Cabin Batteries in Winter
plymaniac
UP. I'd like to leave the battery bank at the cabin rather than
bringing it home. But I'm worried about the batteries freezing...even
if I leave them fully charged.
Can I safely leave the batteries connected to a couple of properly
inclined solar panels over the winter? Would the charge controller
prevent overcharging?
Thanks for any help and advice.
clare .ca
You should be fine - just make sure the batteries are in a protected
spot. An insulated pit, below the frost line, in the middle of the
cabin would be best. A good charge controller will not overcharge
them, and the heat from the charge controller will keep the batteries
above freezing if the controller is in the battery compartment.
mark Ransley
charged. Is your car battery below the frost line.
JME
days..
I have 16 L-16 Trojans in a plywood box behined my house. They have never
given me any problems.
Here is some Battery info I found a couple of years ago It should answere
your questions.
A word of caution. Batteries contain a sulfuric acid electrolyte which is a
highly corrosive poison, that will produce gasses when recharged and explode
if ignited. This will hurt you--BAD! When working with batteries, you need
to have plenty of ventilation, remove jewelry, wear protective clothing and
eye wear (safety glasses), and exercise caution. Whenever possible, please
follow the manufacturer's instructions for testing, jumping, installing and
charging.
This FAQ assumes a 12 volt, six cell, negative grounded, lead acid battery
found in most recreational applications in North America and temperature in
degrees Fahrenheit. For six volt batteries, divide the voltage by two; for
eight volt batteries, divide by 1.5; for 24 volt batteries, double the
voltage; and for 48 volt batteries, multiple by four.
The technical stuff is in [brackets].
CONTENTS
a.. 1. WHAT IS THE BOTTOM LINE?
b.. 2. WHY BOTHER?
c.. 3. HOW DO I TEST A DEEP CYCLE BATTERY?
d.. 4. WHAT DO I LOOK FOR IN BUYING A BATTERY?
e.. 5. HOW DO I INSTALL A BATTERY?
f.. 6. HOW DO I CHARGE (OR EQUALIZE) A BATTERY?
g.. 7. HOW DO I INCREASE THE LIFE OF A BATTERY?
h.. 8. WHAT ARE THE MOST COMMON CAUSES OF BATTERY FAILURES?
i.. 9. HOW CAN I STORE BATTERIES?
j.. 10. WHAT ARE THE COMMON MYTHS ABOUT BATTERIES?
k.. 11. HOW LONG WILL A DEEP CYCLE BATTERY LAST ON A SINGLE CHARGE?
l.. 12. WHERE CAN I FIND MORE INFO ON BATTERIES?
1. WHAT IS THE BOTTOM LINE?
1.1. Remove the surface charge before testing and check specific gravity in
each cell. (Please see Section 3.)
1.2. Recharge as soon as possible after discharge. (Please see Section 6.)
1.3. Size charger so that it will recharge the battery over an eight to ten
hour period. (Please see Section 6.)
1.4. Buy the freshest and largest ampere hour battery that will fit your
requirements. (Please see Section 4.)
1.5. Perform preventative maintenance, especially during hot weather.
(Please see Section 7.7.)
1.6. The shallower the average discharge, the longer the battery life .
(Please see Section 7.5.)
1.7. Temperature matters!
2. WHY BOTHER?
Because only the rich can afford cheap batteries.....
A good quality deep cycle lead acid battery will cost between $50 and $200
and,if properly maintained, will give you at least 150 deep discharge
cycles.
The purpose of a deep cycle battery is to provide power for trolling motors,
golf carts, fork lift trucks, uninterruptible power supplies (UPS), and
other
accessories for marine and recreational vehicle (RV) and commercial
applications.
Dead batteries almost always occur at the most inopportune times, for
example,
across the lake or during bad weather or on the 17th tee.
[A twelve volt deep cycle battery is made up of six cells, each producing
2.1 volts that are connected in series positive to negative. Each cell is
made
up of an element containing positive plates that are all connected together
and
negative plates, which are also all connected together. They are
individually
separated with thin sheets of electrically insulating, porous material that
are used as
spacers between the positive and negative plates to keep them from shorting
to each
other. The plates, within a cell, alternate with a positive plate, a
negative
plate and so on. A plate is made up of a metal grid that serves as the
supporting
framework for the active material which is "pasted" on it. The cells are
inserted into a polypropylene case, connected to the terminals, covered,
filled with a dilute sulfuric acid electrolyte and formed (initially
charged).
The electrolyte is replaced and the battery is given a finishing charge.
A battery is created when two different metals such as Lead Dioxide (Pb O2),
the positive plates, and Sponger lead (Pb), the negative plates, are
immersed
in Sulfuric Acid (H2SO4), the electrolyte. The types of metals and the
electrolyte
used will determine. A typical lead-acid battery produces approximately
2.1 volts per cell. The chemical action between the metals and the
electrolyte
creates the electrical energy, that flows from the battery as soon as there
is a load, such a light bulb, between the positive and negative terminals.
The electrical current flows as charged portions of acid (ions) between the
battery plates and as electrons through the external circuit. The action
of the lead-acid storage battery is determined by chemicals used,
temperature, and load.]
Normally a battery "ages" as the active positive plate material sheds (or
flakes off) due to the expansion and contraction that occurs during the
discharge
and recharge cycles, the positive grid metal corrodes in the electrolyte,
or the negative grid shrinks. Deep discharges, heat, vibration, over
charging,
or non-use accelerate this "aging" process. Sediment or "mud" builds up
in the bottom of the case and the can short the cell out. Another major
cause of premature battery failure is sulfation. When batteries are stored
discharged or stored fully charged for over three months without being
recharged,
the plates slow discharge and become coated with hard and dense layer of
lead sulfate. Over time, the battery can not be recharged. Using tap water
to refill batteries can produce calcium sulfate, which also will coat the
plates. Recharging a sulfated battery is like trying to wash your hands with
gloves on. When the active material in the plates can no longer sustain a
discharge current and the battery "dies".
Most of the "defective" batteries that are returned to the manufacturer
during
free placement warranty periods are good. This suggests that most sellers
of new batteries do not know how or take the time to properly load test or
recharge batteries.
3. HOW DO I TEST A BATTERY?
There are six simple steps in testing a deep cycle battery--inspect,
recharge,
remove surface charge, measure the state-of-charge, load test, and recharge.
If you have a non-sealed battery, it is highly RECOMMENDED that you use a
temperature compensated hydrometer, which can be purchased, at an auto parts
store between $5 and $20. A hydrometer is a float type device used to
determine
the state-of-charge by measuring the specific gravity of the electrolyte
in each cell. It is a very accurate way of determining a battery's
state-of-charge
and weak or dead cells. To troubleshoot charging or electrical systems or
if you have a sealed battery, you will need a digital voltmeter with .5%
(or better) accuracy. A digital voltmeter can be purchased at an
electronics
store,for example, Radio Shack, between $20 and $200. Analog voltmeters
are not accurate enough to measure the millivolt differences of the
battery's
state-of-charge or the output of the charging system. A battery load tester
is optional.
3.1. INSPECT
Visually inspect for obvious problems, for example, loose of broken
alternator
belt,electrolyte levels BELOW the top of the plates, corroded or swollen
cables,corroded terminal clamps loose hold-down clamps, loose cable
terminals,
or leaking or damaged battery case.
If the electrolyte levels are low in non-sealed batteries, allow the battery
to cool and add DISTILLED water to the level indicated by the battery
manufacturer
or to 1/4 inch BELOW the bottom of the plastic filler tube (vent wells).
The plates need to be covered at all times and avoid OVERFILLING, especially
in hot climates, because the heat will cause the electrolyte to expand and
overflow.
3.2. RECHARGE
Recharge the battery to 100% state-of-charge. If the battery has a
difference
of .03 specific gravity reading between the lowest and highest cell, then
you should equalize it. (Please see Section 6.)
3.3. REMOVE SURFACE CHARGE
Surface charge is the uneven mixture of sulfuric acid and water within the
surface
of the plates as a result of charging or discharging. It will make a weak
battery
appear good or a good battery appear bad. You need eliminate the surface
charge
by one of the following methods:
3.3.1. Allow the battery to sit for four to twelve hours to allow for the
surface
charge to dissipate. [RECOMMENDED].
3.3.2. Apply a load that is 33% of the ampere hour capacity for five
minutes and
wait five to ten minutes.
3.3.3. With a battery load tester, apply a load at one half the battery's
CCA rating for 15 seconds and wait five to ten minutes.
3.4. MEASURE THE STATE-OF-CHARGE
If the battery's electrolyte is above 100 degrees, allow it to cool. To
determine
the battery's state-of-charge with the battery's electrolyte temperature at
80 degrees,
use the following table, which assumes that 1.265 specific gravity reading
is as
fully charged battery:
Voltmeter Hydrometer
Open Circuit Approximate Average Cell
Voltage State-of-charge Specific Gravity
12.65 100% 1.265
12.45 75% 1.225
12.24 50% 1.190
12.06 25% 1.155
11.89 Discharged 1.120
[Source: Battery Council International]
[Electrolyte temperature compensation, depending on the battery
manufacturer's
recommendations, will vary.
If you are using a NON-temperature compensated HYDROMETER, make the
following
adjustments, and if the temperature of the electrolyte is BELOW 80 degrees,
SUBTRACT .004 specific gravity per 10 degrees below 80 degrees FROM the
Specific
Gravity indicated in the table above. For example, at 30 degrees, the
specific
gravity reading would be 1.245 for a 100% state-of-charge. If the
temperature
of the electrolyte is ABOVE 80 degrees, then ADD .004 specific gravity per
10
degrees above 80 degrees TO the Specific Gravity. For example, at 100
degrees,
the specific gravity would be 1.273 for 100% state-of-charge. This is why
using a temperature compensated hydrometer is highly RECOMMENDED and more
accurate.
If you are using a digital VOLTMETER, then from the table above make the
following
adjustments, if the temperature of the electrolyte is BELOW 80 degrees,
SUBTRACT
.0012 to .028 volts (1.2 to 28 millivolts) per 10 degrees below 80 degrees
from
the Open Circuit Voltage indicated. For example, at 30 degrees and using 28
millivolts, the reading would be 12.51 VDC at 100% state-of-charge. If the
temperature of the electrolyte is ABOVE 80 degrees, then ADD .0012 to .028
volts
(1.2 to 28 millivolts) per 10 degrees above 80 degrees. For example, at
100
degrees and using 28 millivolts, the Open Circuit Voltage would be 12.71
VDC.]
For non-sealed batteries, check the specific gravity in each cell with a
hydrometer and average the readings. For sealed batteries, measure the
Open Circuit Voltage across the battery terminals with an accurate digital
voltmeter. It is the only way you can determine the state-of-charge. Some
batteries have a built-in hydrometer, which only measures the
state-of-charge
in ONE of its six cells. If the built-in indicator is clear or light
yellow,
then the battery has a low electrolyte level and should be refilled and
recharged before proceeding. If sealed, the battery is toast.
If the state-of-charge is BELOW 75% using either the specific gravity or
voltage test or the built-in hydrometer indicates "bad" (usually dark),
then the battery needs to be recharged BEFORE proceeding. You should
replace the battery, if one or more of the following conditions occur:
3.4.1. If there is a .05 or more difference in the specific gravity reading
between the highest and lowest cell, you have a weak or dead cell(s). If
you are really lucky, applying an EQUALIZING charge may correct this
condition. (Please see Section 6.)
3.4.2. If the battery will not recharge to a 75% or more state-of-charge
level
or if the built-in hydrometer still does not indicate "good" (usually
green, which is 65% state-of-charge or better).
[If you know that a battery has spilled or "bubbled over" and the
electrolyte has
been replaced with water, you can replace the old electrolyte with new
electrolyte
and go back to Step 3.2 above. Battery electrolyte is a mixture of 25%
sulfuric
acid and distilled water. It is cheaper to replace the electrolyte than to
buy a
new battery.]
3.4.3 If digital voltmeter indicates 0 volts, you have an open cell.
3.4.4. If the digital voltmeter indicates 10.45 to 10.65 volts, you
probably
have a shorted cell or a severely discharged battery. [A shorted cell is
caused
by plates touching, sediment "mud" build-up or "treeing" between the
plates.]
3.5. LOAD TEST
If the battery is fully charged or has a "good" built-in hydrometer
indication,
then you can test the capacity of the battery by applying known load and
measure
the time it take to discharge the battery until 20% capacity is remaining.
Normally a discharge rate that will discharge a battery in 20 hours can be
used [C/20]. For example, if you have a 80 ampere hour rated battery, then
a load of four amps would discharge the battery in approximately 20 hours
(or 16 hours down to the 20% level). New batteries can take up to 50
charge/discharge cycles before they reach their rated capacity. Depending
on your application, batteries with 80% or less of their original capacity
are considered history.
3.6. RECHARGE
If the battery passes the load test, you should recharge it as soon as
possible
to restore it to peak performance and to prevent lead sulfation.
4. WHAT DO I LOOK FOR IN BUYING A NEW BATTERY?
4.1. Ampere Hour (or Reserve Capacity) Rating
The most important consideration in buying a deep cycle battery is the
Ampere Hour (AH) or Reserve Capacity rating that will meet or exceed your
requirements and how much weight you can carry. [Most deep cycle batteries
are rated in discharge rates of 100 amps, 20 amps, or 8 amps.
Higher the discharge, the lower the capacity due to the Peukert Effect and
the internal resistance of the battery. Reserve Capacity (RC) is the number
of minutes a fully charged battery at 80 degrees is discharged at 25 amps
before the voltage falls below 10.5 volts.] To convert Reserve Capacity to
Ampere Hours, multiple RC by .6. For example, a battery with 120 minute RC
will have approximately 72 Ampere Hours. This means that the battery should
produce one amp for 72 hours of continuous use. More ampere hours (or RC)
are better in every case.
Within a BCI group size, the battery with larger ampere hours (or RC) will
tend to weigh more because it contains more lead.
[If more ampere hours are required, two new and identical six volt batteries
can be connected in series (positive terminal of Battery One to the negative
terminal of Battery Two). Two (or more) new and identical 12 volt batteries
can be connected in parallel (positive terminals to positive terminals and
negative terminals to negative terminals with identical cables). When
connecting in series or parallel and to prevent recharging problems, do NOT
mix old and new batteries or ones with different types. Cable lengths
should be kept short and cable sized large enough to prevent significant
voltage drop [.2 volts (200 millivolts) or less] between batteries.]
4.2. Type
Car batteries are especially designed for high initial cranking amps
(usually 200 to 400 amps for five to 15 seconds) to start a car and not for
deep cycle discharges. Deep cycle (and marine) batteries are designed for
prolonged discharges at lower current. [The plates in car battery are more
porous and thinner than in deep cycle batteries and use sponges or expanded
metal grid instead of solid lead.] A deep cycle battery will typically
outlast two to ten car batteries when used in deep cycle applications.
Starting an engine will typically consume less that 5% of a car battery's
capacity. Whereas, deep cycle (or marine) batteries are used for
applications that will consume between 20 and 80% of the battery's capacity.
A "dual" or starting marine battery is a compromise between a car and deep
cycle battery. A deep cycle or "dual marine" battery will work as starting
battery if it can produce enough current to start the engine, but not as
well as a car battery.
For RVs, a car battery is normally used to start the engine and a deep
cycle battery is used to power the RV accessories. The batteries are
connected to a diode isolator. When the RV's charging system is running,
both batteries are automatically recharged. An excellent and easy to
understand free booklet on multi-battery applications, "Introduction to
Batteries and Charging Systems", can be downloaded from
this link
or by calling (800) 845-6269 or (503) 692-5360.
The two most common types of deep cycle batteries are flooded (also known as
wet or liquid electrolyte) cell and valve regulated (VR).
4.2.1. Flooded cell
Flooded cell deep cycle batteries are divided, like their car battery
counterparts, into low maintenance (the most common) and maintenance free,
based on their plate formulation. [Low maintenance batteries have
lead-antimony/antimony or lead-antimony/calcium (dual alloy or hybrid)
plates; whereas, the maintenance free batteries use lead-calcium/calcium.]
The advantages of maintenance free batteries are less preventative
maintenance, up to 250% less water loss,faster recharging, greater
overcharge resistance, reduced terminal corrosion, up to 40% more life
cycles, and up to 200% less self discharge. However, they are more prone to
deep discharge (dead battery) failures [due to increased shedding of active
plate material and development of a barrier layer between the active plate
material and the grid metal], and if sealed, a shorter life in hot climates
because lost water can not be replaced. Maintenance free batteries are
generally more expensive than low maintenance batteries.
4.2.2. Valve Regulated
Valve Regulated Lead Acid (VRLA) batteries are generally divided into two
groups, gel cell and Absorbed Glass Mat (AGM). VRLA batteries are spill
proof, so they can be used in semi-enclosed areas, are totally maintenance
free, and longer shelf life. Their greatest disadvantage is the high
initial cost (two to three times), but arguably could have an overall lower
cost due to a longer lifetime and no "watering" labor costs, if properly
maintained and recharged.
4.3. Size
An internationally adopted Battery Council International (BCI) group
number (U1, 24, 27, 31, etc.) is based on the physical case size,
terminal placement and terminal polarity. Within a group, the ampere
hour or RC ratings, warranty and battery type will vary in models of
the same brand or from brand to brand. You can also find BCI size
information online at
Exide. Generally,
batteries are sold by model, so some of the group numbers will vary for the
same price. This means that for the same price you can potentially buy a
physically larger battery with more ampere hour or RC than the battery you
are replacing. Be sure that the replacement battery will fit, the cables
will correct to the correct terminal, and that the terminals will not touch
anything else.
4.4. Freshness
Determining the "freshness" of a battery is sometimes difficult. NEVER buy
a wet lead acid battery that is MORE than THREE months old because it has
starting to sulfate, unless it has periodically been recharged.
[Sulfation occurs when lead sulfate can not be converted back to charged
material and is created when discharged batteries stand for a long time
or from excessive water loss.] Dealers will often place their older
batteries
in storage racks so they will sell first. The new batteries can often be
found in the rear of the rack or in a storage room. The date of manufacture
is stamped on the case or printed on a sticker. It is usually a combination
of alpha and numeric characters with letters for the months starting with
"A" for January (generally skipping the letter "I") and digit for the year,
e.g., "J6" for September 1996. If you can not determine the date code then
ask the dealer or contact the manufacturer. Like bread, fresher is
definitely better and does matter.
4.5. Warranty
As with tire warranties, battery warranties are NOT necessarily indicative
of the quality or cost over the life of the car. Most manufacturers will
prorate warranties based on the LIST price of the bad battery, so if a
battery failed half way or more through its warranty period, buying a NEW
battery outright might cost you less than paying the difference under a
prorated warranty. The exception to this is the FREE replacement warranty
period. This represents the risk that the manufacturer is willing to
assume.
A longer free replacement warranty period is better.
5. HOW DO I INSTALL A BATTERY?
5.1. Thoroughly wash and clean the old battery, battery terminals and case
or tray with warm water to minimize problems from acid or corrosion. Heavy
corrosion can be neutralized with a mixture of one pound of baking soda to
one gallon of warm water. Wear safety goggles and, using a stiff brush,
brush away from yourself. Also, mark the cables so you do not forget which
one to reconnect.
5.2. Remove the NEGATIVE cable first because this will minimize the
possibility of shorting the battery when you remove the other cable. Next
remove the POSITIVE cable and then the hold-down bracket or clamp. If the
hold down bracket is severely corroded, replace it. Dispose the old battery
by exchanging it when you buy your new one or by taking it to a recycling
center. Please remember that batteries contain large amounts of harmful
lead and sulfuric acid.
5.3. After removing the old battery, be sure that the battery tray or box
and cable terminals or connectors are clean. Auto parts stores sell a cheap
wire brush that will allow you to clean the inside of terminal clamps and
the terminals. If the terminals, cables or hold down brackets are severely
corroded, replace them. Corroded terminals or swollen cables will
significantly reduce starting capability.
5.4. Use red and green paraffin oil-soaked felt washer pads [RECOMMENDED]
found at auto parts stores or thinly coat the terminal, terminal clamps and
exposed metal around the battery with a high temperature grease or petroleum
jelly (Vaseline) to prevent corrosion. Do not use the
felt washers between the mating conductive surfaces with side terminal
batteries.
5.5. Place the replacement battery so that the NEGATIVE cable will connect
to the NEGATIVE terminal. Reversing the polarity of the electrical system
will severely damage or DESTROY it.
5.6. After replacing the hold-down bracket, reconnect the cables in reverse
order, i.e., attach the POSITIVE cable first and then the NEGATIVE cable
last.
5.7. Before using the battery, check the electrolyte levels and add
distilled water to cover the plates. Check the state-of-charge and recharge
if necessary. Then recheck the electrolyte levels after the battery has
cooled and top off with distilled water as required, but do not overfill.
6. HOW DO I RECHARGE (OR EQUALIZE) MY BATTERY?
There are three phases of battery charging--bulk, absorption and float. The
bulk stage is where you can give the battery whatever current it will accept
not to exceed 20% of the ampere hour rating and that will not cause
overheating. The absorption phase is voltage-regulated current charging
until the battery is fully charged. This is normally when the charging
current drops off to 1% or less of the ampere hour capacity of the battery.
For example, end current for a 72 ampere hour battery is .7 amps or less.
Float charging at a lower voltage is used to maintain a fully charged
battery. Please refer to Section 9 for more information about storing
batteries and float charging them.
Equalizing is a controlled 5% overcharge to equalize and balance the voltage
and specific gravity in each cell of a wet lead acid battery. Equalizing
reverses the build-up of the chemical effects like stratification where acid
concentration is greater in the bottom of the battery. It also helps remove
sulfate crystals that might have built up on the plates. The frequency
recommendation varies by manufacturer from once a month to once a year, 50
to 100 deep cycles, or a specific gravity difference between cells of .03 or
.015 volts (15 millivolts). To equalize, fully recharge the battery.
Then increase the charging voltage to the manufacturer's recommendations,
or if not available, ADD 5%. Heavy gassing should start occurring. Take
specific gravity readings in each cell once per hour. Equalization has
occurred once the specific gravity values no longer rise during the gassing
stage.
It is important to use the battery manufacturer's charging recommendations
whenever possible for optimum performance and life. In addition to the
earlier cautions, here are some more words of caution:
6.1. NEVER, NEVER disconnect a battery cable from vehicle with the engine
running because the battery acts like a filter for the electrical system.
Unfiltered [pulsating DC] electricity can damage expensive electronic
components, e.g., emissions computer, radio, charging system, etc.
6.2. For non-sealed batteries, check the electrolyte level and be sure it
is covering the plates and is not frozen BEFORE recharging.
6.3. Do NOT add distilled water if the electrolyte is covering the top of
the plates because during the recharging process, it will warm and expand.
After recharging has been completed, RECHECK the level.
6.4. Reinstall the vent caps BEFORE recharging and recharge ONLY in well
ventilated areas. NO smoking, sparks or open flames while the battery is
being recharged because batteries give off explosive gasses.
6.5. If your battery is an AGM or a sealed flooded type, do NOT recharge
with current ABOVE 12% of the battery's RC rating (or the 20% of the ampere
hour rating). Gel cells should be charged over a 20 hour period and never
over the manufacturer's recommended level or 14.1 VDC.
6.6. Follow the charger manufacturer's procedures for connecting and
disconnecting cables and operation to minimize the possibility of an
explosion, but generally you should turn the charger OFF before connecting
or disconnecting cables to a battery. Good ventilation or a fan is
recommended to disperse the gasses created by the recharging process.
6.7. If a battery becomes hot (over 125 degrees) or violent gassing or
spewing of electrolyte occurs, turn the charger off temporarily or reduce
the charging rate.
6.8. Insure that charging with the battery in the car with an external
MANUAL charger will not damage the vehicle's electrical system with high
voltages. If this is even a remote possibility, then disconnect the
vehicle's negative battery cable from the battery BEFORE connecting the
charger.
6.9. If you are recharging gel cell batteries, manufacturer's charging
voltages can be very critical and you might need special recharging
equipment. In most cases, deep cycle chargers used to recharge wet
batteries can not be used to recharge gel cell and AGM batteries because of
their higher charging voltage.
Use an external constant current charger, which is set not to deliver
more than 12% of the RC rating of the battery and monitor the
state-of-charge.
For discharged batteries, the following table lists the recommended
battery charging rates and times:
Reserve Capacity Slow Charge Fast Charge
(RC) Rating
80 Minutes or less 15 Hours @ 3 amps 5 Hours @ 10 amps
80 to 125 Minutes 21 Hours @ 4 amps 7.5 Hours @ 10 amps
125 to 170 Minutes 22 Hours @ 5 amps 10 Hours @ 10 amps
170 to 250 Minutes 23 Hours @ 6 amps 7.5 Hours @ 20 amps
Above 250 Minutes 24 Hours @ 10 amps 6 Hours @ 40 amps
[Source: Battery Council International]
The BEST method is to SLOWLY recharge the battery at 70 degrees over eight
hour period using an external constant voltage (or tapered current charger)
because the acid has more time to penetrate the plates. [RECOMMENDED] A
constant voltage "automatic" charger applies regulated voltage at
approximately 13.8 to 16 volts based on the manufacturer's recommendations
and temperature. A 10 amp automatic charger will cost between $30 and $60
at an auto parts store. Some sulfated batteries, depending on the size and
degree of sulfation, can be recovered by applying one or two amps for 48 to
120 hours.
[An excellent automatic constant voltage battery charger is a 15 volt
regulated power supply adjusted to the manufacturer's recommendations or, if
not available, to voltages below with the electrolyte at 70 degrees:
Battery Type Charging Float Equalizing
Wet Low Maintenance 14.4 13.2 15.1
Wet Maintenance Free 14.8 13.6 15.5
AGM 14.6 13.8 N/A
Gel Cell 14.0 13.5 N/A
Wet Deep Cycle 15.0 13.2 15.8
To compensate for electrolyte temperature, adjust the charging voltage .0028
(2.8 millivolts) to .0033 (3.3 millivolts) volts/cell/degree. For example,
if 30 degrees, then INCREASE the charging voltage to 15.19 volts for a wet
low maintenance battery. If 100 degree, then DECREASE the charging voltage
to 13.81 volts.]
If left unattended, a cheap, unregulated trickle battery charger can
overcharge your battery because they can "boil off" the electrolyte. Do NOT
use fast, high rate, or boost chargers on any battery that is sulfated or
deeply discharged. The electrolyte should NEVER bubble violently while
recharging because high currents only create heat and excess explosive
gasses.
7. CAN I INCREASE THE LIFE OF MY BATTERY?
7.1. Recharging slowly and keeping your battery well maintained are the
best ways to extend the life of your battery.
7.2. Recharging every two months will prevent lead sulfation.
7.3. In the warmer climates and during the summer "watering" is required
more often. Check the electrolyte levels and add distilled water, if
required.
Never add electrolyte to battery that is not fully charged--just distilled
water and do not overfill. The plates must be covered at all times.
7.4. High ambient temperatures (above 80 degrees) will shorten battery life
because it increases positive grid corrosion.
7.5. Shallower the average depth-of-discharge (DoD), increases the battery
life.
For example, a battery with an average of 50% DoD will last twice as long or
more as 80% DoD and 20% DoD will five times longer than 50% DoD. For
example,
golf cart batteries will average 225 cycles at 80% DoD and increase to 750
cycles at 50% DoD. Try to avoid DoD that is less than 10% and greater than
80%.
7.6. Recharge a deep cycle battery as soon as possible after each use.
Maintaining the correct state-of-charge while in storage, electrolyte
levels, tightening loose hold-down clamps and terminals, and removing
corrosion is normally the only preventative maintenance required for a deep
cycle battery.
8. WHAT ARE THE MOST COMMON CAUSES OF PREMATURE BATTERY FAILURES?
8.1. Loss of electrolyte due to heat or overcharging,
8.2. Lead sulfation in storage,
8.3. Undercharging with voltages less than 13.8 volts,
8.4. Old age (positive plate shedding),
8.5. Excessive vibration,
8.6. Freezing or high temperatures,
8.7. Using tap water causing calcium sulfation,
8.8. Corrosion.
9. HOW CAN I STORE BATTERIES?
Batteries naturally self-discharge 1% to 15% per month while in storage and
lead sulfation will occur over time. If left in a vehicle, disconnect the
negative cable to reduce the level of discharge. Cold will slow the
process down and heat will speed it up. Use the following six simple steps
to store your batteries:
9.1. Physically inspect for damaged cases, remove any corrosion, and clean
the batteries.
9.2. Fully recharge the batteries.
9.2. Check the electrolyte levels and add distilled water as required, but
avoid overfilling.
9.4. Store them in a cool dry place, but not below 32 degrees.
9.5. Depending on the ambient temperature and self-discharge rate,
periodically test the state-of-charge using the procedure in Section 4.
When it is below 80%, recharge the batteries using the procedures in
Section 6. An alternative would be to connect an automatic [voltage
regulated],
solar panel or "smart trickle" charger to "float" batteries using, based on
the manufacturer's recommendations or 13.02 to 13.8 volts for wet batteries
and 13.38 to 14.1 volts for VRLA batteries, compensated for temperature. An
automatic or smart charger will prevent you from overcharging the batteries.
9.6 Equalize only wet or flooded batteries when you remove the batteries
from storage using the procedure in Section 6.
10. WHAT ARE SOME OF THE MYTHS ABOUT BATTERIES?
10.1. Storing a battery on a concrete floor will discharge them.
Modern lead acid battery cases are better sealed, so external leakage
causing discharge is no longer a problem. [Temperature stratification
within very large batteries could accelerate the internal "leakage" or self
discharge if the battery is sitting on an extremely cold floor in a warm
room or installed in a submarine.]
10.2. Driving a car will fully recharge a battery.
There are a number of factors affecting charging system's ability to
charge a battery. The greatest factors are how much current from the
alternator is diverted to the battery to charge it, how long the current
is available and temperature. Generally, running the engine at idle
or short "stop-and go trips" during bad or hot weather at night will not
recharge a battery.
10.3. A battery will not explode.
While spark retarding vent caps help, recharging a battery produces hydrogen
and oxygen gasses and explosions can occur. They can also occur when the
electrolyte level is below the top of the plates. If a spark or flame
occurs, an explosion can occur. When this happens, thoroughly rinse the
engine compartment with water, then wash with a solution of one pound baking
soda to one gallon of water to neutralize the residual battery acid. Then
thoroughly rewash the engine compartment with water. Periodic preventive
maintenance and working on batteries in well ventilated areas can reduce the
possibility of battery explosions.
10.4. A battery will not lose its charge sitting in storage.
A battery has self-discharge or internal electrochemical "leakage" at a 1%
to 15% rate per month that will cause it to become sulfated and fully
discharged over time. (Please see Section 9.)
10.5. Wet maintenance free batteries never require water.
In hot climates, the water is "vaporized" or "boiled off" due to the high
underhood temperatures. Water can also be lost due to excessive charging
voltage or charging currents. Non-sealed batteries are recommended in hot
climates so they can be refilled with distilled water when this occurs.
10.6. Test the alternator by disconnecting the battery with the engine
running.
A battery as like a voltage stabilizer or filter to the pulsating DC
produced
by the charging system. Disconnecting a battery while the engine is running
can destroy the sensitive electronic components, for example, emission
computer,
audio system, cell phone, alarm system, etc., or the charging system because
the voltage can rise to 40 volts or more. In the 1970s, removing a battery
terminal was an accepted practice to test charging systems of that era.
That is not the case today. Just say NO if anyone suggests this.
10.7. Pulse chargers, aspirins or additives will revive sulfated batteries.
Using pulse chargers or additives is a very controversial subject. Most
battery
experts agree that there is no conclusive proof that more expensive pulse
charges
work any better than constant voltage chargers to remove sulfation. They
also
agree that there is no evidence that additives or aspirins provide any long
term benefits.
10.8. On real cold days turn your headlights on to "warm up" the battery up
before starting your engine.
While there is no doubt that turning on your headlights will increase the
current flow in a car battery; it also consumes valuable capacity that could
be used to start the engine; and therefore, is not recommended. For
extremely
cold temperatures, externally powered battery warmers, battery blankets,
engine block heaters or AGM batteries are highly RECOMMENDED.
11. HOW LONG WILL A DEEP CYCLE BATTERY LAST ON A SINGLE CHARGE?
Discharging, like charging, depends on a number of factors. The important
ones are the initial state-of-charge, depth-of-discharge, age, capacity of
the battery, load and temperature. For a fully charged battery at 70
degrees, the ampere hour rating divided by the load in amps will provide the
estimated life of that cycle. For example, a 72 ampere hour battery with a
10 amp load should last approximately 7.2 hours.
12. WHERE CAN I FIND MORE INFO ON BATTERIES?
Additional information sources about deep cycle batteries can be found
in the Battery Related Links on the Web server at
Battery Links
Most of the battery manufacturers have a Battery FAQ posted on their web
sites
and addition to product information. Web addresses will often change, so
you can use an Internet search tool like www.google.com or www.dogpile.com
to locate the new addresses.
Comments are always welcomed by Bill Darden at
bjb_d...@yahoo.com For
additional information on car batteries, the Car Battery FAQ maybe found on
the Web server at The Car Battery FAQ or by requesting one via email from
bjb_d...@yahoo.com.Back
clare .ca
I didn't say necessary, but preferred. IF something goes wrong with
the system, which is unsupervised, and the batteries drop below half
charge, they will not be ruined if below frost line.
I lost a bank of batteries due to loss of trickle charge while in
"cold storage" in electric vehicle. Nasty, expensive, un-necessary
mess.
BugHunter
plywood box for more than four winters.
I make sure to have them fully charged in the fall (mid October), before I
close up for the winter. If I visit in the winter, I'll run the generator to
top them off., but that is not more than once mid-winter, and often not at
all. Last winter it got to -45F which is not uncommon in northern NH.
I currently have no trickle charger on the bank.
So far, I have not had any problems.
If it were a big expensive bank, then I'd make sure to have some PV to keep
the batteries topped off automatically all winter.
You would be a lot safer with some PV, and a functional charge controller. A
charge controller should do it's job all winter long.
"plymaniac" <plym...@yahoo.com> wrote in message
news:43954401.03112...@posting.google.com...
Alan Wallace
frame in the front room of the camp, just below the ceiling, the sun shines
in, and warms up the room. I have been using the same second hand battery
for the last 3 years. In the winter I will charge the battery from the
generator. So between 1 and 5 times a season "6 months". I haven't had any
problems with freezing, yet. However at $17. for a used battery I don't have
the same investment as you.
regards......
"plymaniac" <plym...@yahoo.com> wrote in message
news:43954401.03112...@posting.google.com...