PD4655 Charging Lithiums September 30, 2023, 05:57:35 pm I just replaced the OEM converter with a PD4655VL. I changed the jumper setting to lithium per the PD website and retained the stock distribution board. I hooked up a 100ah lithium with a 25% state of charge. The converter is charging 30.6 amps but only 13.65 volts. I was expecting to see 14.6 volts. Is this normal? Thanks.jor
Re: PD4655 Charging Lithiums Reply #1 – September 30, 2023, 06:06:52 pm Quote from: jor - September 30, 2023, 05:57:35 pmI just replaced the OEM converter with a PD4655VL. I changed the jumper setting to lithium per the PD website and retained the stock distribution board. I hooked up a 100ah lithium with a 25% state of charge. The converter is charging 30.6 amps but only 13.65 volts. I was expecting to see 14.2 volts. Is this normal? Thanks.The voltage should go up as the battery charges with 14.6 volts being a full charge. With the charger off, a fully charged lithium battery should float at 13.3-13.6 voltsLarry 1 Likes
Re: PD4655 Charging Lithiums Reply #2 – September 30, 2023, 06:17:13 pm QuoteThe voltage should go up as the battery charges with 14.6 volts being a full charge. This is my first exposure to lithiums. This battery is at 25%. So are you saying that if I just leave the converter on that the voltage will eventually rise to 14.6. I thought that the normal charging voltage was supposed to be a constant 14.6. Thanks.jor
Re: PD4655 Charging Lithiums Reply #3 – October 01, 2023, 07:08:54 am The pd4655 will adjust the charging voltage as the batteries charge level increases. I leave my unit plugged in while in storage and the battery voltage shows 14.5 then. This is normal.
Re: PD4655 Charging Lithiums Reply #4 – October 01, 2023, 12:02:20 pm What you're seeing is a charger in bulk mode. Remember how bulk charging works: the charger pumps in current as fast as it can, at a gradually increasing voltage (determined by the battery) until the voltage reaches a setpoint--14.6 volts in your case. Then it switches to absorb mode, which holds the voltage constant while feeding current at a decreasing rate; and finally to float--trickle-charging at a lower voltage.That's with lead-acid batteries. With lithium batteries, there's no need for absorb; the charger pumps in the amps "full bore" in bulk mode until the setpoint is reached, and then switches to float. (In some cases there's a very brief absorb phase--my chargers are set to spend one minute in that mode, because I had to set something.) This results in much faster charging than with lead-acid batteries. So in short, your charger is doing what's expected. The voltage will gradually rise to 14.6 V (assuming that's its bulk setpoint), and then pretty shortly thereafter switch to float charging at 13.5 V or thereabouts.
Re: PD4655 Charging Lithiums Reply #5 – October 01, 2023, 12:03:44 pm Quote from: jor - September 30, 2023, 06:17:13 pmThis is my first exposure to lithiums. This battery is at 25%. So are you saying that if I just leave the converter on that the voltage will eventually rise to 14.6. I thought that the normal charging voltage was supposed to be a constant 14.6. Thanks.The voltage will rise to 14.4-14.6, at which point the batteries’ BMS will stop allowing charging.The BMS controls the battery charging and discharge rates, preventing too high a charge or discharge rateIf you have a battery monitor, you will notice the charge rate significantly decreases as the voltage nears 14.6, during this period, the BMS equalizes the charge level of each cell in the battery(ies)Larry
Re: PD4655 Charging Lithiums Reply #6 – October 01, 2023, 12:37:07 pm Thanks, guys. That's exactly what happened. All is well!!! jor 1 Likes
Re: PD4655 Charging Lithiums Reply #7 – October 03, 2023, 01:24:40 am Jor - Your unit is a 55 amp charger (info gotten from progressive’s pages).If you are on shore power you should get close to 55 Amps charge (minus your current battery usage - vampire stuff and any 12v you are charging or using). We have a PD4060CSV 60 Amp and run 2-6 Amps below 60 depending on what we are charging.However on generators they often don’t do the full amps as they are not producing they many watts. I saw a table that showed kw generators and max they would supply to the charger/converter and it matched for our 2.8k generator (some lower number that I currently don’t remember) and our 4k generator (closer to 60).I am guessing the 36amps was on a generator.