Another battery charging question

Thanks Mainey, I didn't realize that the charging regime would vary between manufacturers as long as I was comparing AGM to AGM.

cHEERS OB

since your charger seems to only have two settings, 'flooded' and 'gel' it's a good idea to follow Maîneÿ's advice and find out from your AGM battery supplier what the recommended settings for float and boost charge voltages are.
If your charger's boost charge setting for gel matches this, you're on a winner. Be careful not to select flooded, because some chargers add an equalization charge which makes the terminal voltage rise above what an AGM can stand.
As a rule of thumb, during summer asian sourced AGM batteries want to see 14.4 to 14.6V. In winter, increase this to 14.7 to 14.9V.

It's probably safe to adjust for a float voltage of 13.6V since this seems to be average for any asian sourced AGM battery.
Reduce this by 0.25 V if the battery is warmer than 30 degrees, and increase it if it's cooler than 15 degrees.
Chargers with temperature compensation achieve this on their own.

Best regards, batterymeister

Thanks for that info, I will try the gel setting for charging and monitor the voltage. Temperature may be a little harder.

Cheers ob

batterymeister
Wow someone that acknowledges Asian AGMs are different instead of people thinking all AGMs are the same.

I hope the charger is Exide Gel Spec and not US Gel spec if it only has 2 settings.
Ian

Ok you guys you've got me intrigued (and worried) would you (anyone) care to enlighten me as to what the difference is. I'm almost at the point of thinking I should throw my existing charger in the bin along with my old battery. The last thing I want to do is stuff two new deep cycle (AGM) expensive batteries by using what may be an inadequate charger. I guess for a lot of people (well me anyway) battery charging is a bit of a black art with so many types of batteries, and now you tell me it is important where they are made.
No I'm not trying to start WW3 just trying to get a bit more edgumicated.

Cheers ob

Me too, roll out the info.

Ob
The posters do not want any conflict but do need better information from you to determine something that could be to your benefit.

Tell them what the charger is with details and tell them what brand and model the batteries are.

The battery chargers that I am aquainted with have 4 charging regimes for Battery Selection.
(1) Flooded wet cell Max Charge voltage 14.8V Float 13.65V
(2) Gel Exide Specs Max Charge voltage 14.4V Float 13.80V
(3)Sealed Lead Acid & AGM Max Charge voltage 14.4V Float 13.65V
(4)Gel & AGM US Specs Max Charge voltage 14.1V Float 13.5V

All the above is based on 20oC so from this you might understand what I said about AGM and Gel and in reality the Asian AGM is suited to Exide Specs but is more suited to Dealed Led Acid & AGM for the lower float and having an exide spec with adjustable float should be ok.

So with 2 battery setting which 2 as we all know one will be flooded wet cell but which one is the second one.

If your AGM are Asian then the two setting you have may be suitable but you would have to remember change from the higher setting to the lower setting winter to summer unless you have temperature compensation.

I hope I havnt made it worse but Im sure with more info from you you can get the help you need from any of the posters that have tried so far.
Ian

ob
To me the charger is specked for US AGM OK but with a 14.6V boost and absorbtion in winter you might battle with the higher voltage needed.

Basically with what Battery Meister posted and emphasized and what I posted it gives you all you need to determine it for yourself .
Good luck
Ian

no worries ob,

your charger seems to be suitable for Asian AGMs.
Select the 'flooded' which gives you 14.6V bulk/absorption, and select 13.5V float in summer, and 13.8V float in winter.
Make double sure the charger never enters an equalization charge routine which is something for 'flooded' only as the higher voltages will hurt your AGM.
Another word of caution: check the voltage with a voltmeter as the voltage regulation in some chargers can be sloppy.
And keep in mind that for winter temperatures, the 14.6V is a bit on the low side as has been said before - so try to keep the battery temp during winter charging above 25 degrees.

As to the questions on the difference in charging voltages in different AGMs:
Rule of thumb: if there is any antimony used in the lead alloy, absorption voltage is 14.4V (these batteries are called hybrid, because lead/antimony forms the anode, and lead/calcium the cathode)
Many US batteries still use antimony in the positive grids for mechanical rigidity, and better 'castability' during grid production. Drawback is gradual 'poisoning' of the cathode by traces of antimony drifting over from the positive electrode. This over time, reduces the gassing voltage on the negative electrode thus the lower charge voltage acceptance.
In more advanced designs, the antimony gets replaced with calcium in both anode and cathodes, tin is added for extra strength, and sometimes silver to increase corrosion resistance under high temperature.
All modern Asian AGMs are made antimony free (sometimes called calcium/calcium, or lead/silver) thus can receive a higher charge by accepting a higher charge voltage, and at the same time the grids can be made thinner yet strong enough which means there is scope to increase the battery capacity again by adding a higher number of plates.

Hope this short compilation of information from various sources answers your questions.

Best regards, batterymeister

Ian and batterymeister, many thanks for taking the time and effort to point me in the right direction. Your info and what I gleened from the web site should help me make the right choice. Quite a revelation that not all AGM's are created equal. I will keep a closer eye on things this time.

Once again many thanks

Cheers
ob