Anotherpower.com Forum
Renewable Energy Questions/Discussion => Automation, Controls, Inverters, MPPT, etc => Topic started by: birdhouse on February 01, 2012, 07:29:27 pm
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hello-
i've got a 24v battery bank as part of my renewable energy set-up at my ranch. the bank is about 450Ah @ 24v. there are times in the winter when the solar and wind just don't keep up with the use.
i also use a honda eu-1000 to power up a 32' airstream trailer. that will slowly be put on the RE system, as bulbs get changed out ect.
so i was looking on ebay at 24v chargers, and anything ove 3-4 amps starts getting really expensive. so, then i found these chargers designed for Mac laptops. at $9.65 for 2.6 amps, they're the cheapest "dollar per amp". idea being, buy maybe 6 of these chargers and wire them up all in parallel. so 6 would give a 15+ amp charger that could be plugged into the eu-1000.
would this work? any ideas?
is it easy to make a "dumb" 24v charger? i've got a ts-60 in dump mode, so it could be the "smarts" for the dumb charger.
thanks!
adam
specs for laptop charger:
Features:
1.Input: 100--240V, 50-60Hz
2.Output: 24V 2.65A
3.Power: 65 Watt
4.Smart device surge protection for over voltage, temperature and short-circuit protection
5.7.5*2.5mm
Specifications
Package include:1*APPLE G4 PowerBook 15" 17" AC adapter
Compatible with
G3/G4 all Snow/White Apple iBook 500 mhz+ Apple iBook 12-inch Dual USB
Apple iBook Late 2001 Model
Apple iBook G4 14.1-inch M9165B/A
Apple iBook G4 14.1-inch M9165CH/A
Apple iBook G4 14.1-inch M9165J/A
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Hey birdhouse,
It's time to build a lawnmower generator out of your Fanuc motor.
You can use the C-60 for regulation but you still have to keep an eye
on it.
You'll be happier with a better motor for the turbine when you find
it anyway.
Or find a 24 volt alternator, I use a 48 volt G.E. out of a dozer, got
it for $50.
The servo's for 24 volt charging are getting harder to get a deal on
or I'd make a trip down to see ya. :)
Mike
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mike-
yea, that'll be a long term solution. i "think" i've got a free 3.5hp briggs to play with. i think semi alternators are all 24v...
at this point though, a possible $60 for a 15 amp charger sounds like the go for me!
adam
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The cheapest most useful devices I have found for the money are these things.
http://www.ebay.com.au/itm/New-24V-15A-360W-Switch-Power-200-240V-Supply-Driver-LED-Strip-light-Display-/120799021110?pt=AU_B_I_Electrical_Test_Equipment&hash=item1c202ec836
http://www.ebay.com.au/itm/350W-24V-14-6A-Regulated-Switching-Power-Supply-/170607332827?pt=LH_DefaultDomain_0&hash=item27b8fd4ddb
They are nominally 24v with adjustable voltage control on the output.... if you change the series resistor going to the trimmer pot, you can push it up a few more volts without danger. These ones go up to 26.4 or thereabouts, it's no problem extending this a bit.
There are 27volt versions, but more rare/dearer. (26-31v)
They are switch mode power supplies. You can dial up your voltage... but most importantly, for battery charging you will have terrible power factor... and these things have internal power factor correction, and so leave your alternator with much better control (less current in the windings for the same actual power output)
or
Grab an old microwave oven transformer, haul out the secondary, pull out the shunts (metal plates between the primary and the secondary) and rewind the secondary with heavy wire.
I did one a long time ago here:
[attachimg=1]
[attachimg=2]
good for about 20A or more@42v.. or 40A@22v
This transformer is wound for saturation, so best run with a decent AC capacitor in series to stop it from heating up, and keep the low batt voltage surge to reasonable levels..
..............oztules
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thanks oz!
i saw those LED power units while hunting. i was concerned on weather they'd go higher than 24-25 volts, but sounds like they're a go, especially if you mod them.
i hope you don't mind if i PM ya once i get it, cause i'm really kinda lost on replacing a resistor with a different value. i mean, i understand what your saying but would have no idea what value to use, or where to find this particular resistor within the unit.
adam
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No problems with the PM.
If you look at the pictures in the first link, you will see the trim pot on the left hand side where the V adjust is labled.
It is a simple task... see which way the pot turns for max voltage. If it pulls the rail to ground for higher voltage, then the pot shorts for max voltage... but it will be in series with another resistor to stop you driving it really to ground, and pushing the V out through the roof .
So we find that series resistor, and change it by 10% lower..... then when we use the trim pot, it will end up 10% closer to ground when fully turned up.
If you think about it, as you pull the voltage sense closer to ground, it will have to have a higher output voltage in order to develop the same control voltage the PWM chip is looking for... so it increases the pulse width until it gets what it wants.
I have the smaller 24v meanwell unit, and use it for a variable voltage / current controlled source... so I can control the current from 0-15A, and the voltage from 18 to 48v.... they suffer a fair amount of thuggery and still survive. (I don't get 15A at 48v though with this setup... too many watts ). (uses a tl494 in this model)
They also have a 27v unit that will require no messing about with, but will be dearer as they are usually not competitive in stock units.
.........oztules
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thanks again oz!
ended up getting a 15A 24v unit. $34 to my door.
i'll let you know when i get it!
adam
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You mind giving a link or something? I also have an old Honda EX1000 (pre-inverter model) and was recently looking for a cheap 24V charger to help with bulk.
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VF-
http://www.ebay.com/itm/24V-15A-360W-Switch-Power-Supply-Driver-LED-Strip-light-Display-200V-240V-/390347714048?pt=LH_DefaultDomain_0&hash=item5 (http://www.ebay.com/itm/24V-15A-360W-Switch-Power-Supply-Driver-LED-Strip-light-Display-200V-240V-/390347714048?pt=LH_DefaultDomain_0&hash=item5)
adam
edit: it says 200 240v, but if you read in the listing, there's a manual switch on the side of the case to have it run at 110 120v.
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Why wouldn't an inverter charger work? Just hook the gen output up to the inverter's AC input.
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Chris
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Because when an inverter charger is charging batteries, the only power coming into the house straight out of the same generator that I'm trying to charge batteries with. So if I'm putting 500 watts into batteries with a 1000 watt generator, and the refrigerator comes on, things are going to get ugly.
Also, most of the decent inverter/chargers for 24V are running in excess of $1000. This thing is $34 :)
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Because when an inverter charger is charging batteries, the only power coming into the house straight out of the same generator that I'm trying to charge batteries with. So if I'm putting 500 watts into batteries with a 1000 watt generator, and the refrigerator comes on, things are going to get ugly.
Oh, OK. That must be different than mine then. Mine "blends" power and uses the gen to run loads and charge the batteries, and if the load exceeds the gen output the inverter quits charging and uses battery power to help the gen until the load goes away, then it goes back to charging.
Carry on :)
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Chris
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Oh, OK. That must be different than mine then. Mine "blends" power and uses the gen to run loads and charge the batteries, and if the load exceeds the gen output the inverter quits charging and uses battery power to help the gen until the load goes away, then it goes back to charging.
+1
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Yeah it is a shame the SW was one of the only inverters with "Gen Support" this feature allows the inverters to add to the generator. It truly is a shame this never got put into the other brands.
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Yeah it is a shame the SW was one of the only inverters with "Gen Support" this feature allows the inverters to add to the generator. It truly is a shame this never got put into the other brands.
Mine isn't a SW, but it has it.
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i don't have an inverter charger either. my xantrax pro-sine 1800 was spendy enough!
like VF- a $34 charger hooked to a baby genset should make me very happy!
eventually, i'd love to make a charger from a pma/servo/alternator with a brigs or something with the exhaust through a car muffler or something to keep it quiet, or something, but thats a whole different thread! or something :P
adam
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Oh, OK. That must be different than mine then. Mine "blends" power and uses the gen to run loads and charge the batteries, and if the load exceeds the gen output the inverter quits charging and uses battery power to help the gen until the load goes away, then it goes back to charging.
Hmmm, I just learned something there. I thought all inverter chargers operated as mine does. Interesting!
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eventually, i'd love to make a charger from a pma/servo/alternator with a brigs or something with the exhaust through a car muffler or something to keep it quiet, or something, but thats a whole different thread! or something :P
Something like this is probably overkill then: http://www.anotherpower.com/board/index.php/topic,148.0.html (http://www.anotherpower.com/board/index.php/topic,148.0.html)
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A very nice example to try and duplicate rossw!
I know adam is carving a paradise out of the wilderness for his ranch.
It will take some time but man, he is doing some awesome building. Top notch.
More power to ya adam! :D
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Yeah it is a shame the SW was one of the only inverters with "Gen Support" this feature allows the inverters to add to the generator. It truly is a shame this never got put into the other brands.
I thought Outback did that too?
Xantrex calls it "Peak Load Management". It's really nice and I wouldn't be without it. Say, for instance, my wife goes downstairs and throws a load of clothes in the dryer. That pulls about 4.5 kW. Now she comes upstairs and turns on the electric range. Now we got 9 kW.
The inverters are rated for 4 kW continuous each. But they will carry the 9 kW load long enough to bring the gen online. The master starts the gen and warms it up for 40 seconds while it syncs the sine waves on both inverters to the gen output. Then it gradually loads the gen - it's not a slam-bang transition.
It loads the gen to the full capacity of what I have entered in the menu for the Max Gen Input Amps. So now the gen is carrying 6 kW of the load and the inverters only have to supply 3 kW. But the oven gets up to temp and the element starts to cycle on and off about every minute or so to maintain the temp. The inverter watches this and keeps the gen running until the load drops below 4.8 kW for two consecutive minutes (the way I have it set).
So now the clothes dryer gets done and shuts off. The inverter sees the load has dropped below the Peak Load Management threshold. So it looks at bank status and if the voltage is above 24 it disconnects the gen, cools it down for one minute and shuts it off. If the voltage is below 24 it does a maintenance charge on the bank before shutting it off.
During all the above of how the inverters manage the loads, there is never even a single flicker in a light bulb anyplace. It is super-smooth.
I know the XW's do this, as well as the SW's. We have never had any other inverters (that were worth a crap) so I just (possibly wrongly) assumed that all the big name inverters do it.
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Chris
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Chris
Outback nor Magnum do Generator support of any form. I do not know if the new Radian does Gen Support but I suspect it does not.
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Hmmmm. That's surprising. Didn't pretty much the same group of engineers that went from Trace - > Outback - > Magnum -> Midnite design all those inverters?
Edit: I looked on Xantrex's new website and even the new Freedom inverters do this, quote:
The second generation 2000 watt model has been completely redesigned to include many of the same great features found in its high power counterpart. A key feature enhancement is ‘Generator Support Mode’ which enables the Freedom SW to supplement a generator when AC loads exceed the generator’s capacity.
It's possible that this is something that Xantrex dreamed up after they bought Trace Engineering.
What I do know is that it is really nice for an off-grid application because you don't need near as big of a generator (or inverters) to meet peak loads when you can combine the output of both of them to run stuff.
In VF's case where he says the 'fridge might kick out the gen if it's charging batteries, it would seem the logical solution would be to get a bigger generator. I would assume Outback or Magnum inverters do have enough common sense to at least stop charging the batteries and divert all gen power to intermittent starting loads like that, even though it may not be able to help on the top end of the load.
And if I read this correctly, an Outback or Magnum inverter must not sync their sine wave with the gen output? So it it don't, what happens when the internal transfer switch flips over? You get a blink in the lights?
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Chris
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Chris you are correct when the Outback kicks if the relay there is a slight blip. Robin and boB always intended to add this to the Outback inverters and the other majority owners said no and after the parting of ways it was just set aside. I hope when we build the ultimate inverter we for sure add this as it is such a great feature.
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MidNite is going to someday build the ultimate inverter? I can hardly wait to see that one! ;D
Yes, it makes a HUGE difference on how you size your equipment to meet loads. If VF's inverter had that in it, he would have no problem charging his batteries with his Honda 1000 when another load kicks in. And that's kind of the beauty of it - you don't need near as big of a gen to "do the job".
I learned something new as I had thought all along this was a pretty "standard" thing in all of the big name inverters.
I took a photo of the menu options in my inverters. It's under Menu Heading 26, Gen Auto Run Setup:
[attachimg=1]
I currently have it set for 4.8 kW with a 2 minute delay and five minute "wait" period before shutdown after the load drops below the threshold:
[attachimg=2]
[attachimg=3]
[attachimg=4]
I am certain Outback inverters have this in them. The menus are not well laid out in the Mate, IMHO. But there's a guy that lives about 40 miles north of me that has dual Outbacks and he has electric clothes dryer and all that stuff too. I am certain he has his set up the same way we have ours, so the gen starts for Peak Load Management. The Outback may not have the feature to help the gen out above the gen's max output capability, that I don't know. But I'm pretty sure that when it starts the gen for peak load that it only charges batteries if there's enough extra power to do so.
When they start the gen because of low battery condition, then the inverter uses gen power for battery charging as first priority and loads are secondary. But in VF's case, it should not "get ugly' when the Honda is charging and the 'fridge starts. The inverter should merely "spit the gen off" due to gen overload to prevent its breaker from kicking out. Then reload it under Peak Load Management Mode to run the load that came on, and using only extra power to charge batteries.
If it doesn't I don't think the inverter is programmed correctly because I'm 99% certain of it based on other people I know that got Outback units.
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Chris
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Chris
You are correct in that the outback has settings to tailor its ability to charge and use the generator but it does not do generator support. What I find here with my small generator and stacked Outbacks is that if I set charging to 14A on Port 1 and Port 2 and I set the allowable current draw from the generator to 16A on port 1 and port 2 it works pretty good.
That said I have a Lister clone that can power through a couple seconds of overload. Say my well pump kicks on the OB's try to catch up and unload the chargers but they are not instant. I can see my lights sag and then they catch up. I can see where this would or could be a problem with a real small generator IE1-2kw. One of the inherent problems with the OB stuff is the Mate and all the settings that are hidden in that thing. If one truly understands it and looks through there they will find a lot of settings to help make life better. I always advocated for a new Mate that was layed out in a more user friendly format but never did get one.
On a side note you will see in the Mate there is a "Generator Support" function and it is set to "Yes" interestingly it can not be set to "No" and if you get some one at OB that knows the Mate they will laugh and say yeah that doesn't matter it does not have gen support that was put in there in anticipation of that function years ago.
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On a side note you will see in the Mate there is a "Generator Support" function and it is set to "Yes" interestingly it can not be set to "No" and if you get some one at OB that knows the Mate they will laugh and say yeah that doesn't matter it does not have gen support that was put in there in anticipation of that function years ago.
LOL! OK, that makes sense, and I'll bet that's what I saw in there at one point when I was fiddling with the Mate on a system that I helped install a few months back. That system had a grossly over-sized generator that can run anything so I just assumed it was "working". :)
I know I had to have the manual in front of me and study the "road map" for the Mate menus to figure out how to get there.
After reading this I can see where in VF's case, if he was charging with the Honda 1000 and the 'fridge starts up it could indeed overload the gen and get a big momentary sag in the power then. If the internal transfer relay in the inverter has to flip to drop the gen and save it from stall, going back to invert to recover from the load situation, I wondered if the Outback inverter will then bring the gen back online and use it to run the new load? And if it does do that, then does it limit how much power can go to the charger to keep the gen under the setting you have for max input amps?
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Chris