2s Life Charger - Page 1
Forum section: electronics / beginners

author: Dave Wave
author_rank: Contributor
timestamp: February 09, 2020, 09:38:22 pm
content: I have a project that uses a 1500 mah 2S Life battery for power (A hobby battery with leads for power and a balance lead).I want to be able to charge it in the device through the balance lead.I was hoping to find a board I could build into the device that would charge and balance the device.I found a couple TP5000 charger boards, 1S chargers so I assume if I try to run two in parallel, it will lead to isolation issues? Would it make a difference if I powered each Tp5000 from and individual buck/boost supply?https://www.ebay.com/itm/TP5000-3-6v-4-2v-Charger-Module-3-7v-Lithium-ion-3-2v-LiFePO4-Battery-Charging/143482390497?epid=2305263656&hash=item21683787e1:g:46oAAOSwA-VeAyMhI also found a BMS board that is supposed to balance the boards and do protection, but does not have an integral charger.https://www.ebay.com/itm/2S-3S-4S-18650-Lithium-Li-ion-LFP-LiFePo4-Battery-BMS-Protection-Board-W-Balance/312772150203?ssPageName=STRK%3AMEBIDX%3AIT&var=611500761627&_trksid=p2057872.m2749.l2649Any ideas how to put this all together with something that can safely charge a Life battery?Thanks,-Dave

author: aix
author_rank: Regular Contributor
timestamp: February 10, 2020, 07:35:23 am
content: I'll let someone more qualified chime in on the balance charging aspect, but I wanted to mention that TP5100 natively supports 2S batteries (as well as 1S). There are plenty of boards on eBay, AliExpress etc.

author: mvs
author_rank: Frequent Contributor
timestamp: February 10, 2020, 07:54:29 am
content: TP5100 is a Li-ion charger with 4.2/8.4V cutoff, a bit to high for LiFePO4 battery.CN3722 should work fine.

author: beanflying
author_rank: Super Contributor
timestamp: February 10, 2020, 08:58:54 am
content: Most BMS boards are not chargers as well. The basics of them is they are simple voltage protection for each cell that breaks the circuit using a fet. So they are only a protection device and not an appropriate method to charge cells with as their is no multistage or current control.With using seperate 1S charge boards I have used theseeBay auction: #371947835700and providing you don't need high charge rates they work fairly well. Just pay attention to the datasheet and give yourself some head room.

author: Dave Wave
author_rank: Contributor
timestamp: February 12, 2020, 02:12:15 pm
content: With using seperate 1S charge boards I have used theseeBay auction: #371947835700and providing you don't need high charge rates they work fairly well. Just pay attention to the datasheet and give yourself some head room.I'm confused. My understanding is that the 1S boards can only do 1S, there is now way to set them up to do 2S (using two modules, due to common ground issue). Not true or did I just misunderstand you are using 1S board and 1s battery?Thanks,-Dave

author: beanflying
author_rank: Super Contributor
timestamp: February 12, 2020, 04:31:23 pm
content: 3am here and just had a visit on the roof by some very noisy Possums in heavy shoesbut I Re found an old thread I made using the Mornsun modules and in that case LiPo 1S boards but LiFe boards would sub in just the same.https://www.eevblog.com/forum/projects/multi-cell-lithium-charger-from-a-single-5v-supply/msg1454259/#msg1454259The Mornsun modules are effectively isolated power supplies because of this you can power them ALL from a common low voltage supply to power the 1S boards. The outputs of the 1S charge boards are then all isolated electrically from each other. Because of that you can gaisy chain these outputs and charge each cell by hooking up to them when the cells are in series. That is hook the positive of one 1S board into the ground of the next and so on.If this doesn't make sense I will sketch up a wiring diagram of some sort when I wake up after hopefully some sleep.

author: Dave Wave
author_rank: Contributor
timestamp: February 19, 2020, 06:21:30 pm
content: In terms of hooking the 1s boards in a daisy chain....are you talking about the outputs?I would appreciate a diagram if you have time.I found the part on ebay and ordered up a couple.Thanks for the help!-Dave

author: beanflying
author_rank: Super Contributor
timestamp: February 19, 2020, 09:31:25 pm
content: What you are creating is two floating power supplies with chargers attached to their outputs. So if you used just te Mornsun modules without the chargers you could create a 10V output from a single 5V supply by hooking the positive of one with the negative of the other like a conventional dual power supply.So after adding the chargers Negative Charger board 1 goes to pack negative and positive goes to the positive of the first cell which is also the junction with negative of cell 2. The Negative of Charger board 2 goes to the junction between the cells and then the positive goes to pack positive or the positive of cell 2.

author: Dave Wave
author_rank: Contributor
timestamp: February 20, 2020, 11:24:19 pm
content: Got it.Thanks for the help.Ill give it a go when the parts come in.-Dave

author: beanflying
author_rank: Super Contributor
timestamp: February 20, 2020, 11:54:25 pm
content: No probs. Handy modules for all sorts of jobs