Power And Battery Equirements

[thainet]

I have a remote location with sensitive electrical equipment that requires 24/7 power for the

computor and associated VSAT equipment.

Does one of Thaivisa's experts know how I can calculate how many 12v 100-15-amp hr batteries I'd need to

run the above equipment pulling about 180 watts.

My big problem is we only have 2 hours of commercial power available each day to charge the batteries.

I know I can use solar power (but this is expensive) so was thinking of only batteries/charger.

Any answers or information would be much appreciated.

[monty]

You'll need some special custom made equipment for that I would think.

As far as I know none of the existing stuff is designed to charge the batteries in two hours and then run on batteries for 22 hours!

If you put in a regular installation to supply the 180 watts of electricity, you'll probably blow up the batteries trying to cram enough energy in them!

I'll do some calculations with equipment I have the data of (Leonics stuff). and post later...

[thainet]

I have a remote location with sensitive electrical equipment that requires 24/7 power for the

computor and associated VSAT equipment.

Does one of Thaivisa's experts know how I can calculate how many 12v 100-15-amp hr batteries I'd need to

run the above equipment pulling about 180 watts.

My big problem is we only have 2 hours of commercial power available each day to charge the batteries.

I know I can use solar power (but this is expensive) so was thinking of only batteries/charger.

Any answers or information would be much appreciated.

Sorry just for clarification I should have said -how many 12v 100-150 amp hr batteries...

[Guest Reimar]

Monty is right with that.

Why you didn't consider to use an Wind- and/or Water Dynamo for to run the Battery Charger?

You can also consider an motor driven generator while the motor used LPG or even NGV. LPG you can get nearly all over Thailand.

Many of the equipment you can find on the 2. hand market for quite low cost.

Solar energy is the other alternative which is working within daytime. here you should check with Amorn because they import that staff from China at low cost.

2 hour electricity per day isn't for sure enough to charge the batteries.

Cheers.

[monty]

Quick question, does the equipment run on 12 Volts, or do you need an inverter to generate 220 VAC?

If the stuff runs of 12 Volts then it's a fairly quick calculation:

180 Watts on 12 volt will draw 15 Amps. 15 amps multiplied by 22 hours is 330 Amp hour. In the charging cycle you'll have at best 80% efficiency, so this would mean that you''l need to charge around 200 Amps per hour (of the 2 hour charging cycle).

Considering that regular lead acid batteries are best charged at a current 10% of their capacity, would mean you'll need a whopping 2000 Ah of total battery capacity!

Ten 200 Ah truck batteries will set you back around 40,000 Baht, and an automatic charger charging at 200 Amps on 12 volts (haven't seen such a beast yet) will not be cheap either!

In the above scenario you'll run your batteries between 100% and 85% of capacity.

Actually the charger would have to be even bigger, since the initial charging current should be higher and then taper of while topping the batteries of to 100%

You really can't reduce the amount of batteries by much, because the charging current would become quite high compared to their capacity, which will severely shorten the lifespan of your batteries, additionally a lot of heat will get produced!

If your stuff runs on 220 Volts, It'll get a bit more complicated due to the losses incurred in inverting the DC to 220 VAC. And much more expensive!