Testing 6V deep cycle batteries?

[AB]

Hi All,

I might be able to get my hands on a dozen Yuasa 6V 160Ah deep cycle batteries at a great price.

However, they are second hand....

This will not be for camping more towards setting up part of my house for dedicated solar, etc.

What is the best way to test these batteries to ensure they hold charge and are in good working order.

I'm not sure on the history and haven't asked the owner any questions so any particular questions I should ask would be appreciated!!!!

[taslucas]

What is the best way to test these batteries to ensure they hold charge and are in good working order.

Put your tongue on them

FanTapstic!

[Cuppa]

Age, pattern & type of usage, what they have regularly been taken down to before being recharged, any lengthy periods of sitting without being fully charged. How they have been charged. Whether you'll get truthful answers depends on the seller, it's like buying a second hand car except there are no rounded off nuts & oil leaks to look for. The 'great price' should take this into account. The biggest killer of batteries is chronic undercharging or sitting uncharged for lengthy periods resulting in heavily sulphated plates leading to a short life.

To test them, first ensure that all cells are topped up with distilled water at least to above the plates, preferably to the 'high' mark then fully charge them (serial connected in pairs to make 12v units) with a smart charger until it goes into float mode, or with a not so smart charger, regularly checking terminal voltages until they reach 14.4v or 14.5v then switch off. The batteries by then should be bubbling/gassing. Then put a load on them, something like a 12v 60w headlamp globe would suffice, & let it shine for 60 minutes, remove the globe, let the batteries sit for another 20 or 30 minutes & then check the voltage across the terminals (neg on one battery, pos on the other). If the batteries are in good shape you should expect to get a reading of 12.5v or better. This is not a guarantee that they will last, but more a check of their present condition, which is probably as good as you are going to get.

Cuppa

[Maxhead]

I suppose you need to load test them some how....

Whats your plan for the house, As I understand tyhe 2V ones are the best for house installations but its only what I heard.

You might want to take them to a battery shop and get them them tested..

Where they UPS batteries?? if so they could be very good as they get replaced on a very regular basis.

[Cuppa]

I don't have any direct experience, but have read that the sort of load testing that most auto battery places can do is not suitable for deep cycle batteries. If taking them somewhere for testing I would be asking questions to determine whether the tester understood the need for different testing to the 'normal' load test. Personally I'd stick with the sort of 'load test' I referred to above, or ask that this be done. Starter batteries are built to provide high current for very short periods, which is just about the opposite of what deep cycle batteries are built for.

Cuppa

[the evil twin]

If they are out of a UPS application then you will probably find they have a low (in Vehicle Terms) max draw down current and max recharge current specs so any Load Testing will need to take that into acccount.

No reason at all why they won't be suitable for your house as most UPS systems are treated with the utmost of TLC so if you know the history I would grab them.

[Yendor]

Put your tongue on them

FanTapstic!

That is a very efficient way of testing them. The problem is, it's very hard to gauge the results while you are doing the test.

AB, I recommend you do the tongue test and post the video up here so we can all review the results and comment.

[AB]

Thanks blokes for the tech answers and of course the answers I expect from some certain muppets...lol

I've asked the basic questions first via email so will see how the response is first before driving out and checking them personally.

I'm seriously considering a DIY solar set up off grid at my place so trying to learn as much as I can about this.

If I didn't have a family I would of sold up long ago and moved to an isolated bush block away from society...lol

[AB]

Here is his reply....Bit of mystery to it.

Hi I only know what I was told and that these batteries came of a boat (yacht) which was damaged in the Brisbane floods. When moored they were on a trickle feed system and when not solar fed. As to pattern I do not know, as to age approx 4-5 years as that was the age of the yacht. I tested them with a battery load tester and they did not drop out of the green when load applied . Hope this helps but as I was not the original owner I can really only confirm that they still are holding a charge.

[the evil twin]

Here is his reply....Bit of mystery to it.

Hmmm... kinda up to you, Cobber.

Given the temps and humidity on boats and the age of the batteries I would say they are probably around 50% thru their life expectancy.

If they are at the right price they could still be a bargain but ex marine batteries are a gamble.