator for Golf Cart Club Car LED Strip Light https://a.co/d/hQ1OuCb

Male/female 12/24v plug:
I would split this putting the converter in between and use the male end for the up stepped 12v socket and the female end for the output side to connect to the male 12v plug for the laptop:
KEWIG 4.9FT Cigarette Lighter Extension Cord, 12V 24V Cigarette Lighter Plug to Socket, 16AWG Heavy Duty Extension Cable with 15A Fuse and LED Indicator https://a.co/d/6QuOeVF

Thanks!

 

Hi chez,
Welcome to AAC,
Could you post a simple sketch showing your battery connections to their loads etc.
Your description is a little difficult to follow.
E

 

Hope this helps explain it a little better...

 

Hi Chez,
Is this modified drawing showing how you will connect the units, if yes then it should be OK.
If you plan any changes to the layout, ask for confirmation.
The fuse is essential for all battery powered projects.
E

 

Hi Chez,
Is this modified drawing showing how you will connect the units, if yes then it should be OK.
If you plan any changes to the layout, ask for confirmation.
The fuse is essential for all battery powered projects.
E

Awesome! There is a 15amp fuse contained within the male 12v plug that would connect to the stepup converter and plug into the box. Would that be sufficient or should I also install a fuse where you suggested?

 

Hi,
I would recommend a fuse close to the battery, that should protect the battery and wiring from any system wiring short circuits.
I assume the connectors are polarized so that they cannot be plugged together reversed?
E

 

My suggestion would be to have the two batteries in series and then a step-down switcher from the 24 volts to provide the 19 volts for the computer. That would avoid having to match battery voltages to have them in parallel. Also, step-down switchers seem to be a bit more efficient.