Thread: Interesting battery information

Hi Mundy, sorry mate but most of that info your “EXPERT” gave you is based on many of the myths surrounding batteries and there uses.

For a start, AGM and GEL batteries are two different types of batteries and a Gel battery is more similar to a flooded wet cell battery and has many of it’s characteristics and while Gels make for good cranking batteries, a flooded wet cell battery is far better all round because they tolerate automotive environments better than most other types of batteries, including most AGMs.

While different types of batteries do have different voltage levels while discharging, the difference is so marginal that it is irrelevant for what they are being used for, like running a fridge and certainly will not make one battery type better than an other based on this.

The reference to Calcium batteries is a bit vague as most batteries have some % of calcium in them and you will find that it is batteries specifically labelled as Calcium/Lead/Calcium batteries that require the 15 volt charge to get them to a full charge but even this is deceptive because the additional voltage will at best only add about 5% to this type of batteries total capacity and will have little, if any effect on this type of batteries overall life span.

The one I love is this crap that you can’t use batteries of different types, size, age and so on. It surprises me they don’t demand that the batteries bo of the same colour, have the same size hand grips, what a load of BS.

If you have two identical batteries and one dies, for what ever reason, there is every chance that the other battery will be stuffed as well, unless you find the problem quick enough and there is a lot more to it but the fact that your so called “EXPERT” made such a statement shows just how little he really knows.

Now to fusing cables. To my knowledge, unlike AC wiring, there are NO mandatory requirements to fusing anything in a motor vehicle. There are STANDARDS and if you don’t meet these STANDARDS, if an insurance company actually knows about these STANDARDS then there is every chance that they will use these STANDARDS as a means of trying to avoiding a pay out.

To prove my point, have a look at your own vehicle and see how long your cable is between the alternator and the battery, and the battery and the starter motor. One or both will most likely be longer than 30cm and if it was a MANDATORY requirement that there be fuses in such situations, don’t you think the vehicle manufacturers would be in breach of such a requirement if it existed.

Many people confuse standards with laws. Laws require an act of parliament, standards can be anybodies standards. And the one about battery types have to match has been going around for along time. I know plenty of people who have wet cells for starting and agm for second and no problems(me). Many experts try to push their own products alot he said about short trips and chargeing with a charger are correct, he didnt have a line of batteries and chargers for sale did he.(if he did were any of them good value) Not picking on you Mundy

I guess its going to be up to everyone to make up their own minds. That means checking out reputable sites not just forums (the irony of my own email is now not lost on me). One of the best sites can be found at: Technical Information. Read the articles. You can find others, too.

In particular response to Bodger and Drivesafe, I make the following comments
1. I made no judgement on whether wet cell, agm or gel batteries were better, just described the differences.
2. Of my 10 points, Drivesafe, you disparage the whole thread while making reference to 2 items only. I don't know about the discharge rate and/or discharge state versus voltage output; I will have to look into it more. But on the matter of dissimilar batteries, you are just wrong. Different batteries can have significantly different internal resistances which means if you connect two batteries with a large difference one battery will be flattened well before the other, to the long term detriment of both. On my other 8 points I will say to others, go do your research.
3. Clearly, Bodger you didn't read/understand the point regarding connection of different batteries. I too, have had a wet cell starter battery a AGM deep cycle but they are not connected (in parallel or otherwise) when the car engine is off ie when the second battery is providing the electrical current, because of the isolator. The context of the advice, which I should have included it seems, was in having a second and third battery as power supply, for some of those people who camp in one place for days at a time. It was suggested to stick to a single second battery and top up with a solar panel.
4.There are not just standards and laws, there are design rules and regulations and its my understanding that the fusing requirement is not just a myth. I haven't read the design rules and there may be an exception for the cable from alternator to battery for other good reasons.

I don't wish to start a debate; just wanted to help out.

Mundy

Hi Mundy, my first post was not aimed at you but at the incorrect info your “EXPERT” was spouting, this post is aimed at you.

I only cover two or three points in your thread as I didn’t have the time to go through every point one at a time.

There is no legitimate reason for not connecting dissimilar batteries in parallel.

As to one battery going flat before the other, yes that could happen if you applied a load of say a couple of hundred amps to an AGM and a flooded wet cell ( FWC ) battery connected in parallel.

The AGM would go flat before the FWC but it would be a difference of only a few seconds to maybe a minute and both batteries would be permanently stuffed

Back in the real world, there would be no difference in the discharge rates of two batteries connected in parallel when supplying power for a fridge, an inverter and a few lights all at the same time, the battery voltages would be the same from full charge to what ever level of discharge they were taken down to.

This is not a case of battery types but the laws of physics.

I design, manufacture and supply dual battery charge control equipment to the trade and I can assure you that connecting batteries in parallel is no problem and again, I can assure you your “EXPERT” was anything but.

As to your link, the guy has some good info there but while reading it, remember, he sells AGM batteries and some of his info is very heavily weighted in favour of these batteries and I’ve met him and found him to be very helpful but he is a SALESMAN, not a technician.

As with drivesafe i wasnt picking on you just some of the things said by the "expert" i agree short drives will not charge batteries properly and that charging with a charger is often the best way to go when not out in the bush.
I have had in a previous 4wd 2 secondary batteries 1 x agm deep cycle 1 x marine deep cycle(wet cell) they worked well for about 3 years till the wet cell shorted internally.


By the way if there are two different ways of looking at something it will cause a debate on most forums here is no different so dont get upset about anything its not personal.

Fair enough guys. I'll try not to be so sensitive i future.

Mundy

Originally Posted by Mundy

8. Legally, any cable attached to the battery which is over 30cm in length must be fused.

The leads to the starter motor aren't fused. They'd need a flaming big fuse to carry the hundreds of amps drawn by a starter motor.

Originally Posted by p38arover

The leads to the starter motor aren't fused. They'd need a flaming big fuse to carry the hundreds of amps drawn by a starter motor.

While fusing has become a lot more popular in recent years, I would point out that Series 1 had exactly one fuse, and the only protected circuits were those that came on with the ignition (but not the ignition). Series 2a added a second fuse - but this only protected the optional interior light.

John