How Many 12v Solar Panels Needed To Charge 24v Battery?
Jul 01, · The most popular way to charge a volt trolling motor battery system is with an onboard two bank battery charger like the Minn Kota Mkd. Another option for charging your volt battery bank is to use a volt charger like the Samlex SECUL. Three Stage Battery Charging. The BULK stage in a 24 volt charger involves about 80% of the recharge, wherein the charger current is held constant (in a constant current charger), and voltage increases. The properly sized charger will give the battery as much current as it will accept up to charger capacity (25% of battery capacity in amp hours), and not raise a wet battery over ° F, or an AGM or GEL (valve regulated) battery .
One thing that sometimes puts people off 224 a more efficient 24v system is the difficulty and expense in getting 24v chargers. So the question arises how can we go about charging a 24V battery from a 12V source?
The circuit below shows how to arrange switching so that two 12v batteries can be connected in series to supply 24v, yet can be charged in parallel from a 12v charger. Two 12v automobile relays are used for a 24v system. These relays are available with a 30 amp continuous rating. You could of course use a single double pole relay instead of two of single pole ones, but these are not generally available with more than a 10 amp rating.
The 30 amp relays we suggest have contacts capable of voolt well over amps for short periods so are fine for most volf in this application. Consider the 24v system above. When the relays are not operated, the two batteries are connected is series through the normally closed contacts solid black. When both relays are operated the batteries are in parallel.
The relays are operated by a third contact, B, and are energised automatically by connecting the 12v charger. It is tempting to connect the NC contacts effectively in parallel instead of series as here: this would give better current handling — but there is a danger that, is ever a relay contact stuck, one battery could be shorted out, destroying the other hcarge as well. With this system you must make certain that the 24v or 36v which will, for an instant, be applied to the 12v charger, chare not damage it.
Alternatively you must arrange that contacts B and C make first, energising the relays before aa charger is connected. Sales enquiries: esales 4qd. Technical support: esupport 4qd. Buyers: buyer 4qd. Webmaster: webmaster 4qd.
Skip to content Current models. The 30 amp relays we suggest have contacts what does the common wire do of carrying well over amps for short periods so are fine for most controllers in this application Consider the 24v system above. Other versions of this system are jow, this diagram shows a 36v system which uses 4 relays. If you have found this article useful please share it to help others discover tp Share on Facebook Share on Twitter Share on Linkedin.
The circuit below shows how to arrange switching so that two 12v batteries can be connected in series to supply 24v, yet can be charged in parallel from a 12v charger. Two 12v automobile relays are used for a 24v system. These relays are available with a 30 amp continuous rating. You could of course use a single double pole relay instead of two of single pole ones, but these are not generally available with more . Plug the battery charger in. Turn the battery charger on, set the rate of charge to 20 amps. The charging time will vary depending on how deeply your battery is discharged, but at that rate, most batteries will be fully charged in six to 12 hours. Set the charging voltage at volts. To charge AH 24 volt battery bank you will be required between 10 - 15% current of the total battery power i.e. 20 - 30 Amps hour. Assuming your battery usually drains 50% and to restore amps in your battery 10 amps will take 10 hours and 15 amps or some more will charge your battery in 5 - .
These are the "smart chargers", and quality units generally are not found in discount stores. The three stages or steps in lead acid battery charging are bulk, absorption, and float or sometimes complete shut off in some cases. Qualification, or equalization are sometimes considered another stage, usually for promotional purposes. A 2 stage unit will have the bulk and float stages. It is important to use battery manufacturer's recommendations on charging procedures and voltages, or a quality microprocessor controlled charger to maintain battery capacity and service life.
The older 24 volt charger would feature a fixed charging voltage, high enough to "force" energy amps into the battery. The lower the initial battery voltage state of discharge , the easier this forcing process is, so you may see the amp meter if so equipped run up to the charger's maximum output amperage, and stay there a while.
As battery voltage rises, as it does as the state of charge increases, the harder it is for the 24 volt charger to force the amps in, so the amp rate decreases. Eventually, the charger reaches a point where it's output voltage can't force any more into the battery, so current almost stops, but depending on where this voltage point is, it may be high enough to overcharge over time, or keep the battery in the gassing stage, drying out a flooded type battery.
These chargers should be monitored for this reason, and disconnected when the amp meter drops to the low point. Some of these older technology units have timers, and depending on the setting and battery charge status at the beginning of the charge, may end up over charging, if too long, or under charging, if the timer is not set long enough.
Either condition can damage batteries, overcharging damaging quicker. Repeated undercharging allows sulphation to build, and eventually harden on the plates, diminishing battery capacity. The "smart chargers" are profiled with contemporary charging philosophy in mind, and also take information from the battery to provide maximum charge benefit with minimum observation.
The microprocessor allows a full charge cycle without need of setting a timer, and doesn't undercharge or overcharge, allowing proper battery management and maximum battery life, if used regularly. True Gel batteries generally require a specific charge profile, and a gel specific or gel selectable or gel suitable charger is called for. The peak charging voltage for Gel batteries is 2. Exceeding this voltage in a Gel battery can cause bubbles in the electrolyte gel, and permanent damage, as the bubbles in the gel do not dissipate when the over voltage condition ceases.
The target voltage for a 24 volt charger for AGM or some flooded batteries is 2. If the battery won't hold a charge, or the current does not drop after the expected recharge time, the battery pack may have some permanent sulphation.
This mode can be used to maintain a fully charged battery pack indefinitely. Some chargers shut off instead of maintaining a float voltage, and monitor the batteries, initiating a charge cycle if necessary. A deeply discharged battery deviates from this formula, requiring more time per amp to be replaced. Recharge frequency recommendations vary from expert to expert.
It appears that depth of discharge affects battery life more than frequency of recharge. Basically, lead acid batteries, including the sealed types AGM and Gel like to be kept fully charged when possible. This is called "opportunity charging". Equalization is essentially a controlled over charge. Some charger manufacturers call the peak voltage the charger attains at the end of the BULK mode absorption voltage an equalization voltage, but technically it's not.
Higher capacity wet flooded batteries sometimes benefit from this procedure, particularly the physically tall batteries. The electrolyte in a wet battery can stratify over time, if not cycled occasionally.
In equalization, the voltage is brought up above typical peak charging voltage to 15 to 16 volts in a 12 volt charger well into the gassing stage, and held for a fixed but limited period. This stirs up the chemistry in the entire battery, "equalizing" the strength of the electrolyte, and knocking off any loose sulphation that may be on the plates.
The construction of the sealed batteries AGM and Gel , all but eliminates any stratification, and most all manufacturers of this type do not recommend it advising against it. Some manufacturers notably Concorde list a procedure, but observing voltage and time specifications are critical to avoid battery damage. A 24 volt charger can be had from a low milliamp output , , milliamps , up to 40 or 50 amps, that will plug into a volt wall outlet chargers above about 30 amps usually require a 20 amp circuit, so check.
Some of the smaller units are unregulated, and simply have a fixed voltage output, like the chargers of old. These tend to take longer to charge, and should be avoided when possible. Smaller amp capacities are appropriate for smaller batteries, like electronic and security type applications in the 1. They also can be used for maintenance on larger batteries. A medium amp output 24 volt charger would be in the range of 15 to 20 amps or so, and be used for many applications using about amp hours of battery and up, or applications with a constant amp load power supply application.
For a power supply type situation, the constant draw should be a low percentage of the charger maximum amp capacity, to keep the charger from going back into the boost or bulk stage, or the charger should have selectability for the power supply or "battery with load" mode.
Larger units in the 24 volt charger models are about 25 to 40 amps output except commercial, VAC input types, or 3 phase. These are used in large amp hour battery banks, or applications desiring faster recharge times possibly at the expense of maximum battery life. Sometimes the larger units are used where a generator is the AC power source, and generator run time is a consideration. Thus, a ah 24 volt battery pack would take about a 25 amp 24 volt charger or less. Larger chargers may be used to decrease charge time, but may decrease battery life.
Smaller chargers are fine for long term floating, e. For more information, or 24 volt charger application specific recommendations, email us or call the tech line. Equalization Equalization is essentially a controlled over charge. Home Tutorials Battery Charging. Links: 12v chargers 24v chargers 36v chargers 48v chargers marine multi-bank converters inverters solar Secure Processing By: Chargie graphic by Dennis Hart.