Since my visit to McConnell AFB, I have been researching Li-ion Batteries. Those 3.7V batteries that sometimes blow up.
I have found out that it's because they are not "protected" like in Cheap Vaping devices or "Hover Boards".
They require inexpensive conditioning and equalizing electronics if you are going to place them in series.
But here is the deal. 3.7V Li-ion you need 3 or 4 in series. 3 gets you? 11.1 volts - you can run a rig on that, but not full output, or 4 cells in series gets you 14.8.. some hams use 4 and undercharge them about 70% capacity to run in that 12.2 to 13.8 V range.
FYI- 18650 cells on Ebay and Amazon claiming up to 6000mAh.. are NOT. I've tested them at 1024 to 1400mAh..about $1.50+ BTW
The li-ion battery disadvantages include: Protection required: Lithium ion cells and batteries
are not as robust as some other rechargeable technologies. They require
protection from being over charged and discharged too far. In addition
to this, they need to have the current maintained within safe limits.
The alternative is to use another Lithium type battery. Lithium iron phosphate battery or LifePO4 battery. Considered safer, greater recharge cycles and higher initial cost. LifePO4 batteries are 3.2Volts, therefore 4 in series gives you 12.8 - an excellent voltage to run a GO BOX. So you can fully charge LifePO4's and it's safe for ham gear.
LifePO4's can put out 100 amps if you are not careful. There are YOUtube video's showing a 1/2" open end wrench turning cherry red across one of these batteries.
I am considering building at least 1 maybe 2 or 3 for Go Boxes. I have a line on? 2 styles of LiFePO4 Nominal Capacity 8Ah Charging voltage 3.65V Nominal Voltage 3.2V Cut-off Discharge Voltage 2.0V Charging Method CC/CV Maximum Discharge Current(continuable) 200A Maximum Charge Current(continuable) 80A
Cycle Life 1500cycles 1C 100%DOD
?????????????? 2000cycles 1C 80%DOD
Work temperature??? Charge -10℃ to 45℃ ????????????????????????????? Discharge -20℃ to 65℃ Dimension(mm)???? Diameter 38mm ?????? ? ? ? ? ? ? ? ? ? ?? Length 120mm(152 with screw) Weight 360 grams
These are commonly known as 38120S (Diameter Length S=screw terminal)? I can get them for $11 each +8 for $10.50 and +40 for $10.00 So for 8 -$44 plus shipping I would have the major components for 12.8V 16Ah but could draw 400amps for 2.4 minutes!!
I can also buy smaller 18650 1.1Ah cells? 100 count for $150 or $2 each. (the above is more Ah per $)
Then finally they have 18650 1.5Ah cells? 24 count case for $48..
18650 would require battery holders, which can be had for about $2 that holds 4 cells.
Shipping out of Pennsylvania, These are my costs through my wholesaler. I am considering selling them at hamfests and on ebay. Connectors and conditioner (BMS) pc-boards are under $10.. then a container woul dbe needed. Some Li-ion batteries are simply assembled and placed in shrink wrap to hold them together. Other are in plastic cases..
If anyone would like to work on this project with me contact me...
Larry Macionski