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Author Topic: Grid Hopping  (Read 66160 times)
Scruff
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« Reply #195 on: April 25, 2017, 08:35:55 AM »

Holey Moley Kibi they must be 1000A but dare I say more!

Copper is a great retirement plan Biffer, if it's not providing you with free lecky then you're at least pretty much guaranteed it's worth more in the future than you paid for it.
« Last Edit: April 28, 2017, 09:52:58 PM by Scruff » Logged
Scruff
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« Reply #196 on: April 26, 2017, 08:56:25 AM »

Im a big fan of retirement Scruff, Grin

Hey Biff, I got the joke...after 3 coffees and 5 hours...  Embarrassed

 Cheesy
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biff
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« Reply #197 on: April 26, 2017, 09:28:11 AM »

I would not worry Scruff,
                 When you produce classy gear like that, there cannae be a lot wrong.
 Do you think it would be possible to design a relay of sorts, to step in if and when our DC immersion in the domestic hot water tank fails, (and it will fail eventually),
  Something along the lines of two returning wires from the poles in the immersions that note the dump load voltage climbing to say 144vdc and then automatically reconnect to the big green resistors that are already lying dormant in the the Wind Turbine controller. There is another 2kw controller that carries 2 strings=2kw and that uses the same bank but dumps into our thermal store. The third controller is left on during the long bright summer months or when I start the charger.
It does bother me somewhat, that the turbine could go awol big time if that DC immersions happened to burn out. Fortunately, I spotted the very first w/t digital controller failure last week in low winds and replaced it with a new one. So the inverter and the controller should be Ok for a good few years but the life span of the immersions is dubious.
  144dc is rather a high voltage for an ordinary relay,, but if there was no other way, I could tap a 12volt connection out of the bank and use some form of relay/solenoid to take the 144 to the dormant resistors in the wind turbine controller. It would be easy to test at any given time, Just disconnect the dump load immersion in the thermal store and watch the voltage climb,
    Would such a fail safe idea be hard to design, ?
                                                   Biff
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Scruff
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« Reply #198 on: April 26, 2017, 10:35:58 AM »

I do my best work after dark Biff.  Grin

Something like this?



I haven't tested it so it may need a capacitor to hold the relay coil. Also need to tap the wire between the t-stat and the element which may be difficult..or use a second t-stat in parallel. The TS45 won't like your battery voltage. But it's a working principle.

A second diversion controller with a higher threshold would be best I think.

Probably be alright using a 'Murican 115VAC relay.
« Last Edit: April 26, 2017, 10:52:42 AM by Scruff » Logged
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« Reply #199 on: April 26, 2017, 01:51:58 PM »


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biff
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« Reply #200 on: April 26, 2017, 06:43:08 PM »

Hi Scruff,
       Thanks for that, there is only one problem, The system is 120vdc and the battery is 2 ton of 60 forklift cells in series.. But while working outside, I came up with the idea of using another controller and taking two leads of the poles on the immersion, Then take the _ and a + and plum them into the battery connections on a new controller. These controllers have the big resisters already set up inside.
The immersion should take all the power before it reaches this controller, There would be a delay anyhow with the controller having to come alive and the dump load activate those few seconds later.
The only problem with that is that it means that a full valuable controller gets ties up all the time..and maybe it would not work reliabley, being switched on and off like that.
  I think, also have a special one, somewhere, that has an adjustable voltage setting pod for the dump load. which means that I could also set it up to be permanently alive but with just the dump load voltage set a couple of points higher.
                                          Biff

 
« Last Edit: April 26, 2017, 06:49:14 PM by biff » Logged

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eabadger
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« Reply #201 on: April 26, 2017, 07:58:53 PM »

you can get voltage sensing relays which you set at voltage you want, get relay to switch a contactor if you want a serious load switching.

steve
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1600w PV main array at 24v, excide 2v 1000a forklift cells now x 2, 320w PV secondary array at 12v. Enfield 1944 ex RAF 5.6kw diesel genset (now in pieces, big ends gone), Petter AC1 28v diesel charging set at 2.8kw.
1kw wind turbine.
26kw wood stove back boiler to underfloor heating and dhw
Scruff
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« Reply #202 on: April 26, 2017, 08:55:54 PM »

Hrmm I don't like the idea of load controlling a load controller Biffer.. sounds iffy. How do you know the immersion will use the power first? There's several other ways to do it. Use two immersions, two parallel controllers (not upstream downstream), a voltage sensing relay. A programmable relay driver, voltage or SOC triggered meter relay....

What about a dodgey China special? A current sensing relay?
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jonesy
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« Reply #203 on: April 26, 2017, 11:12:48 PM »

That current sense and a BFO contactor is a really good idea, particularly with the delay setting.
It'll detect the immersion failure immediately and switch in the dump load.  To be truly fail safe, the contactor will need to be normally energised which will eat a few watts. A switched series resistor on the coil will help.
I'd use an aux contact to cut the power to the board so that once it's fired, you have to manually reset the system.
What d'you reckon Scruff?
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Scruff
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« Reply #204 on: April 26, 2017, 11:43:57 PM »

the contactor will need to be normally energised which will eat a few watts. A switched series resistor on the coil will help.
I'd use an aux contact to cut the power to the board so that once it's fired, you have to manually reset the system.
What d'you reckon Scruff?



The SW80 is a 100A not a 200A and the pictured one is a latching type.
The 10A is actually a 5A double pole I paralleled the switches on.

I've devised a scheme to use a DPDT microrelay set to forward/reverse polarity, to trigger two delay off relays to pulse a latching relay from a continuous source. I'll post a schematic later...not fail-safe..get two.  Jelly bean parts China's almost paying you to buy them;)

Good thinking on the electronic lock...could be detrimental to the battery if undetected though.

« Last Edit: April 27, 2017, 12:00:56 AM by Scruff » Logged
Scruff
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« Reply #205 on: April 26, 2017, 11:47:06 PM »

Look what I found under a cabbage!



Naughty!  bike
« Last Edit: April 26, 2017, 11:49:23 PM by Scruff » Logged
eabadger
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« Reply #206 on: April 27, 2017, 09:51:40 AM »

what about.....
you get a relay in series with load? the relay when activated closes its contacts which make the circuit, if load disappears the relay will open, you can then use other contacts to bring something in?
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1600w PV main array at 24v, excide 2v 1000a forklift cells now x 2, 320w PV secondary array at 12v. Enfield 1944 ex RAF 5.6kw diesel genset (now in pieces, big ends gone), Petter AC1 28v diesel charging set at 2.8kw.
1kw wind turbine.
26kw wood stove back boiler to underfloor heating and dhw
biff
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« Reply #207 on: April 27, 2017, 09:59:41 AM »

Thank you all for your help,
                              I am still working out where to locate the goodies, It would make sense to put them in the corner of our living room where i have my desk. At present we have to go downstairs to have a peep at the controller that manages the thermal store to see what power is left in the bank (it is a hell of a lot better than walking down the yard to the W/T controller) so a box containing emergency dump loads and amps and voltage readings would save us a load of hassle and running around, It would also be in a position to alert us to any immersion failure including the in downstairs in the thermal store. The most important one is the wind turbine immersion dump load immersion.
 To be honest, I have been quite lucky down through the years with our installation but I would hate to push it too far and a fail safe standby dump load in case of the Wind Turbine immersion dump load failure would make good sense. It is the only way to go.
I am wondering what exactly it is you found under that perfect cabbage Scruff,? It looks to me like an adjustable voltage regulator, perhaps a soft start one,? but I am guessing of course.
                                                                                Biff
                      
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Sean
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« Reply #208 on: April 27, 2017, 10:07:15 AM »

what about.....
you get a relay in series with load?

The current drawn by the load would destroy​ the relay coil.
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Scruff
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« Reply #209 on: April 27, 2017, 12:24:37 PM »

12VDC to 230VDC (loaded) DC - DC Converter for ABB motorised switch motor or anything that's not an inductive load.
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