Air pumps for better battery charging

stephendv

Quite a few manufacturers of forklift batts sell the option of an air pump electrolyte circulation system which is basically a system of tubes that reach into the bottom of each cell and are then attached to a small air pump. During bulk charging, the pump is turned on to help mix the electrolyte and according to a number of different manufacturers this provides:
- cooling during charging
- more efficient charging (they say 30% better)
- reduced water consumption
- shorter charging time
- reduced need for equalisation charges

Does anyone have experiences with these types of systems for RE applications?

john p

Re: Air pumps for better battery charging

Have never heard of this before anywhere.. but have to say its interesting.. Would love to see test results of doing this.
I give another something to think about that has worked for me. but have no actual measured evidence to back it up.
I use "truck" type batteries for solar storage as deep cycle batteries are just not available where they are used,, What I do every few months is put them in the back of my truck take them for a ride over very rough dirt road (about 16 miles 20klm) then as soon as they home again they are recharged . and they seem to charge better,and hold the charge better..

stephendv

Re: Air pumps for better battery charging

Here are some links to the systems:

- http://www.hoppecke.com/products/applications/industrial_trucks/trak_r_air
- The "Electrolyte agitation" paragraph in this PDF: http://www.exideindustrialbatteries.com/pdf/Enhanced-Traction.pdf
- http://www.enersys-hawker.com/pdf/waterless/water_less_gb.pdf
- http://www.sunlight.gr/UPLOADS/PZS.pdf


and while googling, bumped into this abstract:

http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6TH1-44V4BCN-19&_user=10&_coverDate=10/31/1984&_rdoc=1&_fmt=high&_orig=search&_origin=search&_sort=d&_docanchor=&view=c&_searchStrId=1533707224&_rerunOrigin=google&_acct=C000050221&_version=1&_urlVersion=0&_userid=10&md5=929688bfb74a657fc6235b04e9ecb5fb&searchtype=a

niel

Re: Air pumps for better battery charging

i don't know if pumping air past the plates is a good idea for i would think they should've come up with a way to just keep it as electrolyte. air on plates has always turned out badly.

RCinFLA

Re: Air pumps for better battery charging

Agree with Niels.

The less oxygen introduced the better.

A good absorb voltage topping charge should be enough bubbling.

stephendv

Re: Air pumps for better battery charging

Thanks all. I've also not heard of anyone using systems like this for RE applications, but it's difficult to ignore claims of 30% better charging efficiency, especially when coming from 4 different manufacturers. Anyway, ordered the vanilla batts so will see how they perform.

john p

Re: Air pumps for better battery charging

I know it doesnt seem the right thing to do. but if 4 major manufacturers are doing it there must surely be some truth in the claims? or there would be a lot of unhappy customers wanting replacements under warranty??

Im going to try it in next few days after setting up 2 systems as close as possible and going to try using fish tank air pumps and see what happens.Have talk my work place into buying the pumps and giving me some batteries to use for the test..

stephendv

Re: Air pumps for better battery charging

That would be great John! I was thinking more about this morning and the difference in the usage between forklifts and RE systems. One thing that springs to mind is that perhaps the air bubbling helps improve the efficiency of the bulk phase, but not so much absorb (since it's already bubbling then). The difference being that forklifts are typically drawn down to a SoC of 20% before being recharged - so they could be spending a lot more time in bulk. Whereas RE systems might spend more time in absorb. Just guessing
Would be VERY interested in your test results!

john p

Re: Air pumps for better battery charging

Yes it will be interesting to see what the results are as already some have said its a bad idea.. but so what ??? if 4 companies are doing it then I want to try, To me it is better to try a real test than just talk mabe this mabe that.. I like REAL TESTS DONE AS WELL AS POSSIBLE SO THE RESULTS CAN BE DUPLICATED.
Real tests are what I do just about every day,, mostly to prove or disprove theory.
I will present the results at least one a week.

stephendv

Re: Air pumps for better battery charging

Agree 100% go for it

Also interesting though, is that all of those companies that offer those systems also make stationary batteries, but none of them offer this system for stationary batts. Only for the forklift ones.

BB.

Re: Air pumps for better battery charging

From one point of view, the gas on a recharging battery is normally two parts hydrogen and one part oxygen. Normal air is only 21% oxygen (normally during charging it is 100% oxygen at the positive plates from electrolysis).

So pumping air does not seem to be the worst thing in the world.

-Bill

niel

Re: Air pumps for better battery charging

john p,
i'm looking forward to hearing of your test results also as you bring up a good point of the manufacturers doing this.

john p

Re: Air pumps for better battery charging

Part 1
testing lead acid batteries .
The pros and cons of pumping air into a lead acid battery.
The following items will be used in the test.. this list does not include the test instruments

Starter batteries
2 x 1000 cca 12v batteries
2 x 950 cca 6v batteries

Golf cart batteries
2 x 225 ahr 12v
2 x 195 ahr 6v

Solar batteries
2 x 215 ahr 12v

10 X 50a shunts

10 x 10 a battery chargers

5 x fish tank air pumps

1of each battery will be used as per "normal" use and "normal" mains grid battery charger
The other set of batteries will each have a seperate large"(no idea on size as no rated output) fish tank aereator. but hope to find someone with siutable instrument here at work to measure it
Each battery will be charged by its own 10a battery charger
A 50a shunt will be used from charger to battery .secondary use as fuse
A 50 a shunt will be used on battery output to resistive load .Important to be able to verify what the charging currents are and what the load current is.
Batteries will be considered fully charged when at 14.2 v for 12v and 7.1 v for 6 v
Batteries will be disconnected when they reach 11.5v for 12v and 5.7v for 6v

All batteries are brand new and will be all normally charged and discharged once a day for 5 days. to get them to reach consistant good charge holding

stephendv

Re: Air pumps for better battery charging

Wow, you don't mess about do you

Are the chargers multi-stage? Do you by any chance have any kind of data logger to watch the charging process?
How tall are the tallest batts? Just thinking out aloud that efficiency might be greater with deep cells that tend to stratify easier.

Looking forward to the results!!

niel

Re: Air pumps for better battery charging

be sure each charger is outputting the same as small variances are possible.

CaptClarke

Re: Air pumps for better battery charging

Submarine batteries us an air system to keep the electrolite stired up. It is usually in a tube from the bottom to the top with the air introduced at the bottom. The rising air bubles act as a pump moving the electrolite from the bottom to the top. I think this is to prevent stratafication.

blackswan555

Re: Air pumps for better battery charging

CaptClark, You beat me to it I was thinking along the lines of trying to get and even amount of bubbles passing over the plate`s is going to be tricky (and need a big pump) bubble up the side, the air ( and poss pollution/contaminants) does not touch the plates, just provides an up-flow to stir ?
Tim

ps Just RTF`M `d , Yep that`s what it does

Cariboocoot

Re: Air pumps for better battery charging

A somewhat related thread:
http://forum.solar-electric.com/showthread.php?t=3936&highlight=circulating

And thanks for poking me in the memory, guys!

john p

Re: Air pumps for better battery charging

Part 2
So far ,, all batteries are daily on charge discharge.
The chargers are 3 stage chargers with adjustable voltage and current output,
Verified by measuring the voltage and current across the shunts between chargers and batteries.
During the tests all will be conected to data loggers. logging in volts and current to batteries output voltage and current, Automatic timers will shut down the chargers after each 20 mins charging then batteries will rest for 20 mins the their voltage will be taken Charging will cease at 14.2v and 7.1v
Have found someone to measure the air output of each air pump, but it cant be done until monday,, claims he has "real" work to do..
All progressing as planned EXCEPT

Getting the air tubes into the batteries. it seems simple but it isnt
If I just feed the 3/16 internal plastic tubing into the battery through the filler it goes to the side but wont go around the plates to go down to the bottom.. the space is too narrow to let the tube bend.
IF I put wire inside the tube I can get it around the top edge but as soon as I take out the wire the tubing collapses at the top corner
I have x rayed all the batteries . they are all different inside .in an important way some have good space at sides of plates others have no space almost, some have some space at ends of plates others almost none..

That took up most of Wed
Today Thurs drilled 2 holes in one cell top of the battery in the space at ends of the cells and inserted a 1/8 thin walled hard plastic tube long enough to reach the bottom of the cell .. pumped some dye that shows up on x rays to see how well it travels through the battery acid. it appears to go fairly evenly through the acid.
Fri am going to try now air into the acid and do ultrasound on it to see how well the bubbles are distributed.. At the moment I dont think that each air pump is going to have enough power to agitate the acid with such a small size tube..

niel

Re: Air pumps for better battery charging

variations in the batteries i can see as a problem for you to get the air down to the bottom of the batteries. this may limit the number of batteries you can test on unless solved. i first thought of bypassing that and somehow tap the bottom of the battery and place a check valve there to prevent the acid from backflowing. it would need to be done on every cell though and a failure could be a messy catastrophe not to mention a ruined battery.
if you solve that then be sure to also discharge the batteries in a similar fashion. for instance pick a discharge rate percentage and the degree of dod percentage so that they all would match that spec and take that out as a variable that could thwart results.
john, this is one complex little experiment and i commend you for trying to tackle this one. i have to wonder that, even if it works, if it really would be worth all of this effort with the added costs, complexity, and risks.

john p

Re: Air pumps for better battery charging

Niel there is no way im even going to attempt to drill holes on the side of the battery just below the plates, And as you are aware the problems if the check valve failed it would mean battery acid everywhere..
Its bad enough drilling holes in the top of the battery,,
doing the tests on charge discharge it no problem at all as I have every piece of equipment needed to do this with great accuracy.
Ihave an idea for today. im going to slice the top of a battery off and then can see the plates in a cell andthen get a tube to the bottom and see how much agitation of the acid occurs and if all the acid is being agitated,, As I see it as a problem if some plates get a lot better "washing" than others.

Just as a side note In the Philippines I just take the batteries for a ride over in the back of my truck about 20k (16m) of rough dirt roads each 6 months and it improves their charging ability a lot. and their ability to hold a charge..

The tests will go on.. im having an elec engineer and another tech have a look to see if they can come up with how better to do what im doing..
I cant spend endless time doing this as have a lot of other work to do.. So far have only permission to spend a collective total of 5 days on this test.. and already have spend 14 hrs out of the 35 hrs

niel

Re: Air pumps for better battery charging

we await to hear of the tests being able to move forward as i'm keeping an open mind on this.

as to,
"Just as a side note In the Philippines I just take the batteries for a ride over in the back of my truck about 20k (16m) of rough dirt roads each 6 months and it improves their charging ability a lot. and their ability to hold a charge.."

i have no argument with you on the subject of agitating the electrolyte by physical means as i know that works to keep things going well even though i don't know how much physical activity a battery can take before a physical problem may arise with the battery's construction. i suspect that will vary between battery manufacturers and i agree it may be quite a bit of physicalness before that kind of a failure can occur. i don't see me putting batteries in a rocker or something similar for me to put a bit of physical agitation to the electrolyte and most automatic means of agitation will consume power to do so, including pumping air past the plates.

blackswan555

Re: Air pumps for better battery charging

John, That`s not work, that`s playtime with all the top toy`s !! any spare job`s ? lol:D

Have a good one
Tim

john p

Re: Air pumps for better battery charging

blackswan . yes its not a bad job for an old man like me that is past retirement age..there are not many places a person can work at where just about everything we work on ends up broken and as scrap.
here there are hundreds of thousands of dollars test equipment. and we can just about order anything new and wonderful..
you can have the job after I really do retire next July.:D

blackswan555

Re: Air pumps for better battery charging

I am very qualified in testing stuff to destruction But gona be a long way to work in the morning

Have a good one
Tim

BilljustBill

Re: Air pumps for better battery charging

john p wrote: »

Part 2
......I have x rayed all the batteries . they are all different inside .in an important way some have good space at sides of plates others have no space almost, some have some space at ends of plates others almost none..

..

I'd like to hear how and where you can get someone to X-ray a battery... Is it a snapshot X-Ray, or something like the old Fluoroscope X-Ray machines that show in real time and were used in all the 1950's shoe departments?

A twist to your concept of air pumping inside the battery for keeping the acid well mixed, uses air, but to vibrate the whole battery rack.... Concrete contractors use a vibrating device to get the air pockets out of the deep side wall forms of a large pour. Some are electric and some are driven by compressed air. From a local artist foundry that poured bronze, I bought a similar device that measures only 6" long. One end has the compressed air disconnect and the other has bolt holes to attach it to the frame. If you have a battery rack on some thick rubber mounts, a few minutes with it should keep your batteries well mixed..

john p

Re: Air pumps for better battery charging

the xray machine is an industrial xray device its used to xray metal parts for cracks. it has a lot more output then a human xray machine..
on many items a dye is forced into the item first to show fractures.flaws .
it works almost in real time as you see the image on computer screen a few seconds after the xray taken.
the "how and where you get someone to xray a battery" is at work .. its part of the testing equipment here

part 3 tomorrow night . just need a few more tests done today

BilljustBill

Re: Air pumps for better battery charging

john p wrote: »

the xray machine is an industrial xray device its used to xray metal parts for cracks. it has a lot more output then a human xray machine..
on many items a dye is forced into the item first to show fractures.flaws .
it works almost in real time as you see the image on computer screen a few seconds after the xray taken.
the "how and where you get someone to xray a battery" is at work .. its part of the testing equipment here

part 3 tomorrow night . just need a few more tests done today

You Lucky Dog!!! Blending work with a hobby is the best of both worlds. Thanks for sharing your work and results...;)

john p

Re: Air pumps for better battery charging

Bill if you interested the machine is rated at 3kw and opperates at 350kv Made by GE . Can get you one at good price, aprox $175,000 ex tax. If you can buy 2 (one for you one for friend) most likely you get better discount.
I cant give you much more details as Im not the operator , but its powerful enough to penetrate 4" steel,, it can xray a v8 car engine block.

john p

Re: Air pumps for better battery charging

Part 3

Have had the output of the air pumps measured the output pressure is 3.6 lb per sq inch at a flow of 384 cubic inch per minute

Have connected 2x 3/16 inside dia soft plastic tubes to each cell,,, (total tubes per battery is 12)
air flow per cell is 64 cubic inches per min
The difficult parts have been first to find the exact place to drill the 2 holes 5/16 th dia in each battery cell top, The second to get the tubing to go straight down the sides of the cell plates , between the lead and the cell case divider

The correct place to drill was found after examining the x rays,, no problem
Getting the tubing down to near the bottom of the cell involved using a stainless steel rod with small bend 1/8 th from end and sharpened to a point , Then it was inserted into the tube and the tube pushed down the sides of the plates ,, There is only about 1/4 of and inch clearance, After the tube inserted the steel rod is easily removed from the tubing

The air pump delivers enough air bubbles to create enough movement so all solution is in constant motion over all the cell plates,, This was verified by doing an ultrasound on the batteries . I feel like a doctor testing a pregnant mother to listen to a baby. But could not use the ultrasound we have it would most likely badly damage a baby. as its caution says "dont touch pad when turned on"

This all took about 4 hours to do for the 5 batteries.

All non air supplied batteries and the air supplied batteries are now in test stage,,
The temperature of all batteries is loggged and so is the charge time ,discharge time and charge rate..
That is all for now, will post readings after a few days testing

niel

Re: Air pumps for better battery charging

you know that brings up the question of air flow rate as to what would be best. do you blow up the baby like it has high blood pressure, a trickle of small bubbles, or somewhere in between?