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!!!

 

[Pip]

I'll raise the issue of the load bank with the customer, as the use it has now is well under its capacity.

I'll speak to the Alarm guys and discourage the auto start, I have installed a couple of sockets near the inverter so that the battrey chargers can be used, when the gennie is on for other reasons.

Any recommendations on type and size of loab bank?

 

[Engineer54]

I'll raise the issue of the load bank with the customer, as the use it has now is well under its capacity.

I'll speak to the Alarm guys and discourage the auto start, I have installed a couple of sockets near the inverter so that the battrey chargers can be used, when the gennie is on for other reasons.

Any recommendations on type and size of loab bank?

The auto start is fine for powering up the overall installation from the gate, but definitely not for the sole purpose of charging alarm batteries!! lol!!

Whatever your normal running load might be, then add an appropriate KW number to bring the Gen-Set's running load to around 65 to 70% of it's rated capacity That will be the size of load bank required to sustain long service from your Genny... Virtually all load banks are resistive, they can be brought on line in stages, preferred (also giving you a wider scope of normal running loads for the present and the future) or direct on line.

 

[Knobhead]

Take in to account the load bank is just wasting energy. Energy that has to be paid for in terms of fuel used.
So much for green energy using solar power for the alarm when next to it will be a load bank producing 30/40KW of waste heat.
The whole set up is ridiculous.

 

[Engineer54]

Take in to account the load bank is just wasting energy. Energy that has to be paid for in terms of fuel used.
So much for green energy using solar power for the alarm when next to it will be a load bank producing 30/40KW of waste heat.
The whole set up is ridiculous.

Hence the very reason for always specifying a gen-set to the load it is expected to supply, plus a realistic surplus, for any foreseeable future loading increase(s)....

In this instance, your spot on Tony, it is indeed a ridiculous set-up!! Mind they could always locate the load bank in the mess hut or whatever, to heat the place up for the lads!! lol!!!

 

[Knobhead]

The tea will be boiling in the cup!

 

[Pip]

Unfortunatley there was no conversation regarding Gen Set specification, as there was no know spec regarding the load, The Genny came out of a Bank which was being developed by the customer, he just had it shipped on site and said hook it up and put a few lights and sockets in the workshop, and when you joke about the mess hut, we put a few extra sockets and lights in there as well!!!

I know it's mad, but to say it's all arse about faced, going forward who knows what the customer will think of adding next.

Originally they had a little single phase portable petrol genny, which just about boiled the kettle, but that got pinched when the break in happened...

 

[Knobhead]

I know I’ve been a bit cruel but look at it as I did when I read you’re first post. I know the situation is not of you’re making. If the owner caries on with this gen set it’s not going to last five minutes before the engine is knackered, that added to the fuel costs, it’s going to end up costing a fortune.
I don’t envy you trying to get him to see sense.

 

[Pip]

Tony, Don't apologise, I agree with all your comments, yes it is a mad set up.
The Solar panels were not put in for green energy, they were there to power the alarm system before the genny came on to the scene, so I'm not losing sleep over that expense.
And as far as fuel is concerned, again I don't think the customer is worried too much either.

The Genny came as a freebie I believe from one of his developments as I mentioned earlier, If I can persuade him to extend the life of the set beyond the end of the year, then great.

One other question, would bringing a load bank on a rental term every couple of months or so, just to clear the wet stacking, would that be a viable option?

 

[Knobhead]

No, it needs a reasonable loading most of the time to keep the engine clear of deposits. A load bank just every so often will cause more trouble as you’re likely to get deposits flying around from the periods of light running. If it’s got a turbo, that’s not going to be happy either.
I had this problem about ten years back. We had a 1.5MVA set on emergency standby. To be honest I don’t know why we had it at all, it would just about keep the lights on. It was started once a week and run light, come the fateful day we needed it. It started OK, went on load and within 3 or 4 minutes the temperature went sky high and it shut it’s self down. Turbo and both cylinder heads knackered.

 

[Pip]

Thanks for the info Tony, have had a conversation with the customer regarding the Load Bank, and the auto start for the alarm guys, and he still wants to go with the auto start for their battery charger, and I have to research on pricing up a load bank....

So the saga continues...

Meanwhile going back to my original question, running two sources to the auto start on the genny should not be a problem should it?

Many thanks

 

[Knobhead]

If you've all ready got a remote start just parralel to that at the gen set.

Sounds like you've got a right divy there :bomb2:

 

[Pip]

Thanks Tony,

You could say more money than sense, but as long as he keeps paying the bills....

 

[Knobhead]

Thanks Tony,

You could say more money than sense, but as long as he keeps paying the bills....

You'll keep printing them

 

[Knobhead]

You could be eco friendly and e-mail them. Hug a tree (it's dead though through carbon monoxide poisoning).

 

[GLENNSPARK]

you mean like this (but without the leaves)..

View attachment untitled.bmp

 

[Pip]

Ironic really as the genny is situated in the middle of a wood!

 

[Billynm]

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

Iv'e come across a lot of generators in Afghanistan, if there is not enough load on them they will "wetstack" ie: it won't be long untill the conrods pop through the block !! VERY expensive ..

 

[vaughant]

Couldn't you just run a cable from it to your own house to power that for free?
Doesnt look like the guy would notice much anyway!!!