Batteries
Posted: 30 Apr 2019, 16:56
Im interested in comments on people who have made or even thinking or have thought about making li-ion/li-po batteries, as you may know i have gone to a 7" screen on my sounder this raised an issue with battery storage, so I've opted for an FPV 17.5 li-ion battery.
I have been investigating making my own battery using 18650 li-ion cells after several vids and forums later i decided on purchasing the FPV one, the reason for this was not because i wasn't confident to make it, it was because of sourcing genuine parts and testing equipment.
Sourcing the batteries was the easiest part, when making a battery bank you really need a BMS (battery management system) this regulates the input and output voltages to protect the battery from over/under charge/use it also balances the battery charge state, these can be defective so need testing and some circuit parts relaced, the cells (each 18650) could/should be tested to determine it's capacity and arranged in a specific order to get the best longivity out of the battery, then there is the charger, this is suitable to charging li-ion/li-pol batteries.
My issue is of a result of watching perhaps too many vids, ok if you find a reputable store (online or not) that you can buy everything needed then alls good but is it? You can buy cells (18650s or others) they are 3.6v nominal and upto 3.6ah this is there rating not what they are, as stated they should be tested to find where they are placed in your battery bank, for example to get 12v at 17ah i need to have a 3s5p bank of 3.5ah 18650 cells, 3s = 3 18650s in series 3 x 3.6v =10.8v nominal 12.6v charged, 5p = 4 18650s in parallel 5 x 3.5ah =17.5ah, now for proper and safe charging/discharging you need a 3s BMS the rated amps needed is determined by 1. That rated for the cells 2. What your intended usage will be so for a kayak battery i would be looking at 10amps rated output so the PMS would be 3s 10amp.
Ok to summarize so far your 18650s, need testing, this can be done using an of the shelf 2, 4 or 6 battery compartment li-ion/li-po charger/tester, your battery bank 3s 5p needs a BMS and a charger, all of these items, 18650s, cell tester, BMS, and charger need to be purchased from a reputable dealer? But have they been tested before they get to you? How accurate are they in their intended function?
After watching many videos on YouTube of people making battery banks of many shapes and sizes, anyone can do it! But can anyone do it properly? The item being made is only as good as the person making it. Does the person know what they are doing? The person in the vid is my teacher! How good is my teacher? Ok so i watched many vids of guys building these battery banks, then testing these banks only to the put a BMS rated to the job on the correctly built bank then test the input and output voltage to make sure it was within specifications. All looked good! However i then watch another guy build a similar bank, but! He tested the BMS and found it to be faulty.
Let me explain a bit about 18650s. They have a nominal voltage of 3.6v and a rating of a certain amperage, you can drain a 18650 pretty much to zero amps however the voltage should go now lower than 3v, and when charging they should not charge higher than 4.2v, also they they have an input/output rating in amps if you exceed any of these parameters then you reduce the life of the battery.
Now back to testing the BMS if when testing your built battery bank you find one channel or more on the BMS or battery bank (depending on your test location) charge over 4.2 (if this is the stated max for the cells) and or deplete lower than 3v (if this is the stated min) then the faulty charge or discharge ic's need to be replaced and retested.
When building a new battery bank you should test each cell to find it's capacity, so you can arrange the cells evenly in the bank, this protects the cells and bank for premature failure.
Chargers: in some situations banks dont have an internal BMS so the charger is required to have one, most of the better battery chargers for charging li-ion/ li-pol battery banks are made to charge remote control toys?..... but dont have built in BMS so the chargers do, as these are the better chargers suited to charging li-ion / li-pol battery banks then it's these that would be the best to use to get the best out of your battery bank
My conundrum, am i garrenteed that if i buy/build my batter bank,tester, charger and BMS that they will be as stated? Even if all part are purchased from a reputable dealer? I dont think so! So without going to extremes, i need the tester, batteries, charger and BMS, the tester tels me the batteries are good or not, also where in my bank they shouod be placed for besr performance and if they are as rated (if not they are returned), the BMS this you have 2 choices build your own or buy but it MUST be tested in use, if not your bank will not last as it should, at worst it will explode, or catch on fire.
Buying goods over the Internet as we all know can be risky, especially from overseas as overseas dealers arnt governed by our laws, this can be a major issue when spending lots of money on faulty items, the reason for buying items from overseas is usually the price, sometimes you just cant source what you need here or have trouble finding an Australian supplier, so in the case of li-ion/li-po and anything to do with safety, test, test, test.
Ok sorry for the long road to get here but now the questions, who has used 18650 or similar for use in kayaking, camping and any other activity? What are they used for? Where did you get them? Did you make your own bank? And if so did you use a BMS? What if any testing was done on it/them? And finally (for now) are you happy with them?
Ps, this is im hoping to open some discussion on the use of an alternative to using SLA batteries in mainly kayaking and associated camping and any other use you have for them.
I have been investigating making my own battery using 18650 li-ion cells after several vids and forums later i decided on purchasing the FPV one, the reason for this was not because i wasn't confident to make it, it was because of sourcing genuine parts and testing equipment.
Sourcing the batteries was the easiest part, when making a battery bank you really need a BMS (battery management system) this regulates the input and output voltages to protect the battery from over/under charge/use it also balances the battery charge state, these can be defective so need testing and some circuit parts relaced, the cells (each 18650) could/should be tested to determine it's capacity and arranged in a specific order to get the best longivity out of the battery, then there is the charger, this is suitable to charging li-ion/li-pol batteries.
My issue is of a result of watching perhaps too many vids, ok if you find a reputable store (online or not) that you can buy everything needed then alls good but is it? You can buy cells (18650s or others) they are 3.6v nominal and upto 3.6ah this is there rating not what they are, as stated they should be tested to find where they are placed in your battery bank, for example to get 12v at 17ah i need to have a 3s5p bank of 3.5ah 18650 cells, 3s = 3 18650s in series 3 x 3.6v =10.8v nominal 12.6v charged, 5p = 4 18650s in parallel 5 x 3.5ah =17.5ah, now for proper and safe charging/discharging you need a 3s BMS the rated amps needed is determined by 1. That rated for the cells 2. What your intended usage will be so for a kayak battery i would be looking at 10amps rated output so the PMS would be 3s 10amp.
Ok to summarize so far your 18650s, need testing, this can be done using an of the shelf 2, 4 or 6 battery compartment li-ion/li-po charger/tester, your battery bank 3s 5p needs a BMS and a charger, all of these items, 18650s, cell tester, BMS, and charger need to be purchased from a reputable dealer? But have they been tested before they get to you? How accurate are they in their intended function?
After watching many videos on YouTube of people making battery banks of many shapes and sizes, anyone can do it! But can anyone do it properly? The item being made is only as good as the person making it. Does the person know what they are doing? The person in the vid is my teacher! How good is my teacher? Ok so i watched many vids of guys building these battery banks, then testing these banks only to the put a BMS rated to the job on the correctly built bank then test the input and output voltage to make sure it was within specifications. All looked good! However i then watch another guy build a similar bank, but! He tested the BMS and found it to be faulty.
Let me explain a bit about 18650s. They have a nominal voltage of 3.6v and a rating of a certain amperage, you can drain a 18650 pretty much to zero amps however the voltage should go now lower than 3v, and when charging they should not charge higher than 4.2v, also they they have an input/output rating in amps if you exceed any of these parameters then you reduce the life of the battery.
Now back to testing the BMS if when testing your built battery bank you find one channel or more on the BMS or battery bank (depending on your test location) charge over 4.2 (if this is the stated max for the cells) and or deplete lower than 3v (if this is the stated min) then the faulty charge or discharge ic's need to be replaced and retested.
When building a new battery bank you should test each cell to find it's capacity, so you can arrange the cells evenly in the bank, this protects the cells and bank for premature failure.
Chargers: in some situations banks dont have an internal BMS so the charger is required to have one, most of the better battery chargers for charging li-ion/ li-pol battery banks are made to charge remote control toys?..... but dont have built in BMS so the chargers do, as these are the better chargers suited to charging li-ion / li-pol battery banks then it's these that would be the best to use to get the best out of your battery bank
My conundrum, am i garrenteed that if i buy/build my batter bank,tester, charger and BMS that they will be as stated? Even if all part are purchased from a reputable dealer? I dont think so! So without going to extremes, i need the tester, batteries, charger and BMS, the tester tels me the batteries are good or not, also where in my bank they shouod be placed for besr performance and if they are as rated (if not they are returned), the BMS this you have 2 choices build your own or buy but it MUST be tested in use, if not your bank will not last as it should, at worst it will explode, or catch on fire.
Buying goods over the Internet as we all know can be risky, especially from overseas as overseas dealers arnt governed by our laws, this can be a major issue when spending lots of money on faulty items, the reason for buying items from overseas is usually the price, sometimes you just cant source what you need here or have trouble finding an Australian supplier, so in the case of li-ion/li-po and anything to do with safety, test, test, test.
Ok sorry for the long road to get here but now the questions, who has used 18650 or similar for use in kayaking, camping and any other activity? What are they used for? Where did you get them? Did you make your own bank? And if so did you use a BMS? What if any testing was done on it/them? And finally (for now) are you happy with them?
Ps, this is im hoping to open some discussion on the use of an alternative to using SLA batteries in mainly kayaking and associated camping and any other use you have for them.