Expired Hot Deals

[Home Depot] Battery Tender JR, 750 ma, 12 V - $17 @ Home Depot (YMMV)

  • Last Updated:
  • Feb 19th, 2018 4:09 pm
Deal Addict
User avatar
Jan 14, 2013
2016 posts
616 upvotes
Burnaby
paid $35 @ HD a year ago. use it on my altima in storage and to top off another 12v car battery in the garage. works great.

its a battery tender, not really a charger so to speak.

$17 is a killer deal
Deal Fanatic
User avatar
Nov 18, 2008
5955 posts
1001 upvotes
Mont-Royal
so this price is only available in gotham city?
"Every marathon you run, your heart scars and you will die faster. If you think running a marathon is fitness, then you know NOTHING ABOUT HEALTH & FITNESS."
- Training 101
Jr. Member
Oct 15, 2016
165 posts
201 upvotes
craftsman wrote:
Feb 11th, 2018 11:20 pm
However, I disagree with your statement of 'From dead to full takes 12-24 hours.'. The charger will only do 0.75A per hour so for a 45 Ahr battery (which is about average), you will need over 60 hours for a dead to full situation under ideal theoretical conditions (ie. the battery accepts a charge of 0.75 A throughout the 60 hours which doesn't happen in real life as the rate of charge when getting close to full slows down by a lot).
We're both making assumptions that won't always be valid.

Your math is fine, but "dead" isn't zero; it's "clicks instead of cranks" and a fair way from zero. I'm not sure revival from zero is even possible.

On the other end, by "full" I mean "cranks at healthy speed for some minutes" which might be 8Ah (240A * 2 minutes) or even less. Full as in "like new from store" is probably also not possible with this or any other device.
Deal Addict
User avatar
Dec 20, 2004
1467 posts
719 upvotes
Montreal, QC
redbag wrote:
Feb 12th, 2018 7:25 am
We're both making assumptions that won't always be valid.

Your math is fine, but "dead" isn't zero; it's "clicks instead of cranks" and a fair way from zero. I'm not sure revival from zero is even possible.

On the other end, by "full" I mean "cranks at healthy speed for some minutes" which might be 8Ah (240A * 2 minutes) or even less. Full as in "like new from store" is probably also not possible with this or any other device.
From Zero, most "smart" chargers will not even start a charge. I know CTEK states "Most models can handle batteries as low as 1.5V. The US 800 charges from 6V, while the XC 800 charges from 3V". So depending on the model, if the voltage drops below this threshhold, the charger either displays a fault, or doesn't even start. I have a small Black&decker one, and it needs a minimum of 6V to start. Often in these cases, I use my Mastercraft bulk charger, set it to 2A, and leave it for an hour first. Then I will switch it to 12A for about 2 minutes.. Then I will pull that charger and use the CTEK. If it still has not recovered to minimum for the CTEK to work, then the battery is dead.. If it starts, I'll switch the CTEK into RECONDITION MODE. Obviously regular SLA batteries are not designed to go to zero, like deep cycle ones, so success is not guaranteed.

For the battery tender jr, I don't know what that threshold is. However since it is a low current model, I did have one occasion (first time I used it on my father-in-laws car) where the battery was below 10V. The battery Tender Jr had no issues starting, but after about 24hrs, it went into a fault mode. I suspect that it may have a timer, and if it doesn't get where it expect to be within a certain time, it will trigger the fault. I unplugged/re plugged it, and it started the cycle again, and this time it had no issues topping it up and going into trickle mode where it stayed for a few weeks.

What do you mean by "Full as in "like new from store" is probably also not possible with this or any other device". "like new from store", you are again making an assumption, on how long it's been on shelf, etc.. They do slowly self discharge. I've seen one store, not far from me, where they have all the batteries connected in parallel to a small float charger to keep them topped up. It was pretty interesting to see a whole rack of wired batteries.
Sr. Member
Nov 22, 2012
948 posts
764 upvotes
MARKHAM
The Eliminator @CT 2A charger goes on sale at about $20 ~ $25 periodically. Just an FYI.

It is a nice deal, too.
From RFD:
Self-propelled gas mower for $120 - Sears;
2-stage snowblower for $399 - Lowes;
Koodo $40/6GB PM migration plan;
Public Mobile $8 50/50 limited talk/text plan;
3GB LTE data monthly plan for $15 - Fido.
More to come for sure...
Sr. Member
Nov 22, 2012
948 posts
764 upvotes
MARKHAM
I usually charge my cars twice a year - When winter begin and end. So far it worked great.
From RFD:
Self-propelled gas mower for $120 - Sears;
2-stage snowblower for $399 - Lowes;
Koodo $40/6GB PM migration plan;
Public Mobile $8 50/50 limited talk/text plan;
3GB LTE data monthly plan for $15 - Fido.
More to come for sure...
[OP]
Deal Guru
User avatar
Jan 6, 2005
10179 posts
1933 upvotes
bennyxyz wrote:
Feb 12th, 2018 8:57 am
The Eliminator @CT 2A charger goes on sale at about $20 ~ $25 periodically. Just an FYI.

It is a nice deal, too.
This is the one I use currently on my MC, works great. Even from a dead MC battery. You're right. I think I paid $25, regular price of $47
The first rule of RFD is, you do not talk about RFD.

The second rule of RFD is, you DO NOT talk about RFD.
Deal Addict
Jul 14, 2002
1636 posts
589 upvotes
Not to deflate the hot deal, but it looks like just a power adapter that provides 12V 750mA constant power.
For the true RFD's, I wonder if you can just frankenstein an unused power adapter with the same power output 12V 0.5-1A to do the job.
Sr. Member
Nov 22, 2012
948 posts
764 upvotes
MARKHAM
dantey wrote:
Feb 12th, 2018 12:53 pm
Not to deflate the hot deal, but it looks like just a power adapter that provides 12V 750mA constant power.
For the true RFD's, I wonder if you can just frankenstein an unused power adapter with the same power output 12V 0.5-1A to do the job.
I might try this - Let me pull out the box of adapters...
From RFD:
Self-propelled gas mower for $120 - Sears;
2-stage snowblower for $399 - Lowes;
Koodo $40/6GB PM migration plan;
Public Mobile $8 50/50 limited talk/text plan;
3GB LTE data monthly plan for $15 - Fido.
More to come for sure...
Deal Fanatic
Jan 27, 2006
8860 posts
3068 upvotes
Vancouver, BC
redbag wrote:
Feb 12th, 2018 7:25 am
We're both making assumptions that won't always be valid.

Your math is fine, but "dead" isn't zero; it's "clicks instead of cranks" and a fair way from zero. I'm not sure revival from zero is even possible.

On the other end, by "full" I mean "cranks at healthy speed for some minutes" which might be 8Ah (240A * 2 minutes) or even less. Full as in "like new from store" is probably also not possible with this or any other device.
'It clicks instead of cranks' isn't zero for the battery... it's very low - well below 50% state of charge (probably closer a lot closer to zero than you think - > ie 20%) as it doesn't take much to click that starter relay. Revival from zero is possible after as long as it's done slowly and the battery is in good physical condition.

As far as the definition of full is concerned, I'm just going by what you posted... BTW. 1/4 of a battery's capacity is no-one's definition of FULL.
Deal Fanatic
Jan 27, 2006
8860 posts
3068 upvotes
Vancouver, BC
dantey wrote:
Feb 12th, 2018 12:53 pm
Not to deflate the hot deal, but it looks like just a power adapter that provides 12V 750mA constant power.
For the true RFD's, I wonder if you can just frankenstein an unused power adapter with the same power output 12V 0.5-1A to do the job.
Simple float chargers are basically A/C adapters at 12V DC but to charge or maintain a car battery without causing long term damage is the problem. Car batteries like to be charged in the range of 14V to 14.4V - anything lower won't do much except for maintaining a charge and anything higher, you risk causing the battery to off gas reducing the levels of the electrolyte which could permanently damage the battery if you don't remember to top off the battery.

And on the A/C adapter side, most of them aren't regulated very well so you could get over or under voltage situations very easily.
Deal Fanatic
User avatar
Nov 21, 2002
7654 posts
1135 upvotes
Winnipeg
Emporium wrote:
Feb 12th, 2018 8:52 am
From Zero, most "smart" chargers will not even start a charge. I know CTEK states "Most models can handle batteries as low as 1.5V. The US 800 charges from 6V, while the XC 800 charges from 3V". So depending on the model, if the voltage drops below this threshhold, the charger either displays a fault, or doesn't even start. I have a small Black&decker one, and it needs a minimum of 6V to start. Often in these cases, I use my Mastercraft bulk charger, set it to 2A, and leave it for an hour first. Then I will switch it to 12A for about 2 minutes.. Then I will pull that charger and use the CTEK. If it still has not recovered to minimum for the CTEK to work, then the battery is dead.. If it starts, I'll switch the CTEK into RECONDITION MODE. Obviously regular SLA batteries are not designed to go to zero, like deep cycle ones, so success is not guaranteed.

For the battery tender jr, I don't know what that threshold is. However since it is a low current model, I did have one occasion (first time I used it on my father-in-laws car) where the battery was below 10V. The battery Tender Jr had no issues starting, but after about 24hrs, it went into a fault mode. I suspect that it may have a timer, and if it doesn't get where it expect to be within a certain time, it will trigger the fault. I unplugged/re plugged it, and it started the cycle again, and this time it had no issues topping it up and going into trickle mode where it stayed for a few weeks.

What do you mean by "Full as in "like new from store" is probably also not possible with this or any other device". "like new from store", you are again making an assumption, on how long it's been on shelf, etc.. They do slowly self discharge. I've seen one store, not far from me, where they have all the batteries connected in parallel to a small float charger to keep them topped up. It was pretty interesting to see a whole rack of wired batteries.
its 3v threshold 80hrs. But that may vary on your deltran. I think my old one is 4v. It won't pound a battery continuously longer than a few days before it shuts off. Better to have that feature than not.

great price if you can get it. Most cheap chargers todays have such awful cheap wiring and connectors. The old deltran is top notch build.

Top