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Warpspeed Guru Joined: 09/08/2007 Location: AustraliaPosts: 4406
Posted: 10:14pm 28 Dec 2021
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Its traditional to make cells relatively tall and narrow, and that makes good practical sense for stacking multiple cells most efficiently for higher voltages.
But for a home solar battery, its going to be a large and heavy battery anyway, and efficient packing into a really compact volume not such a high priority for us.
Why not short wide plates ? Or at least rectangular. That should be more mechanically robust and no more difficult to fabricate.Cheers, Tony.
phil99 Guru Joined: 11/02/2018 Location: AustraliaPosts: 2134
Posted: 10:44pm 28 Dec 2021
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"Why not short wide plates ? Or at least rectangular." Plenty of plastic storage boxes fit that specification, with clip-on lids.
Warpspeed Guru Joined: 09/08/2007 Location: AustraliaPosts: 4406
Posted: 11:13pm 28 Dec 2021
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Many years ago I visited the showroom of a company that produced a fantastic range of plastic trays, boxes and bins. From tiny things you would use to store food in your refrigerator to massive really heavy duty industrial bins you could climb into. Many different styles some with lids and even wheels.
There must surely already be something out there in a suitable size and material and strength for this...Cheers, Tony.
Clockmanfr Guru Joined: 23/10/2015 Location: FrancePosts: 429
Posted: 07:09pm 29 Dec 2021
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Hi Tony,
Yes, there are companies that will make boxes to my specs, either in PVC or Polypropylene as both of those plastics will stand a neat 80% sulphuric acid.
Sadly most that i knew here in Europe have ceased doing one offs, and most stuff comes from China now.
Regards Plate size, i will keep my plates tight in their case in their socks.
Regards height. Mine will be used for a 48v system so that's 24 of them, so for me its keeping the footplate reasonably small, and being tall and thin i can keep the actual acid inside each battery to smaller quantities.
Plus there is the acid circulation issues to also consider, so tall and thin will create a reasonable acid self circulation in each battery.
Phil99,
These are test and R&D batteries if they give good results then the case design can be modified accordingly. But i have to also consider weight and them being accidentally tipped over etc.
Also there is the plastic itself, real difficult getting true plastic specification from box sellers. Polypropylene and PVC are very resistant to sulphuric acid, other plastics are not.
Remember this is me experimenting and trying to keep this battery as safe and repeatable as possible. And eventually any do it yourself-er could make there own with a few instructions and materials that are readily available and safe.Everything is possible, just give me time.
3 HughP's 3.7m Wind T's (14 years). 5kW PV on 3 Trackers, (10 yrs). 21kW PV AC coupled SH GTI's. OzInverter created Grid. 1300ah 48v.
Warpspeed Guru Joined: 09/08/2007 Location: AustraliaPosts: 4406
Posted: 08:23pm 29 Dec 2021
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How about buying an old completely stuffed fork lift battery and just recycling the outer cell casings ?Cheers, Tony.
Clockmanfr Guru Joined: 23/10/2015 Location: FrancePosts: 429
Posted: 08:56am 30 Dec 2021
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Hi Tony,
Yes did think about using old cases. But its getting the socked plates into an already defined case size.
At the moment my case design size is not absolute, and will wait until i have all 13 plates socked in their 400gsm polythene porous material, then i can see what the thickness of the case would actually be.
For a PLANTE cell design the 13off lead plates at 210mm x 530mm x 2.24mm thick will give me about 550ah. Probably more if the grid matrix grooves are consistent. A modern forklift version of the same size will be over double the ah.
Also there is the need to dismantle and take the top off the case safely, for future maintenance and repairs or 30 years away replacing the lead sheets. Making and joining PVC case structures is not difficult I have done a few before and the materials and the adhesives and plastic welding gear is easy to get.
As I have said this project is about making PLANTE batteries that are as simple and robust as possible with everyday obtainable materials.
Although i do expect that some designs and materials i have now may change as i proceed with the project.
Family have all been here for Christmas, so got all 4 boys down the fields Chain sawing and logging, hedge cutting etc and making huge bonfires of bracken. Once they return back to college and universities at the weekend, then i can get on with the PLANTE battery again.
Also i have another static 9.6kW PV array to put up here. Another 2 bed house to total re-build inside a medieval building, and finish the Kitchen and WC in the Sheep Lecture Theatre. Just a good job that i don't have much of my professional work on at present due to COVID, most of my customers are very elderly specialist collectors, and travel at present is a nightmare between countries, so just keeping my head down and slowly getting on with stuff.Everything is possible, just give me time.
3 HughP's 3.7m Wind T's (14 years). 5kW PV on 3 Trackers, (10 yrs). 21kW PV AC coupled SH GTI's. OzInverter created Grid. 1300ah 48v.
Bryan1 Guru Joined: 22/02/2006 Location: AustraliaPosts: 1344
Posted: 03:15am 03 Jan 2022
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Hi clockman, Have you ever thought about using an alkaline solution instead of the acid as I have now done 2 old N70 12 volt 4wd batteries that just keep going on.
I use them for powering the fan on the radiator of my listeroid and after several hours of running they just keep putting out the amps. I did notice under load they would drop to 11 volts then when the load cut out they would bounce back to 14 volts. I just used aluminum sulphate as the new precursor and made a saturated solution after using baking soda several times to get rid of all the acid.
All I did to reform the conversion was leave the battery outside with 20 watts of solar directly connected for a couple of months and the first time i used the battery it started my tractor first kick.
I do have a heap of lead sheet here so now you got me interested I'm going to have a go at making my own. Now for the case i have a heap of perspex and i just need to get some MEK to glue the box together.
Cheers Bryan
Bryan1 Guru Joined: 22/02/2006 Location: AustraliaPosts: 1344
Posted: 06:22am 03 Jan 2022
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G'Day Guy's, While playing round today I got some of my lead sheet out and flattened it all out then thought a bout that perspex tank I made years ago for etching then looked at one of the sheets and thought what the hell.
Folded it in in 1/2 and cut it then as I have a heap of lead 1/4" round just wrapped that around for a stiffener and brought one end out for the terminal. Made 2 of them and for a seperator I just cut some of that big roll I have for motor rewind insulation.
Made up a saturated solution of Aluminum sulphate and slowly added that in, then connected 2 of my 5 watt solar panels I have in parallel and hooked up my cheap multimeter to the terminals.
0.6 volts came up straight away and by the time I spat the dummy with my phone for the camera not working the voltage was 2.5 volts.
So the plates are approx 180mm wide and 270mm high and with my tank measuring 200x300mm they made for a nice fit.
I have left the solar panels connected and I'll check the voltage tomorrow night and for a bit of fun I may of just made a battery
Cheers Bryan
Bryan1 Guru Joined: 22/02/2006 Location: AustraliaPosts: 1344
Posted: 06:39am 03 Jan 2022
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G'Day Guy's, YAY a factory reset of my cheap phone did the trick so below is a pic of today's effort of fun
Now I took one of leads from the solar off and left it a bit for the voltage to stabilize
So for just over 2 hours of charging it's holding voltage so that is a good sign and it will be interesting thru the week to what actual voltage it gets to.
I am thinking of machining up a mold for making the plates in 2 halves then just before pouring the molten lead in preheat the mold so the lead will flow thru out the mold and as each plate only needs to be 1mm wide not much lead will be needed to make a plate and then it will be an easy exercise to make a heap.
Then the fun can start, i mean why bother reading what everyone else has done when one can make it from thoughts.
Cheers Bryan
CaptainBoing Guru Joined: 07/09/2016 Location: United KingdomPosts: 2075
Posted: 08:00am 03 Jan 2022
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very nice Bryan! now put a load across it and see what it can give and for how long.
really interesting thread
Bryan1 Guru Joined: 22/02/2006 Location: AustraliaPosts: 1344
Posted: 10:01am 03 Jan 2022
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I'm going to leave it on the PV panels all week and check on the voltage each night just to see what voltage it does get to as this one was a quick thought well I got this perspex tank and 2 plates of lead so lets make it and see. To seal the top of the tank to stop the critters falling is just some plaster tape.
Also this is a test to prove a pool floculant can be used as the liquid for a battery which is a cheap non toxic solution.
Clockmanfr Guru Joined: 23/10/2015 Location: FrancePosts: 429
Posted: 09:07am 04 Jan 2022
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Yes Bryan1, what your doing is the basic cell arrangement.
I have seen this arrangement in early 1900s manufactured Master Electric clocks where 2 lead plates are dug into the ground outside and a 1.5v is produced to energise a coil every 15 seconds or so, to impulse a mechanical pendulum. Those plates are about 18 inches by 18 inches and 1/2inch thick. Once a week the owner would water the plates that were buried in the ground.
I personally experimented with your shown/photos basic concept about 15 years ago. I could get the volts up but the amperage for each cell was extremely poor and therefore discarded this simple cell method.
As regards acid, yes there are alternative acid/alkaline etc for batteries, but for me i will stick to 15 to 1 sulhuric acid, as we need to self form the lead plates for the PLANTE design.
Its the lead oxide on the surface of the lead sheets that gets the amperage up. Commercial batteries makers use lead oxide pastes that are mixed with several other secret ingredients and held in a lead mesh matrix that form the positive and negative plates.
The PLANTE battery cell i am trying to produce has fine pressed grooves in the surface of all plates. This then allows the first 0.6mm of the plate surface to form into the correct Lead oxide. Basically the surface becomes spongey as the lead is transformed with the charge and discharge and swap the positive and negative plates around. This is normally about 30 to 40 times. Then the final charge will set the battery to what is positive and negative.
The grooves are the modern twist to the PLANTE battery and the charge and discharge regime are also a modern twist. But the grooves need to be within parameters. I have some test results that show the sizes i have as suitable to get the lead oxide to form correctly, and also hold the lead oxide in position.
Once the battery is formed then the oxide will get thicker as the battery is used and the amperage will slowly rise. However there is an offset against the thickness of the lead and its structural integrity, again this is part of my test procedure.
Eventually, 30 years or so, the lead positive plates will completely turn to mush lead oxide, and the lead plate will just collapse. Then its my intension to remove the plates and replace with new positive plates and start the charge and discharge process all over again. Although in 30 years or so i may not be around.!!!! But my boys will be, so hence me doing a book about my batteries.
Most of you will know that its normally the Positive plates on any lead acid battery that just crumble away to nothing and the battery ceases to be useable battery.
Its the commercial boys and the consumer wanting high amp hour at minimum materials but then sacrificing longevity of the battery by using ready formed lead oxide in their lead matrix frames that is not very structural stable.
Those 30 to 40 Charge and discharge and reverse process with the PLANTE is very important and sets the final battery amp hour rate. Charge must be precise and discharge must be precise. Again i have some preliminary data on this, but at present will not give any figures until i have well tested the process.
Again these PLANTE batteries I am making need to be as efficient as possible, easy to make, but safe, with readily available materials. And any specialist bits like the stainless steel roller for the grooves in the lead plates must be easy to make and give consistency to each lead plate and yet require simple skills to operate.
Away to my workshop/machine shop now, to set up my Swiss machine and cut some stainless rollers with either direct parting off tool or rotating 1mm thick slitting saw.Everything is possible, just give me time.
3 HughP's 3.7m Wind T's (14 years). 5kW PV on 3 Trackers, (10 yrs). 21kW PV AC coupled SH GTI's. OzInverter created Grid. 1300ah 48v.
zeitfest Guru Joined: 31/07/2019 Location: AustraliaPosts: 482
Posted: 12:06am 05 Jan 2022
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I saw a DIY method once, where the lead plates were perforated with countersunk holes filled with a lead oxide paste. After drying, a DC current for a few days then formed the plates into the working chemistry. It used 20% acid by weight as electrolyte. The lead oxide was "red lead" as sold in hardware stores to mix into paint, not any more !! I wonder if lead could be plated onto graphite cloth and then used, probably not cost-effective though.
Bryan1 Guru Joined: 22/02/2006 Location: AustraliaPosts: 1344
Posted: 07:16am 08 Jan 2022
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G'Day Guy's, Well after a week on charge it got to 2.75 volts so decided to do a load test, I found an old DC motor with a reduction gearbox on which is lucky to do 3 rpm.
I took off the solar and the voltage stayed at 2.55 volt and when the load was connected it took around 4 minutes of running and the battery dropped to 0.5 volts and the motor kept running. I decided to put a load on the output shaft and the voltage dropped to 0.4 under load for well over 2 minutes.
So it's back on charge again and I have noticed some white stuff growing on the lead plates, the plates were cleaned before I put them in so it does look like it could be lead oxide forming.
Clockman if you feel I'm hijacking your thread just say so and I'll start a new thread on this trial.
Cheers Bryan
Clockmanfr Guru Joined: 23/10/2015 Location: FrancePosts: 429
Posted: 09:26am 08 Jan 2022
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Bryan,
You do not want white stuff on the plates.
No problems about your posts here, just you carry on forming those plates.
To form the correct oxide on both plates you need to fully discharge the cell, then reverse your cell connections and recharge. then discharge and reverse your connections and re-charge, about 30 times, then do a full charge on what you want to be the positive and negative plates.
The battery cell will improve its ah.
However there are strict discharge rates and re-charge rates to get a real good oxide to form and stay formed.
This thread was really away of keeping you all informed of my build and R&D processes. Other comments are good.
I do post on other forums, but as you guys have always helped me and others i thought it was good to also post here. Edited 2022-01-08 19:50 by ClockmanfrEverything is possible, just give me time.
3 HughP's 3.7m Wind T's (14 years). 5kW PV on 3 Trackers, (10 yrs). 21kW PV AC coupled SH GTI's. OzInverter created Grid. 1300ah 48v.
Bryan1 Guru Joined: 22/02/2006 Location: AustraliaPosts: 1344
Posted: 10:44am 08 Jan 2022
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Thanks for that info mate so in the morning I'll connect that motor and leave it running until zero volts then swap the leads as you say.
Also I will take out the plates and give them another good clean, as it is a sunny day here tomorrow a good fresh water wash first to neutralize the electrolyte then after the clean a fresh rinse then out in the sun to dry.
I do have some sulphuric acid so I'll use that instead of that pool floculant which is actually ph3 so mildly acidic where I thought it was a base. it wasn't until I got some some PH papers I found out what it was.
Bryan1 Guru Joined: 22/02/2006 Location: AustraliaPosts: 1344
Posted: 12:33am 09 Jan 2022
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Ok this has me stumped
Connected that motor and got the voltage down to 0.2 volts so removed the plates and washed them then out in the sun to dry.
Reassembled the battery and put 34% sulphuric acid then for fun decided to measure the voltage WTF 1.4 volts so put the motor back on and sure enough it started straight away and just checked now and it's down to 0.149 volts.
For reference I measured the current of that reduction motor and free running 40mA then when under load 150mA and it is good to see this motor work at such a low voltage.
So time to put the solar on and leave it for a week then the forming can start. Edited 2022-01-09 10:37 by Bryan1
Clockmanfr Guru Joined: 23/10/2015 Location: FrancePosts: 429
Posted: 10:56am 09 Jan 2022
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Bryan,
There are a lot of things happening.
Firstly, with a anode plate and a cathode plate, ie one lead plate and another plate facing each other this is called a single cell, the usable voltage of this cell will not exceed more than 2.3 volts, in practice its about 2.22volts.
Secondly, on bare lead when you first fill with acid solution the cell becomes live, the acid solution is fully charged ie, its specific gravity is up at the appropriate levels this will change as the cell is discharged. Normally its about 1.265 and during discharge it will drop to about 1.150 and the electrolyte will only be 17%. When recharged the battery will rise again to 36% electrolyte and about 1.265 again. As the battery gets old in normal batteries, the specific gravity will drop as the internal plates deteriorate and the useful amp hour rates also drop. For our PLANTE its the other way around. Our initial Amp Hour rate is not as good as a modern commercial battery, ie only about 1/3rd but over the many years it will be used the battery gets better until eventually all the lead plates internally are just a oxide paste. So we need to hold that oxide as long as we can, and not allow it to short out the cell within the battery itself.
Thirdly, when first filled you will see that the Cell is Bi- sexual, ie put your voltmeter leads on each plate, then remove the leads and swap them around and hay presto it gives voltage the other way around as well.
Okay so we need to form the correct oxides to form on the correct plates. So to form we charge at 20% to 23% voltage of the 2.3 volt cell and at 10% to 13% of the rated Amp hour capacity of that cell.
12 volt batteries are normally 6off 2.22v voltage cells with each 2.22v cell have about 7off 2,22v cells parallel connected to get the Amperage out put up of each of the 2.22 cells in the 12v battery.
Rated Amp hour capacity of your 2.22v cell for a PLANTE battery is defined roughly by surface area of each POSITIVE plate in that cell. So for your plates of 270mm x 180mm and at say 2mm thick, we need to know the plate weight to get the surface area that we can form to get the amp hour. however a rough guide for your plates of one cell would be very approx. about, 9amp hour for a kg of your size.Everything is possible, just give me time.
3 HughP's 3.7m Wind T's (14 years). 5kW PV on 3 Trackers, (10 yrs). 21kW PV AC coupled SH GTI's. OzInverter created Grid. 1300ah 48v.
Clockmanfr Guru Joined: 23/10/2015 Location: FrancePosts: 429
Posted: 10:58am 09 Jan 2022
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And Charge and discharge equipment.
Everything is possible, just give me time.
3 HughP's 3.7m Wind T's (14 years). 5kW PV on 3 Trackers, (10 yrs). 21kW PV AC coupled SH GTI's. OzInverter created Grid. 1300ah 48v.
Clockmanfr Guru Joined: 23/10/2015 Location: FrancePosts: 429
Posted: 11:04am 09 Jan 2022
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Discharge rates for PLANTE battery plate oxide forming.
Each of the 30 times minumum charge and discharge should be the same rates to form the correct Ozide. And remember the polirity should be revesed on each charge.
On the 31st charge you will then make the positive palates positive from then on.
Discharge should be about 10% of the battery capacity in voltage and amperage.Everything is possible, just give me time.
3 HughP's 3.7m Wind T's (14 years). 5kW PV on 3 Trackers, (10 yrs). 21kW PV AC coupled SH GTI's. OzInverter created Grid. 1300ah 48v.
Notice. New forum software under development. It's going to miss a few functions and look a bit ugly for a while, but I'm working on it full time now as the old forum was too unstable. Couple days, all good. If you notice any issues, please contact me.
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