Charging a Lifepo setup with a switched PS vs a non switched and a diode

[TheSniper]

Schematic of using a diode? in these scenerios? what about the diode it self. does it matter the size?
relative to the charge being accepted and or the size of the battery bank?
TIA.
-S

 

[nosys70]

diodes in panels are here to prevent reverse current flow if they are setup in serie or parallel, or connected directly to a power source.
the diode must be able to support current going thru (so a 8A panel should have at least a 8A diode).
Since high current diodes are expensive, putting several diodes in parallel is possible.
They also need to support reverse voltage , so if you have a panel outputing 20V or 60V, you need to find a diode that support the equivalent reverse voltage.
Diodes have a resistance, so they dissipate thermal power and create a voltage drop.

 

[Danny]

Schematic of using a diode? in these scenerios? what about the diode it self. does it matter the size?
relative to the charge being accepted and or the size of the battery bank?
TIA.
-S

My impression is that you don't need diodes if you will be using a charge controller as a general statement unless you have shading on one panel. As mentioned you give up power if you used diodes and they are built into some panels. I just did a project where I am using a blocking diode and I display in detail voltage drop and the Blocking diode function. You could easily play around with this using your car battery and a $13 dollar solar panel as I have done in this video.

 

[TheSniper]

Just want to clarify,.. No panels involved. this is just charging from a PS.. No Solar.

 

[Danny]

Just want to clarify,.. No panels involved. this is just charging from a PS.. No Solar.

If you are using a charger, the charger / power supply has components to prevent current back flow from the battery to the charger. You won't need to add anything I think. In general, most types of diodes allow current flow in one direction. Mostly we want to current to flow from a charging source to a battery or load. My video does show how it is important to match amps and voltage with a particular diode.

 

[TheSniper]

If you are using a charger, the charger / power supply has components to prevent current back flow from the battery to the charger. You won't need to add anything I think. In general, most types of diodes allow current flow in one direction. Mostly we want to current to flow from a charging source to a battery or load. My video does show how it is important to match amps and voltage with a particular diode.

My Batts: 8 prismatic 195ah Batts. they will end up 2 individual 12v setups (14.6) then sit side by side an an RV. (no solar in my application) Anyways. I bought them new they were A quality Batts. when they arrived I tested them all they were all @ 3.2. I began my charging with all of them paralleld together. after 2 days on a el cheapo charger? no diff in voltage. I then seperated them into 2 seperate banks of 4 paralleled. and resumed charging of one of the banks only.. Day 1? no noticable increase in voltage even though they have been sucking +/-4Ah@3.6v I then increased the V to 3.99 and the AH is now at about 7. After 12 hours they went up to 3.3v. 1 v in a day and a half? is this normal? Im thinking I'll set up each bank in its final 14.6 setup and use my mega charger (automotive charger) get them up faster.. as they approach the top? Ill reconfigure them in parallel. for the final topping.
Im a little worried I wont lie! advise?

 

[Danny]

My Batts: 8 prismatic 195ah Batts. they will end up 2 individual 12v setups (14.6) then sit side by side an an RV. (no solar in my application) Anyways. I bought them new they were A quality Batts. when they arrived I tested them all they were all @ 3.2. I began my charging with all of them paralleld together. after 2 days on a el cheapo charger? no diff in voltage. I then seperated them into 2 seperate banks of 4 paralleled. and resumed charging of one of the banks only.. Day 1? no noticable increase in voltage even though they have been sucking +/-4Ah@3.6v I then increased the V to 3.99 and the AH is now at about 7. After 12 hours they went up to 3.3v. 1 v in a day and a half? is this normal? Im thinking I'll set up each bank in its final 14.6 setup and use my mega charger (automotive charger) get them up faster.. as they approach the top? Ill reconfigure them in parallel. for the final topping.
Im a little worried I wont lie! advise?

PLEASE STOP CHARGING HOW. Don't change anything! Read this article. https://marinehowto.com/lifepo4-batteries-on-boats/ and search for revised top balancing area in article. Charge in parallel and up to your max charge voltage tailing off the current. I use a $200 bench charger like the article recommends. Cheaper bench chargers can be used maybe 10A but you need to drive them at 70-80% or you will burn them out. Read the entire article about 5 times before you start making changes. The batteries have a flat charge curve don't worry if you are pumping in amps and don't see voltage go up. Look at the charge curve in the article. TOTALLY TRUST THIS ARTICLE , until you have much more knowledge. You are learning. Take some time and read this now! Don't look at you tube videos until you read and understand this article. Be ready to let your pack sit for several hours in parallel.
Danny