This is not Volvo specific.

I purchased a new battery that was reading 12.45 v. From everything I have learned about auto batteries and this being new I would expect it to be reading 12.6 v. It is an Interstate battery so I have confidence in the quality.

Avoiding all the run around to this point that includes two dealers that did not know how to test the cranking amps for this particular battery, I have put it on a charger.

With time and weather conditions I have not been able to keep the charger on it for the full 4 1/2 hours anticipated. The charger is automatic and drops the amps supplied until the battery is fully charged.

I find it odd the charger meter indicates more amps being applied when I reconnect it than when I removed it two days before. I have noticed this on other occasions with the old battery.

All this arising from a starting failure that I want to remove a potential battery problem from.

THE QUESTION:
If a battery is not charged to 100% at one time does it loose charge? Is the charging not cumulative? Am I hurting the battery by charging it when I can instead of waiting for a piece of time and weather to allow the charger to be ON until the charger meter drops to zero?


--
1988 244 DL; B230F; LH-2.2; Manual 5-speed (M47)

My charger is about 8 years old, and whenever it is turned on, it does go to a higher rate than is was when it was disconnected - but the rate goes down quite quickly if the battery has been charged recently.

Are you charging the battery in your car? Do you disconnect it if you do this?

I charged the battery in our '90 744TI in the car when I had trouble starting it. I eventually found that it had a bad computer - I hope that it did not have to do with my charging it while still connected to the car.

BTW - NA computers for that year were $150 they had about 100, turbo computers were unavailable used at the same junkyard - a Volvo specialist!

Hello, you need to shop for better battery dealers.
The capacity of the battery is on the label.

Second of all that battery was not fresh.
A battery siting is always discharging itself internally.
It must have been sitting a long time on the shelf as 12.45 was putting it almost dead or about 60% for sure. I consider a battery is dead or in need of some quality time on a charger @ 12.3 V.

What is the manufacturing date on the battery? I like seeing a "burn code" melted into the casing best.
Lately I have seen freshness "stickers" put on batteries, if you care to trust them, but it's a start like buying food with a date stamp. At least it shows someone is watching the stock.

I have casually walked around some auto part stores, Home Depots and other low volume turn over places and found quite a few batteries that are six months to fours years old on lower shelves!
Some sizes move slower than others.
It not good to let batteries sit more than a month without a float charger or a recharge right around that time. Personally, if I'm not going to use a battery for like ten days, it gets a float charger or battery maintainer hooked up.
I have batteries lasting lasting me 10 to 14 years but I'm an exception to the rule because I like the challenge or maybe I'm a cheap or thrifty person with some control over waste.

The Interstate company used to and I still see them sometimes, stop by and rotate batteries at small shops, as it was their stock, not the auto shop or stores. Part of a slogan and reputation I think they built.
The owners make 20% off the battery if they sell one. It pays them for the floor space. Also, if the shop needs one late, they don't wait for a special delivery or the next day.
I don't know why your Interstate would be low unless the distributor has dropped the ball on that store unless there was a issue between them.

I get my Interstate batteries at Costco because they have lots of sales there. Turnovers!
Interstate has a deal with Costco that the battery cannot be over a certain age but Interstate does not rotate or do anything with their batteries sold to Costco on their contract.
Once they get it, it theirs!
Kirkland Batteries used to be made by Johnson Controls. Interstate is made by Johnson Controls.
They are still good buddies in the battery business. J.C. just cuts their labor out of the picture.
If Costco has a battery returned, they eat the battery for the customer. The customer gets a new battery or anything warranty related. This is why the prices on them are better that in small stores.
The battery goes straight back through a recycler contact of Costco's contract biding. Whatever that is?

It is normal for a batteries voltage to drop after being removed from a charger. The voltage should not do it very rapidly though but it will drop. A shorted cell will make a battery drop really fast.

The battery charger only sees the voltage on the battery in tenths of a volt. The more the spread between its set top value the more the amperes will go up within a set range or trip out.
A real dead battery can be nursed onto a charger with a length of lamp cord.
A Short, is not a good word to use around batteries at anytime especially if there is no fuse in line with it.

A good trickle charger, will make it seem like watching grass growing to bring a large battery back up to snuff. (:-) Never used that nose treatment myself (:-) but the battery will not warp its plates from too much energy transfer and boiling the acid out of the plates and back into the solution. A "boost" charge mode is never good for a battery.
You can apply the charger as many times as you would like. Lead acid batteries do not create a memory platform like Nickle Cadium's have been know to do.

You will need to read up on the battery charger though.
You need to know if the charger can be left clip onto the battery when it is not plugged in.
The output side of the charger can drain a battery back down through it own circuitry.
Some chargers use a relay or a transistor that opens the clip side when off but they are usually the more expensive chargers.
They are handy if there is a power outage and if you are using a timer to maintain a battery.

A ampere reading on a multimeter can check for that inconvenience. You don't want to see any or only a few milliamperes of discharge when it's off.

Hope this help answer you question.

Phil

Thanks Phil.

The battery is 2 months old delivered direct from the warehouse.
Curiously all the batteries on the sellers shelves are the same 2 months old.

I do not leave the charger hooked up when it is not charging.
I did read through the charger owner's manual. The manual indicates the only way to know if a battery is fully charged is to check the Specific Gravity. See below for more possible bad news.

I hooked the charger back up and it took another 5 hours of charge until the meter was almost zero and I had 13.8 v across the battery while charging. Probably due my low end Craftsman multi-meter but it was holding 13.85 v 15 minutes after being disconnected.

I purchased a floating balls (low end type) battery specific gravity tester (Napa, 7001140). At 53 degrees F, directly after charging all cells were indicated to be at 75% Specific Gravity - same as before I started charging.

I am as of now going to let the van sit for a couple days so, based on reading, I can get a more accurate reading of what the voltage is.

After that I am going to have to drive the battery back to the Interstate distribution warehouse for them to check it because based on comm with the warehouse the "batteries leave in good condition". ... But the battery I have was supposedly only out of the warehouse 2 hours.

??!!!
Something is very wrong, like I found the sales shops were testing the cranking amps of the battery incorrectly, or my specific gravity test tool is not even close to being accurate or the warehouse is lying.
--
1988 244 DL; B230F; LH-2.2; Manual 5-speed (M47)

Thanks for the update.
I agree that there is something wrong with the batteries age as it appears with your inspection.

I think the operative word here is warehouse. A place to store things, not to manufacture them.
Let alone keep them at peak charge.
I have asked why don't they float charge them on the shelf in the stores and stall the decline?
The answers I get are fire liability insurance, the cost of electricity or of said equipment to do it.
Add on, that the customer knows nada and "In most cases" couldn't comprehend it or care less.
It's so not happening!

I went out and looked at one of my Interstate batteries in a car with a date on it of 6/16 according to adhesive stickers. I bought it about three months or more ago from Costco. It was fresh.
I trust stickers to be only a stock reference for easy reading by a customer or a stock person responsible to rotate stock.
When shopping I look over the whole stock of batteries for symmetry of color codes along with actual numbers.
I like to think it's a Code breaking skill. Same as a license plate sticker that policemen use.
Policemen scan our yearly stickers on plates, almost unconsciously, for a probable cause squeezing.
Very similar to looking for a fresh loaf of bread but on batteries you cannot put the squeeze on them.

For your reference, there is usually a machine applied spray pattern of letters and numbers on a side of a battery or a place where a code is melted into the casing somewhere.
This is on top of labels.
On my Interstate battery, there is a melted one right around the negative post. E6TAD code melted into it. About 1/8" high. It's probably the same on yours.
If you can find yours, you might like to contact a dealer or the company feedback site. They can tell you what the manufacturing date was and the possible plant or region it was manufactured within.
If the stamp is located elsewhere than mine, that can indicated the region or country being different than where I got mine.
Trust me all manufacturers have ways of tracing batches of batteries. It may be a federal DOT requirement like on tires.

IMO you paid for and thought you were buying a fresh new battery. It should last as long as its minimum years of life expectancy with reasonably care.
If not, it should be pro rated at that time. I bet pro rated from the "newer end" is never mentioned. It is Buyer be aware!

Another thing the date does not take in an allowance for damage done to a battery sitting for months sulfating.
A battery "in service" suffers less and is the reason batteries can make their life term or longer.
Batteries suffer worse from sitting than tires and oil seals by a guess of ten fold!
They need reasonable care.
That is why I watch mind like a hawk or mother hen! (:0)

As far as the electrolytes number, in my experience, it takes quite awhile to get them up to the very top as there are some variations that move that chemistry number around. Temperature, charge and rest time.
It is a far better indication for finding a bad cell or weak lead cell with an electrolyte absorption problem. Comparing voltage and hat number
This is usually a sulfide film or a cell has been eaten away more while enduring various causes during sitting.
An even reading across all the cells is more important. Not so much as it must have the highest number obtainable.

Now with that all said, the retailer has a catch-all clause on electrical items which means you keep it or exchange it. No refunds on electrical.

If you think your battery is old, don't let them get away with it.
Be a pain in their +SS and it will keep batteries fresher for everyone.
Consumers can still rule!

Phil