Uninterruptible power supply for PC and cellular modem running on haul truck 1

[yuvalk]

Hello,

I planning to run a PC and cellular modem on haul truck - both coponents are 12 Vdc input and with maximun current capacity of 10 Amp.

The UPS system I will need should be capable to work in rough enviorment such as open pit mine. and vibrations inside the truck.

Many thanks if someone will recomend to me about UPS that will fit to those requirements.

Thank you guys alot!

Yuval Kremer

 

[VEBill]

OP "...a PC and cellular modem... ...both components are 12 Vdc input..."

Assuming that the components are 12 Vdc input, then you don't need a traditional AC-output UPS.

If the haul truck has a 12 volt system, then how about another lead acid battery (of suitable Amp-hours capacity) connected to the truck's 12-volt system with a simple Battery Isolator system to ensure that these devices don't accidentally discharge the vehicle's main engine-start battery.

Perhaps I've misunderstood...

edit: this assume that these devices are 12 volts 'nominal' and can operate safely on vehicle battery voltages (~13.8 volts).

 

[DanEE]

Yep.. in plain sight 12VDC requirement not 120VAC... reminder to self... drink more coffee before posting.. Just saw the UPS statement and brain? jumped to larger 120VAC requirement.. no need for what I posted above... deleted the post

 

[ScottyUK]

If the truck is 24V DC then step-down regulators to suit 12V equipment are fairly common. There's a tremendous variation in quality though: some have nasty failure modes which feed 28V to your 12V equipment, or lack over-current protection beyond a simple fuse which the semiconductors helpfully melt to protect. Choose carefully...

 

[FreddyNurk]

Or just buy the 24V versions of the PC and Cellular modem. Its unlikely that the specific performance requirement would only be met with equipment that only has a 12V input. That said, my understanding of 'haul truck' might be a bit bigger than others, depending on location and application, I'm thinking along the lines of the very large yellow ones.

 

[yuvalk]

Thank you alot for taking a moment of your time for me.

well let me be more clear about what I'm asking.

the main system of the haul truck is 24V
the idea of adding a DC-UPS system is because of the reasone we want to keep runnig the computer and the cellular modem while the truck is off between shifts.

hope now it's more clearly.

many thanks!

 

[IRstuff]

No, when the truck is off, you can still use it's battery. A typical UPS is ONLY intended for providing sufficient power to make an orderly shutdown. It's still unclear what power your computer and modem directly uses. Are you simply asking about an inverter? You can buy those at almost any truck stop, Best Buy, or Fry's Electronics, etc.

TTFN
I can do absolutely anything. I'm an expert!
faq731-376 forum1529

 

[VEBill]

If you can't find an off-the-shelf solution, then build it up as follows.

1) You don't want to drain the vehicle's primary battery. So use a 'Switched' power source that's only on when the vehicle is on / running.

2) Perhaps a battery charger for 12 volt battery that can be powered by 24 volts.
A couple of sub-issues:
a) Make sure it can provide enough current to also run the devices while still charging too
b) Make sure it's not too noisy (some chargers are noisy, being DC-DC hopefully not).

3) A 12 volt battery with enough capacity to last as long as required (with a healthy safety margin).

There are likely other concepts that would work as well.

System would need all the usual safety features (fuses and more).

 

[yuvalk]

Ok... I will try to explain more parameter must be considering:

When you turn the truck on the system voltage is drop down because of the starter motor (there are 2 like those in those trucks, starting current about 400 ampers each)
the system voltage and the charging voltage from the alternator is 24 V - I cann't connect any 12 V battery to the system. and I don't want to drain the battery system while the truck is off.
I want to make sure the PC and the modem stays on constantly.
I cann't connect just a step-down DC - DC inverter because then I will drain the batteries.

therfore what became the best solution for this is a DC-UPS system with independment 12 V battery. but the issue now is about finding a shelf solution that capable to work in those conditions, such as high vibrations and corosive enviorment.

I'm atteching one of the DC-UPS wiring solution

Many thanks to all you!

 

[VEBill]

The concern about draining the vehicle's battery...

Use a 'Switched' 24-volt power source (found in the vehicle's fuse box) that's only on when the vehicle is on / running. Do NOT connect directly to the vehicle's 24-volt battery.

This obvious and rather trivial power source wiring suggestion fully addresses this issue about draining the vehicle's battery.

Does this make sense?

----

Obviously, the subsequent 'UPS' will require and must have its own 12-volt battery.

Therefore, the only thing that's actually required (the conceptual 'UPS') is a battery charger that can charge the new 12-volt battery while being powered by 24-volts.

That's your 'UPS'.

Done.

 

[ScottyUK]

As your load appears to be 24V DC, you might consider using a split charge system with an independent battery for the load (the 'UPS' battery in the sketch above). What you're doing looks like a leisure battery system from the RV world. First google hit I got is typical - I've no connection to this company other than through Google.

 

[VEBill]

At the top, OP wrote "a PC and cellular modem on haul truck - both components are 12 Vdc input".

The diagram seems to be just in support of the discussion.

 

[ScottyUK]

Solving this one is like knitting fog...

 

[yuvalk]

Thank you everyone

I will look for shelf solution for this one.

if you want to know more about what I looking at you can check the attechment

1
2

I'll realy appritiate it if you will take a moment to check this with me.

Have a nice weekend!

 

[IRstuff]

Again, UPS' are not intended for long term power consumption. Your first link will barely run my laptop for 1 hour.

TTFN
I can do absolutely anything. I'm an expert!
faq731-376 forum1529