How to - Modify a Harbor Freight float charger for correct float voltage

[Save Old Iron 1,568]

This topic came up in a recent discussion on proper battery maintenance and storage techniques.

I usually keep 3 or 4 batteries on float charge thru the winter and have performed a simple modification on $5 Harbor Freight float charger to allow it to peform as it should.

I purchased several chargers two or three years back and found each of the chargers put out a different voltage. The range varied from 12.8 to 13.4 volts.

A float voltage of 12.8 is too low and 13.4 is just a tad too high, If you are using this item to float charge your batteries, please take the time to measure the DC voltage between the red and black charger clips WITHOUT THE CHARGER CONNECTED TO A BATTERY.  Any voltage significantly outside a 13.0 to 13.3 range could be slowly compromising your battery.

 

I will post pics on a simple modification which will allow setting of a precise 13.2 volt output needed to properly maintain a wet lead acid battery thru winter storage.

 

Stay tuned as my camera memory card appears to have issues of its own.

Edited December 11, 2015 by Save Old Iron

[Ed Kennell 39,869]

[Coadster32 793]

Will we watching this thread.

[JC 1965 1,532]

Thanks Chuck, can't wait to get more info. on this.      

[Ed Kennell 39,869]

            Sure hope that bushy tailed rodent didn't go into hibernation.

[JackC 617]

How about some tips / advice on using one maintainer to maintain multiple batteries?  

[KC9KAS 4,742]

I have used the HF chargers just like the one shown on my motorcycles for 3 years and never had a problem....Now I am worried!

Better get out the FLUKE!

[squonk 41,988]

In the thread SOI mentioned, I said I used a HF maintainer on my Power King. The first time I started it I thought the engine was going to fly out from under the hood it spun so fast! 

[Save Old Iron 1,568]

13 hours ago, KC9KAS said:

I have used the HF chargers just like the one shown on my motorcycles for 3 years and never had a problem....Now I am worried!

Better get out the FLUKE!

There really is nothing to worry over, that is not the purpose of this thread. I would encourage you to measure the voltage from the float charger to confirm the voltage to the battery is around the 13.2 to 13.4 DC volt range.

 

INSPECT what you EXPECT.

Edited December 12, 2015 by Save Old Iron

[Save Old Iron 1,568]

17 hours ago, JackC said:

How about some tips / advice on using one maintainer to maintain multiple batteries?  

Can do Jack!

 

The first step is to explain the capacity and intended use of a "float" charger or maintainer.

 

Due to a very low current rating on all the components within the product,

 

FLOAT / MAINTAINER CHARGERS ARE NOT INTENDED TO CHARGE A BATTERY.

 

Attempting to charge a depleted or damaged battery with a floater may damage the floater.

 

The output current from a float / maintainer is a fraction of an amp - usually 1/2 amp maximum.

Charging several batteries simultaneously off a single float/ maintainer is not advisable as if any one battery in your group is defective or compromised, the whole group will not charge. The HF floater has a simple over-current circuit which shuts the floater off if more than 1/2 amp is pushed thru the battery.

 

There may be floater / maintainer devices out there with several charging ports within one case. I'm thinking these are devices with multiple independent floater circuits all mounted in the same case.

Edited December 12, 2015 by Save Old Iron

[Save Old Iron 1,568]

20 hours ago, ekennell said:

            Sure hope that bushy tailed rodent didn't go into hibernation.

still waiting on the arrival of a new compatible memory card ... won't be much longer

 

maybe a little entertainment from nature's A students as you wait ?

 

https://www.youtube.com/watch?v=CRJ-Sqm1cK4

Edited December 12, 2015 by Save Old Iron

[JC 1965 1,532]

Did you teach those squirrels to dance like that Chuck ?      

[JackC 617]

8 hours ago, Save Old Iron said:

Can do Jack!

 

The first step is to explain the capacity and intended use of a "float" charger or maintainer.

 

Due to a very low current rating on all the components within the product,

 

FLOAT / MAINTAINER CHARGERS ARE NOT INTENDED TO CHARGE A BATTERY.

 

Attempting to charge a depleted or damaged battery with a floater may damage the floater.

 

The output current from a float / maintainer is a fraction of an amp - usually 1/2 amp maximum.

Charging several batteries simultaneously off a single float/ maintainer is not advisable as if any one battery in your group is defective or compromised, the whole group will not charge. The HF floater has a simple over-current circuit which shuts the floater off if more than 1/2 amp is pushed thru the battery.

 

There may be floater / maintainer devices out there with several charging ports within one case. I'm thinking these are devices with multiple independent floater circuits all mounted in the same case.

 

The multiple port maintainers are pricey.  Walmart lists a "Battery Tender 4-Bank Battery Management System" for $142.75. Four individual maintainers and a power strip to plug them into would be much less.

 

Thanks for the info.

Edited December 12, 2015 by JackC

[Coadster32 793]

That dance was better than listening to musac. Too funny.

[DougC 2,642]

I have a hard time leaving stuff made in China plugged in when I'm not in the garage. Had a cheap wireless security camera systems transformer burn up and scorch and burn the outlet exterior. Wonder the place didn't burn to the ground. Have no trained dancing squirrels to warn me if something goes wrong...... 

[Save Old Iron 1,568]

7 hours ago, DougC said:

 Wonder the place didn't burn to the ground.

 

 

But it didn't and that is significant. Thermo-formed plastics (the wall war case) have a high degree of resistance to catching on fire and are can be made to self-extinquish..

 

I hear your concern, but look around the house at what stays plugged in and is manufactured in China  - smart phones, computers, TV, stereo,refrigerator, alarm clock, clock on your stove, your wife's electric can opener. Statistically speaking (and looking at it thru the eyes of your insurance company) its a low risk. Your house is more likely to burn down from an electrician leaving a breaker or wall socket with an improperly tightened connection, an older Ford ignition switch in your car, sparks from your Lincoln welder or using a wood stove to heat your home - all those made in the USA.

 

Anyhooo, the HF cheapo charger does have a protection circuit in the device which will trigger and turn the floater off if you attempt to abuse it. Trying to connect it to a severely undercharged battery or shorting the output leads of the floater together will shut down the current flow out of the floater. I cover that aspect of the electronics and show the circuit in action when I get my camera back into operation.

 

As a public service and my nice guy good deed for the week, I will leave you with this video from a friend of mine that frequents another electronics forum. This is a true danger and pay close attention to the last few seconds of the video.

 

 

 

 

Stay tuned

Edited December 13, 2015 by Save Old Iron

[DougC 2,642]

So the cheap China stuff won't catch on fire and burn you to death while you are asleep, Just electrocute you when you least expect it????

[Save Old Iron 1,568]

I guess the only advice left to give someone who lives in constant fear of dying in their sleep in a fire or being electrocuted by cheap electronics is don't buy cheap electronics and unplug everything you own before settling in for a long winter's nap. Unplug the made in China alarm clock and keep a reliable rooster close to your bedside to wake you in the morning. And PLEASE, anyone reading this with similar phobias, do not attempt to perform this update to any chargers you may have. We don't want to loose anyone to the first ever confirmed HF float charger garagehome fire.

 

Me?  I sleep fine but I do have to make an appointment with my local Chevy dealer to take my (made in the USA) Chevy Impala and Chevy Malibu in for ignition switch and electronic steering recalls that have been confirmed to be involved with 125 deaths and 275 injuries in the last few years. And then there is the Dewalt drywall driver that blew up in my hand the other day. Pink Chinese USB chargers with no know deaths attributed to them don't even make my list..

 

http://fortune.com/2015/08/24/feinberg-gm-faulty-ignition-switch/

 

A helpful holiday inquiry. Do all your safety switches work on your tractors?

Edited December 14, 2015 by Save Old Iron

[cleat 6,876]

Actually, Made in the USA Impala is only partly true. I was working on my Mothers Impala last spring and when I popped the center caps off of the aluminum wheels they were very plainly marked "Made in China".

 

Go figure.

 

Cleat

[C-101plowerpower 1,606]

i think most is assembled in USA

[Coadster32 793]

Don't forget about the $.045 wall outlets sold at Home Depot that we are plugging everything into. No need for something to be plugged in to catch fire. (How far do you wanna go?)

 

Looking forward to your pics and instructions Chuck. Patience with your time is always well rewarded.

[TDF5G 2,069]

I've been trying to check manufacture labels on items that I come in contact with for the past 3-4 months or so.  It seems many things are made in China or other countries.  

 

I probably shouldn't advertise this but I handle GM parts everyday and I've noticed that most are made in Mexico & Canada. I have seen some made in China, Brazil, Germany & Taiwan.  I saw one the other day made in Slovenia, wherever that is!      Some say made in Canada with imported parts.   A few still made in USA.

 

I'm not sure where all GM vehicles are assembled.  I think mostly in USA.  Fairfax Assembly Plant here in KC KS builds Chevrolet Malibu and Buick LaCrosse.

 

Someone the other day said he heard a research study that claimed the foreign owned company vehicles were assembled with more made in USA parts than domestic owned car company vehicles.  Go figure.

 

What are some well known products that are made in USA?  Besides cheeseburgers?  

Edited December 15, 2015 by TDF5G

[Coadster32 793]

I use the "Battery Tender" brand. It won't give me a reading for volts unless I have it hooked up. I checked the volts on my car battery at 12.4 volts, and hooked up the tender. It then read 12.6 volts. Must be doing something. I have used it for years between 5 different batteries, and haven't had a problem yet. Would like to check it out the right way though. Maybe I'll get a cheappy HF one like in this thread and modify it correctly. 

[JC 1965 1,532]

I've got three of the Harbor Freight brands. I checked all of them and they all read over 14 volts. Anxious for Chuck to post  the modification fix for these. Has anyone else had readings in the 14 volt range on the HF battery maintainers ?     

[Save Old Iron 1,568]

I'll be taking pics tonight and posting in the next day or two

 

14.0 is too high for a maintainer as the electrolyte starts to release oxygen and hydrogen above 13.6 to 13.8 volts.

 

14.0 is not bad for a pop top battery where you can top off the cells with water but a maintenance free or AGM battery will permanently loose electrolyte and capacity.