Equalizing Batteries using Alternator

[sailinglegend]

Originally Posted by Fuss

For people who anchor out with FLA batteries you need...
1- Alternator that is 30%, not 25% of the battery.............
2........

It doesn't matter how many ideas you list you will never fully charge you batteries at anchor with your alternator - probably not even with solar - so equalising once a month can go a long way to minimising the damage caused by sulfation - they will start to lose their capacity and die prematurely.

It may help to try and explain what sulfation is.

During discharge part of the chemical process converts parts of the lead plates into Lead Sulfate crystals, and during charging the Lead Sulfate is converted back into Lead + Sulfuric acid. This is over simplified, lots of other stuff with electrons and hydrogen and oxygen are also going on!

It takes a very long time to diffuse the charge current deep inside the plates to convert all the Lead Sulfate back to Lead and Sulfuric Acid, and that's why batteries seldom get back to 100% charged. If left these Lead Sulfate crystals harden and no amount of charging at normal voltages will remove them, but Equalising at voltages of 15.5v may remove them if they haven't hardened too much.

So the bottom line is if you can't guarantee that the batteries have been recharged to 100% at least once a month then they should be equalised. Shorepower charging for 24 hours should guarantee a 100% recharge! Batteries are fully charged when the current going into the battery at 14.4v is 0.5% of the capacity. So a 400Ah bank will be taking 2 Amps. This can't be measured at a lower float voltage so chargers need to be forced back into Absorption Mode to check the charging current.

This is why it is so difficult to really know if your batteries have been fully, fully, 100% charged. A little green light on the charger saying 'fully charged' is lying to you.

[u4ea32]

I have read a recommendation that made sense to me: always (solar) charge at 15.5 volts. When the current gets low, then start other stuff, like freezer compressors, water makers, air conditioners.

I dunno if this **works** it just seems like an interesting strategy.

[Maine Sail]

Originally Posted by TacomaSailor

Why equalize?

I've never done it in 20 years

7.5 years on 2x8D gelcels
7 years on 4xT105s
5.5 years on 6xT105 and they are still perfect

if you charge the batteries properly you shouldn't need to equalize

GELS can't be equalized so you had no need on those. 6-7 years is about the "average" I see for T105 / GC2 6V batts. "Average" assumes average use and the average boater does not usually equalize. They can easily go 8-10 if charged and cared for better. I have even seen a few GC2's at year 11... If you are happy with that performance then stick with what you are doing. If you are not equalizing just bumping absorption to 14.7-14.8, temp compensated, will make a difference...

[zboss]

My Trojans are only 310 days old, we have a balmar at165 alt and 614 regulator. We have 554 watts of solar and a wind gen.

On my master volt shunt I have set the voltage at 14.8 and 13.2 for bulk/abs and float, respectively. Our full charge is set for .5%

We generally use 80 to 100 amps at night.

We get "fully charged" at least once a week, everyday if lots of sun. If we hit 130 amps out, we use the engine to charge.

We have water miser battery caps and have only needed to add water about 5 times.

We have never equalized.

Now, we are seeing very low voltage (below 50% as per utilization charts) after only pulling 100 amps out of the system.

Which is why I asked about equalizing with the alt.


Sent from my iPhone using Cruisers Sailing Forum

[transmitterdan]

If you are charging based on some kind of amp counter then maybe you aren't 100% charged like you think. Do you stop
charging based on AH or do you weekly charge fully based on the battery manufacturer charge profile? It's not simple to fully charge a bank when the charger is also supplying other loads like fridge/freezer.

[zboss]

Originally Posted by transmitterdan

If you are charging based on some kind of amp counter then maybe you aren't 100% charged like you think. Do you stop
charging based on AH or do you weekly charge fully based on the battery manufacturer charge profile? It's not simple to fully charge a bank when the charger is also supplying other loads like fridge/freezer.

Our "full" is measured by the Mastervolt shunt based on the number of amps going into the batteries married to the absorption voltage. I have my peukert set at the value recommended by Mainesail for trojans... 1.25 I think (I am at work).

Here is the mastershunt info:

13.4 STATE OF CHARGE (SOC)
The state of charge is expressed as a percentage.
This value is automatically compensated by the
charge efficiency factor (C.E.F.) and the Peukert
exponent. When the battery is fully charged, the
State of charge will be reset to 100%. A battery is
considered to be fully charged if conditions 1 and 2,
1 and 3 or 1 and 4 are met:
1 Parameters below are met for at least 30
seconds:
• All of the Ah's discharged are charged back
into the battery (real counting without CEF)
• The actual charge current is less than the
setting for charge amps for full battery.
2 For at least 4 hours the actual battery voltage is
higher than the float voltage plus 1.0/2.0/4.0V(at
nominal battery voltage 12/24/48V)
3 For at least 8 hours the actual battery voltage is
higher than the float voltage plus 0.3/0.6/0.9V (at
nominal battery voltage 12/24/48V)
4 For at least 12 hours the actual battery voltage is
higher than the float voltage minus 0.1/0.2/0.3V
(at nominal battery voltage 12/24/48V).

13.5 AMP = FULL
This value represents the charge current below
which the battery is considered to be fully charged,
provided the float voltage (see chapter 11) is met as
well. The percentage expresses this charge current
related to the battery capacity (C20). Example: If the
battery capacity is 200Ah, and this percentage is set
to 2.0%, the battery is considered to be fully charged
when the charge current has dropped below 200 x
2.0%,= 4 Amps. An older battery (beyond its normal
lifetime) might start to consume more current when it
is fully charged. Setting this value higher may be
usable for old batteries which are beyond their
economical life but have not been replaced yet.

[transmitterdan]

I suspect your amp hour counter is "out of calibration" and your batteries are not 100% charged like you think they are. AH counting using Puekert is not an exact science like the sales brochure makes it sound.

My advice is to charge from shore power for 24 hours and then see what happens. If the batteries seem like they have "recovered" then you know it is just a calibration problem. If not then use shore power to equalize. It takes many hours to equalize properly.

But you can't rely on AH counting for a year in my experience. It just isn't that accurate. If you have budget and space consider using the Smart Gauge battery monitor. I believe it to be more useful than AH counting.