Navitron Renewable Energy and Sustainability Forum

Energy/Electricity Storage and Use/Grid Connection => Off-Grid, Batteries & Inverters => Topic started by: andrewellis on November 09, 2018, 06:33:53 PM



Title: Industrial battery opportunity charging
Post by: andrewellis on November 09, 2018, 06:33:53 PM
Billi posted on another part of the forum that a 60kwh forklift lead acid battery would give 80%*60*1500 = 72,000kwh. 

Having read around the subject it would seem that opportunistic charging which is what timeshifting solar pv would be is a big no no.  Each small charge counts as a cycle.  How do people run lead acid batteries?  Do you have two separate blocks whereby one is used to power the house until 20%.  Meanwhile the other is being charged by spare solar until full.  Then swap the two?


Title: Re: Industrial battery opportunity charging
Post by: billi on November 09, 2018, 07:48:10 PM
It really does not matter too much, to what DOD you discharge   in that calculation   if you have a look at the attached graph  for PZS  cells ...

If one takes only 20 KWh out of my example  of a 60 kWh total sized batterie  then one has a warranty of 6000 cycles


Title: Re: Industrial battery opportunity charging
Post by: andrewellis on November 09, 2018, 08:03:55 PM
Hi Billie, thanks for that.  It is interesting.  So it is more like a lithium battery in that respect.  But say during the day say I am producing 3kw for an hour and then its cloudy producing not much but with a reasonable load on the house.  With this repeating for the day, does the battery age as though those are multiple cycles.  You could eat through the 9000 cycles reasonably quickly.  In practise, do you find they last 15 years or so?

The other question would be if something like that arrived off a truck.  How do I move it in to a shed?  Can you disassemble cells and move them individually.  How much filling do you have to do? ie maintenance schedule.


Title: Re: Industrial battery opportunity charging
Post by: daveluck_uk on November 09, 2018, 09:20:32 PM

Innotec have a interesting say on cycling batteries....it starts on page 4


http://www.studer-innotec.com/media/document/0/partial_ac_coupling_in_minigrids.pdf


Title: Re: Industrial battery opportunity charging
Post by: nowty on November 09, 2018, 09:28:37 PM
The other question would be if something like that arrived off a truck.  How do I move it in to a shed?  Can you disassemble cells and move them individually.  How much filling do you have to do? ie maintenance schedule.

Mine arrived heavily boxed with timber on a pallet. Truck had tail lift and the pallet was moved to the front door by a pallet truck. I moved each cell individually which each weighs 50kg by strapping them to a hand truck. I had to place some decking boards down over the rear lawn so the hand truck did not sink into the wet lawn as I took each one round the back.

They are already filled and maintennance is topping them up with distilled water every couple of months or so, doing equalisation charges (long heavy charge) several times a year and taking specific gravity readings on the acid every now and then.

Mine are 6 years old now and are the same as when they were new.


Title: Re: Industrial battery opportunity charging
Post by: billi on November 09, 2018, 09:33:24 PM

Innotec have a interesting say on cycling batteries....it starts on page 4


http://www.studer-innotec.com/media/document/0/partial_ac_coupling_in_minigrids.pdf

 :) good  write -up  that was and still is


Title: Re: Industrial battery opportunity charging
Post by: Nickel2 on November 10, 2018, 09:52:56 AM

Innotec have a interesting say on cycling batteries....it starts on page 4


http://www.studer-innotec.com/media/document/0/partial_ac_coupling_in_minigrids.pdf

Useful info now saved in battery maintenance files - thanks  :)


Title: Re: Industrial battery opportunity charging
Post by: andrewellis on November 10, 2018, 12:00:43 PM
Thanks for the detailed responses.  So I have the house set up with a manual switchover to run some of the circuits from a generator. However, instead of buying a generator, it would might make sense to put some of the budget across to a battery setup.  I've been doing some reading around but am slightly lost on the lead acid battery options. 

Is there a lead acid inverter/charger that could sit on the ac side of the solar panel inverter which could do the following-

1. In the winter not drop below a certain % of battery /voltage in order to have backup load of 3-4kw on a single circuit.  This could keep the cooker/fridge/water pump going for a few days with a 60kwh setup.  I have a reasonably high base load in the winter with GSHP, electric everhot so most of the power is used from the solar.  The battery would be considered a backup in those months during inclement weather. Running only the water/fridge/lights would need a max output of 1.5kw.

2.  Automatically balance the batteries at the required interval.

3.  Have a higher normal operating charge of 4kw and output of at least 6kw.


Title: Re: Industrial battery opportunity charging
Post by: billi on November 10, 2018, 02:54:29 PM
Hi , Why are you thinking of a generator ,  you are Grid connected !

So the trick would be to me ,  is to import as little as possible from the grid and use the grid as a backup generator  and  possibly just use E7 units for recharging

The Victron Quattro   battery inverter (Sunny Island , Studer Xtender , Outback , etc )  will do all of what you want

For exampe the Victron quattro  https://www.victronenergy.com/live/system_integration:hub4_grid_parallel

https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&ved=2ahUKEwilufmPjMreAhXFLcAKHS8xA3kQFjAAegQICBAC&url=https%3A%2F%2Fwww.victronenergy.com%2Fupload%2Fdocuments%2FWhitepaper-Self-Consumption-and-Grid-independence-with-the-Victron-Energy-Storage-Hub-EN.pdf&usg=AOvVaw0XpMYf-gJrQVezGohr1zE9

Or Studer here  http://www.studer-innotec.com/en/applications/solar-applications/self-consumption-systems/


They are pretty clever  and  a lot of options on how to programm them  to do what they should



Title: Re: Industrial battery opportunity charging
Post by: kristen on November 10, 2018, 03:01:52 PM
Why are you thinking of a generator ,  you are Grid connected !

For me that would be because The Grid is not 100%. It might be close, but I work from home and have a couple of colleagues who come here to work, so a power outage for a few hours means we can't get any work done.

I don't feel the need for a generator because the times when I am off for more than 4 hours are rare (once a decade / less, and if it is an isolated thing, like a local fault, rather than a storm that has destroyed the infrastructure, then the Utility will bring a generator to me (and they have done in the past ...)

So a battery would do for me for the 4H max powercut, and also give me time-shift to buy Off-Peak and consume at Peak


Title: Re: Industrial battery opportunity charging
Post by: billi on November 10, 2018, 03:16:59 PM
Ok i see   :)

I had bad luck with generators and i guess i spent far too much on then not only monney   wackoold whistle

so a bigger battery and keep some hours of usage in the battery for powercuts is way way cheaper  and as well it can then stherfore absorb more during sunhours  than a tiny little one



Title: Re: Industrial battery opportunity charging
Post by: andrewellis on November 10, 2018, 03:24:20 PM
Hi, thanks, I'll look at that.  We are grid connected but are on a private water supply.  In the big storms 4 years ago a large proportion of scotland ended up with no power for three days, which included us.  We could probably get through ok but have horses who drink a lot of water (no streams).  Your comment the other day about 60kwh of battery got me to thinking that I could offset the generator cost into batteries and also make more use of the solar pv making the setup almost zero cost.  The generator hookup point is only good for a lower level of power so I'd never be able to power the whole house.  However I have a 50 amp cable from the garage that could feed back as much from the battery system as I wanted.  

We are on economy 10 at the moment which gives quite a good rate in the cheap periods of about 10.5p per kwh and a running average of 13.1p per kwh.  The savings from shifting even looking at that make it seem like it would cover the costs of the battery/inverter.

We use about 30kwh a day in the summer on average so a 60kwh battery would help average it out the usage without draining too much at a time.  Oh dear I can feel a big spend coming on again.  My poor wife is getting fed up with me spending all our money with the long term in mind.


Title: Re: Industrial battery opportunity charging
Post by: billi on November 10, 2018, 03:45:53 PM
..... 30 kWh per day , hmm .... i would say you could do with 5 kW more PV   acording to PVGIS tumble: help:  via chargecontroller ...


Title: Re: Industrial battery opportunity charging
Post by: andrewellis on November 10, 2018, 03:56:41 PM
..... 30 kWh per day , hmm .... i would say you could do with 5 kW more PV   acording to PVGIS tumble: help:  via chargecontroller ...


Yes you are probably right, but funds only go so far unfortunately.  We use close to 20000 a year so the the current 5kw is a small dent in the use. I didn't realise I could get 60kwh relatively cheaply or I might have planned it all differently. I am hoping I'll be able to retrofit more in at a later date without it being too complex.  The current 5kw panels have full output but the inverter will export 3.68kw over and above the house usage.  It'll be a tricky problem to look at with the wiring setup we have.


Title: Re: Industrial battery opportunity charging
Post by: andrewellis on November 10, 2018, 04:00:55 PM
..... 30 kWh per day , hmm .... i would say you could do with 5 kW more PV   acording to PVGIS tumble: help:  via chargecontroller ...


Is it as simple as running two charge controllers in parallel on the batter? One using the grid connected supply and the other using the solar panels?


Title: Re: Industrial battery opportunity charging
Post by: billi on November 10, 2018, 04:30:17 PM
dead simple , i let one of the chargers ,  charging slightly higher in the last  charge sequences  ... to finnish the charge 



Title: Re: Industrial battery opportunity charging
Post by: kristen on November 10, 2018, 04:39:14 PM
We are on economy 10 at the moment which gives quite a good rate in the cheap periods of about 10.5p per kwh

E7 and e.g. Tide would get you down to around 5p off-peak ... but I don't know if the day rate would penalise you (compared to your current) and Tide has an even higher "peak evening rate"

I expect you've considered all that, so only mentioning it on the off chance ...


Title: Re: Industrial battery opportunity charging
Post by: offthegridandy on November 10, 2018, 06:19:56 PM
A bit more to  ponder re FLA battery cells and general useage.

To reduce the watering of cells periodically you can purchase special caps which I believe condense out the water lost to atmosphere and return it to the cells.

Periodic "high charging or equalization"   can usually be programmed into good quality inverter chargers so you don't have to remember your self.

FLA batteries are in fact very tough and can take a lot of abuse and miss management. My first set (24 V 850Ahr C5) lasted 12 yrs with  8 to 9yrs of good service and last 3 decreasing charge retention.  They were left very dry on at least one occasion. We learn!

FLA batteries are best charge at a 10 to 15% rate of their capacity therefore, if you have a 2000Ahr battery other parts of the system need to be able to work with that level of current demand (200amps @ 24v say) to effect proper charging.

For a good deal I'd get a quote from Manbatt, Manchester based supplier http://www.manbat.co.uk/ .I hope this OK Mods, I don't believe Navitron sell this type of product now?

They supplied me with my last new set, 12 off 2V 1000Ahr C5, supplied all interconnects and take off cables, prompt palletised delivery, helpfull staff. 1650 plus VAT about 3 yrs ago.


Title: Re: Industrial battery opportunity charging
Post by: billi on November 11, 2018, 02:39:25 PM
I bought mine  second hand  was used in a forklift  it is built in 2003  and i got it  in 2008  (so intotal she is 15 years old )  , so had 5 years of heavy work behind her

i would say that even when i got her the rated  40 kWh capacity (C5) was not existing anymore , but i never drained her  completly to find out
Our dayly consumption is about 9 kWh  and we shifted most of the heavy  power consumers  to dayhours
 so most of the year  the  dayly discharge  over night was not more then 10-30 %   of the whole capacity   and maybe 20 times a year i  discharged her   by 50 %  ( i think 800 ah  or 20 kWh was the deepest discharge )
For me it was not much benefit  to  discharge her too deep , cause  the PV  had troubles to  reach a full charge  for days after.....
that was the reason i built my hydro storage lake battery
Anyway i paid 1300 Euro for her
So trying to match  as much  consumption  as possible  when the sun is out  is a bonus  as well that the draw of the battery  when loads are high , say  electric oven  runs and other appliences  the sun adds power so does not stress the battery so much
I would not like the idea of charging an electric car with 7 kW draw  on a too small industrial lead acid battery over night  , so if possible  reduce the charging Amps
The capacity of the battery is bigger  if charged and discharged slower
I once came home after a weeks holliday and my battery was 100 % charged  when i left , but  AH counter told me 200 AH (5 kWh) surplus in the batt  :garden
A kWh of  PzS  Traction battery (C5)  costs about 55 GBP   so i would not size the batt too small  cause the charging and inverter gear is  costly
It kindoff makes me smile  when  super small costly  batts are installed  wjth highly expensive gear ....









Title: Re: Industrial battery opportunity charging
Post by: eabadger on November 11, 2018, 03:14:10 PM
ours s/h has been in constant use by us for 8 years now, 900a c5, was about 4 years old when we bought it for 100 with a wind turbine :)
yes we need to check water but capacity seems fine, worse bit is connectors die, i think it needs these removing and cleaning maybe once a year or is that just us? one terminal is poorly and gets a couple of * warmer than rest when sun is putting out full charge at about 140a.
lowest we ever run normally is to 60% but the other week due to me programing the ashp wrongly it was on all night and ran batts down to 17%!! at which the inverter switched off and the victron battery monitor sent me an email, which i didnt get as router went off!!
keep looking at new sets, but lots more than we paid, but must get soon, we do have another standby set, but like others not yet figured out what to do with them, they just sit trickle charging off some spare pv.

steve


Title: Re: Industrial battery opportunity charging
Post by: daveluck_uk on November 11, 2018, 03:17:58 PM

For me it was not much benefit  to  discharge her too deep , cause  the PV  had troubles to  reach a full charge  for days after.....

Is there an easy rule of thumb that gives Panel size / battery bank ratio?

I know there is a lot of variables...



Title: Re: Industrial battery opportunity charging
Post by: billi on November 11, 2018, 03:41:50 PM
.... as Any meantioned  (http://LA batteries are best charge at a 10 to 15% rate of their capacity)

That what i have stored in my brain too    and  thats  exactly what i have 4 kW PV and a 40 kWh battery

But i would have no issue to connect much more PV  ; one can limit the Ampere  by choosing the right  chargecontroller , and as well as far as i know in the bulk charging phase its not an issue , mor important is the absorbtion charge after bulk charge  , and this is kindoff the inefficient  time  of charging FLA s ,
Surely high charge may cause more water usage  , if new i would get  RECOMBINATION PLUGS  for saving water and time



Title: Re: Industrial battery opportunity charging
Post by: Nickel2 on November 11, 2018, 03:53:16 PM
Before I got my current batteries, I was looking at a set of these on flea-buy:

http://www.enersys-hawker.com/pdf/xfc/th/xfc_gb.pdf

They are traction/sweeper batteries, but are specced by the manufacturer for opportunity charging, See page 12 of the above manual for cycle-life and charging details. They probably make similar but smaller/larger as required.
I know they are not FLA, and a dozen people will say they are not fit for purpose, but I was considering them on spec. as fit for my purpose. Obviously forkie-batts are a better bet S/H; you pays your money, you takes your choice!


Title: Re: Industrial battery opportunity charging
Post by: andrewellis on November 11, 2018, 09:56:59 PM
Thanks to everyone for the as ever extremely interesting replies.  It has given me a lot to think about.


Title: Re: Industrial battery opportunity charging
Post by: fourfootfarm on November 20, 2018, 02:47:51 PM
I've not had any real issues with connectors yet but I undo them all give them a wire brush and a light smear of conductive grease once a year all the same.

Running a similiarly 'vintage' battery pack from a forklift and she's still chugging along.