You need to get an accurate hydrometer. Without one you are blind. Might as well trying to determine if a person has high blood pressure by having them stick out their tongue.Disconnect negative cables from 12 volt sideFill all cells with distilled waterIf you have a PARALLEL set of batteries, unparallel them:Wait overnightMeasure voltage across positive and negative terminals of EACH battery separately. It does not matter if they are 6 or 12 volt. MEASURE and write it down!If a pair of 12 volt batteries differ by more than .3 volts or one 6 volt differs by more than .15 volt note which battery has what. Low batteries need more careful inspectionCharge each battery at 10 amps until every single cell in that battery is bubbling. Stop the charge then go on to the next batteryIt's better to charge 6 volt batteries independently rather than in a series pairWith all batteries fully charged let the battery temperature return to normalHydrometer test each cell independentlyWrite each cell down. A diagram figure showing cells is the easiest way to remember If you draw a sample and the electrolyte is SMOKY cloudy end of test for that battery. It's doomed. Same for a reddish tintDo all the cellsI do hope you are wearing safety glasses and latex kitchen gloves right? You do have a ready made up jug of baking soda mixed with water, right? The hydrometer bobber MUST float freely within the glass tube. Tilt the hydrometer upright to let the bobber run up and down freely Did you remember your reading glasses and fit them under the safety glasses?Every cell on your diagram should have a number next to it.If any two cells in one battery have a .15, that's point one five difference between the highest and lowest cell, it's due to be equalizedCull that battery from the bunch and MARK the low cell with a marking pen or splotch of paint or whateverIf you have a pair of Golf Car batteries that each have a .15 spread in density you may consider connecting them in series just like you have them in the coach to make 12 volts.Take your time! Make sure they are connected in series!A pair of golf car batteries can be charged at 11 amps. This is not easy to achieve nor to sustain but do the best you canAmperage will drop and voltage will rise as the equalization process continuesWhen a series pair of batteries reaches 16.0 volts stop the charging. Go to the next battery or batteries and let the first ones cool off.This is why record keeping is so importantRepeat the exercise on the 2nd set of batteries. If you are doing a single 6 volt battery apply 11 amps until 8 volts is reachedRedo the hydrometer check.If any cell did not return to 1.275 or 1.280 you have a troublemaker on your handsIf the battery is fairly new and had been abused, repeat the 11 amps equalization chargeIf the battery is more than 3 years old it's dying.How soon it's going to die is anyone's guess, but batteries that do not recover fully are not up to doing full task workThe harder a battery is to equalize and the faster the cells become unequal in gravity the closer it gets to the recycling center. You can count on it.Harbor Freight sells an inexpensive 500 amp adjustable load test machine. I love it as doing a load test alongside a hydrometer inspection and equalization is a great dose of truth serum.Get proficient doing this and charge fellow RV'ers to do their batteries. No one else does this right so you'll be the exclusive agent in your area.I hope to get a 3 amp VARIAC soon. They cost fifty some odd dollars and with a VARIAC I can play a charger like a pipe organ. Maintain 10-11 amps with precision.My fingers are aching. I hope this becomes a sticky. I would get censored if I wrote what I think of arthritis.

MEXICOWANDERER wrote:I do hope you are wearing safety glasses and latex kitchen gloves right? You are wearing a plastic apron or a garbage bag with holes for the arms and neck, right? The little spits of acid that you can't even see make little holes in your shirt (damhik).You do have a ready made up jug of baking soda mixed with water, right? Thanks. I would add the step above.

Wool is impervious to battery acid. I'm hoping folks will add stuff. Thanks!

How accurate are the $5 and $10 float type hydrometers?

Thanks Mex, lots of good info there.I don't know how doomed is doomed though. I saw smokey and then I didn't see smokey. I know it is down there lurking, but if it doesn't come up every time, you can ignore the first time you saw it, right? :)My "previously enjoyed" T-1275s have been worked up a bit at home with alternating Equalize and Recondition (pulse charging that does not raise voltage)sessions using the VEC1093DBD charger.They were mostly near 1.255 all cells when "found," but after four days of nursing at home, they are mostly between 1.260- 1.265 with one cell on one battery at 12.75. No smokey.I have not done a new load-test, but have them back in service at our camp site. I feel confident in these batts. They do everything demanded in the way of high amp draws and recharge well.I don't know how many deep cycles we do a year, but I am thinking these two-year old beat-up batts could last us the rest of our RVing time (we just turned 70) based on the number of cycles per year we manage. (Not counting the shallow cycles under solar that we do in the summer---are they even "real cycles" against the cycle-count limit?)There hasn't been much discussion of T-1275s. New they cost near $275 each and weigh 82lbs. So a pair is 300AH and 164lbs for $550Four 6s (232AH) at $175 each at 67lbs is $700 for 268lbs and 464AH.Three T-1275s is 450AH for $825 and 246lbs. So three T-1275s is sort of like four 6s except they cost more. They do high inverter loads better in that they have less voltage drop towards the dreaded 11v inverter alarm. It makes an interesting choice between three T-1275s and four 6s until you can get those 6s for half price at Sam's or Costco.

Thanks Mexi saved that info in text file

MEXICOWANDERER

Explorer

Aug 30, 2013

Equalizing Formula (We'll Use A Pair Of Golf Car Batteries)

You need to get an accurate hydrometer. Without one you are blind. Might as well trying to determine if a person has high blood pressure by having them stick out their tongue.

Disconnect negative cables from 12 volt side
Fill all cells with distilled water
If you have a PARALLEL set of batteries, unparallel them:Wait overnight
Measure voltage across positive and negative terminals of EACH battery separately. It does not matter if they are 6 or 12 volt. MEASURE and write it down!
If a pair of 12 volt batteries differ by more than .3 volts or one 6 volt differs by more than .15 volt note which battery has what. Low batteries need more careful inspection
Charge each battery at 10 amps until every single cell in that battery is bubbling. Stop the charge then go on to the next battery
It's better to charge 6 volt batteries independently rather than in a series pair
With all batteries fully charged let the battery temperature return to normal
Hydrometer test each cell independently
Write each cell down. A diagram figure showing cells is the easiest way to remember
If you draw a sample and the electrolyte is SMOKY cloudy end of test for that battery. It's doomed. Same for a reddish tint
Do all the cells
I do hope you are wearing safety glasses and latex kitchen gloves right? You do have a ready made up jug of baking soda mixed with water, right?
The hydrometer bobber MUST float freely within the glass tube. Tilt the hydrometer upright to let the bobber run up and down freely
Did you remember your reading glasses and fit them under the safety glasses?
Every cell on your diagram should have a number next to it.
If any two cells in one battery have a .15, that's point one five difference between the highest and lowest cell, it's due to be equalized
Cull that battery from the bunch and MARK the low cell with a marking pen or splotch of paint or whatever
If you have a pair of Golf Car batteries that each have a .15 spread in density you may consider connecting them in series just like you have them in the coach to make 12 volts.
Take your time! Make sure they are connected in series!
A pair of golf car batteries can be charged at 11 amps. This is not easy to achieve nor to sustain but do the best you can
Amperage will drop and voltage will rise as the equalization process continues
When a series pair of batteries reaches 16.0 volts stop the charging. Go to the next battery or batteries and let the first ones cool off.
This is why record keeping is so important
Repeat the exercise on the 2nd set of batteries.
If you are doing a single 6 volt battery apply 11 amps until 8 volts is reached
Redo the hydrometer check.
If any cell did not return to 1.275 or 1.280 you have a troublemaker on your hands
If the battery is fairly new and had been abused, repeat the 11 amps equalization charge
If the battery is more than 3 years old it's dying.
How soon it's going to die is anyone's guess, but batteries that do not recover fully are not up to doing full task work
The harder a battery is to equalize and the faster the cells become unequal in gravity the closer it gets to the recycling center. You can count on it.
Harbor Freight sells an inexpensive 500 amp adjustable load test machine. I love it as doing a load test alongside a hydrometer inspection and equalization is a great dose of truth serum.
Get proficient doing this and charge fellow RV'ers to do their batteries. No one else does this right so you'll be the exclusive agent in your area.

I hope to get a 3 amp VARIAC soon. They cost fifty some odd dollars and with a VARIAC I can play a charger like a pipe organ. Maintain 10-11 amps with precision.

My fingers are aching. I hope this becomes a sticky. I would get censored if I wrote what I think of arthritis.

27 Replies

westend
Explorer
Sep 09, 2013
onecb wrote:
"•Harbor Freight sells an inexpensive 500 amp adjustable load test machine. I love it as doing a load test alongside a hydrometer inspection and equalization is a great dose of truth serum." I bought one of the load testers and I really do not understand the test or the results when used on a pair of 6 volts? Could one of you knowledgable people explain it to me? Thanks Alvin

HF 500 amp tester manual (in case you don't have one).

You need to know the amp hour rating of one of the two identical 6V batteries. Connect the battery clamps from the tester to your batteries. Turn the "Load" knob on the tester until the left side analog meter reaches the amp hour rating. Wait 10-15 seconds and read the indicated scale on the right analog meter of the tester. It should point to the Green ranges if your batteries are good and charged.
Canadian_Rainbi
Explorer
Sep 09, 2013
MEXICOWANDERER wrote:

Boy talk about aching fingers* causing the brain to fingers to short-circuit. Yes,.015 is correct my figure as listed is incorrect.

*Shoulders, knees, #4 lumbar disc, toenails, hair, etc.

My father used to joke: "What doesn't hurt doesn't work" Now I know he wasn't joking!
onecb
Explorer
Sep 09, 2013
"•Harbor Freight sells an inexpensive 500 amp adjustable load test machine. I love it as doing a load test alongside a hydrometer inspection and equalization is a great dose of truth serum." I bought one of the load testers and I really do not understand the test or the results when used on a pair of 6 volts? Could one of you knowledgable people explain it to me? Thanks Alvin
Salvo
Explorer
Sep 04, 2013
Salvo's equalization differs from Mex's. 16V is too high in hot weather. You could destroy the batteries waiting for the voltage to get to 16V. At 80F, my golf cart batteries never get to 16V. During equalization, voltage does not rise continuously. Battery voltage will peak and then drop.

My procedure is to record battery voltage every 10 to 15 min. Once voltage peaks and is on decline, continue equalization for 2 hours.

Sal

MEXICOWANDERER wrote:
Amperage will drop and voltage will rise as the equalization process continues
When a series pair of batteries reaches 16.0 volts stop the charging. Go to the next battery or batteries and let the first ones cool off.
If you are doing a single 6 volt battery apply 11 amps until 8 volts is reached
Redo the hydrometer check.
mena661
Explorer
Sep 01, 2013
Works like a champ too. Haven't done a regular equalize in at least a year and a half.
pianotuna
Nomad III
Sep 01, 2013
Hi Snowman,

As Mex said

"Top charge is a mild equalization".

I believe it is to help prevent hard sulphate build up.
KendallP
Explorer
Sep 01, 2013
Snowman9000 wrote:
So what is top charging, then? Just a quick bubbling to equalize the electrolyte?

More of a quick bubbling to break up sulfate on the plates and revert it back into solution.
Snowman9000
Explorer
Sep 01, 2013
So what is top charging, then? Just a quick bubbling to equalize the electrolyte?
MEXICOWANDERER
Explorer
Aug 31, 2013
Here I was on a beach way the heck and gone down Mexico way. My neighbor was having fits with his 4 8-D "high top" batteries.

His rig had one of those old NHE Onans, and his charger was a Magnatek 775-2 ferroresonant 75 amp charger. Not a "converter". He was ensconced in a remote parking spot, awning out, carpet laid, cobwebs gluing the wheels to the ground.

The old Magnateks used to put out 14.0 volts. It wasn't enough to zap those high tops (8-D high-tops were 1-1/2 8-D's tall).

Solution?

Turn off ALL the breakers. Connect the generator directly to the Magnatek. Tear off a matchbook cover. Shim the throttle on the NHE (volts per hertz). So what the generator was now running at 64 hertz? The Magnatek popped up to 14.8 volts and got the job done. The cost was prohibitive. Mexicans do not have matchbooks. I was out a matchbook cover.

Can't do that with this new-fangled crap. New stuff is so smart it out-stupid's itself.
MEXICOWANDERER
Explorer
Aug 31, 2013
The best way to charge batteries is cell-by-cell. This is why 2-volt cells can be manipulated so much. That and .300" thick positive plates.

TOP CHARGING. Just to reach 15.00 Then pull the plug. If your battery is a hard nose and likes to sulfate fast, drop drop to 3% and do the same. Fifty three dollars for a VARIAC big enough to twist the HF charger's tail. Combine that with a nice Intermatic 6 hour spring wound mechanical timer and you have a genuine Mother Fletcher's Do it Yourself Sulfation Outsmarter...