The problem with paralleling batteries it that they never are at exactly the same voltage. There are always equalising currents flowing between them. And the bigger the gap in internal resistance - the bigger such a current will be, no to mention that the external currents will divide not exactly as you have planed
I am not an electrician but a financial guy. My one friend is an electrician but he is not an expert on batteries. I understand this concept of paralleling different capacity batteries as I am doing it for years. He falls back on his book knowledge and say it can't be done and after a lot of discussion he still say I am wrong and it will damage the batteries.
Thank you, nice job explained this and why batteries do what they do spreading the amps draw when connecting to parallel. and also the importance of same voltage when making connection.
Wow thank you! I understand now .. cause I was planning to get an extender pack for my e scooter but at a lower capacity so I was worried of burning my other battery if I connect them in parallel.. anyway thank you this video was a big help.
You could put the load (red) on the other side of the battery array and still be in parallel which would give you equal charging and discharging capabilities. It would also increase the battery life expectancy because it’s better balanced. Often the battery at the beginning of a parallel circuit does the majority of the work will the battery at the end does the least. Food for thought. Balance your load. =] LoL
Informative..can you tell us the formula on how you came up with the figures of 3.6A and 2.4A?..because when I did ratio calculation I end up with 4.26A for the 17.5ah and 1.74A for the 7ah = 6Amps..but you said in the video that you calculate it with the internal resistance..please can you give me the equation formula on how to calculate including internal resistance?..thanks for the video..
Hey on my one battery i have2 +s and 2 -s wire going in to each controller but my second battery only has 1+ and 1 -. Can I get away with just hooking it up to only 1+ & negative on the first battery
I want to use two recharagable batteries in parallel, though I understand their will be voltage difference between them. I want to avoid any flow of charge from higher to lower voltage battery is their any way this may be avoided ? Thanks
What if I put a BMS with lower Amp rating on the pack with lower capacity, Would they still discharge at the same rate? What If I put a BMS with higher Amp rating, would it limit the discharge rate of the pack with the lower capacity to adjust to the pack with the higher capacity? Thanks. I still have a lot of questions in my mind that I would like to ask hope that you could answer my question.
Will the total deplete faster mixing Ah ? Scooter batteries I have 2x12v20ah and 2 other 12v with one 7.5ah and one 12ah Would this be ok to run in parallel for 48v
Very well explained. Another question rises - What if the smaller 12v battery is used for a while and the bigger 12v battery is fresh? The smaller one suposedly have lost 20% of its ability. Will it act like a leach to the bigger battery all the time and create power loss?
Not an expert but I would expect so. As the batteries discharge the voltage drops as well. So by running them seperately the voltage of the flat battery is lower than the fully charged battery.
As the battery ages, I would imagine the "tank" capacity just gets smaller. The fully charges and discharge voltages are still the same. So in his example, the 7.5ah or (300liter tank) just becomes smaller. It still contributes but much less over time.
Parallel lead acid batteries can help charge one that won't accept a charge due to high internal resistance...or i think even a capacitor in parallel can do the same
for 10 batts hooked in parallel 12v 70 amp each would a 80a circuit breaker installed between the batts and the charge controller be ok or is has to be greater amp breaker?
What if you put 2 different batteries with different voltages, and you put a diode at the end of the lower voltage battery, will it run normally and protect the lower voltage battery from overcharge and explosion?
Diodes conduct current only when voltage (potential) is higher on anode than cathode. So if you connected a high current diode with its anode at the positive terminal of a lower voltage battery, and its cathode at the intended "parallel" (+ve) connection of the higher voltage battery, then that diode would become reversed biased, (IE: higher voltage on cathode than anode) and would pass no current at all from the lower voltage battery. Even multiple diodes with anodes connected to different voltage batteries +ve terminals (with all diode cathodes on an outgoing parallel bus) will be reversed biased on lower voltage sources. So no, it would not work. Only when a higher voltage battery discharged to a voltage lower than the diode connected to a lower voltage battery, would the diode conduct, and the resulting voltage would be the lower battery voltage. (Ignoring voltage reduction across the diodes.)
While I understand you want the batteries at the same voltage when connecting ... if you need to ... is there a way to protect the battery/limit the current (in particular with lifepo4 or would the BMS control this for you?)
For charging a small and a big battery could u bridge it one terminal on positive of one battery and one terminal of other battery on negative? Or is it recommended to charge seperate
sir can you explain about wire gauge for those parallel need. my problem is when we gain out put with higher A level what wire gauge should use..? i am new to this electric side so kindly can you do a video thank you.
I have been trying to figure out how much current each battery would contribute to the 6A required. I've tried figuring by the Ah ratio of each battery compared to the total Ah of the batteries connected together. So 17.5 Ah + 7 Ah = 24.5 Ah. With a 6A load the batteries would last 4.08 Ah. Things fall apart after this. I tried to figure out how much each battery is giving. I divided 17.5 Ah / 24.5 Ah = 71% for the first battery and I got 29% for the second battery. How do you figure out how much current would be drawn from each battery? Also, this is assuming a linear relationship. I am interested in this because I am playing with solar panels and golf cart batteries. With one test, powering an inverter @ 12V 50A the solar panels were supplying 20A and the batteries were supplying 30A. I don't know how to figure this out with the math. What determines how much current comes from the batteries and how much current comes from the solar panels? Thanks in advance for any comments or ideas.
Sir can i make 12v battery by using 3.7v different capacity of batteries means All are 3.7v batteries but 1200+1200+2000=4400mah ,3.7v 1200+1200+2000=4400mah,3.7v 1200+1200+2000=4400mah,3.7v Like this total 9cells One set contains 3cells=4400(1200+1200+2000) So 3sets = 11.1v 4400mah Can I make it ? Is it safe
I wouldn't say wires act like fuses I've burnt stuff or fried batteries but the wires were perfectly fine. People might miss your point and literally think that the wires will burn before something worse happens. Caution.
Are you certain this is accurate with Li-on/LiFePO4, because they have *flat voltage curves*. Your premise is that due to the significant drop of voltage with SLA/AGM/GEL batteries -- the batteries will discharge proportionately based upon their capacity, which is correct. *However,* when you have batteries whose voltage does not go down for the bulk of their discharge (as with LFP) then this premise wouldn't hold true.
I love ur explanation Just one question when u say the batterie should be at the same voltage you mean full charge ? With the condition of knowing that the specs of the batteries are for example 48v 21ah and 48v 13ah I should know my both batteries are at 48 v when they are fully charged yes ? And 0 v when they are fully spent i hope i got this right 😅
do you need to use parallel lead or use pig tail to join can you connect 1 charger to leader and charge both at same time or do you need to charge seperatly
Use the parallel lead. You can charge both together but charge times will be doubled. Both batteries should be charged full before putting the batteries together in parallel.
@@brandongoh8900 thanks will do have ourchased your new green light and pro charger and usb charger and hub for my new hobbie pro 12 foot 360 so may have a another question later thanks for guidance
It depends. If your goal is short term, and the voltages match, then yes. The problem comes when it depletes under 50%. Your car battery will not like that, but the deep cycle might be okay with a lower percentage. Also, the load is a big question. Solar batteries are not designed with peak load in mind, car batteries are built for peak load/start the engine/. So yes, you can, but several things to take into consideration, to avoid damaging your batteries.
Excellent Video i need help please reply can i put Analog / digital dc amp meter on parallel batteries for showing amps when charging and discharging from batteries all the time ? is that this analog / digital dc amp meter draw some amps from battery ? Thank you
You can buy fairly inexpensive nanometers to mount on each battery to compare charge rates. eBay has them for about $6 US. the last time I bought a half dozen. While not totally accurate, they give you a good idea of how many amps are going to each battery. GOOD LUCK!
Nothing. Parallel is used to combine Ah with same voltage (12v 50Ah + 12v 150Ah = 12v 200Ah). Series is used to combine voltages with same capacity (12v 50Ah + 24v 50Ah = 36v 50Ah).
@@marks9127 I Mark thanks for your answer. I have a huge bank of batteries of 1.2v each but I have different capacities to connect them in series for example I have 36 batteries of 1.2volt 138 Amps each but I need 4 more batteries in order to get 48volt battery bank. Can I add 4 more batteries of 1.2V with 180 Amps of capacity?
Excellent video, i have a question i have 2 185AH Batteries connected in parallel working fine but i want to know how amp using each battery when i put on load or charging ? can i put 2 digital amp meters ( like a volt meter ) on each battery for see the load and charging amp of individual batteries ? i am waiting for your reply Thanks in advance
@@brandongoh8900 thanks so i need to put a single digital amp meter on battery 1 positive and battery 2 negative i hope that will show total amp draw and charge ? I am waiting for your reply Thanks
@@brandongoh8900 suggest me , i think i can use digital dc amp meter because it will show amps when charging and discharging from batteries all the time without any hassale ? 2 is that this disgital dc amp meter draw some amps from battery ? 3. is that safe to attach digital dc amp meter with battery ? Thank you so much for your help
@@brandongoh8900 what about batteries connected in parallel with same voltage and different capacities? Do they split the current draw in half or divide the load according to the capacity? What about charging? Does the higher capacity battery charge with more current?
How would you ensure the voltages are the same? Its very unlikely they would be so they would rapidly self discharge. Clearly you never actually tried this for real.
from your question... it shows your lack of knowledge on how batteries work... when u connect two batteries they will self-equalize..... why don't YOU go and test it first .... and report back... use any battery... say a 12v lead acid... 100ah and another one at 150ah etc... Clearly.. u HAVE never tired this.. lol
Your water analogy is incorrect. The water pressure at the bottom of each tank will be exactly the same. Therefore the flow rate will be the same from each tank. If l measure the water pressure at 100 meters in the ocean and l measure the water pressure in a 100 meter 1 meter diameter tube the water pressure will be the same. And the ocean has a lot water in than the pipe. Batteries do the same .
If you parallel two or more batteries, the voltages must be within .2V, and the capacities must match. The date codes MUST match! This is especially true among solar power systems, or automotive applications. You must match the charging amperage of your alternator for the car/truck batteries that are paralleled or neither battery will ever be fully charged. Keep the tops of your batteries squeaky clean, or you will create a high impedance short that will make your solar or alternator work much harder to charge up the batteries. This is especially true in car/ truck batteries up in the "rust belt". That dust that collects on the top of your battery is actually not dirt, but powdered rust from other vehicles that will short out the battery by making a path between terminals on your battery. Always use distilled water to clean the top of the battery, a dampened cloth will do fine.
It does not work that way. A battery is an electro-chemical device. Ohm's law applies only electrically. Battery internal resistance is dynamic, it changes under load, Ohm's law follows the chemistry, not the other way round. The video presumes chemistry ill follow Ohm's law. It will not!!! A test would not be very difficult, or expensive, to perform. New batteries will differ minimally, as they age, it will be statistically impossible for two such batteries to follow Ohm's law as claimed in the video.
Oº.ºOps... know what you are saying; go learn practical stuff before talking»»»» a 24 volt and a 12 volt batteries in parallel *IS NO ff EXAMPLE** They WILL eat each other, E X P L O D E Choose better examples edit at 04:00 you say it
