TM-2030 Technical Manual

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have multiple charging sources, for example if you have a stand alone generator, a charger or converter, and also solar, or
perhaps also your engine alternator, ideally all chargers should be set identically according to what the battery
manufacturer recommends. Often that’s not possible (say, for engine alternator) then the voltage value for that charger
should be lower—however then you should have another charger to back that one up to periodically charge to the proper
absorption voltage if you want to maximize battery life. Although some chargers just have a switch that says “AGM” or
“Liquid electrolyte” to set this voltage, it is useful for you to know this actual voltage number since you now own a
TriMetric, to check that the charger is really charging correctly. If all chargers are not set correctly you may be buying
replacement batteries before you expected.
Battery temperature: If the battery temperature varies considerably the charging source should adjust its voltage to
temperature. A well designed charger will have a temperature sensor, and adjust its voltage a little higher at cold, and
lower at warmer temperatures. As mentioned above, the absorption charging voltage is usually given for a battery at 25° C.
(77° F.)
You can use the TriMetric to determine what your charger is adjusted to by watching “Volts” as the charger is charging the
batteries—and eventually you should find that the voltage does not rise any more as the batteries approach full charge. An
easier way which doesn’t require that you constantly monitor the meter is to use the “History data” (see Section 4, item H7.
and H8.)
Charging for sufficient time: Not only must the voltage be high enough, but it is the nature of battery chemistry requires
the passage of some time at the “absorption voltage” to fully charge. So this means not only adjusting the voltage correctly
as mentioned above, but charging for enough time to get the battery well charged. There are three ways commonly used to
measure this. (1) charge at absorption voltage for a set time, sufficiently long: from 1-8 hours. (2) Better is to retain the
absorption voltage for a long enough time for the charging current (in amps) to drop to a low enough value (sometimes
called the “return” value). This is what the TriMetric measures when it makes a judgment about whether the battery is
charged. A practical value for this value of amps is to take the total “amp hours” capacity of the battery system and divide
by 50 to 200 to get an “amps” value to which the batteries should reduce before charging is completed. We often suggest
capacity ÷50, (2% of capacity) not because it is absolutely ideal, but it is a compromise for getting them charged in a
reasonable amount of time. (3) Often considered the best way is to return a specified additional percentage of amp hours—
for liquid electrolyte batteries returning 110% to 115% of the charge that was just previously discharged is often
recommended--for AGM batteries the number is 104%-108%. Very few chargers use this method, but our SC-2030 solar
charger has this capability (when paired with the TM-2030 monitor.) (4) The “classic”, but rather inconvenient method
which works only for “liquid electrolyte” batteries is to use a hydrometer to measure the specific gravity of the battery acid
of each cell to see that it comes up to a high enough value as specified by battery manufacturer. But if you have liquid
electrolyte batteries this is worth occasionally checking—to be done just after your batteries have been pretty well charged.
Why solar panels can be good for batteries: Even if you don’t get all your energy needs from solar, these are often
a very useful complement to your engine chargers to reduce the amount of engine time required to charge and yet
get a good charge on your batteries. Use your engine charger(s) to begin charging when your batteries are low,
which is when they absorb energy at a higher rate, making more efficient use of your engine. Then once they
approach full charge turn off the engine and let the panels deliver a slower, but much longer charge to get your
batteries well charged without having to run a generator for a long time.
Charging to full sufficiently often: It doesn’t hurt to discharge a “deep discharge” battery to 50% or less—that’s what
they are designed to do—but lead acid batteries should not be left uncharged for a long period. The reason is that if the lead
sulfate reaction product that is produced as the battery is discharged is left too long it changes its form so as to be harder to
convert back to its “charged” state—lead, lead dioxide and sulfuric acid--so you will not be able to retrieve as much energy
from the batteries. We suggest charging to “full” at least every five days or so. To help, the TriMetric has a “battery
reminder” function to remind you to charge the batteries fully after a certain number of days have elapsed in which they
have not been brought to full charge(which you set using Program P5). Once you fully charge them the flashing reminder
will cease. See Section 2.2.1. Also, the “days since charged” display on the “secondary displays” page 3 will tell you how
long it has been since they have been fully charged.
"Equalization" refers to a process of occasionally overcharging your batteries--which is usually recommended by
manufacturers of "wet cell" lead acid batteries--but, however is usually not recommended for “AGM” OR GEL sealed lead
acid batteries, and overdoing it can damage these types. More recently some companies making AGM batteries
occasionally recommend this. (Example: Concorde Battery Co.) The Trojan battery company recommends that their wet-
cell batteries be equalized every 1-2 months. This helps to completely recharge the battery--which helps maintain the
battery capacity. Some charge controllers, or battery chargers have an "equalize" mode which is controlled either manually
or automatically. The SC-2030 now has the capability to do a manual equalization (when controlled by the TM-2030). This