Anyone use the Harbor Freight $4.99 12v Batt charger?

[downeykp]

No, the Harbor Freight charger is only good for maintaining a fully charged battery.

Newbie here and a few questions about when to use these chargers - When leaving the Leaf for a few days? Once a week/month for maintenance? What about if the car has been left in ready mode overnight and the battery drains completely. Will the charger be enough to power the 12V system to turn the car on?

 

[ebill3]

No, the Harbor Freight charger is only good for maintaining a fully charged battery.

Well, my little experiment said differently:

I picked one of those up the other day.
At the start, the LEAF battery was just barely over 12 volts (it is always low).
By bed time, it was up to 13.19. Uncomfortable leaving it overnight, disconnected.
Reconnected this AM at 12.6 volts.
Eight hours later, 13.72 - too high for a float, and the open circuit voltage is >14 volts, so it was probably going higher.

 

[downeykp]

Again, I can only speak from experience after using these for over 10 years. I have not had any issues with these on the six batteries that I hook them up to each summer for 3 months.

No, the Harbor Freight charger is only good for maintaining a fully charged battery.

Well, my little experiment said differently:

I picked one of those up the other day.
At the start, the LEAF battery was just barely over 12 volts (it is always low).
By bed time, it was up to 13.19. Uncomfortable leaving it overnight, disconnected.
Reconnected this AM at 12.6 volts.
Eight hours later, 13.72 - too high for a float, and the open circuit voltage is >14 volts, so it was probably going higher.

 

[JeremyW]

No, the Harbor Freight charger is only good for maintaining a fully charged battery.

Well, my little experiment said differently:

I picked one of those up the other day.
At the start, the LEAF battery was just barely over 12 volts (it is always low).
By bed time, it was up to 13.19. Uncomfortable leaving it overnight, disconnected.
Reconnected this AM at 12.6 volts.
Eight hours later, 13.72 - too high for a float, and the open circuit voltage is >14 volts, so it was probably going higher.

What multimeter are you using to get the voltages? I've had several lower quality meters lie to me.

Also do note lead acids are temperature sensitive, just like any other battery, but specifically when it comes to voltage. They also tend to read high coming right off of charge. You should be checking teh open circuit voltage several hours after it is off the charger. When you got the 13.72v reading, was it around 50 degrees?
Here's a good PDF on lead acid cell voltages vs temperature.

Also to note when you over charge lead acid you're just breaking down water in the electrolyte (making mostly hydrogen gas), it's not a insta-death like it is with lithium. If it's an excessive amount you can boil the batteries dry but if the electrolyte level is maintained (by occasionally adding distilled water) and the over charge rate is not excessive then no harm is done. It is of course not efficient to excessively "gas" though... (guess where the power comes from to break the bonds!)

If you really want to see state of health, get a hydrometer and measure the electrolyte's specific gravity. Battery Hydrometers are $10-$30 on amazon and you don't have to wait for the voltage to settle, or know the temperature of the battery (if you get one with temp compensation). Heck you could even check the SOC under load (not recommended ). Of course with AGM batteries you normally don't have access to the electrolyte...

 

[michapok]

No, the Harbor Freight charger is only good for maintaining a fully charged battery.

What about the CTEK one? Same questions as before - are these only for maintaining battery level over periods of time when the car isn't on, or is there any maintenance/recharging run-down battery advantages to having one?

 

[Ingineer]

No, the Harbor Freight charger is only good for maintaining a fully charged battery.

What about the CTEK one? Same questions as before - are these only for maintaining battery level over periods of time when the car isn't on, or is there any maintenance/recharging run-down battery advantages to having one?

The small CTEK is only 800ma, so it will charge a dead one, but it'll take a long time. (Best to disconnect the Leaf's negative terminal first)

CTEK does have larger models.

If you had the 800ma CTEK, you could probably revive a dead LEAF in with about 30 minutes of charging (negative term disconnected). Once the LEAF is powered up, the DC-DC can put out 130 amps to rapidly recharge the 12v. Leaf the LEAF in ready mode for about 20 minutes, then later you can top it off overnight with the CTEK to get your absorption phase (which the LEAF will not do).

Better, just use another car to jump the LEAF instead of the 30 min CTEK charge. Finish with the overnight CTEK.

-Phil

 

[Stoaty]

I am still unclear about where I should connect the black lead of the CTEK (not to the negative terminal of the battery, that much I know). Can someone give an answer in very simple and specific terms to help me out (i.e., clamp it onto this part shown here in this photo).

 

[Ingineer]

I am still unclear about where I should connect the black lead of the CTEK (not to the negative terminal of the battery, that much I know). Can someone give an answer in very simple and specific terms to help me out (i.e., clamp it onto this part shown here in this photo).

See this post.

-Phil

 

[Nubo]

The problem is that floating a battery doesn't allow it to actually "complete" charging. Anyone familiar with lead-acid batteries knows from experience that most only last a few years with a "float".

You need a proper 3-stage intelligent charger to get the final absorption phase to fully complete the chemical reactions and halt sulfation. This is also why in many automotive systems, you'll see voltages well over 14. It's fine as long as it's not continuous, and for that you need intelligence. Many modern cars do implement a proper 3-stage charge algorithm, but sadly, the LEAF doesn't appear to do this correctly, and it's high idle draw doesn't help!

Phil, I have a smart charger with an AGM cycle, and I've an AGM in the car. Would it be worthwhile for me to give it a periodic complete charge, and how often would be effective? Or is this something that pretty much has to be a daily regimen?

This:

http://www.sears.com/diehard-microp...-charger-and-tester-80/p-02871225000P?prdNo=7

 

[Ingineer]

Hard to say, and I don't have any specific knowledge about how good that charger is.

Anytime I'm under the hood, I do mine. I'd say daily would be silly, but once a month is too long. Maybe once a week, Bi-monthly?

-Phil

 

[atlleaf]

never used one, may buy one today

 

[michapok]

On the 2013 where is the negative terminal of the DC-DC converter? I looked around and my best guess is that it's on the driver's side of the big motor stack thing (I think the top is the PDM) towards the front. Is that right? Anyone have any engine compartment pictures pointing this out?

 

[Ingineer]

It's not critical, any nice bolt on the PDM will be equivalent.

-Phil