navitron
 
Renewable Energy and Sustainability Forum
Welcome, Guest. Please login or register.

Login with username, password and session length
News: Anyone wishing to register as a new member on the forum is strongly recommended to use a "proper" email address. Following continuous spam/hack attempts on the forum, "disposable" email addresses like Gmail, Yahoo and Hotmail tend to be viewed with suspicion, and the application rejected if there is any doubt whatsoever
 
Recent Articles: Navitron Partners With Solax to Help Create A More Sustainable Future | Navitron Calls for Increased Carbon Footprint Reduction In Light of Earth Overshoot Day | A plea from The David School - Issue 18
   Home   Help Search Login Register  
Pages: [1] 2 3   Go Down
  Print  
Author Topic: Running a solar gti from a battery bank, possible?  (Read 3999 times)
Stevieboy118
Full Member
***
Offline Offline

Posts: 154



« on: March 20, 2015, 04:34:23 PM »

I've been offered an ABB 3.6kW inverter (waiting to get the exact model number)bnib at mates rates and was wonfering if i can drive it from my battery bank (my friendly car workshop just shut down and i've half inched the duff battery pile and i'm currently working my way through them with a couple of chargers and desulphators).

I'm thinking the problem is that the invertor is setup to generate as much power as possible, it would pull every bit of power it could from the batteries and push it all out to the grid.

Could i get away from that by have an isolator on the incoming mains? If the inverter has nowhere to output the power to (no national grid) will it just consume what needs to run the drains on it (fridge/freezer, boiler pump,etc)? or will it just draw on the batteries and make lots of heat?

I've already got a small inverter that runs our lighting circuit to get around the "no mains power down" safety.

Just thinking what else could go wrong Smiley

Obviously a big gti is overkill for a battery bank but i've still got the summer to sort these batteries out before i make any decisions  (and if swmbo sees that it works i'll be able to divert f unds and get some proper batteries!)
Logged

4kW pv (16x250+good-we inverter)
Wood burner
Pile-o-tatty-batteries
107L water tank solar dump
Anything else the wife will let me play with.
skyewright
Hero Member
*****
Offline Offline

Posts: 1769


« Reply #1 on: March 20, 2015, 05:32:42 PM »

If the inverter has nowhere to output the power to (no national grid) will...
If it's a GTI then typically it will want to see a grid before it does anything (unless there is an "Anti-Islanding" setting or some such to allow off-grid use).
Logged

Regards
David
3.91kWp PV  (17 x Moser Baer 230 and Aurora PVI-3.6-OUTD-S-UK), slope 40, WSW, Lat 57 9' (Isle of Skye)
biff
Global Moderator
Hero Member
*****
Offline Offline

Posts: 12248


An unpaid Navitron volunteer who lives off-grid.


« Reply #2 on: March 20, 2015, 06:52:10 PM »

Hi SB118,
                  There is also the danger that SWMBO might get annoyed with you spending all the time trying to bring dud batts back to life and for the wrong impression about your R/e efforts. If you can buy the GTI at the right money (mates money) ,you can store it away in a nice dry place and get more experience and power with the system that you are already running. You can always flog the GTI for UNmates Money later and use the extra cash towards a decent set of batts.
  If you are sorting through old batts and hit upon the big truck batteries 130ah x 12v,  pull them out to the one side and when you get time, check each cell.
  These batts usually have the two poles on the one end. Don't waste your time on any s/h battery that weighs less than 40kgs but I have brought a few of those 130ah truck batts back to life.
                                   Biff
Logged

An unpaid Navitron volunteer,who has been living off-grid,powered by wind and solar,each year better than the last one.
Stevieboy118
Full Member
***
Offline Offline

Posts: 154



« Reply #3 on: March 21, 2015, 08:05:53 AM »

Thanks for the pointers. I'm lucky in that the wife will put up with any amount of silly buggers when it comes to my projects, i'm still in the process of unloading roughly 2500L of used veg from my biodiesel days (not doing as much mileage + bought a car with a secondary water heater which won't run on bio = bye bye bio kit)

The batteries are mostly around the 75-80ah, maybe half a dozen around the 100ah mark. Not impressive capacity and totally the wrong discharge pattern but if i can get the "proof of concept" passed her, i can throw a few quid at it.

The expected use for the system would be to cover the background load overnight and cover the first few kettle runs until the sun shows up and i can start to refill the batteries.

I am looking at supporting this with the sheer volume of batteries rather than their peak capacity (good job there is no loss in the cabling, eh?)

If reality has it's say i'll end up with two smaller inverters, again to cover the overnight load on each circuit (biggest load overnight is the fridge pump so that's the only one that needs any real umph)

On the other hand i've got the wood burner heating the back half of the house (might need a couple of bathroom type ventilation fans to push the warm air between rooms) so i've reduced our demand for gas by a chunk anyway.

edit, in a perfect world this pile of batteries would have shown up when the pair of 2kW chinese inverters were in the for sale section and i would have grabbed them instead!
« Last Edit: March 21, 2015, 08:10:51 AM by Stevieboy118 » Logged

4kW pv (16x250+good-we inverter)
Wood burner
Pile-o-tatty-batteries
107L water tank solar dump
Anything else the wife will let me play with.
Tinbum
Hero Member
*****
Offline Offline

Posts: 1226


« Reply #4 on: March 21, 2015, 08:33:51 AM »

I've been offered an ABB 3.6kW inverter (waiting to get the exact model number)bnib at mates rates and was wonfering if i can drive it from my battery bank (my friendly car workshop just shut down and i've half inched the duff battery pile and i'm currently working my way through them with a couple of chargers and desulphators).

As its the duff battery pile and they have probably been sat there a while I'd be tempted to get decent money by weighing them in and buying a couple of good batteries with the money. I find batteries rarely come back to like.
Logged

85no 58mm solar thermal tubes, 28.5Kw PV, 3 x Sunny Backup 5048, 3x Sunny Island 5048, 2795 Ah (135kWh) (c20) Rolls batteries 48v, Atmos wood gasification boiler, Brosley wood burner, 2000lt buffer tank and 250lt DHW
Stevieboy118
Full Member
***
Offline Offline

Posts: 154



« Reply #5 on: March 21, 2015, 08:47:00 AM »

As its the duff battery pile and they have probably been sat there a while I'd be tempted to get decent money by weighing them in and buying a couple of good batteries with the money. I find batteries rarely come back to like.

I've been lucky so far, 2 back to almost full power.
Logged

4kW pv (16x250+good-we inverter)
Wood burner
Pile-o-tatty-batteries
107L water tank solar dump
Anything else the wife will let me play with.
biff
Global Moderator
Hero Member
*****
Offline Offline

Posts: 12248


An unpaid Navitron volunteer who lives off-grid.


« Reply #6 on: March 21, 2015, 09:00:17 AM »

Good morning SB118,
                   You were doing fine until you mentioned the couple of runs with the kettle. Then I kind of staggered and sat down with the shock.
  I have 2 ton of forklifts cells and I would not use an electric kettle. It is totally against my religion. The earth would open up and swallow me.
          Gas under the kettle is your man,  Or even a cuppa in the microwave is still quicker @800watts as opposed to 4mins @3kw on lecky kettle.
         BUT! I can see you getting a genuine first class induction education on old Batteries and the long list of things that they "cannot" do.
    Tinbum said it, Weigh them in and get rich enough to go and buy a 48v forklift pack fingers crossed!
                                                                                             Biff
Logged

An unpaid Navitron volunteer,who has been living off-grid,powered by wind and solar,each year better than the last one.
camillitech
Hero Member
*****
Offline Offline

Posts: 5477



WWW
« Reply #7 on: March 21, 2015, 09:05:48 AM »

In my loooooooooooooooong experience off vehicle batteries and living 'off grid'. Fourteen years in a garage then 25 years 'off grid' I can quite categorically say you 'are flogging a dead horse'. Still, I wish you well in your project Stevie and am sure you will have hours of fun trying  Grin Tinbum's advice would be hard to beat, last lot I weighed in fetched 400.

Good luck, Paul

Logged

http://lifeattheendoftheroad.wordpress.com/

'Off grid' since 1985,  Proven 2.5kW, Proven 6kW direct heating, SMA SI6.OH, 800ah Rolls, 9kW PV ,4xTS45, Lister HR2 12kW, , Powerspout pelton, Stream Engine turgo, 60 x Navitron toobs and a 1500lt store. Outback VFX3048 and 950ah forklifts for backup,
Stevieboy118
Full Member
***
Offline Offline

Posts: 154



« Reply #8 on: March 21, 2015, 09:07:32 AM »

Good morning SB118,
                   You were doing fine until you mentioned the couple of runs with the kettle. Then I kind of staggered and sat down with the shock.
  I have 2 ton of forklifts cells and I would not use an electric kettle. It is totally against my religion. The earth would open up and swallow me.
          Gas under the kettle is your man,  Or even a cuppa in the microwave is still quicker @800watts as opposed to 4mins @3kw on lecky kettle.
         BUT! I can see you getting a genuine first class induction education on old Batteries and the long list of things that they "cannot" do.
    Tinbum said it, Weigh them in and get rich enough to go and buy a 48v forklift pack fingers crossed!
                                                                                             Biff

Our kettle is rated at 650w. Microwave is rated 800w, but pulls 1500w to do it. (according to our plug in meter)

Even picked up a couple of metal teapots so i can make a few drinks on the burner (slowly!)
« Last Edit: March 21, 2015, 09:09:17 AM by Stevieboy118 » Logged

4kW pv (16x250+good-we inverter)
Wood burner
Pile-o-tatty-batteries
107L water tank solar dump
Anything else the wife will let me play with.
Tinbum
Hero Member
*****
Offline Offline

Posts: 1226


« Reply #9 on: March 21, 2015, 09:14:26 AM »

I must admit though I am always sceptical about garages. I've had occasions when a lights been left on in one of our works vans and its been flat in the morning. Take it to a garage and they will say you need a new battery- but you don't. It depends on how long they have been flat and how deeply discharged.

I've found one quality make of battery never seems to come back to life once deeply discharged but treated well they last years. Our 9 year old Golf is still on its original battery!!
Logged

85no 58mm solar thermal tubes, 28.5Kw PV, 3 x Sunny Backup 5048, 3x Sunny Island 5048, 2795 Ah (135kWh) (c20) Rolls batteries 48v, Atmos wood gasification boiler, Brosley wood burner, 2000lt buffer tank and 250lt DHW
Scruff
Guest
« Reply #10 on: March 21, 2015, 12:10:55 PM »


Microwave is rated 800w, but pulls 1500w to do it.

Heat output versus electrical input, unfortunately both measured in watts.
Logged
pj
Sr. Member
****
Offline Offline

Posts: 313

Nom de Plume


« Reply #11 on: March 21, 2015, 12:26:18 PM »


Microwave is rated 800w, but pulls 1500w to do it.

Heat output versus electrical input, unfortunately both measured in watts.

Surely you mean 'fortunately'? It shows that 700W is essentially wasted by the microwave.
Logged

North Hampshire
knighty
Hero Member
*****
Offline Offline

Posts: 2831


« Reply #12 on: March 21, 2015, 01:04:54 PM »

is it not just 1500watts peak while it starts up ?

I can't see a microwave wasting 700watts.... to waste that much, the heat coming out of the vent would practically burn you ?
Logged
Scruff
Guest
« Reply #13 on: March 21, 2015, 01:20:38 PM »

Some of it is inrush, more of it is conversion loss. So not entirely 700W wasted. Transformer microwaves are ~ 50% efficient. Inverter types are a little higher maybe 60%-70%.
Unfortunately because it causes confusion.
Logged
biff
Global Moderator
Hero Member
*****
Offline Offline

Posts: 12248


An unpaid Navitron volunteer who lives off-grid.


« Reply #14 on: March 21, 2015, 02:47:36 PM »

Well 3 minutes in the microwave makes pretty good porridge,
90 seconds for a scrambled egg that don,t make a mess
20 minutes approx. for plum jam.
  The microwave even beats the gas for efficiency and economy in certain cases.
   I cannot argue scientifically about the merits of either. We run the washing machine and the microwave together quite often and there is no way that our microwave could be pulling 1500watts along side our washing machine and our 2kw Chinese inverter not even starting to breath heavy. Perhaps the start up is a heavy load but 1500watts,?
                                                                     Biff
Logged

An unpaid Navitron volunteer,who has been living off-grid,powered by wind and solar,each year better than the last one.
Pages: [1] 2 3   Go Up
  Print  
 
Jump to:  

Powered by MySQL Powered by PHP Powered by SMF 1.1.20 | SMF © 2013, Simple Machines
SMFAds for Free Forums
Simple Audio Video Embedder
Valid XHTML 1.0! Valid CSS!