Trickle charging for 4 to 6 months

[GearheadTool]

Can we elaborate n "Battery tender" vs "smart charger?"

All I can think of reading this thread is "CTEK." It says you can leave it plugged in for months.. and I believe it! It senses when the battery doesn't need charge, and would be in some kind of idle/standby 90% of the time, right?

(Said right on the brochure: "Can be left plugged in for months." Probably because CTEK knows when to not deliver current.)

I would also imagine this to be a more common scenario, and if the battery is in good health and not otherwise hooked up to the car's electrical (or even if it is?) then should be OK.. because, how can the car's electrical suffer damage from only occasional, very low-current charging on a supremely topped-up but not overcharged battery>

 

[Danh]

With any kind of unattended charger there will always be something to worry about. Just disconnect the battery instead.

In your climate there's no freeze worry and the battery should maintain its charge for the duration of your absence. I take the battery out of my MX5 and store it in the basement for 6 months in winter. It doesn't need recharging in the spring.

 

[Virtuoso]

Originally Posted By: rjundi
Undo the negative terminal on the battery and your battery will be fine when you come back.


Cheapest and most fool proof method.

 

[OldSparks]

I leave my 3 stage 'smart' charger connected to my motorcycle battery all winter long, with minimal worries. When it hits 'float' mode, there should be no outgassing.

Ok, I still worry, but I also worry about using conventional oil instead of synthetic for regular OCIs - that's just OOCD - Oil obsessive-compulsive disorder

Battery powered emergency lights are left on float charge continuously.

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

 

[Smokescreen]

NOCO Genius or CTEK are designed to do what you (the OP) describe.

 

[Clevy]

Originally Posted By: GearheadTool
Can we elaborate n "Battery tender" vs "smart charger?"

All I can think of reading this thread is "CTEK." It says you can leave it plugged in for months.. and I believe it! It senses when the battery doesn't need charge, and would be in some kind of idle/standby 90% of the time, right?

(Said right on the brochure: "Can be left plugged in for months." Probably because CTEK knows when to not deliver current.)

I would also imagine this to be a more common scenario, and if the battery is in good health and not otherwise hooked up to the car's electrical (or even if it is?) then should be OK.. because, how can the car's electrical suffer damage from only occasional, very low-current charging on a supremely topped-up but not overcharged battery>


Battery tender is a brand name for what is considered a "smart charger".

 

[Smokescreen]

NOCO and CTEK are one step smarter than Battery Tender. CTEK has the backing and endorsement of BMW, Lamborghini, Audi, Alpha Romeo, Peugot, Maserati and many other names. These smarter chargers also have AGM mode and other features and the casing is more impervious to moisture and dust.

 

[JHZR2]

Agm mode just uses a higher charge voltage.

I'm not convinced that CTEKs are all temperature compensated. Many name brand units of smart chargers are not temp compensated.

While generally ok, for long term abandonment, no way id go without a temperature compensated.

Battery tender plus model is temp compensated at the electronics. The battery minder units I mentioned are temp compensated wherever you want the measurement. The pulse desulfation is also good.

Plus it uses standard SAE plugs, unlike ctek.

 

[Fleetmon]

I'm glad my Vette didn't read this post...I only treated it with a disconnected negative cable every time I would leave it for months and never had an issue....as a matter of fact, it was a 1998 with 63k miles and on it's second battery....I guess I SHOULD have used a battery tender huh?

The first battery only lasted five years but I guess that's because I rarely disconnected the cable....when I replaced the battery in 2003, I started disconnecting the cable and NEVER charged it once connected back.

The second battery lived through being stored in a Texas garage where the summer temps could easily exceed 115'F and then garaged in Pa where it could see regular week-ling lows af 5'f-10'F. I worried more about the tires dry-rotting than a dead battery.

 

[Quattro Pete]

Originally Posted By: Danh
Just disconnect the battery instead.

On a modern BMW, this is more complicated than one would think. Once the battery is disconnected, a lot of the electronics in the car go bonkers and it typically requires a visit to the BMW dealer to have the battery synced up with the car and all systems reset when a battery is connected again.

Not sure if OP's car is like that or not.

 

[Fleetmon]

On BMW's, you are supposed to let the electronics go to sleep first (about 20 minutes or so....just watch the shifter light or trunk light)....I've disconnected mine many times without ill effects but I always let it shut down first also. This is on a 1999 528i (disconnected many, many times) and a 2011 X535d (a few times). Also, when you disconnect one of these, disconnect it promptly....don't wiggle the cable end back and forth (making/breaking contact, etc)pull it straight up and off...same going back.

However, Quattro Pete is exactly correct....if you don't wait then you will eventually have troubles.

 

[JHZR2]

Originally Posted By: Fleetmon
I'm glad my Vette didn't read this post...I only treated it with a disconnected negative cable every time I would leave it for months and never had an issue....as a matter of fact, it was a 1998 with 63k miles and on it's second battery....I guess I SHOULD have used a battery tender huh?

The first battery only lasted five years but I guess that's because I rarely disconnected the cable....when I replaced the battery in 2003, I started disconnecting the cable and NEVER charged it once connected back.

The second battery lived through being stored in a Texas garage where the summer temps could easily exceed 115'F and then garaged in Pa where it could see regular week-ling lows af 5'f-10'F. I worried more about the tires dry-rotting than a dead battery.


So are you a battery engineer or are you going to claim your one data point as being statistically significant?

Have you validated impedance growth or energy loss after these "non issues"?

You speak like its the rule, when practical experience states otherwise, backed up by a basis in the fundamental chemistry.

 

[Fleetmon]

nah....engineers take too long to figure simple things out so I conducted my own scientific tests....I hooked up the battery and started the engine.....merely saying what worked for me. I don't need a battery tender, at least not in my case, and if gawd forbid, one of my batteries goes dead, then I'll just hook up a charger and if that fails then I reckon I'll have to break down and buy one. Either way, I try really hard to NOT worry about something as trivial as this.

I only stated what works for ME....if someone doesn't like it or has a better way then by all means DO IT....you certainly won't find me getting in the way.

I guess it's not what I said but how I said it ,huh pal? No offense meant folks.

FWIW, we have a total of eight batteries in my fleet with none younger than the '11 X5...and one as old as our '96 Dakota.....the original.

 

[oldhp]

I hook up my battery tender every time I put the Charger away.
Always starts better at full charge and alt doesn't have to work as hard to recharge the bat. Sometimes sits, like now for 3-4 mos at a time.

 

[J]

Originally Posted By: Quattro Pete, I remember you

On a modern BMW, this is more complicated than one would think. Once the battery is disconnected, a lot of the electronics in the car go bonkers and it typically requires a visit to the BMW dealer to have the battery synced up with the car and all systems reset when a battery is connected again.

Not sure if OP's car is like that or not.


Yes, I like the idea of charging with a CTEK (already on order) than unhooking the battery. Modern cars are only trouble free when they're driven daily.

I'll put the CTEK in my metal trash can so that if a short develops in the battery, the batery charger can burn itself up without causing trouble.

Even if CTEK is not temperature compensated, that's okay. I live in Los Angeles. I think that my profile says Berkeley still.

I figure that the amount of water that will be converted to hydrogen and oxygen is very small, and the garage door is not air tight.

 

[PandaBear]

Originally Posted By: Quattro Pete
Originally Posted By: Danh
Just disconnect the battery instead.

On a modern BMW, this is more complicated than one would think. Once the battery is disconnected, a lot of the electronics in the car go bonkers and it typically requires a visit to the BMW dealer to have the battery synced up with the car and all systems reset when a battery is connected again.

Not sure if OP's car is like that or not.


As a software/electrical engineer, I have to say such design or tolerating such design is ridiculous.

It almost sounds like they just finished 90% of the work and leave bugs in the system because "if the customers follow the procedure they will never need to worry about this".

 

[JHZR2]

Originally Posted By: Fleetmon
I guess it's not what I said but how I said it ,huh pal? No offense meant folks.


No offense taken. Just want to make sure that people understand that there is a real chemical basis to keeping the battery at full state of charge, and just because a battery starts an engine doesnt mean that it isnt irreversibly damaged...

 

[JHZR2]

Originally Posted By: J
Originally Posted By: Quattro Pete, I remember you

On a modern BMW, this is more complicated than one would think. Once the battery is disconnected, a lot of the electronics in the car go bonkers and it typically requires a visit to the BMW dealer to have the battery synced up with the car and all systems reset when a battery is connected again.

Not sure if OP's car is like that or not.


Yes, I like the idea of charging with a CTEK (already on order) than unhooking the battery. Modern cars are only trouble free when they're driven daily.

I'll put the CTEK in my metal trash can so that if a short develops in the battery, the batery charger can burn itself up without causing trouble.

Even if CTEK is not temperature compensated, that's okay. I live in Los Angeles. I think that my profile says Berkeley still.

I figure that the amount of water that will be converted to hydrogen and oxygen is very small, and the garage door is not air tight.


On a properly functioning smart charger, the gassing rate will be so slow that it will recombine within the battery. Most chargers do constant current to a specific voltage, and then constant voltage to a very low current draw, at which point it drops the voltage to get further away from the voltage at which gassing (electrolysis) occurs.

If a battery shorts out and/or dries out, the charger will push current into a battery to the point of thermal runaway, when the battery starts on fire. Low current chargers (2A types) cant get enough energy in to start that fire practically speaking. Id not be concerned with the charger melting down.

LA is hot, right? The float voltage DROPS as temperature goes up. Most smart chargers that are not temperature compensated set the voltage for 70-77 degrees. If it is going to get warmer than that, you want compensation. SImilarly if it is colder, the float voltage must go up else the battery will be undercharged.

Good luck.

 

[JimPghPA]

Originally Posted By: PandaBear
Originally Posted By: Quattro Pete
Originally Posted By: Danh
Just disconnect the battery instead.

On a modern BMW, this is more complicated than one would think. Once the battery is disconnected, a lot of the electronics in the car go bonkers and it typically requires a visit to the BMW dealer to have the battery synced up with the car and all systems reset when a battery is connected again.

Not sure if OP's car is like that or not.


As a software/electrical engineer, I have to say such design or tolerating such design is ridiculous.

It almost sounds like they just finished 90% of the work and leave bugs in the system because "if the customers follow the procedure they will never need to worry about this".


The trouble is that in many companies the Electrical Engineers are not the ones with the job title that gets to make the decisions about how money will be spent to engineer electronic things.

Bureaucratic decisions like over-clocking a microprocessor instead of paying for one designed and tested to be ran at the higher frequency, and then selling the item with specifications that can only achieved with the overclocked speed, come to mind. And then they act surprised when it fails in the field, when all along the EE said don't do it.

 

[andyd]

Heh Heh another vote for disconnecting the neg strap. I'm not surprised modern BMWs have some over engineered ritual.
Battery DC is the cleanest voltage there is. As long as care is taken..

I put my '94 Ranger in a tent and proceeded to slowly revive it. $ months later, I put the shiny neg clamp back on and the Rat started right up.

I was correct the dollar sign. Please consider it an upper case 4.