Battery Voltages

Hey man i got one of those ,how do you post pictures!!!!!

G'day Matthew go to photobucket and sign up and then look for your pics on your computer and upload them. Then use insert picture link when making a post just check at the front of the link http is not shown twice.
I hope i explained it clearly.

The boxer is Urly and the bulldog is Stacy what do you have a boxer or a bulldog.

We have a Bulldog, ive put a picture in members rigs and profile .but she's older now.

Matt

Hi Stephen, before you do anything, go and check your engine on voltage again.

14.9 is way too high for ANY type of battery, you will end up cooking them.

Cheers

>14.9 is way too high for ANY type of battery, you will
>end up cooking them.

That may be a little high for a vehicle charging system but some (many) batteries are quite happy with that voltage - not my favourite manufacturer but check Ritar AGM data sheets for cyclic use - and most others iirc.

http://www.ritarpower.com/products.aspx?catid=16&pcatid=13

Mike Harding

Sorry guys it should have read 14.09

Battery readings are as follows

Aux 10.92 engine off 14.11 engine on

Main 12.52 engine off 14.05 engine on

Aux 13.49 engine on lights on

Main 13.43 engine on lights on

Cheers

Stephen

Stephen 14.2 volts is about right, some of the alternator manufactures bring out 14.7 volt ones for high demand applications.

I think you have a cell in your aux battery gone.

On most new vehicles you will not be able to test charge voltage correctly as the engine ecu controls it.

Non of the alternator manufactures have a test box avaliable as yet so we can't even test them.

About 4 months ago Redarc changed there cut in and cut out settings on there battery isolators to suit the new settings.

Our Hilux only charges between 13.2 and 13.6 volts.

Regards Richard

Hi Mike, correct me if I’m wrong but that site doesn't give any reference to a constant charging voltage.

It does refer to a 15 volt equalisation charge for wet cell batteries but this is meant to be a high voltage charge for a short period of time not a constant voltage as would have been the case in Stephen's situation if his alternator was running at 14.9v and you can pretty well use that reference for use with most wet cell batteries.

On the other hand, the site also states that the maximum voltage for an AGM is 14.1v and in this case that would probably be for their specific brand of battery.

The problem with info for AGM batteries is that every make of AGM battery has it’s own specific specs and you can’t just say that the info on one make of AGM will be common to all makes of AGM batteries.

This misunderstanding of how much difference there is between the many makes of AGM batteries is something people should be aware of before they by one.

Contrary to popular belief VERY FEW AGM batteries perform as well as standard wet cell batteries, when these AGMs are used in automotive use.

I doubt if there 5 brands of AGM batteries that are specifically designed for automotive use and the rest are just designed for UPS and RAPS use.

A perfect example of what I mean is the misconception that most people have that an AGM battery will charge quicker than a flooded wet cell and that you can put any amount of current into them while charging.

If you have an Optima or Odyssey automotive type battery then yes you can charge them quicker but if you read the specs for MOST AGM batteries, they nearly all say that the charging current for most AGMs should not exceed 20% or 25% of the batteries total A/H or in other words, if you have ( for example ) a 100A/H Fullriver AGM battery, the maximum charge current for the battery is just 20 amps and to make matters worst, this is based on a temperature of 25C and the hotter the battery gets, the lower both the maximum charge current AND charge voltage should be.

The Fullriver has better specs than the Riter battery with a maximum charge voltage of only 14.1v, would not risk using a Riter for automotive use. There are few vehicles that don’t exceed this voltage all the time.

Cheers.

Hi Drivesafe

The Ritar specs (I just picked the RA12-65 as being the sort of size one would use for a starting battery) show 14V4 to 15V0 as both an equalisation and a cyclic charge max. V. But I do agree with you that when 14V9 becomes an, effective, float charge once the battery is fully charged it is too high.

I also agree about AGM specs and their variations - I grabbed the Ritar ones because I've recently done some work with them and knew where they were - it's usually too hard to find decent specs for wet cell batteries.

Again I agree about under-bonnet use of AGMs with a couple of, expensive, exceptions they are not suitable for this type of use.

>A perfect example of what I mean is the misconception that
>most people have that an AGM battery will charge quicker than
>a flooded wet cell and that you can put any amount of current
>into them while charging.

This is a flag you and I have been waving on this forum - pretty much in isolation - for some time but we are correct and have the manufacturers specs to prove it - why people, who should know better, continue to disagree confounds me!

Upon reflection my original post was loosely worded and implied Stephen was OK with a 14V9 quiescent charging voltage - I agree with you that he will cook batteries if that condition is allowed to remain for very long – thanks for highlighting it.

Mike Harding

G'day guys you seem to know what your on about when it comes to batteries i was wondering if you could explain to me what all the jargan on my battery means.

Battery manufacture is Crown its a Supreme deep cycle model # 27dc-36 115AH

20Hr. AH =115 5Hr. AH =90

Reserve capacity (minutes) 170 @ 25AH

Regards

Stephen

Hi Stephen

>20Hr. AH =115 5Hr. AH =90

These figures refer to the capacity of your battery. At the 20hr rate your battery has a capacity of 115Ah and at the 5hr rate it has a capacity of 90Ah.

To explain: the capacity of a battery is not a fixed number it varies depending upon how much current is drawn from it. With a 115Ah battery, discharging it at the 20hr rate would mean that if you put a load of 115/20 (ie. 5.75 amps) the battery would be flat after 20 hours use. However if you placed a load of 18 amps on the battery it would be flat after only 5 hours use (5 x 18 = 90). So your 115Ah battery is only a 115Ah battery if 5.75 amps is being drawn from it - if you take less current it will have a greater capacity and if you take more current it will have a lesser capacity.

The Reserve Capacity is another measure of battery capacity, it refers to the battery's ability to supply 25 amps for X minutes - in other words your battery (when fully charged) can supply 25 amps for 170 minutes, at least, that's what the manufacturers claim :)

Mike Harding

Hi Stephen, there three links below that will give you a fairly sound education on batteries in general.

The first 2 links are actually on the site that Mike posted and it good info.

The last one link is to a site with a huge amount of info, much of it is excellent BUT it does have some errors plus and this may seem unimportant but the info is primarily based on car usage not RV usage and there is some major differences.

Cheers.

Battery Terms Glossary

Battery FAQ

Battery Data

Mobile Power Solutions web site has the following info about this battery "Top quality American made Trojan (27TMH) equivalent battery made by Crown Batteries USA, and marketed as Supreme Batteries in Australia."

Mike Harding explained that the quicker you discharge a battery the less you get out of it. If you wish to read more abut this see this link If you are going to purchase a battery monitor that will give you the percentage capacity your battery has left, make sure it has the ability to have the setting for Peukert's constant to be adjusted, a lot of them don't.

PeterD