Assessing 12v battery health

[jago25_98]

A friend and I are looking to setup a battery swap setup to reduce charge times by swapping out with precharged batteries.

However, if we are swapping batteries what are all the things to think about when it comes to assessing the battery health?

Here are the observations I have chanced upon in reading on this subject in the past:

- the electrodes can be furred up. There are electrical devices that somehow (estimate?) measure how much a problem this is. Some can even condition the battery for you. I have no idea what is going on when this happens though.

- the water (what's the word for that?) could be low. Sealed batteries say this is reduced. Yes it is but personnally I think it's about disposability. We need something servicable.

- i think there are other variables involved that can effect how well a battery works.

- a basic way of seeing how well a battery is performing is to measure amps under load. Quite however what `under load` means though I don't know.

- I wonder if batteries designed to be servicable are available? The ability to replace the electrodes and disassemble the whole assembly would be good. Perhaps we should make our own batteries out of old ones. I know this is fraught with issues but this is backyard science here so let's not worry about the details just yet.

I need to read up more on how battery conditioners work. And indeed different types of battery because I'm only really familiar with lead based ones. in my head I imagine other metals to be used for other types and that's about it.

This seems to be a complex subject. Can you recommend any resources on this?

-j

 

[Marvo]

Hi jago25_98,

You haven't siad where you're located but I would imagine you might be as concerned about local health and safety regulations as much as the technical side of reconditioning batteries. Nearly all batteries contain at least one substance which would be regulated in most areas. Heavy metals and acids are not the easiest substances to work with so maybe check up on your local regulations regarding this before you go any further.

 

[PeteC]

The acid solution of approx. 33% is at fully charged state, which reduces to 100% water at full discharge. Vented batteries can loose solution through over charging (gassing). Topping up and diluting the acid level, can cause the plates (and therefore terminals) to oxidize (fir-up) once the acid has been used up but there is still charge in the cells. Charge controllers need to be spec'ed for the connected battery ie floating charges vary from flooded-cell to gel type batteries. Some chargers only charge at higher voltages which is OK for daily shortburst (>2hrs) periods. Higher spec. controllers maintain a low charge rate to bring up the charge of all cells evenly if one is weak, and may have a short burst of higher (gassing) voltage at end of charge, and then a floating charge to maintain the battery at "full" counteracting the self discharge rate. The more control the charger has, the longer the batteries will last~ a lot longer (x2/3) in some comparisons~ in real terms they are more likely to give the battery it's expected full design life. Chargers with a flooding voltage MUST have temperature monitoring/cutoff protection.

 

[Des 56]

Battery condition can be obseved by looking at the state of the plates,whether they are buckled or no,the casings are secure etc
You can smell them whilst on charge for excessive gassing (typical sulpher stench for a knackered lead acid)
They can be discharge tested,using a heavy duty discharge tester for larger batteries, and an electronic test indicator for smaller ones

Knackered lead acids can be serviced sometimes.
If the plates are ok,they can be charged,discharged ,the electrolyte removed and washed out with distilled water,re filled with the correct mixture of electrolyte
Some batteries have electronic control for emergency connection for loss of power and the components can be serviced

There are so many types uses manufacturers sizes etc that providing a buisness for the service of batteries would be a no go
The disposal of batteries as stated involves a lot of cant just throw away materials and again not an ideal venture
For local disposal,the local authority provide outlets,so being competetive against a generally free service would be very difficult

 

[jago25_98]

Thank you for the info.

You haven't siad where you're located

^ I want to stay away from geographical legal thinking for the moment. I just want to get the knowledge first. I'm actually working in the North Sea at the moment. I spend a lot of time in South America.

Even so, it's the mix of water and acids that is a problem.

I see what you mean by the variation across battery types. That's something that can be ironed out - both of us agreeing on a common type already makes it a lot simpler. Any exchange we do will be with identical battery types.

Hearing what I am here it seems as expected that being able to inspect the electrodes visually would be very handy. A pH meter is on it's way to us. One thing we can certainly do already is make a note of the pH and instead of topping up with just distilled water, replace the water with the correct pH. The only question then may become, can we get hold of the correct acid type to match whatever battery we go for. Certainly at first we're going to be wanting to experiment with throw away batteries and keep waste to a minimum.

In terms of disposal I think we better look into that. Perhaps the best answer is recycling. The water will be acidic. What use is there for that? I don't think it can be filtered and reused too easily as it would just eat away the filter so fast you'd just end up with a contaminated filter. That seems like another subject though. There must be professionals working on battery disposal. I'll look up the company that dispose of the small batteries we use at work and see if I can find out how they do it.

What 12v battery would you choose for experimenting? We use a custom made battery bank at work with separate cell charging. This is wired in series when in use though for high voltage and it's purpose made. I don't think it needs to be that specialist though. The same thing could be achieved just by using many cheap individual chargers, each connected to and monitoring each cell rather than a multi charger monitoring many cells in one go. Why do we have individual cells rather than one big cell for that matter?

I know forklift truck batteries have some servicability in that they are designed to be topped up. But the serviceability is only by replacing cells. The electrodes themselves are not screwed in ready for easy inspection. I wonder if there's something better out there. Of course in the past there wouldn't be much motive for producing such a thing because you'd sell sell as it would be made to last. But the market has changed since then; more demand for durability, certainly from myself.

I wonder if perhaps another more eco friendly electrolyte could be used...

Thank you in particular to Des56&PeterC. To me, knowing that the furring is due to higher pH shows that if the electrolyte is monitored regularly (automatically?) and topped up again with the correct pH (automatically?) then is there anything that can deplete the battery life?
Certainly a basic pH meter can be altered to automate pH regulation. In fact, there may even be something from the hydroponics industry for this... (searching)

http://www.stealthhydroponics.com/product.php?xProd=135

 

[Jimmy Boy]

When I was playing with Boats and other Marine fun these Batteries were considered to be the Dogs Danglies, if nothing else you may find some useful info on their site..........


ODYSSEY Batteries - Official Manufacturer's Site