I had a thread on this subject at one time but it is so old now is been archived and it won't let me resurrect it. 

 

At the time i had some issues with the truck but they should be fixed now. I also had replaced my batteries as they were still giving me problems. It may be because of the issues i had. 

 

So i have new batteries, but it seems like they are still getting drained. I'm thinking the recent cold sub Zero weather has something to do with it. 

 

I was going to purchase a minder, tender but didn't know which one to get. Amperage wise i mean... i can get the Jr tender but it's .75a. So is that enough to maintain a float in two large batteries?

I'll have to try what you speak of this weekend. I replaced these batteries less than a year ago!

Sadly new means very little these days, and quality is hard to find.

There is only 3 or 4 companies building batteries so brand name is rather meaningless.

True there are only a few manufactures of batteries.....  But of those, they build batteries for specific brand name companies per the proprietary designs for those specific brands.  So point being is the Autozone battery is likely not the same as the NAPA battery or the Walmart battery or the Interstate battery.  Strangely the same thing applies to chocolate too.....

Well, over the weekend, I disconnected the batteries and charged them individually. Let them sit, and the next day checked their charge state. Each battery was very close to 12.6 volts. +- .05mv variance. So it appears the batteries are in working order.

 

So I cleaned everything up, and reconnected them to the truck. Cranked the truck over to run it for a few moments and just to watch the batteries being charged by the alternator. After, I let the truck sit once the alternator recharged the batteries from grid heater cycling.

 

Left for 30 min to come back to the battery dropped down to 90% charge! So I recharged the batteries while hooked up. Took a few minutes to do so, and then left again. Came back and was down to 85%! OK, WTF. Remember my parasitic draw test showed less than 50ma draw.

 

So, I thought, hmm, lets try a trickle charge on this instead. My schumacker is a smart charger so it only gives me the option of small battery, regular, or agm. I selected small battery and used it as a way to trickle charge them. Came back a little later and 100% charge. Disconnected the charger and let sit. I came out a few hours later and it did not go down at all!

 

I will see tomorrow before work how they fare after sitting for a more extended period of time after charging in this manner. Hoping that all they needed was a trickle charge to get them back on track. Begs to wonder as to why this is so?

 

We had some subzero weather as we all know because we all pretty much had that experience this year. Would a battery being subjected to that cold cause adverse damage? Such as electrolyte freezing and then using the truck while cold? I'm just spit balling here...

3 hours ago, hex0rz said:

Such as electrolyte freezing and then using the truck while cold?

 

Electrolyte will only freeze if the battery is dead. As long as the battery is charged up the electrolyte can't freeze.

On ‎1‎/‎23‎/‎2017 at 3:33 PM, Mopar1973Man said:

My big solar system battery bank failed in the same manner. The batteries would get an internal short and the battery volts would bleed out over a 24 hour span to the point of being dead again without another hooked up to them. 

 

Just remember all batteries can get this issue including AGM batteries. The trick to preventing this issue...

• Never let a battery go dead. Dead in a manner of speak for 12V is anything under 11 volts (some state 10.5v but I like to error on the side caution).
• Never let the plate become exposed to the air. When the electrolyte get low enough that the plates are exposed to air that section of plates are now ruined. 
• Always recharge the batteries fully before leaving to rest. This mean don't go out start the truck on cold morning move 100 feet and shut down again the batteries cannot and will not recover their charge in that short time. Batteries require warmth to charge and time so if you start up make sure to fully charge before shutting down again. 
• When adding distilled water to the cells make sure to disconnect the batteries and do a equalize charge on the batteries to ensure that the distilled water and electrolyte is stirred back together again. If not this is what's called stratification and the acid become concentrated on the lower part of the plates. Also equalizing the batteries will also help repair sulphation of the plates. WARNING: Do not equalize an AGM battery you will most like do damage and dry out the cells.  

Good info. Now a few questions. As long as water level is above the plates no need to add correct? Mine rarely seem to need any. And an equalize charge is what exactly? I mean like how many amp charger for how long?

On ‎1‎/‎23‎/‎2017 at 1:13 AM, hex0rz said:

Now what?

 

Still losing battery despite coming under 50ma...

I'm confused. Shouldn't an amp draw test be done between the pos. lead  on the other battery? And a voltage drop test be done with the ground?

4 minutes ago, dave110 said:

As long as water level is above the plates no need to add correct?

 

Kind of like saying don't need to add oil because it's above the ADD mark. I would still top off and do a equalize charge afterwards. 

 

5 minutes ago, dave110 said:

And an equalize charge is what exactly?

 

This is a controlled over charged state. For 12V batteries it would be raising to 15.5 voltage. So like most battery chargers with high amperage setting typically go higher in voltage. So monitor your charging voltage and basically run the amps down low. Like my 24V battery bank goes to 31.5 volts for about 2 hours. 

 

http://batteryuniversity.com/learn/article/equalizing_charge