Charge New Battery?

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My wife bought a new Highlander just two weeks ago. I have read here that charging a battery can make it last longer. Last night I put my charger on her battery. I was shocked that it only showed 50 percent charge. Could sitting on a lot cause this? She had taken one trip of about 50 miles. It showed full charge after about 4 hours on 4 amps.
 
Depending on your particular charger, the reported "only 50%" charge state may be misleading. But it is possible that the battery got depleted quite a bit during extended sitting if the dealer did not keep it topped off. Modern car electronics do eat up batteries faster.
 
A battery will slowly discharge if a vehicle isn't driven. How much depends on the slight draw going on while sitting. When I park my car for winter it gets the battery tender put on every 2~3 weeks to keep the battery fully charged.
 
What was the actual resting voltage. I've got a smart charger and I don't trust its initial reading. For instance, it will indicate somewhere around 90% charged after I just charged it, after turning the headlights on for a minute. As soon as it charges, it goes very quickly to high 90's and then 100%.

I believe I was told before that specific gravity is a better way of determining state of charge. Is that right?

Finally, yes, a battery can deplete while on the lot, both due to parasitic drain, starting and stopping the engine quickly while moving it around the lot, or while people hop in to check it out, but not test-drive it.

I've seen new cars with the plastic still on them need to be jumped after possibly being subjected to the above.
 
The state of charge reading on so called 'smart' chargers, is based solely on the voltage it sees from the battery when first hooked up and plugged in.

This number can be wildly inaccurate depending if the battery was just charged or discharged and the battery itself. I have an AGM which fully charged rests at 13.06v. I have a flooded battery which rests fully charged at 12.67v

All lead acid batteries want to be kept cool and fully charged, always.

A temperature compensated hydrometer sampling the specific gravity of a 12v battery's 6 cells is quite accurate as to state of charge, an batteries whose electrolye can be accessed, but Specific gravity can vary from battery to battery from 1.260 to 1.310, so a baseline for comparison is needed.

Most smart chargers actually stop charging the battery at about 92 to 95% charged, and drop to a float/ maintenance voltage. Charging does still occur at these lesser electrical pressures but it is much much slower and aged batteries might never reach 100% charged at these lesser voltages, no matter how long the float voltage is applied.

92 to 95% charged can be 'just fine' for most, but a true 100% achieved regularly would have the battery last significantly longer.
 
Is the charger putting out 4A the whole time? Even if it did, I wouldn't consider 16A-Hrs to be significant. That may be only 25% or less depleted.
 
Originally Posted By: Quattro Pete
Depending on your particular charger, the reported "only 50%" charge state may be misleading. But it is possible that the battery got depleted quite a bit during extended sitting if the dealer did not keep it topped off. Modern car electronics do eat up batteries faster.


It's somewhat useful having a reading like that, but for the most part it's only a rough estimate. When you start it up all that it really has is a voltage reading that it's correlating with expected charge percentage. I've got one myself (a Schumacher SC-1200A-CA) and I take those readings with a grain of salt. You get a surface charge that will go away overnight. I mean - I can try to top it off in the morning after fully charging it the night before, and it's reading 80-85%.

Now I do believe that the voltage reading when it's not charging should be accurate. I'm not sure it's terribly practical to charge batteries on the lot. Now I suppose a good thing to do would be to charge up the battery while it's being prepped for the customer with something like a wheeled shop charger.
 
Originally Posted By: Chris142
I always charge a new one. I have some for sale at work. I put them on a charger once a month or so.

How do you do it? I've just placed the clamps straight on the terminals, but then I checked my charger's manual for the recommended procedure. It recommended using a ground cable as an extension to avoid making the connection (and possibly sparking) right at the battery. When I connect it to the ground (my usual point is at a grounding wire on my wife's Civic) for normal in-vehicle charging I can see it spark.
 
Originally Posted By: y_p_w
Now I do believe that the voltage reading when it's not charging should be accurate.


Just to clarify (I'm sure you agree and meant this): Open-circuit voltage, with the surface charge removed.

Originally Posted By: y_p_w
Originally Posted By: Chris142
I always charge a new one. I have some for sale at work. I put them on a charger once a month or so.

How do you do it? I've just placed the clamps straight on the terminals, but then I checked my charger's manual for the recommended procedure. It recommended using a ground cable as an extension to avoid making the connection (and possibly sparking) right at the battery. When I connect it to the ground (my usual point is at a grounding wire on my wife's Civic) for normal in-vehicle charging I can see it spark.


At the time of initial hookup there's no H2, so the risk of explosion from sparks is zero; that is, unless the engine was literally just shut down and the alternator voltage resulted in excessive voltages (overcharging), in which case you have other problems.

Unless you're charging at higher amperage (not necessary for maintenance charges), H2 generation is minimal. Even so, I've never seen a spark emitted from a smart charger.

I really wish my smart charger came with ring connector-to-plug-in-type connection, like what's available for the BatteryMinder. I understand that the small cabling is too low of gage to handle the smart-charger's max amperage, and they can't rely on the consumer to be smart enough to read the manual and NOT melt the cable by choosing too high of an amperage setting. I get it. I still would like to hookup without have to hookup alligator clips. 1st world problems, I know...
 
Originally Posted By: gathermewool
Originally Posted By: y_p_w
Now I do believe that the voltage reading when it's not charging should be accurate.


Just to clarify (I'm sure you agree and meant this): Open-circuit voltage, with the surface charge removed.

I was really thinking of open circuit, but maybe the difference between a surface charge there or not. I've watched it while I stopped the charging. I could literally see it go from about 13.7V and start dropping. I suppose once all the surface charge is gone it should at about 12.6 V the next morning.
 
Originally Posted By: gathermewool

I really wish my smart charger came with ring connector-to-plug-in-type connection,.......


Void the warranty, and make some ring terminals.

The common SAE12v connector is OK but the (+) on the battery side should be covered:

215uycP2RLL.jpg


I much prefer Anderson powerpoles as reversing polarity would ake effort, and they can handle much more current, and many more connecting/disconnecting cycles. The 30 amp powerpoles can accept 12awg and be crimped with a normal dimple crimper but the 45's are more tricky and are for 10AWG.


41fXLXDZmJL.jpg


Alligator clamps only really make a solid electrical connection when they are digging into the lead posts. On top of the cable post clamps alligator clamps might heve very little surface area for the electrons to pass.

Ring terminals attached to or near battery posts should be closed ended, no exposed copper stranding visible.
 
Def. charge it up. It won't do any harm and will put less strain on your alternator. I make this a habit over night every couple of months or so with a slow 1.5amp inexpensive charger I use.
 
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