Battery tender on Elise - LotusTalk - The Lotus Cars Community
 
LinkBack Thread Tools Display Modes
post #1 of 6 (permalink) Old 12-02-2017, 07:41 PM Thread Starter
Registered User
 
cornbeef's Avatar
 
Join Date: Jul 2007
Location: Reading Pa
Posts: 1,509
Battery tender on Elise

I know these questions have popped up before but Iím not sure if this specifically has come up.

The battery in the Elise died (not dead, just too low to crank it) a few weeks ago. Started it with a mini battery back up and took it for a ride to charge it up. Put it on the tender when I got back (the one that cycles the charge). I think it ran a few times in between but it was just starting it and pulling it out, letting it warm up and then put away on the charger again.

Went to move it today for winter storage and had a low battery again but this time I needed to jump it. Volts were around 10.5. Ran for a while while moving it. Forgot myself and shut it off but it fired back up fine. Once I put it away the battery had dropped to 10.5 again. Itís back on the tender but itís my other one that doesnít cycle the charge.

The battery is less than 3 yrs old (my original battery lasted over 7 years). This is the only time the current one has gone low.

So will the battery tender bring it back up over time or do I need to put it on a proper charger or need a new battery?

"People think I'm an idiot or something, because all I do is cut lawns for a living. People don't say that about you...as far as you know."

LotusPALS http://lotuspals.ning.com/

2006 Elise
2013 Evora S IPS
cornbeef is offline  
Sponsored Links
Advertisement
 
post #2 of 6 (permalink) Old 12-02-2017, 07:56 PM
The Enforcer
 
oldmansan's Avatar
 
Join Date: Mar 2011
Location: Los Alamitos, CA
Posts: 6,347
Quote:
Originally Posted by cornbeef View Post
I know these questions have popped up before but Iím not sure if this specifically has come up.

The battery in the Elise died (not dead, just too low to crank it) a few weeks ago. Started it with a mini battery back up and took it for a ride to charge it up. Put it on the tender when I got back (the one that cycles the charge). I think it ran a few times in between but it was just starting it and pulling it out, letting it warm up and then put away on the charger again.

Went to move it today for winter storage and had a low battery again but this time I needed to jump it. Volts were around 10.5. Ran for a while while moving it. Forgot myself and shut it off but it fired back up fine. Once I put it away the battery had dropped to 10.5 again. Itís back on the tender but itís my other one that doesnít cycle the charge.

The battery is less than 3 yrs old (my original battery lasted over 7 years). This is the only time the current one has gone low.

So will the battery tender bring it back up over time or do I need to put it on a proper charger or need a new battery?
Voltage doesn't mean squat unless there is a load on the battery.

Take the battery to AutoZone/any other car parts store. They'll put in on a machine that can accurately measure if the battery is toast or not.

San

#8 Metric Allen Key, Plastic Carpet Buttons, Never Been on Fire
oldmansan is offline  
post #3 of 6 (permalink) Old 12-03-2017, 06:24 AM
Nein Kinder
 
Glen's Avatar
 
Join Date: Feb 2011
Location: Golden, Colo.
Posts: 1,568
Quote:
Originally Posted by cornbeef View Post
...
Once I put it away the battery had dropped to 10.5 again. It’s back on the tender but it’s my other one that doesn’t cycle the charge.
...
So will the battery tender bring it back up over time or do I need to put it on a proper charger or need a new battery?
The no-load voltage of a lead acid is important. In this case, 10.5V is a good thing. The minimum discharge voltage for lead acid is 1.75V per cell, where 6 cells x 1.75 = 10.5V. So you probably have a battery that can be recharged and perform well afterwards.

Before charging will take place, a charger has to overcome the internal resistance of the battery. The internal resistance of a battery is what causes it to self-discharge over time - it is as if there were a small resistor directly across the terminals of the battery. A float/trickle/tender-type charger typically provides just enough energy to match the self-discharge rate. This is why you can usually leave a no-brain-box 500mA charger on a car battery forever without over-charging it or boiling the electrolyte off ... the charger output accounts for the self-discharge rate and no more. Also note that small-output chargers can take a very long time to fully charge a completely discharged battery. If you are putting a net 2A per hour (that takes more than 2A output!) into a battery that needs 400A to be charged, it will take 2A x 24hrs x 8.33 days to fully charge it.

So the answer to your question is yes, put the battery on a big charger - one that puts out at least a couple of amps (I usually charge at about 10A for a car battery) and charge it to 100% before you try to maintain it with a trickle charger. A big charger should also have a beneficial current profile where it is high for the bulk of charging then tapers off as you approach maximum voltage. This will not only charge your battery reasonably quickly, it will also bring the charged battery capacity very close to 100% before reaching max voltage.

Note that depending on conditions and a particular vehicle’s system, it can take a long time to charge a severely discharged battery while driving. Automotive charging systems are typically dumb - they just keep dumping energy into the battery. So the usual alternator just keeps up with the electrical loads and dumps a little extra into the battery to account for the few seconds it took to crank the starter. If the alternator overcharges your battery, it will boil electrolyte off - you’ll notice residue around the vent caps and have to add distilled water occasionally (my Toyota 4Runner does this).

It is especially important to recognize what’s happening in severe conditions. In Alaska, I would occasionally have a hard-start session where it might take two or three minutes of intermittent cranking to start the engine at -30įF or -40įF. Not only was the battery capacity severely reduced at that temperature, but it’s ability to charge was also severely reduced. So the drive to wherever I was going after the hard start would never restore the energy I lost during starting. The solution was to wait until the battery came up to room temperature in the garage, then put a big charger on it. Failure to do this was a sure way to experience a dead battery a few days later (especially at -30įF).

Two more things ...

- A charged battery has lead on the cathode and lead dioxide on the anode. Discharging the battery chemically converts the surface of the plates into lead sulfate. Over time, some of this material drops off the plate into a well below: the longer the battery sits in a discharged state, the more lead sulfate will drop off. Any material that drops off is not available to be converted back into the original material during charging ... so the overall capacity of the battery is reduced. As a lead acid battery ages and more and more lead sulfate drops off the plates, the well fills up and the lead sulfate will eventually make a circuit across the bottoms of the cells and short them. This marks the end of the battery’s life.

- All batteries have some internal resistance. The higher the internal resistance, the higher the self-discharge rate. The internal resistance of lead acid, nickel-cadmium and nickel metal hydride batteries are all fairly high in comparison to a lithium ion battery. The low internal resistance of a LiFePo4 battery is what lets it sit (at no load) for 8 - 12 months before it needs charging. A healthy lead acid battery might only last 2 months before it needs to be recharged.

Glen

p.s. - Number of times I’ve used a load tester on my lead acid batteries ... zero. If you know the history of the battery, you’ll have all the information you need to make a replacement decision.

2011 Lotus Elise SC

Last edited by Glen; 12-03-2017 at 07:15 AM.
Glen is offline  
 
post #4 of 6 (permalink) Old 12-04-2017, 11:01 AM
Registered User
 
Roundabout's Avatar
 
Join Date: Jun 2013
Location: California
Posts: 897
Quote:
Originally Posted by cornbeef View Post
Went to move it today for winter storage and had a low battery again but this time I needed to jump it. Volts were around 10.5. Ran for a while while moving it. Forgot myself and shut it off but it fired back up fine. Once I put it away the battery had dropped to 10.5 again. Itís back on the tender but itís my other one that doesnít cycle the charge.

The battery is less than 3 yrs old (my original battery lasted over 7 years). This is the only time the current one has gone low.

So will the battery tender bring it back up over time or do I need to put it on a proper charger or need a new battery?
Each time the battery is dropped below approximately 80% of charge, it is damaged. That calculation is NOT done by taking 80% of 12.9v to get 10.32v. A battery that reads less than 12.5v could very well be below 80% charge. The way to think about this is that because volts x amps = power, most of the power is at the upper end of the charge where the voltage is high. As the battery discharges, the voltage drops and so does the power. Based on your 10.5v reading, I would guess that you are around 40% remaining capacity. You didn't mention whether the battery was AGM or wet cell. That is important to knowing the state of charge from the resting voltage.

If you buy the harbor freight battery tester, it will tell you everything you need to know and will actually show you if the battery is recovering, or is damaged. Sometimes you can use a desulfator to bring the battery back, but I've had no luck getting back more than 20% capacity using a inexpensive desulfator.

Most modern cars have temperature compensating smart charging systems built into the PCM. The PCM uses 5 different charging strategies in my 2006 Mazda 3, for instance.

https://www.harborfreight.com/digita...zer-66892.html
Roundabout is offline  
post #5 of 6 (permalink) Old 12-11-2017, 05:39 AM Thread Starter
Registered User
 
cornbeef's Avatar
 
Join Date: Jul 2007
Location: Reading Pa
Posts: 1,509
Thanks for the replies.

I've been busy so haven't had time to investigate more. It's been on the tender since my post and I checked it yesterday and it's still 10-10.2v. I'll pull the battery this week and bring it to work where I can get it tested and put on a charger. If that doesn't work then I'll get a new one.

"People think I'm an idiot or something, because all I do is cut lawns for a living. People don't say that about you...as far as you know."

LotusPALS http://lotuspals.ning.com/

2006 Elise
2013 Evora S IPS
cornbeef is offline  
post #6 of 6 (permalink) Old 12-11-2017, 07:42 AM
Registered User
 
RapidLotus's Avatar
 
Join Date: Sep 2017
Location: Central Florida
Posts: 721
Garage
Just a note, be prepared to relink the Cobra Alarm to the car after pulling the battery for that long. The remote will lose sync with the car's module. Not a lot of work but research it first to save frustration later. There are posts on it. The one thing left out of some posts is that you may need the key in the "on" position for the sync to succeed.

Also, explore the battery options prior to just grabbing another battery. Lot's of good info in the posts on this site about lightweight options.

Good luck.

2005 Chrome Orange Elise, BWR supercharger, TR Motorsport F1 rims and R888s, Nitron NTR40 Single Adjustables with Eibach springs,Sector 111 308BBL brakes, BWR Silent Touch exhaust, CF side scoops, front splitter, and engine cover.
Central Florida
RapidLotus is offline  
Sponsored Links
Advertisement
 
Reply

  LotusTalk - The Lotus Cars Community > Lotus Discussions > Lotus Elise

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the LotusTalk - The Lotus Cars Community forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:
OR

Log-in











Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode



Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome