Effective charging at recommended voltages with proper time and current limitations extends battery life and maintains battery capacity throughout battery life.
1) maintaining or exceeding the predictive life cycles of the batteries in use,
2) maintaining the maximum rated capacity of the battery throughout the life of the battery,
6) programmable for future size and chemistry of batteries.
There are 3 main types of Lead Acid Batteries being used aboard recreational vessels, flooded, AGM and Advanced AGM. We only recommend AGM and Pure Lead AGM technology.
In no circumstances do we recommend flooded lead acid batteries because the batteries generate hydrogen gas. Most compartments (that batteries are mounted in) do not have enough ventilation to dissipate the hydrogen gas and this can result in a dangerous situation occurring where the battery blows up. The other main reason why we stay away from flooded lead acid is due to the inefficiency of the battery under load and charging. This results in the battery getting hot during a high current discharge. This also results in far higher energy use overall.
AGM
AGM batteries from reputable manufactures are known for long service life when charged correctly.
Due to inaccuracies in the manufacturing processes, batteries age differently and the amp hour capacity of the battery changes uniquely to the battery. This can lead to differing battery voltages, which need correction. This can be accomplished by battery balancers for light current charging like solar, or through the use of one battery charger per battery.
It really is the luck of the draw if batteries stay in balance over their lifetime.
We are concerned with what happens at the end of the batteries life for safety reasons. If batteries are not monitored and controlled on the individual battery level, at the end of the batteries life the voltage of the weakest battery will become spongy, going higher than the rest during charging, and lower than the rest during discharging. Preventing high voltages on weak batteries at end of battery life is important to insure the safety of the system. The onus is on the boat's owner if the system does not do so automatically, so vigilantly monitor your batteries manually! Get yourself a voltage meter. Sears has a great one with a current clamp at a reasonable price.
4 bank battery chargers rarely accomplish their rated charging currents. As these chargers heat up, the charger reduces current to prevent thermal issues. Some 15 amp chargers (per battery) in actuality only produce half that amount during long charging periods.
AGM batteries have minimum charging requirements if you want to obtain the manufacturers cycle life. 7 amps per battery, in most cases will result in the derating of the cycle life of the battery. Depending on how much you use your boat, this may or may not be an issue.
4 bank chargers do not look at the individual battery temperatures. If one battery is located in a different ambient temperature environment, then these chargers cannot do proper temperature compensation. Without a temp sensor on each battery, it is possible to overheat the battery, most likely at the end of the batteries life.
Many AGM batteries require a charge of 20% of the amp hour capacity of the battery or more to obtain advertised cycle life.
BATTERY BALANCERS
Battery balancers shunt up to .7 amps between neighboring batteries. You need three of them in a 48 volt system. They have the added advantages of monitoring for errors in the battery bank by triggering an alarm if any two batteries differ in voltage by more than .2 of a volt. We hook this alarm up to the solar charge controller such that the charge controller is only enabled when the alarm is off, thus preventing over charging of any one battery in the string.
DEDICATED CHARGERS
The simplest and most cost effective way of perfectly charging and monitoring batteries is to use one battery charger per battery with dedicated temp sensor and network capability. The chargers we use give accurate information on the state of each battery in the string over a Canbus network to a touchscreen monitor.
INFORMATION
Since each battery bank in series is only as good as its weakest battery, this information is critical for safe operation of the vessel, especially when the battery starts failing nearing the end of battery life.
OPTIONAL CANBUS NETWORK
Each battery gets its own dedicated temperature sensor with temperature compensation, monitoring, and alarm. When you are dependent on each and every battery, this information is great to have on board. You don't have to wonder each time you take your boat out whats going on with your energy source.
AC DISTRIBUTION
Individual chargers can be mounted near where the batteries are, and AC routed to them easily. Be aware that the initial cost does include good AC distribution. Our charging system is inclusive of AC distribution in a sealed box protected by an RCBO breaker at 30 milliamps fault trip and 30 amps over current trip settings.
National electric code derates Shorepower AC circuit ampacity by 20% for continuous currents longer than 4 hours. What this means to us, is a a 30 amp AC circuit should not exceed 24 amps AC if the charger will be on for over 4 hours. This is a wise rule, worth noting and may be the bottleneck for a larger battery and charging system.
OPTIONS
The chargers we use have the additional capability of monitoring and alarming critical battery conditions. You can start with the 4 chargers and AC distribution box first, then add the monitoring and networking at a later date. If different batteries are used in the future, you can reprogram the chargers at that time by adding a USB adapter for your laptop.
PURE LEAD BATTERIES
When considering your next batteries consider Pure Lead Batteries. Our pure lead batteries are the best in the world. They have modified electrochemistry for partial state of charge operation. Carbon electrodes and specially formulated electrolyte make the best possible battery for the marine environment.
Make sure that the charging system that you use is adequate for the pure lead battery that you choose. Some pure lead batteries require as much as 40% of their amp hour capacity in bulk charging to meet their advertised cycle life.
During partial state of charge charging our pure lead batteries are operating in excess of 97 percent charging efficiency, rivaling even Lithium for Charge Efficiency.
Overall cycle life is near double what you have been getting from standard AGM, yet they are about the same cost overall, making them the best battery deal on the market today in terms of cost per cycle and cost per year of ownership. Electroprop's pure lead batteries are capable of 3,000 cycles at 30% d.o.d, 950 cycles at 50% d.o.d, and 450 cycles at 100% d.o.d. You probably wont run into the cycle life of these batteries during your ownership of your boat. Additionally these batteries are designed with a 10 year float life.
Pure lead batteries are the safest on the market as well. The battery grids do not internally corrode making it impossible to have a shorted cell,( the achilles heal of standard AGM technology.) The end of battery life is graceful.
Electroprop's pure lead batteries are manufactured in the United States.
CHARGING ALGORITHM
The better you charge any battery, the longer they last. Absorption time needs to be calculated and truncated at the proper time and/or current. Voltages need to be perfect for bulk, absorption, and float. Minimum charging requirements need to be met. The deeper you plan to discharge your battery, the bigger your charging system should be to make sure the plates get desulfated properly during deep discharge.
KEEP AN EYE ON YOUR BATTERIES
If you do opt to charge with a 48 volt charger without a method for balancing, then to maintain safety you need to be vigilant in monitoring the battery bank and know and understand your batteries and realize that the batteries are changing as they age. You can do this with the use of a voltmeter and keep a log of the change over time. Monitor the batteries during deep discharge for a load test, and while the batteries are charging at absorption voltage. If the batteries start going out of balance, without a balancing method they will quickly age and fail. All of the batteries may fail due to the incorrect charging voltages of an unbalanced battery pack.
ELECTROPROP'S LEAD ACID BATTERY MANAGEMENT SYSTEM.
We can build these systems up to 100 amps per battery if necessary which can be used for hybrid operation from an AC generator. All the while, all the batteries are kept safe and last the longest possible time.
With dedicated chargers on each battery it is possible to replace only one battery at a time.
Having all the information about your batteries available all the time lets you better understand the capabilities of your electric boat. We are truly lucky to live in a day that all of this is now possible.
INHERENT VALUE
Some batteries could last twice as long or more simply by accurately maintaining the charging voltage. I would rather have a set of batteries with BMS than two sets of batteries any day!
Contact me off list if you are interested in a quote. We will also be offering our Lead Acid Battery Management system as a standalone product in the near future, so keep an eye on
electroprop.com for pricing.
Be kind to your batteries and your batteries will be kind to you!
Be Safe, Efficient and Powerful,
Yours sincerely,
James
James Lambden
The Electric Propeller Company
625C East Haley Street,
Santa Barbara, CA
93103
805 455 8444
james@electroprop.com
www.electroprop.com
I have an Ericson 30+ with a Thoosa 9K motor. My only charging is done with shore power. My charger, a QuadPro has died. Well, half-died It's 4 12V chargers in a package, and 2 out of 4 are dead.
What do people here like for replacement? Another QuadPro? Something that instead would charge the whole 48 bank instead of charging each 12V battery separately? (Battery is made up of four 4D 12v 198 Amp Hour AGMs.)
I would like to maximize options like adding solar or running off a portable generator like Bianka does. Does that impact my charger options?
Any thoughts on Iota? OnNoco Genius? DSR Industries? DualPro Eagle? Others I have not thought of?
The general topic of charging the whole 48V bank versus each battery? If you do that do you use a separate 4 bank charger for equalization?
--Ernie Galvan
S/V Zenergy
