Trickle charger overcharging battery?

[Lexi]

George that sounds good. I had a fellow who runs a battery company tell me that new automotive batteries, in great shape, in theory are good to sit 6 months, but he said in practice it is best to start them at least every 3 months, just to be on the safe side. In the old days that time would be halved due to their means of construction.

Eric, like you I am loathe to use any type of charger un-attended, but in my case I have little choice because of parking arrangements. I asked the battery guy I know about longevity and using these tenders. This guy actually rebuilds batteries so he would be the one to know. His reply was rather detailed, but long story short he said that every time a battery discharges it loses some of its life. The key is to keep them from discharging. That said, he acknowledged that it is difficult to determine how long a battery will last. He noted lots of variables. He did say that when undercharged and/or the electrolyte levels are low, the sulphation process expedites, which shortens battery life.

In a vehicle with a properly run charging system that process is staved off for as long as reasonably possible, because some of those harmful particles that have formed are "knocked off" the plates. He also said that if you were to leave 2 identical batteries; one just hooked up to a smart charger, and another hooked up to a properly running car, (in regular use), the one in the vehicle should last longer. The reason he gave is that the smart charger won't be knocking off sulphation from the plates due to the lower power. That is why he said that when using a smart charger it is still a good idea to hook up a heavier amp charger and connect it to your battery for a few minutes, say monthly or so. He also agreed that if at all possible, bring your battery in for off season storage and monitor it there with the appropriate equipment. This information he gave applied to traditional wet cell batteries.

On a final note, I think it was Deltran who I had on the phone once that said using a smart charger will provide more protection to the battery by making it less prone to freezing. I did not ask why, but at the very least I assume that the current running through it may cause some electrolyte motion, thereby combating freezing. I suspect there may also be another factor also at work, but not sure. Anyone know? Would electrolyte with the proper specific gravity reading have a different freezing point?

Clay/Lexi

Edit: So in answer to Eric, a smart charger may extend battery life by keeping it from discharging, BUT it can also be adverse to the battery to solely rely on it due to the nature of the sulphation process. It is a balancing act.

[fishnjim]

Flammable range for Hydrogen is 4-75% in air.   So doesn't even have to build-up.     

I charge a lot of batteries with the boat, etc., and with a wet cell battery, you have to periodically add water, that's where the hydrogen comes from.   If you top them up too much(high level), the gassing that occurs in the charging will spit some acid out the cap vent.   Needs head space for gas to disengage from electrolyte.   Too low level, exposed plate, isn't good either.   Stay below that little slice up the riser.   Use distilled water.  I use a battery filler, that hydraulically stops flowing.

I leave the negative cable unhooked when car sits.   Clock will run the battery down in two weeks.   I use one of those screw type disconnects.  Negative side so no sparks on connection.   Just charge it up before you use.   No way it can go anywhere.   No wiring fires either - learned the hard way.

[savemy67]

Hello Chris,

Back in the day, many if not most top-post batteries used slightly tapered posts - wider at the bottom.  Often, the cables that came with the battery and vehicle had cable terminals that were tapered as well.  The taper provided full contact between the post and cable terminals, while at the same time allowing easy removal of the cable.  A straight
post/cable was more prone to bind when removal was attempted, thereby increasing the chances that the joint between the post on the outside of the battery case, and the corresponding plate on the inside of the case would be damaged.

I can't tell from your photos if your posts/cables are tapered.  If the posts are tapered, and the cables are not, you may be able to find something that will allow you to deform the cables to the taper of the post.

In addition to the other posts, you may want to double check the level of the electrolyte in the battery.  Each battery manufacturer will indicate where in the battery the electrolyte should be filled to.  Too much electrolyte, the more likely a discharge as there may not be enough room in the battery case for the designed gas expansion space.

Respectfully submitted,

Christopher Winter

[cadillacmike68]

I have one, a Schumacher 1.5 Amp. But I never installed it because I can't find a place where it won't look stooopid and not rattle around. And now I probably won't.

I might use it overnight on the Fleetwood, but the DeVille has two batteries and neither car goes for more than 2 weeks without running any longer. 

I have regular chargers, a 2-10 and a 5-15 amp, that both work fine. Both also have an (80 or 1200) amp start function in case a battery drains. And I have a couple small LI-ion chargers in the newer cars for away from home issues. 

I'd rather wait for AAA or USAA than have an explosion in the car while it's garaged.

I am thinking of getting one of those Autowit supercapacitor chargers to carry along in the older cars.

[Mike Josephic CLC #3877]

Lexi:

In answer to your question, I'll give a brief explanation:

"I suspect there may also be another factor also at work,
but not sure. Anyone know? Would electrolyte with the
proper specific gravity reading have a different freezing
point?"

The answer is "YES"  -- the chemical composition of the
electrolyte changes as the battery discharges.  In simple
terms, the water content increases and this allows the
liquid to freeze more easily. In the old days, wet cell
batteries were checked with an instrument called a
hydrometer. The instrument was used to check each
cell to see if the specific gravity was in spec. 
It was easy to spot a "dead cell" using this method. 

You can purchase one for less than $20 at any auto
parts store.

Mike

[Lexi]

Mike thanks. That makes sense. Another reason for some to put a smart charger on their car battery if left to sit idle for months in the bitter cold. I actually have a hydrometer here that I use, and would like to get a digital load tester for CCA readings. They would be good to have as monitoring tools for a battery, with more info provided than just a voltage check. Thanks again. Clay/Lexi

[dadscad]

Lexi's friend explaining about sulfating in the battery is spot on. That is why I chose the Battery Minder to replace the battery tender plus chargers I was using. The Batteryminder has a desulfation frequency pulse and they adjust the charge and maintaining voltage according to the ambient temperature. They have an ambient temperature sensor built into the charger.

[Lexi]

Dadscad, yep that is exactly what I thought, but when I asked the battery guy about the desulphation battery minder he said they were not worth spending the money on! I was more than a bit surprised, but he said using my old 10 amp charger periodically would do a far better job at shocking those particles of sulphation off of the plates. Just don't leave those old school chargers on too long. I wish I had talked to him more about this. In fairness to him, this was a few years ago so perhaps now the technology is better and worth the investment to buy one. Clay/Lexi

[Roger Zimmermann]

I leave the negative cable unhooked when car sits.  Negative side so no sparks on connection. 

No matter which post is disconnected. By connecting it, if there is a current draw, there will be a spark.

[TJ Hopland]

The reason you disconnect the grounded side first is if the wrench was to come in contact with anything during the process nothing would happen so all you have to avoid is touching the other terminal during the process.   Once the grounded terminal is disconnected same thing, only thing you can't touch is the other terminal. 

If you disconnect the ungrounded terminal first you have to make sure you don't touch anything that is metal with the tool. On some cars this is a lot easier said than done.