Generator auto run switched from two sources?

[Pip]

Hi Guys, Hope I'm in the right forum area.

So Have a 3 phase gennie set up which I've been involved in.

Customer has supplied the 125amp 3 phase gennie to run power at a workshop, and out buildings in the middle of a wood.

All went very well, and as a bonus a key switch was installed on the perimeter of the compound so as to switch on the gennie so that the lights come on before anyone enters the compound. Auto setting on the gennie.

Now the guys who installed the alarm system running off a PV system want to link to this auto start so if the batteries run a little low during the winter months, the gennie will kick in for a couple of hours to charge the batteries.

The inverter they have installed will be there trigger, so if we run the inverter trigger in parrallel with the original key switch, this should not cause any problems should it?

Look forward to your replies

 

[Knobhead]

So you’re going to run an 85KVA generator to charge a battery?
Somebody needs their bumps feeling.

 

[Pip]

I know, it's somewhat over specked, I won't go into details of where this gennie came from or what it's running, and trying to keep enough load on it to keep it happy in the first place is beyond the install, but there you go....

 

[Knobhead]

It’s an alarm system FFS! Sell the PV array on flea bay and buy some batteries that will last a week of so. You/they will make a profit.

 

[Pip]

Alarm guys dont want the batteries to drop below 70% as the life expectancy will also drop, adding PV panel will not help so I'm told, so this is a belt and braces approach.

 

[Bobster]

Why don't they set the genny to charge the batteries during the day? If the batteries drop to say 80% it takes over from the pv? They shouldn't loose to much charge overnight lets face it, it's only an alarm system.


Or is the site not run everyday?

 

[electric will]

It's a secret

 

[ipf]

It's a secret

Send for the 'Mission Impossible' team. This thread will self destruct in 5 seconds.

 

[Knobhead]

Can’t be a government site. Otherwise there’d be four stand by generators to charge the main generator batteries.

 

[jumpin jax]

Who is going to hear the alarm if it does go off? buy a bank of gel filled traction batteries, these should last weeks with just the alarm drawing on them before they drop charge and use the solar to constantly top up between charges. If you make it too complicated it will become a maintenance nightmare.

 

[Pip]

Outbuilding has been broken into recently, which is why the alarm system has been installed, it links back to a board at an employees house and is wifi enabled to a mobile phone etc... Customer very paranoid, and has a few bob.

Buildings not used everyday which is why the solar panels were put in originally, then the gennie came along, and now the alarm guys want to use that facility as well, as I say belt and braces.

What the customer wants the customer gets.... with in reason

 

[Bobster]

You will end up ruining the genny if it keeps starting up to simply charge batteries. There isn't enough load there.

 

[Engineer54]

I know, it's somewhat over specked, I won't go into details of where this gennie came from or what it's running, and trying to keep enough load on it to keep it happy in the first place is beyond the install, but there you go....

If you can't give this Genny at least 65/70% of it's rated load then it ain't gonna last too long. You need to connect either an auto or manual load bank to provide that loading to the Gen-set.

Don't take any notice of these alarm boy's, they are giving you the bum's rush here. They don't give a dam about the Genny damaging itself providing minuscule power, all they are worried about their alarm system's life expectancy, which frankly is a load of old bull.... Charging batteries during normal running times will be more than ample to keep them topped up over night and a dammed site more besides!! Think about it, what keeps this prime power Generator's starting battery topped-up, and that will be a far bigger battery than for this alarm system...lol!!! If they are that worried it, they should of designed their system to suit the site conditions and provided bigger batteries, for longer autonomy periods!! Bloody ridiculous argument on there part....

 

[Pip]

Yes even when the gennie was commissioned it was mentioned that there is not enough load on it, but what can you do?

 

[Engineer54]

Yes even when the gennie was commissioned it was mentioned that there is not enough load on it, but what can you do?

I just told you..... It's the ONLY thing you can do if there is not enough actual working load!! That or supply a suitable sized Gen-set for the working load it needs to carry!!!