So, it is undoubtedly clear that the range of heat should be in between 0 to 400C. There is a lot of difference between lithium battery and lead acid battery. Bulk is very efficient! Please remember that bulk is not a voltage limited stage of charging it is constant current. BULK – Bulk Charging is the constant current stage of charging where the charge source is limited only by what it can deliver in current. When voltage is steady at 14.3V to 14.4V the battery can be deemed 100% full when charging-current,/tail-current/return-amps declines to 0.5% of Ah capacity. Once here in my shop it was cycled to 80% DOD then back to 100% SOC twice. There is a different kind of battery chargers are available in the market. Discharge to 50% = 47.98Ah (left in the battery after discharge), 1 Hour .4C charge then discharged and counted Ah’s delivered back to 50% SOC = 33.43Ah, 47.98Ah + 33.43Ah = 81.41Ah of stored energy, 81.41Ah is approx 85% of the baseline Ah capacity of 95.69Ah’s. I will repeat this, IMPOSSIBLE! Would you like to see more articles like this? is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for website owners to earn advertising fees cord should be free of breaks or cuts and the wall plug should be clean. Smart? Far too many marine charge sources drop to float prematurely. The battery was then recharged for exactly 2 hours at .2C and then discharged back to 50% SOC and the stored energy for that cycle was measured. Bulk charging is not a voltage limited stage of charging despite many companies bastardizing the term bulk for apparent marketing purposes. Who wants to charge their AGM battery they should get knowledge about the right temperature range for it. This image is a screen capture of the Lifeline Battery Tech Manual. AGM batteries have a wide range of functions. So, this point should be kept in your mind. Kinetik HC600 Black Lead_Acid_Battery review 2020. The myth goes something like this: By using a battery combiner, on AGM batteries, and feeding the alternator or battery chargers charging current directly to the house battery bank first, “it will leave your start battery under charged“. It was then equalized at 15.5V for 4 hours, (Lifeline calls this conditioning). This is just represents a percentage of Ah capacity in either charging or discharging current. With a fully adjustable power supply I can control when the battery changes from absorption to float and not rely on an egg timer. This current, 18.75A is .15C or a 15% charging current of a 125Ah battery. Once the charge process switches from constant-current/bulk to constant-voltage/absorption, the charge efficiency continues dropping. The charger cabling should be insulated and free of breaks or cuts. between a charger and a good battery, after that switch on the charger. If you think about the physical charger size, then it was a mistake! Please understand that BULK is not a voltage limited stage of charging, despite the marketing guru’s vastly missing the mark on this one…, Kudo’s to the guys at Lifeline Battery for properly understanding the difference between BULK and ABSORPTION. IMPORTANT: Please understand that you will never likely charge this fast with a typical smart charger. This is why many a boater has burned up their alternators charging AGM batteries. (grin). SCALE IT UP: If we scale this test up, and it should scale well, a .4C charge rate on a 450Ah fairly typical cruising boats house bank would be a continuous 180A. At .4C the battery attained absorption voltage at approx 63.3% SOC and at a .2C charge rate it attained absorption voltage at approx 77.4% SOC. So AGM batteries are essential for everyone. This test was a .4C charge for two hours and when discharged back to 50% SOC, after the 2 hour charge, the stored energy removed was 44.48Ah. This leaves the battery at 49.3% SOC or just about 50% SOC. Suffice it to say it is physically impossible to recharge a 440Ah bank of AGM batteries at 50% SOC to 100% SOC in 1.5 hours with a .34C charge current. The battery delivered -48.33Ah or just about where it had on the previous test which ended at -48.54Ah. This means 97.4% of the energy supplied by the charger, or the 21A for exactly 1 hour, was removable as stored energy when we discharged back to 50% SOC. The steps described above may help you a little bit. Sorry we couldn't be helpful. On a 450Ah bank that would be an alternator or large inverter/chargers that could sustain 180A when hot. The battery used for this testing is a 2015 Lifeline Group 31 AGM Deep Cycle battery. I did not pause and let the battery rest between charging & discharging because this is not actually done on cruising boats. If I desire a timer cut off I simply program a digital wall timer. The discharge current at 77F that will yield a 20 hour run time before hitting 10.5V. Simply put, bulk=constant-current charging not constant-voltage. Automotive Battery Charger 12V/8A 24V/4A Trickle... Schumacher SC1280 15 Amp 3 Amp 6V/12V Fully... CTEK (56-353) MULTI US 7002 12-Volt Battery... NOCO GENIUS5, 5-Amp Fully-Automatic Smart Charger,... DEWALT DXAEC80 30 Amp Bench Battery Charger: 80... AGM battery and gel-based battery technology. Many latest battery chargers and preserves have information collecting microprocessors. AGM batteries made with ultra-thin fiberglass mat squeeze in between the plates that are soaked with battery acid to about 95% of what they can hold. PREFACE: This article looks at the *charging times & achieved state of charge of an AGM battery in multiple scenarios. The charging devices we use on boats are all considered CC > CV charge sources, or constant-current (BULK) then to constant-voltage (ABSORPTION, FLOAT & EQ). Battery voltage will rise pretty slowly from here on but to get to an ACR’s “combine level” is relatively quick and easy, especially if you have your system set up properly. 100% SOC was deemed as 0.525A flowing into the battery at 14.4V per the Lifeline Battery Technical Manual. Here at 20 minutes, with the voltage now held steady at 14.4V (green CV/constant-voltage light on) we can see that the charge current has already dropped from 42A to 41.5A or a .5A reduction in accepted charge current into the battery. Absorbed Glass Mat batteries are making with a different technology than the conventional flooded one. In my shop I use adjustable power supplies to avoid dumb so called “smart chargers”. In this diagram Bulk/CC is the orange area and Absorption/CV is represented by blue. New batteries will perform differently but our batteries on boats rarely stay new for very long. Would you like to see more articles like this? Amperes (Ah) is the unit of a chargers capacity. The problem still remains that the last 4% is critically important to AGM longevity. Adequate procedures for charging a battery not maintain the battery health but also help in renewing an almost dead battery. Your donations help keep the content coming and also help keep it free. Based on this image, and the data logger, I know the battery attained 14.4V at around 19 minutes. Hardly! With the help of the 20 AH capacity and charge current, you may calculate the remaining charge time required for the battery bank to reach 100% state of charge (SOC) using the following equation: We recommend a charge current of 20% of the 20 hr rate for both Bulk & Absorption charge phases on AGM & GEL VRLA models.