Battery Equalization

Thanks MEX for the suggestion of using the low cell for equalizing.

NiberBikes you can find an adjustable 500 carbon pile Load Tester at Harbor Freight for $49.99 on sale. Search the HARBOR FREIGHT site with the words BATTERY TESTER.

A 500 CCA battery should be tested at 1/2 its CCA rating or 250 amps for 15 seconds. The voltage should not droop to less than 9.6 at 68F 20C

You were testing batteries with a genuine adjustable load tester rather than a fixed "potato grater" so common at retail outlets. Same with the FREAS hydrometer. A lot of people who have not worked with a Freas have no idea how much EASIER the Freas is to read. You gave me a chuckle with your care of the instrument - that is how much care I give to my Freas to this day.

OK, I'll throw out a bone with regard to testing golf car batteries.

220 amperes for THIRTY SECONDS.

Voltage should not drop to less than 4.8 volts

L16's to 440 amperes, for 30 seconds. Look into the cells using safety glasses immediately after the test. Cells must not emit "smoke".

Drawing 440 amperes at at 4.8 volts is no easy chore.

Reminds me, I have to get one of the new HF fully automatic chargers and see if I can suck the genius out of it by wiring around the control circuit. Hopefully substituting a robust shottky rectifier will loose the beast in it. The charger still weighs 11 pounds. Thing needs a timer and digital meters and a mini fan.

When I am equalizing a battery I first pick the LOWEST cell out of the bunch. Then I run 5% A/H amperes through the battery (your figures are correct) until such time as OE gravity is reached, or voltage climbs to 16.0

Dipping the one cell once an hour shouldn't be an issue.

When gravity starts to climb, I keep a closer eye on things.

The acid gravity will continue to climb a little even afterthe charger is taken off line.

Yes, 20 hr rating basically gets "converted" to straight amps for this purpose. So, a 150Ah battery should be equalized at a constant 7.5 amps until the SG in each cell stops rising. How fast this gets accomplished depends on the size of the battery bank (larger banks equal slower equalizes) but mine takes 2-3 hours with 10+ amps going in (I don't have any control currently so amps will taper like it does when charging...mine starts somewhere over 12 and will drop to 6 or so). MEX says I need two of those HF's to make it really fast. I could just separate the pairs and do it that way too. For knowing what full is I go by Trojan's guide (mine are Trojan's) of 1.275 at 77F and I do compensate for temp. I figure if the SG rise stops over that I'm good. You get some SG lag anyways so best not to overdo it. Sometimes mine will stop under 1.275 but if I leave them sit with no charging for 8 hrs or so and check again, it will be right at my baseline 1.285 or thereabouts.

mena661 wrote:
Niner, equalization voltage recommended by MEX is 5% of the 20 hr rate. I typically charge until SG stops rising in all the cells or when I hit 16V (I'll let them cool and come back later for another round...only happened once). I have a good charger for this from HF also recommended by him. It's a heavy transformer based one (just need to slow down the voltage rise for it to be perfect). All that is dependent on temps (Trojan has SG and voltage temp compensation in their users guide).

I am confused here. 20 hour rating is in amperage... so 5% of 150Ah is 7.5 amps. Now, at what voltage do we want the battery to finish at at 7.5 amps? 16.0, 15.7, or are we going to be testing the SG every 10 minutes? Is 1.260 SG good on my Nevermax 24 with 75 Ah? Is the chemistry different on a Trojan with heavy plates that 1.280 or 1.275 is where an equalized battery should sit? 1.290 is too high /hot. What about summer blend SG's for semi tropical and tropical temp areas in the desert?

Variables, variables, variables. Think I'll hop on over to a Harbor Freight and give my CTek 7002 US a rest, stupid thing cost me a fortune for a bunch of BS hype.

Niner, equalization voltage recommended by MEX is 5% of the 20 hr rate. I typically charge until SG stops rising in all the cells or when I hit 16V (I'll let them cool and come back later for another round...only happened once). I have a good charger for this from HF also recommended by him. It's a heavy transformer based one (just need to slow down the voltage rise for it to be perfect). All that is dependent on temps (Trojan has SG and voltage temp compensation in their users guide).

MEXICOWANDERER wrote:
:) Ninerbikes my crack about chickens was meant to finish conveying my feelings on this thread about PWM chargers (i.e. smart chargers) and pulse charge de-sulfation.

They don't work. Take T-105's with cell readings of say 1.250, 1.260, 1.235, 1.270, 1.255. 1.230 after thoroughly charging them. Connect a whizz-bang super-smart solid state charger and grab a calendar.

There has been enough written in this forum about the inexpensive Harbor Freight manual 10-amp charger that I hoped you had read about it. I assumed you had.

Go to a gigantic battery battery manufacturing plant. One that has a hundred thousand dollar line charger. What kind of charger is it? It is a series charger designed to run constant amperage through the batteries. If there is a problem in the greening stage of manufacturing, it is resolved (hopefully) by a constant current charge.

Is there a completely manual or adjustable PWM charger? I don't think so. The public has been brainwashed to the point where they won't buy a charger unless it sports some miracle type Ponce de Leon cycle that suposedly would jump start Frankenstein.

This all is no reflection on you. My sarcasm is directed solely at companies that spend eight dollars on a plastic case and two bucks on what's inside then claim it'll do "anything".

Mex, a bit about my backround. I was a lowly grunt in the late 1970's working at Sears Roebuck and company in the Tire Buster and later the battery and electrical department in the Los Angeles area. I tested a lot of batteries, starters, alternators, generators, etc. I gave the thumbs up or thumbs down to a lot of Sears DieHard batteries. I did a lot of load tests for 10 seconds at 500 amps plus and expected the batteries voltage to stay above 9.6 Volts. 10.0 was marginal. I put a ton of customers batteries on a huge rack with a trickle charger that took a couple of days to fully recharge a depleted group 27. A DieHard 4301 was our all time best selling battery. This was a part time job while going to school at a University, it paid a lot better than minimum wage at the time, and I got good raises regularly while there.

I don't know the volts or the amps the trickle charger provided. We were not given access to that info. I looked for 13.7 to 14.4 Volts after a motor started being provided to the battery via an alternator and voltage regulator, depending on the charge state of the battery and what the alternator/regulator could provide.

I am in here to learn. If I repeat an often asked question, forgive me. I don't do much shopping at Harbor Freight, I've no idea what that latest charger does to give 11 amps at what ever finished voltage. that's what works for 225 amp 6v batteries. Is that a different set of amps for a 150 Ah T1275, about 2/3's of 11 amps, due to a T6 being 225 amp hours? I don't know, but is 7 amps better for the T1275? Therefore, I ask... tons of variables from capacities of batteries. All of which effect charge rates, optimal amps to provide and optimal voltage. I worked a ton every day with a Frias No 1. I treated the glass and rubber on them like gold, never broke one, unlike a lot of the other employee guys in the battery shop. That instrument was like gold.

It is likely that more could be done to equalize them but I don't want to overdo it either so they do great but not for long. In this case I would like them to last a while even if not up to full rating.

BFL, I think you could get more out of those T1275's with that manual HF charger and it would take considerably less time to do it. Something about 10+ amps at over 15V seems to get the batts working as they should.