PIP-4048MS and PIP-5048MS inverters

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Post by weber » Mon, 24 Nov 2014, 04:48

PlanB wrote: Dave is it one of your cell top modules that will throttle the absorb & float voltages?
Sort of. The present plan is to use the modified CMU that we call an IMU, for this. It lives on top of the current-shunt rather than on top of any cell. We would put it last in the comms daisy chain, instead of first as it is in Mexy. It would run a PI control loop on the maximum cell voltage, to keep it down to 3.32 V (76% SoC).
If I took your cmds in on an RPi serial port & echoed them to the 4048 (so we can maintain our serial connection) then echoed the 4048 response back at you would your wait for ACK timing be generous enough to allow this to happen transparently?

It would work because there is no wait for any ACK. Our BMS comms is strictly one-way, and if one command packet to the PIP-4048MS is corrupted and ignored, there will be another one along in 1/15th of a second if the value needs to change, and in one second if it doesn't need to change. And if any cell gets to 3.5 V then the IMU will turn off the battery contactor, and perhaps reconnect it and retry after some delay.
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Post by PlanB » Mon, 24 Nov 2014, 13:26

OK & a few more questions;
- the IMU trips the kilovac if any cell gets too low also?
- the IMU stays powered when you disconnect the pack?
- is it possible for the RPi to get a 10s advance warning of pack disconnect?

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Post by weber » Mon, 24 Nov 2014, 21:25

PlanB wrote: OK & a few more questions;
- the IMU trips the kilovac if any cell gets too low also?
No. Instead it will drop out an AC contactor (a 63 amp changeover) that will transfer the AC loads from the inverter to the genset inlet (whether the generator is connected or not). This is to allow the battery to still be charged from either the PVs or the genset, as discussed here:
viewtopic.php?title=pip4048ms-inverter& ... 332#p54028

It's kind of neat that the two IMU microcontroller outputs that controlled the two reed relays for insulation testing in MeXy are here re-purposed to control two contactors (battery and AC loads).

Coulomb did the mods for that and tested it on Saturday. Thanks Coulomb. He replaced the reed relays with MOSFET drivers, TO-220 MOSFETs and freewheel diodes, capable of pulling in two EV200s each.

In the case of the EV200 battery contactor, there will be a second contactor with its coil in parallel, (a Gigavac minitactor) that will disconnect the PV array at the same time. This will allow the emergency shutdown to be a single big red button (with a reminder note to turn off any genset).

For the AC contactor I was planning to use a din-rail Hager ES470 (230 Vac coil, 230 Vac 63 A 2NO+2NC contacts). Its 230 Vac coil drive would have to come from the inverter and would be switched by a Hager EN145 (12 Vdc coil, 230Vac 5 A CO contacts). But does anyone see the problem I just saw by writing this down? Image And can anyone suggest a solution?

An IMU MOSFET would drive the Hager EN145. The 12 V supply will come from a DC-DC separately-fused off the 48 V battery.
- the IMU stays powered when you disconnect the pack?
Yes, it would need to, if we are to have the possibility of it reconnecting the battery without human intervention, which means the 12 V DC-DC has to stay connected to the battery when everything else is disconnected.
- is it possible for the RPi to get a 10s advance warning of pack disconnect?

The PI-control setpoint will be stress level 7. Pack disconnect might occur at stress level 15 (the maximum). The RPi could treat say a stress level of 13 as advance warning, but only testing would show if that gave it at least 10 seconds. Alternatively we could add a 10 second delay after stress 13, to the IMU code.
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Post by PlanB » Tue, 25 Nov 2014, 03:38

So if you're disconnecting the AC loads rather than battery so that the low battery might still get some solar charge why disconnect the solar with minitactor?

The issue with using inverter AC to keep the AC load connector on escapes me alas.

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Post by weber » Tue, 25 Nov 2014, 05:49

PlanB wrote: So if you're disconnecting the AC loads rather than battery so that the low battery might still get some solar charge why disconnect the solar with minitactor?
On cell undervoltage, only the AC loads are disconnected.
On cell overvoltage, or when the emergency stop button is in, both the battery and the PV array are disconnected. The PV array doesn't need to be disconnected on cell overvoltage, but it does need to be disconnected on emergency stop. All sources or storages of energy need to be isolated on emergency stop. It just simplifies things, to parallel the coils of the battery and PV contactors.
The issue with using inverter AC to keep the AC load con[ta]ctor on escapes me alas.

It means you can't use the load-sensing mode to reduce standby losses. If the inverter ever goes off because there actually are no loads (e.g. everyone has gone to bed and the fridge thermostat turns off), it will never come back on again, because it will never see any loads, because the AC contactor will be off.
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Post by weber » Tue, 25 Nov 2014, 21:42

Plan B, T1 Terry and others,

Thank you for not assuming I know what I'm doing. Please, keep questioning anything that seems the slightest bit, well, questionable.

Your recent questions, Plan B, have caused me to question myself as follows: Since I am disconnecting only the AC loads on undervoltage, why don't I disconnect only the charge sources on overvoltage. Why disconnect the battery on overvoltage? Why not keep powering the loads via the inverter? They will just help bring the battery voltage down quicker and upset the customer less.

Why not do battery isolation _only_ on manual shutdown (emergency or maintenance)?

That will require that I have another AC-rated contactor to disconnect the genset AC from the inverter/charger. My biggest worry is explaining how all this works, to the electrician who will have to approve it, and wire it up.

Can anyone suggest a contactor rated at 20 A (preferably 50 A) at 250 Vac, that has a 12 Vdc coil requiring 200 mA or less? This would let me avoid the two stage thing with a Hager EN145 followed by an ES470.

A Gigavac Minitactor would seem ideal for this, if only the datasheet showed AC ratings for the contacts. I note that they are not polarised like EV200s.
http://www.gigavac.com/pdf/ds/pp/p105.pdf

I just took delivery of a Minitactor (from ELMOFO) for the PV array disconnection, and I have no idea how to connect 50 amp cable (e.g. 10 mm^2 or 7 AWG) to their power terminals, which are supposedly good to carry 50 amps continuously, given that the terminal bolt is only M4 and the contact area for the lug is only 6 mm in diameter. The biggest lug I can find with a 4 mm hole is only good for half that wire cross-section (5 mm^2 or 10 AWG). Any suggestions?
Last edited by weber on Thu, 27 Nov 2014, 04:33, edited 1 time in total.
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Post by offgridQLD » Tue, 25 Nov 2014, 22:13

You can get lugs with a blank spade that you just drill out to the appropriate size for your stud. Any electrical suply outlet should have them or be able to get them for you for 10mm2 cable with a blank spade.

16mm example below

http://www.ebay.com.au/itm/Copper-Cable ... 33760c14cd

Kurt
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Post by PlanB » Wed, 26 Nov 2014, 17:45

https://oceancontrols.com.au/RLY-018.html VA looks good, W seems dodgy
https://oceancontrols.com.au/HER-030.html limited stock alas

Some thorny issues with these boxes on just what to disconnect & when, sometimes I worry we over think the why? So I just take the Leaf for a spin then I feel better.

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Post by weber » Thu, 27 Nov 2014, 16:59

Thanks for those links, Kurt and Kris. Very helpful.
PlanB wrote:Some thorny issues with these boxes on just what to disconnect & when, sometimes I worry we over think the why? So I just take the Leaf for a spin then I feel better.

So you reckon I should just take MeXy for a spin. Hmm, I think it's about time I drew up a complete schematic, in case there's something else I'm overlooking.

As much as I love MeXy's "exquisitely intricate mess of copper and iron, all twisted and interwoven" (Richard Feynman's eloquent description of an induction motor/generator), I'm glad they are becoming less popular as domestic loads direct-on-line, since they play hell with relay contacts opening under load. Not so common in fridges and washing machines now, but still used on water pumps.

The annoying thing is that these relays will never be required to open if everything else is working properly, and yet they have to be spec'd to cope with operating every few minutes for days on end without welding, in case no one is home when something goes wrong.

The PIP-4048MS all-in-one inverter/charger/MPPT is convenient for running a PI control loop that uses serial comms to control charging, without having to worry whether it's from PV or genset. It's a pity they won't let us raise the inverter cut-off above 48 volts so we could do the same with discharging. But even if they did, the all-in-one nature of it forces the backup relays for load-disconnect and source-disconnect to be on the AC side (LV), whereas if the inverter was separate from the chargers, they could be contactors on the DC side (ELV).

Hmm. A thought. So that I don't have to worry so much about the AC relays welding their contacts:

Give the BMS control over the battery-isolation contactor too. If it has turned off the AC load relay, and the lowest-cell voltage is still falling, then it can drop out the battery contactor (an EV200). Likewise, if it has turned off both the AC genset relay and the DC PV array contactor (with their coils in parallel), and the highest-cell voltage is still rising, then it can drop out the battery contactor.

Fortunately this doesn't require a third relay-control output from the IMU. The battery contactor's coil can be powered by a diode-OR from the source and load relay-control outputs. Only if the BMS turns both of them off (or you hit the emergency stop) will the battery contactor go off.
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Post by PlanB » Thu, 27 Nov 2014, 19:48

Have you ever seem that Smithsonian video of the middle aged guy that 'live works' HT lines from an out rigger on the side of a H500 helicopter? He says there are only 3 things in the world he fears, electricity, heights & women, then he says he's married too.

I'm supposed to be seeing if the 4048 is recoverable over serial if it goes out on overload in the non auto restart mode. The thought of deliberately overloading a 4kw device to test this scenario is causing me some consternation.

Looking forward to your circuit diagram.

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Post by weber » Thu, 27 Nov 2014, 21:23

I ordered some of those blank lugs. Thanks Kurt.
PlanB wrote:https://oceancontrols.com.au/RLY-018.html VA looks good, W seems dodgy
https://oceancontrols.com.au/HER-030.html limited stock alas.
I found a datasheet for that first one with the changeover.
http://en.forward-relays.com/images/down/304.pdf
I'm still no wiser as to why it's 7200 VA but only 1100 W (or 1200 W as the datasheet says). I thought for a moment that 1200 W was only the DC rating, but it's way too high for that.

But the datasheet does say "Motor load: 2 HP", i.e. 1500 W. So I'm gonna keep looking for something with a higher current rating.
Have you ever seem that Smithsonian video of the middle aged guy that 'live works' HT lines from an out rigger on the side of a H500 helicopter? He says there are only 3 things in the world he fears, electricity, heights & women, then he says he's married too.
I have now:


I'm supposed to be seeing if the 4048 is recoverable over serial if it goes out on overload in the non auto restart mode. The thought of deliberately overloading a 4kw device to test this scenario is causing me some consternation.
Good on you for doing this test. Just do it at ground level and make sure the wife's not around. Image Face shield on and fire extinguisher at the ready.
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Post by offgridQLD » Thu, 27 Nov 2014, 21:30

"The thought of deliberately overloading a 4kw device to test this scenario is causing me some consternation."

I would Have thought it wouldn't be to difficult or dramatic to overload the PIP4048 with a few domestic appliances. Load it up a little first with a few resistive base loads, bar heaters, kettle and the like . Then make it start a hungry motor that should suck any surge capacity out of it and Im sure it will go out on overload.

I tripped out my Selectronics PS1 the other weekend genuine 6kw continuous/ 18kw surge. All it tool was 40C ambient weather (slightly derating the unit) Then my Imiev on charge 2.2kw , washing machine on 2kw, A irrigation pump running 1kw and for some strange fluke of timing I went to get a glass of water from the kitchen tap (0.6kw pressure pump) kicked in to fill my glass at the exact same time that my 15A 3cyl Air compressor cranked up in the garage (slow leak and forgot to turn it off)

So some big base loads close to the continuous rating of the inverter and then on top of that two motors starting at the same time. We had our first black out for 20 seconds in 4 years befor the generator auto started and took over. Its the first time I have ever overloaded that inverter. I only worked out that the Air compressor was on after going to turn the generator off and then there was another noise coming from the shed Image

Kurt
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Post by weber » Fri, 28 Nov 2014, 18:39

After researching for half of yesterday and half of today, I've finally ordered 3 of these Pulset MT2/40/12 contactors. Coil 12 V AC/DC. Contacts 240 V, 40 A, 2NO.
http://www.sparkydirect.com.au/p/480734 ... -12v-.html

But I didn't enjoy doing it at all. No. I don’t go around gratuitously ordering contactors and then bragging about it in seedy electric vehicle forums. I go around gratuitously ordering contactors and then agonising about it afterwards to my wife.

http://www.clivebanks.co.uk/THHGTTG/THHGTTGradio4.htm Search on "Bang" within the page.

One reason I'm agonising about it is that Pulset have put their brand on some devices that are known to be rubbish. Such as circuit breakers. Search on "Pulset" in Whirlpool. But I just couldn't find anything else with a 12 V DC Coil and a 40 amp or more contact rating. I considered solid-state relays but they leak in the off state and generate so much heat in the on state.

Another reason I'm agonising is because I have no idea what the coil current is for these Pulset contactors. I can find no sign of a datasheet or catalog technical section for them anywhere on the web. Since they only come with NO contacts, I plan to use a Hager EN145 12 V, 5 A changeover relay to control two of them, to make a pseudo 40 A changeover.
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Post by offgridQLD » Fri, 28 Nov 2014, 19:39

"But I didn't enjoy doing it at all. No. I don’t go around gratuitously ordering contactors and then bragging about it in seedy electric vehicle forums. I go around gratuitously ordering contactors and then agonising about it afterwards to my wife. "

If I try and involve my wife in any procrastinations or agonizing over my interests I just get the "Hang on you have mistaken me for some one who cares" look from my wife Image

Even if I think I have a captive audience in the car (Friday night 1 1/2 hr EV trip to hinterland). I have often looked to my side and behind to find both wife and daughter asleep...hmm perhaps they just don't share the passion I do on that topic Image

Kurt
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Post by weber » Fri, 28 Nov 2014, 20:37

offgridQLD wrote:If I try and involve my wife in any procrastinations or agonizing over my interests I just get the "Hang on you have mistaken me for some one who cares" look from my wife Image
What! You mean she's not interested in whether or not you might be wasting money? You lucky bastard. Image



I also ordered some Noark double-pole non-polarised DC circuit breakers for string protection and array isolation.
http://www.offgridbatteries.com.au/brands/Noark.html

When I was researching those, I found a forum thread where some poor bastard was considering buying some Noarks for this purpose, and asked whether anyone knew anything about the brand, and he gave a perfectly good reason why he didn't want to use fuses, but all he got for his trouble was people telling him to use fuses. That poor bastard was of course you, Kurt. Image
https://forums.energymatters.com.au/pos ... 4d8#p38046
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Post by offgridQLD » Fri, 28 Nov 2014, 21:33

The Noarks have worked out great. Not that I have tested there performance in any technical way. They just look and feel well constructed. Heavy, well finished quality product.

One thing I will say the new regs will have you installing them on the roof. Though this is one time I just couldn't bring myself to follow the rule book. Why would a want a device that is temperature dependent in it's operation baking in the sun on a tin roof all it's life other than affecting it's triggering points and I'm sure it wouldn't do the life expectancy any good in general to.

So mine went inside the shed.

Next door just had a offgrid install put in. They installed two 6 pole enclosures for the CB on 30cm high stand offs from the Pv racking (facing north) clear plastic door with direct sun on the CB's and shadowing the other panels when PV receives morning sun.

Kurt
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Post by offgridQLD » Sat, 29 Nov 2014, 20:21

I pulled down my PIP4048 today to get the main board out and remove the components ready for the new upgrade. Caps came out ok though I did have to switch to the bad boy soldering iron to wick some quick heat into them.

Fets will be next perhaps tomorrow.

then I just need to remember where all the screws and plugs went to put it back together. Digital camera comes in handy for forgetful people like me Image

I will say it feels kind of strange pulling down a perfectly functional brand new inverter and removing components from it Image

Image

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Post by weber » Mon, 01 Dec 2014, 04:14

Coulomb came over today, and after all our design work and parts ordering we finally started assembling the solar power system. The photo shows how far we got. We got the frame cut and assembled, the cells and inverter in place, and the CMUs wired up and mounted on the cells and calibrated against my new (for me) second-hand Fluke 87 III multimeter (accurate to +- 3 mV when measuring a LiFePO4 cell voltage).

Image
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Post by weber » Mon, 01 Dec 2014, 05:46

Here's Coulomb, seriously hamming it up for the camera, first deeply puzzled by a comms failure in the CMU chain, then insanely happy (and wearing a head-torch) after he fixed it (solder bridging where the wires were soldered on).

Image Image
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Post by offgridQLD » Mon, 01 Dec 2014, 14:03

So this Coulomb's system and Another pip4048 or similar?

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Post by Johny » Mon, 01 Dec 2014, 14:09

The Ironing board appears to make a handy padded bench....
I've lost track. Is this system for your private use or the first CMU LiFePO4 based system for a customer?
Either way - interesting approach.

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Post by coulomb » Mon, 01 Dec 2014, 14:19

offgridQLD wrote: So this Coulomb's system and Another pip4048 or similar?

I guess Weber forgot to mention that this is the customer's system and inverter, but with his test pack; we don't want to risk any damage to the new grey CALB cells while getting the software working.

I'm helping Weber get this system going; this pays for a set of CMU boards and parts for my solar electric system at home.
Nissan Leaf 2012 with new battery May 2019.
5650 W solar, PIP-4048MS inverter, 16 kWh battery.
1.4 kW solar with 1.2 kW Latronics inverter and FIT.
160 W solar, 2.5 kWh 24 V battery for lights.
Patching PIP-4048/5048 inverter-chargers.

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Post by T1 Terry » Mon, 01 Dec 2014, 14:33

Johny wrote: The Ironing board appears to make a handy padded bench....
I've lost track. Is this system for your private use or the first CMU LiFePO4 based system for a customer?
Either way - interesting approach.

What a great idea, ironing boards are one of those things your mother used before wrinkle free clothes were invented.... or is it that we just don't care about the wrinkles any more   Image But as a height adjustable work platform they would be a very hand asset when working at low height levels like sitting on the floor, it avoids the computer and soldering gear getting stepped on as you slowly surround yourself in tools and cables and terminals and ...... Somewhere to put the more delicate equipment would be very handy indeed.

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Post by weber » Mon, 01 Dec 2014, 23:28

Thanks guys. You know, I didn't even think of using the height-adjustable feature of the "padded tapered workbench" when Coulomb was working on the floor. Duh. Sorry Coulomb.

Of course Mrs Weber is real impressed. You see, during the MX-5 project, we SI units took over fully one third of the basement for our mechanical workshop and electronics lab, banishing her sewing equipment and supplies (including ironing board) to the small room at the other end of the basement that was already both the inverter/battery room and the guest bunk-room. Now we're taking over that room too. Image

But the takeover is only temporary. We'll assemble and test it there so I can connect it to one of my 3 existing PV arrays, that already happens to be wired for the right voltage -- 3P6S of nominally 12 V (36-cell) panels -- 18 x Solarex/BP 85 W -- my oldest array -- 15 years old.

The plan is to put the AC relay box on one side of the inverter and the DC switchboard/relay box on the other side and wire it all up and get it working. Then we'll disassemble it into 3 or 4 parts to transport it (in the back of a Toyota Prius) to the customer's site where it will be located on a verandah against the weatherboard outside wall of the house, fire-protected with a sheet of fibro the same size as the frame.

The plan is to make a cover for that frame out of smoked polycarbonate. It will be featureless apart from some unobtrusive black louvred vents in the top, and in the two sides at the bottom. It will have a PV-in conduit, an AC-out conduit, and a conduit from a small box on the wall beside it having an emergency stop button and a Genset inlet. I'm hoping we can make state-of-charge metering (from the IMU) remote and wireless.

I conceived of this small-footprint design as "the black monolith" from the movie "2001 a Space Odyssey". But any second now I'm expecting a phone call from Newton who has put vernier calipers to his computer screen, telling me it doesn't appear to have the correct 1:4:9 aspect ratio of that erstwhile device. Image It's true. I drew up the cutting list weeks ago and somehow failed to update the 4 verticals. They are still sized for the initial design where it was to have finished outer dimensions of 200 x 800 x 1800 mm. But the 200 mm dimension would have made the shelf too narrow for the cells. The final design calls for outer dimensions of 225 x 900 x 2025 mm. Rest assured Newton. This will be remedied. Image

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Post by weber » Tue, 02 Dec 2014, 05:40

It turns out that I have been the one obsessively measuring images on my computer screen, after I realised there's no way the monolith in that YouTube clip has thickness anywhere near 1/9th of its height. It turns out Kubrick preferred the look of a much thinner monolith than Clarke's 1:4:9. The monolith in the movie is more like a 0.5 : 4 : 9 ratio. Something like 200 x 1600 x 3600 mm.

Taking man as the measure of all things, you can see it's about a hand-span thick and about twice as tall [as a man].

[Edit: I later did more accurate measurements off some move frames and found it to be approximately 220 x 1310 x 3040 mm and so more like 0.65 : 4 : 9.]
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