Charging System

[Boon]

Thanks heaps for the help 'link.

So with 1/10c, say my entire system is ~275Ah, and I'm charging at 15.3v with a 1A limit, should I give it ~28 hours and then check float voltages? At the moment they're pretty dicey, all float below 13, because they have been left sitting for a long time now with no activity.

I'll look into a simple bench supply tomorrow.

[missinglink]

Thanks heaps for the help 'link.

So with 1/10c, say my entire system is ~275Ah, and I'm charging at 15.3v with a 1A limit, should I give it ~28 hours and then check float voltages? At the moment they're pretty dicey, all float below 13, because they have been left sitting for a long time now with no activity.

I'll look into a simple bench supply tomorrow.

Boon:

You have what we call "cordless audio" in my shop. Just like a cordless drill, you need to maintain the batteries from an AC source. Works great, as long as you keep them charged.

You can get a decent bench supply from a place like Fry's for about 80 bucks. A good 5 amp bench supply with adjustable current limit & voltage can be used to do all kinds of things. Set the current limit to 5 amps, and the voltage to 14.7 for bulk charge. Set the voltage to 13.8 & current @ 500ma when you go on a long vacation... you get the idea.

1/10c is the accepted safe charging for sealed batteries like small NiCad cells. A recombinant AGM might handle more, but 1/10c is safe. Try an 8 hour run & measure cell voltage 4 hours later. You will quickly find the needs of your particular system.

'Link

[mrrairai]

Link/Chris/MLA so many aliases is correct. The module is not at a constant 15.0 or so volts. It fluctuates with the state of the battery and also the heat. I get a good 15.2 when I'm cold (sometimes .3) but when it warms up it drops and rest around 14.7 or 14.8 depending on how hot it is and what I'm running at the time. The module is an excellent investment.

[Nitr0Racing21]

Missing link pwned you all.

[MECHMAN]

Missing link pwned you all.

Just to clarify, I'm not arguing against Missinglink's module at all, I'm just expanding on their battery discussion-

That being said, I will point out that the 10 year old autozone battery is a flooded battery and can continuously be charged at roughly half a volt higher charge rate than the average AGM battery without being damaged. There is physically much less liquid electrolyte in an AGM battery. The acid is suspended in the fiberglass mats so that less electrolyte is necessary to have full plate coverage, which allows for more surface area in the same battery footprint- that's the advantage to the AGM design. Gassing will be very minimal in an AGM battery, except in overcharging situations. AGM batterys just have a smaller margin of error regarding overcharging, because it doesn't take very much of the electrolyte to be boiled out for the battery to start loosing plate coverage.

The Battery Council International is an independent regulatory and exploratory body regarding all types of batteries. They are not a battery manufacturer, and in the reports that they publish regarding testing and failure analysis, overcharging (classified as a charge voltage higher than 14.8 volts on a 6 cell AGM lead acid battery) was the #1 cause of AGM battery failure. This does not reflect testing performed by BCI, it is merely a statistical observation from contributed data to the council by it's members.

If anyone is looking to further their understanding regarding battery theory, there are severall E-books that have really good instructions on how to properly test and evaluate Lead/Acid batteries, available at www.batterycouncil.org . I think someone may have them stickied over on Termlab.com too.

[mrrairai]

Missing link pwned you all.

I think he only pwned one person on the forum not everyone. Reading is Fundamental (R.I.F.)