Energy Matters Forums

[Tracker]

.
Well - the first day's data is in..
Not as good as I had hoped, and I suppose, consistent with what we might reluctantly expect from the W7.

Pwr Used.............Pwr to Charge....... (Fridges ONLY)
2.92KwH.............7.68KwH

This relates to 116.8c saved during PEAK, and 61.4c paid during Off-Peak..
ie. PRICE wise - that's about a 48% power-cost saving..

The issue is that of the Power-Overhead in the charging phase, is likely wastfull....
I suspect that when I have cause to bash the RAC, then the proportional savings will be higher, as the charge-time will be longer anyway... ie.. I suspect that leaving the W7 on charge from 2200 to 0700 is a waste, and that I really need to build the "Cut-Out" detect, by monitoring the "CHARGED" led and terminate at that time..
..
.

[Bthree]

.
Pwr Used.............Pwr to Charge....... (Fridges ONLY)
2.92KwH.............7.68KwH

This relates to 116.8c saved during PEAK, and 61.4c paid during Off-Peak..
ie. PRICE wise - that's about a 48% power-cost saving...

Bit disapointing really,
I read the unit draws 250watts all by itself, is that for charging, inverter, or both ?

Not going to work for me as my peak is 27.17cents and offpeak = 11.5cents
thats 112% a cost not saving
Regards,

[gyro]

Using the W7 as charger in household situation is not a good idea it is better to use it just as an inverter with solar array doing the charging and then only charge the batteries on night rates if you have consecutive cloudy days.

[Tracker]

Bit disapointing really, ,

YEs - I agree, and again I'm doing it 'cause I can..
At least in MY case, it is just at the "Viable" point.. where I cut out PEAK costs and simply end up with Shoulder and Off-Peak

Using the W7 as charger in household situation is not a good idea

As I have already said, this is phase 1.. A crude system..
I am sure that along with guys like Andrew_electrix, we can improve on things..
At least, NOW, we know what the starting point is..
I strongly suspect that even with the system as it now exists, a good quality A/C charger would be better than the W7 as it stands..
For those unsure of what we are referring to, the W7 is intended to be used on a boat and so the Power used to recharge is likely not that critical, as during that time, it is also supplying "Shore-Power" to the boat.
..
.

[Tracker]

.
After three variable days, it's pretty much confirmed.. 2 to 1 ..
I gave the system a heavy nudge on Monday, using near 9KwH..
so-- First day 2.9, then 8.7, then 3.67.
The recharge power does seem pretty consistent at double the used power.. It is a bit better for heavy usage and this is as expected. ... So for a total of 15.32 consumed, I needed 32.23 to recharge..

If your thinking about using the W7, then keep that in mind.. I am still ahead in having reduced my PEAK power cost from 40c to 20c, but at what break-even cost given the Inverter, batteries and the whole setup.
..
.

[WALL-E]

Hi Guys,

I have just joined this forum and have read all you posts.

I have this exact same concept system which I have been working on some time now
It is an amplified version of yours tracker, but with a more technical timing and voltage disconnect features.
I will take photos and show and tell later.
I also have the Powerstart W7 48V 6000w inverter

Well - the first day's data is in..
Not as good as I had hoped, and I suppose, consistent with what we might reluctantly expect from the W7.

Pwr Used.............Pwr to Charge....... (Fridges ONLY)
2.92KwH.............7.68KwH

Tracker what you need it understand is that the W7 inverter wastes on average 4.8Kw per day just to be on running regardless of load. If you only measure power coming out of the inverter AC side you will not see this!.
I use a Pentametric battery data logger along with 3x spinner meters Morning start MPPT TS-60 data logger to analyse my system performance. if you add the 4.8kw to you above mentioned data you will see it equals up.
off course this type of system is not any where 100% efficient or even 90% efficient but I believe that's where your power is going.

Andrew has just listed a modification for this inverter which i'm super keen to see if it can work to solve this power wastage

[Tracker]

.
Just checked the two meters, giving the TOTAL power used and the power saved..

248 USED == Paid $19.84
96 SAVED = Save $38.40

So, I have saved a whole $19

So, as it now stands I have managed to effectively reduce "SOME" of my PEAK energy usage from an effective cost of 40c to 20c.. a unit.

The important point is the ratio of the USED to SAVED power 248/96...
This is still an unacceptable difference 2.6 times.. The issue now is that I could find a FAR more efficient inverter or just accept the difference as being "Still a 50% saving"..

If you only measure power coming out of the inverter AC side you will not see this!.

Just noticed the last post..
Confirming that I AM measuring ALL the power going IN and ONLY that power being used as "Peak-Replacement"
So these figures are a true representation of the "Inefficiency" of the process.
Needless to say, the next step would be to think about the "Torroidal-Conversion-Option" OR, my preferred option, to convert to SOLAR-CHARGING with Off-Peak grid-charge-boosting..

..
.

[Bthree]

.
248 USED == Paid $19.84
96 SAVED = Save $38.40
.

Hi tracker, can you just simplify this for me please

Units in total ..... units out total as calc from both meters and cost of units in/out ?

Ta

edit.. so the actual base conversion loss of the inverter/battery is 248 units in and 96 units out,
not very efficient @ 39%

[Tracker]

so the actual base conversion loss of the inverter/battery is 248 units in and 96 units out,
not very efficient @ 39%

Yep - Exactly.. But - based upon a PEAK tariff of 40c and an Off-Peak tariff of 8c, the actual "Financial Benefit" is halving the cost. BUT at what environmental cost..

If one accepts that using power in the OFF-PEAK is environmentally good, because generator power is wasted by not having a demand there for, then environmentally it's good..
How's that for justification

Simplifying - I used 248KwH to charge the batteries between 2200-0700hrs, and then used 96KwH power between 1400 to 2000hrs from the battery/inverter system to power refrigerators and an occasional Air-Cond..
The system is strictly controlled by time clocks, such that charging and discharging ONLY happens at set times, and at all other times, it's disconnected.

Elsewhere - There is intense discussions about the efficiency of the W7 inverter/charger, and more importantly, about circuit changes that improve the otherwise dismal efficiency..
..
.

[Bthree]

I understand ... thanks Tracker.

My tarriffs are different 27c peak and 12cents off peak so all this will not work for me

Capital outlay and depreciation of batteries must also be considered