New to the forum & new I-miev

Post by **offgridQLD** » Sat, 06 Sep 2014, 01:01

I'm not trying to justify the 70mm2 in any serious way. Not the 1st silly rash decision in my head i have made. At the time I was thinking the house inverter has 90mm2 or their about it might even be 120mm2 it's dam thick. so I thaught I will go a bit smaller. It's only $50 of cable and $30 of it is payed for by my mate who wants the 2.5 meters for his jumper cables I will make him. They will be the best sub $50 jumper cables he has purchased and I'm not to fussed about my $20 of 70mm2 that's a bit economically wastfull vs 50 or 35mm2but we are not talking big $.

That said having the inverter in front of me now while 70mm2 fits fine 50mm2 would most likely be the best compromise between overkill and just wastfull.

I guess why they used the huge cable on my house inverter could have been a case of that's what they had at the time ( use what you have ) or a do it once on the battery as who knows if I might want a larger 50hz transformer inverter down the track than what waa initialy installed and the cable is good for it.

It,s pizza and beer time and then I can go to the shed and make sparks

.

Kurt

Post by **Peter C in Canberra** » Sat, 06 Sep 2014, 01:10

offgridQLD wrote: I'm not trying to justify the 70mm2 in any serious way. ...
Kurt

I used 70mm2 in my converted car in most places, except when a short tight turn was required and I used some bought new 50mm2. Many meters of fine stranded, double insulated 70mm2 was just a lucky fine at the local scrap metal place! That's my excuse!

Post by **offgridQLD** » Sun, 07 Sep 2014, 01:36

Today I wired in a temporary AC input and AC out feed to the inverter both with a simple 15A 3 pin plug for testing. Feeding the inverter was 12s 5ah lithium cobalt via a 50A Anderson. Just what was handy at the time without building a new pack.

The 12s battery is a tad low voltage for a 48v inverter but OK for testing (about 48v at rest). Well it powered up fine completely silent.40w idle load when in inverter on mode. The on board AC-DC charger works measured 30A output.I connected 400w of PV to it and confirmed the charge controller also works.

The inverter ran my lathe and cold saw under load though starting the air compressor was a no go (more than likely the battery was the issue)

So I can confirm I didn't get a dead box but not much more as I wasn't able to get my laptop to talk to the inverter via the included software. Serial to USB cable I am using could be the issue or a setting in the software setup. Went to do a fresh install of the software then remembered The cd is at the other house 100km away. That was a shame as all the data and configuration is done through the software interface so until I get that functioning I can't set the unit up and test all the features.

I will power it off my house bank so I can put a big load on it probably next weekend when the software/cable is sorted.

I made a small video of me running around the shed plugging random ac loads in and fumbling will the touch pad. Unlike the Selectronic this inverters built in display is only for very basic info and offers no control or ability to change settings so a functioning PC software interface is critical.

Edit: Just printed the manual (should have been the 1st thing I did) and it turns out that most functions can be set via the buttons on the front of the inverter. It's a bit clumsy but gets the job done. Turns out the on board charger is actually good for 60A and 120A combined max. I will have a go at tweaking the setting via the buttons on the inverter tomorrow. (though the pc interface is much nicer and easier to follow along with data logging so need to get that going)

Uploading the utube video I made now, will post when finished.

Temporary cables, plugs

Temporary 400w PV test

Kurt

Post by **offgridQLD** » Sun, 07 Sep 2014, 14:41

Link to Utube video,

starting some AC motors after first power up of the inverter. I will make a more detailed video once I have tweaked the settings and have the software up and running to show all the features.

I'm interested in one setting after reading the manual. If it's anything to go by you can actually run AC loads with PV input only. Provided the pv input is large enough to cover the load. Though I am skeptical of this as I would have thought a battery would be a essential part of the circuit. Perhaps it's just lost in the manual translation and they are just talking about Pv essentially covering loads while the battery's are in float though all power is still taken from the battery the load is essentially zero on the battery as the charge controller ramps up to cover loads and maintain float V. If it's the latter then that's nothing special but perhaps there is more to it.

https://www.youtube.com/watch?v=bbhs14jO-XI

Kurt

Post by **offgridQLD** » Sun, 07 Sep 2014, 19:30

Utube video after playing with some settings via the keypad.

https://www.youtube.com/watch?v=pW2V8Ab ... e=youtu.be

I noticed the inverter did want to fall back to the battery power once the load reached the max potential of the PV at the time.

It's not much different to how my house system works now when the battery's are on float and all loads are more or less provided from the PV though my house system must have a battery connected at all times to the inverter for it to function.

How I could use the new inverters options to my advantage I can't see it being much of a advantage setting it to use PV direct to supply AC out...over just letting battery's get to float and get similar outcome (although the battery would be connected) ideas welcome? Perhaps it would avoid lots of ( micro cycles) on the cells?

Kurt

Post by **Adverse Effects** » Mon, 08 Sep 2014, 00:00

you could connect a bank of caps (like 600V and about 4F of them)

that was it is almost no work on the caps and no risk of them catching on fire (i have lots of Lipos as well for RC and have had 2 just start to smoke even ad storage charged)

also Lipo's dont like being on float

Post by **offgridQLD** » Mon, 08 Sep 2014, 00:56

I have been using lipo for years and know most of the pro's and cons of the chemistry and how to treat it. It's not the intended battery for this project. I was just using it for quick easy DC power for testing of the inverter so long term good practice and precise setting avoiding float and so on are irreverent for the basic inverter tests.

I have set some on fire (on purpose) through destructive experiments. Probably not something you want under your pillow after you have abused the hell out of them but nothing that spectacular or to worry about in general. Much more impressive results when things go wrong with petrol or LPG that most people don't respect.

On that note how was that QLD truck crash on the news. 50 tons of ammonium nitrate and a garnish of diesel .....spectacular result!!!

As for the lipo have so much more balls than any Lifepo4 I have tested They have there place and I wouldn't use anything less for some projects.

Anyhow the intended battery for this inverter is a 16 cell 100Ah - 48v calb lifepo4 bank.

I lugged the inverter back to Brisbane tonight so I can play with the PC interface.

Kurt

Post by **Adverse Effects** » Mon, 08 Sep 2014, 01:20

yep i worked with a powder monkey for 3 years and that 1 explosion would have come close to some of the ones we set off but i am kind of surprised as "Prill"(ANFO) is quite stable

but yes that would have been a nice one to to have seen go off from a distance

love the missing bridge to

Post by **offgridQLD** » Mon, 08 Sep 2014, 05:28

I got the inverter talking to the laptop via the serial - USB cable.

It's a lot easier to setup using the PC software and having everything displayed on the one screen all at once vs scrolling through the menu's on the touch pad display.

The disappointing news is the PV charge controller and the AC- DC charger are very Basic in there settings. When set to user profile you can adjust the absorb voltage to anything you like and the same for the float voltage but that's it. This would be ok as the (constant voltage) set point is all that really matter's with lifepo4.

I'm not real keen on the (typical for basic reg)... time to reach absorb voltage = time in absorb (10min to a max of 8hrs) not adjustable, well at least not with the software provided.

Ideally I would like more control over the charge parameters.

One silly thing is there is no temperature compensation setting. I would have thought that was a essential feature for any charger designed with lead acid battery charging in mind.

Looking at the MPPT inside the unit there is a input terminal labeled (temp sensor) So it looks like the reg its self could have a probe attached but not much good if the software doesn't take advantage of it.

Though using lifepo4 the above lacking feature is a bit of a mute point.

So for my intended purpose it should be ok.

You can defiantly see how basic the inverter and regs settings and features are compared to by other more expensive inverters and charge controllers. Were everything you can fathom can be tweaked and viewed.

Kurt

Post by **offgridQLD** » Mon, 22 Sep 2014, 01:49

Happy to say that now the weather is warming up again my range has returned. Was happy to record the exact same results this weekend as my fist trip on a brand new car.

I would say there is around 3-5% reduction in range over the coldest part of winter.

Overall on my weekly 105km hinterland climb-range test trip.Peek winter 15-18% soc at the end of the trip and summer 18-23% soc. This weekend was 20%soc up And 35%soc on the return trip.

Kurt

Post by **offgridQLD** » Wed, 01 Oct 2014, 16:15

Yesterday I got a chance to install the last 9 panels on my shed. I now have 8.2kw of changing potential. Made up of 24 BP 165w panels an the house facing north east (catching the morning sun though start to get shaded from 4pm) The 21 Doqo 200w panels on the shed face north west and continue to producing power until the sun dips behind the hills around 5:30pm. This gives me a good spread of power throughout the day.

Aim is to be able to recharge the imiev from 20% SOC to 100% SOC in the one day and cover all loads on house and shed and hit float on the same day.

Kurt

Post by **Adverse Effects** » Thu, 02 Oct 2014, 03:21

Post by **acmotor** » Thu, 02 Oct 2014, 04:54

Nice ?
More than nice...... Awesome.

Post by **g4qber** » Thu, 02 Oct 2014, 14:05

Or epic

Post by **offgridQLD** » Thu, 02 Oct 2014, 16:02

It sure was epic carrying them all up there by myself . One hand on the ladder the other holding a 200w panel. Just happy the wind played nice that day.

Might even keep the shed a tad cooler with the panels acting as a sheet of insulation.

I have 8 more 190w panels I picked up 2nd hand (one is damaged) though I'm not sure what I will do with the other 7 . I think I will use 6 of them to play around with the new little high freq AC/DC inverter/mmpt combo unit I got to mobile charge the Imiev.

Perhaps even bring them them along in the back of the Imiev to ev shows and set them up next to the imiev to demonstrate it charging from Pv. If I had a EVSE that I could wind back to around 800 - 1000w or so. Just an Idea once I get the portable charging station built.

Kurt

Post by **offgridQLD** » Thu, 16 Oct 2014, 14:19

Updating on the PIP4048 inverter charger. There is a shortcoming regarding the charge profiles and tricking it to do what I want for lithium cells.

I tried to explain this last night at our EV gathering the but didn't do a very good job at 11:00pm

In the charger settings of the pip4048. Under the battery type when you select custom or as they call it (user) battery setting for the charging profile. Your are only given two parameters to set (Bulk voltage) and (float voltage).

So when charging a lithium battery it's going to want to do a (absorb stage) once the battery reaches the bulk voltage you have set. You don't have a separate absorb setting to configure.

so I see no easy way to fool the charger into dropping to float Voltage once the set bulk voltage is reached. Without it first wanting going through it's automatic time based absorb stage first. Not what I want for lithium.

In my simple (charge once and use) application I would be happy for it to just reach a set voltage and just stop charging. In a offgrid application you would want it to drop to your float so the PV charger would cover ongoing DC loads throughout the day maintaining float V.

Typically you can trick most programmable lead acid chargers into doing what you want for lithium cells by letting it first give the battery all it can muster in bulk charging until the absorb CV-voltage is reached. Say in a 48v system charging to 56.8v (3.55v cell) and then have it drop to float V and just effectively skip the absorb stage.

You can do this by setting the (absorb voltage) at the same voltage as your (float voltage) say 54.6v (3.41v cell) Absorb V. Then float V at 54.6v as well. So basically it become a two stage charger. Bulk charge to a set voltage point then absorb & float are just the same voltage so it essentially just drops to float after bulk.

Unfortunately this PIP4048 unit is always going to want to do a variable time based absorb charge at the same voltage as you have set the (bulk voltage) at before dropping to float. There is no simple way of tricking it to drop to float after it's bulk voltage is satisfied. As you can not set a separate bulk, and absorb voltage they are the same setting

I hope I didn't confuse anyone with that.

Post by **offgridQLD** » Thu, 16 Oct 2014, 16:56

A short utube video showing the PIP4048 software setting limitations in customizing or tricking the charge algorithm for lithium (lifepo4) cell charging. Unfortunately no control over the automatic time based absorb stage

I don't really want my cells to be held at 3.55v for potentially (10min to a max of 8hrs!) before dropping to float

PIP4840 lithium algorithm

Kurt

Post by **acmotor** » Thu, 16 Oct 2014, 17:08

10 min at 3.55V is hardly an issue ?
Most are intended to go to 3.8 to 4.2V anyway.
I regularly run thunder sky/ Winston to 3.85 to ensure top balance i.e. Give the shunts a chance to do their job.
... And you do need to be there for some time if cells are out of balance.

Post by **Johny** » Thu, 16 Oct 2014, 17:10

Hi Kurt.
In the Ad on eBay it said:
"**This unit now supports variable charging programming, and LiFePo4 type battery can be supported. This update currently applies only to 4KW model only."

Can you ask them what they meant by "supported". I realize that communication for something more complex than "does it come in green" will be difficult but it's worth a try. Maybe there is later firmware???

Post by **offgridQLD** » Thu, 16 Oct 2014, 17:34

ACmotor,

"10 min at 3.55V is hardly an issue"

No 10 mins isn't a problem but the trouble is you have no control over absorb times. The only time you will get a 10min absorb is if it takes less than 10min to reach 56.8v.

For example if it took 2.5hrs to reach 56.8v then it will spend 2.5hrs in absorb (56.8v) (capped at a max of 8hrs. You can not adjust the absorb time and set it to a fixed time. It automatically adjusts it based on the time it took to reach Absorb V.

You can't even effectively cancel out the absorb stage by setting absorb V at the same V as float V as You can not set a separate bulk and absorb voltage.

So if you want your cells to reach 56.8 (3.55v) then you have to put up with them being held at that voltage for how ever long it took to get them there.

Text is very small but it reads for absorb stage (T1 = 10* T0, min 10 min max 8hrs)

Johny,
Yes I did assume there would be more user adjust ability in the software based on the listing showing lithium charging adjust ability. I will try and get onto them about the feature (though I think I have the latest spec)

I think all they are saying is now you don't just have preset (AGM) & (Flooded) to pick from and you now can adjust your own (max bulk voltage before switching to absorb) and (float) voltages in 0.1v increments, but no user setting of (time in absorb).

Kurt

Post by **acmotor** » Thu, 16 Oct 2014, 19:54

Yes, I missed that point.
I'm still not certain it is quite as big an issue though.

What voltage do the BMS unit shunt at ?

Post by **offgridQLD** » Thu, 16 Oct 2014, 20:08

"What voltage do the BMS unit shunt at ?"

I haven't purchased the BMS or cell top balance boards yet but I was thinking of using the (Ev power) on cell top balancing boards. From memory around 800 - 1000ma bypass for the ones that fit the 100ah cells and they start to shunt at 3.6v.

The ideal setup I think is to not balance every charge (if the cells are holding balance ok ) and use the EQ mode on a lead acid charger (EQ voltage set high enough to start shunting/ top balancing) Manually activated EQ when a balance charge is needed or another option is to program for say every 7 days to do a EQ charge high enough to balance and for a set time say 1hr.

Unfortunately there is no EQ program at all on the PIP 4048.

The above issues less of a issue with my mobile bank that I just want to charge up then take the full battery with me in the car and consume the energy. Return home and pop it on charge to perhaps 50% soc and store it until next time I need the range extender. As I can manually intervene a little more in the charging proses and cut the charger off after roughly 2.5kwh of input (for rough 50% soc storage) or like you say being held at 3.55 for a little while wont kill it.

That said I potentially want to be able to use this setup for more than just a range extender to get value from it. perhaps take it camping with me with a few hundred watts of PV running through it so a little more automated charge ( set and forget for a few days weeks that is ok on the battery's long term is ideal.

Kurt

Post by **acmotor** » Thu, 16 Oct 2014, 22:57

Why not balance every charge ?
I can see from a historical LA point of view that the gassing eq mode doesn't always want to be entered as it dewatered and since that was the only method of eq as there was no per cell shunting.
Form a lithium position I can see that the iMiEV balances and balances and balances.

I actually leave my e-jerry can fully charged as it doubles for backup house power.
Leaving it fully charged... Well 3.45V coz that is where the BMS shunts so 95%+ SOC.... May be detrimental to cycle life but the very nature of the application means that it will never see thousands of cycles.... More like 100 over 10 years if it lasts that long. Any loss of cycle life from the many thousands potential seems irrelevant if in fact the high SOC storage eats away at the chemistry. I live in hope that in 5 years the battery technology itself will have moved on to the point where the pack lasting 10 years will be of no interest.

Post by **offgridQLD** » Thu, 16 Oct 2014, 23:49

Yes much of what you were saying is the reasoning for not wanting to keep the lifepo4 at a high SOC or take them to a high SOC all the time if I don't need to.

Though I see you logic and it did cross my mind and its probable a few vallid points. I would at a minimum want to avoid the cells being in a high SOC situation at high temps. For example in summer in the back of the Ute or shed as the double whammy combo of high heat high SOC I think is something that might be aggressive.

though On my house bank (when its switched to lithium) I will want that to last a lot longer and it's cycled every day so will follow stricter rules. Fortunately the Midnite classic MPPT solar charge controllers have so much more control and every setting under the sun can be programed to just how you want it. So finding a perfect set of rules will be a walk in the park.

Kurt

Post by **Greg partridge** » Sat, 18 Oct 2014, 22:26

I have just bitten the bullet and brought a iMiev ! $17,500 with 7,000 km on the clock for a 2010 model. Let the fun begin!