Connecting different batteries in parallel/series (AKIO TV)

[@timdavis6088]

You've answered more of my questions in 5 minutes then RPS Solar did in the past 2 weeks. After getting conflicting and contradicting answers from them I finally just gave up and started researching this for myself. Thanks for an easy to understand explanation.

[@peterwilson5528]

Thank you for very simply and precisely answering all of my questions and correcting my misconceptions. Thank you very much :)

[@jws3925]

Nicely presented in a very clear and concise manner. There are a couple of KZbin content creators who need to view this. There are some that have these concepts SO wrong and it is spreading false information.

[@emmarioperalta836]

Within a minute of you talking I spontaneously Subscribed.. Great explanation and well delivered words.. Keep it up Sir..

[@USL.Website]

Thank you for making this video and taking the time to do so, I love the water example you made, you explained it all in 5min flat. 😃 You are a great teacher indeed!!

[@marcusmobley5411]

Helpful demo display, thank you. Great teacher.

[@keegoon123]

Yup! just what I needed - brilliant video

[@boxcutter0]

You are obviously on track for a successful/lucrative career, whether it’s in a more traditional engineering role, teacher, or KZbin creator… it’s appreciated when we get this type of content that caters to small financially constrained tinkerers, before high end sponsors are included & most resource constraints are merely a memory.

[@gunnuts308]

Good explanation. I understand it's not ideal but I have a few optimas that are different capacity. Now I know where to start and implement safety precautions when locating my bank.

[@RobertoGamboaEstrada]

Superb Video, you answer all my doubts.

[@tabprintt]

I just need to say thank you for the amazing video. Well explained!

[@practicaltactical1336]

Very informative! It is what I needed to know! Thanks

[@robertgarrett7007]

Thank You. You explained the connections exactly as I thought they should be. (But I wasn’t 100% positive.)😂

[@paulhurlehurle766]

Be😊st explanation I've seen brilliant.

[@scotlandsforme1]

I have a question, I have 4 x 12.8v 200a lithium batteries connected as 2s2p going to a bus bar and then a 24v 3200w hybrid inverter. Can i connect a battery charger or chargers to this setup to top up the batteries . I live in the north of Scotland, I have 12 x 200w panels and through the winter there is not enough sunlight to keep the batteries charged so if i set timers on chargers to use cheap night time rates for mains electricity and use this power during the day. BUT how and where in the battery setup would I connect the charger/chargers. Hope all this makes sense.

[@autobotsolutions]

Nailed it, thank you for solving my problem.

[@corysamoila]

Well done Interesting and informative Thanks

I agree most of thinks you said but thinks to consider in connecting batteries in parallel also age and capacity effect. - When you connect different age batteries in parallel older batteries will drain the newer ones over time. - When you connect different capacity batteries in parallel, smaller batteries have longer time on charging absoption and bulk. This doesnt have too much effect on 100Ah with 105 Ah battery but it will destroy fast 100 Ah battery with 20Ah battery. - Also different brand batteries even they have the same chemistery they have different plates and different charging charesteristics. This will also increse the chance of 1 battery to supply other battery. - Also when you are discharging, if the batteries has huge difference in capacity and you pull near the limit amps always biggest one tries to compansate the smaller one. This will kill the big one because when you stop discharhing the big one will compansate the smaller one and big one will make work harder which will. Batteries in parallel work as "weakest link" and weak ones damage the strong ones over time. =) But of course if you have batteries lying around and one is not enough, you can parallel them like this and take the most juice out of them. Better than nothing =)

[@jackfarrell4727]

Good information, thanks

[@Zapgod]

This is true. I had 3 group 31 batteries in parallel and was watching my voltmeter slowly dropping from 14.8 to 13v when car was at idle. I thought it was my alternator but when i disconnected batteries one by one i found that the second battery was affecting charge. All batteries were trying to charge that one battery and the alternator was supplying what voltage it was sensing at the positive terminal of the alternator and not the battery. So voltage was dropping between batteries but alternator was not sensing a large change, so it was not compensating for voltage drop. But my voltage monitor was connected to rear battery. Thats how i was seeing charge drop due to bad battery. I replaced that one battery and charged my other 2 before installing and it was working perfectly

[@1uca_115]

really good video

[@SPRAYPAVE]

Very helpful. I connected 12x2 volt batteries in series = 24 volts. 8x 1000ah + 4x600ah. Knowing it's not quite right, but not knowing exacts. So now I've got buy more of the same ah to match. Hope I can fix before a fire!!

[@HughCStevenson1]

Series is a lot more critical than parallel. Even old vs new batteries of the same nominal capacity, brand, type are not good to combine, since their capacity changes with age. Wet cell lead acid is more tolerant of overcharge (which is what happens to the lower capacity cells) - they will "boil off" electrolyte and need topping up. Other technologies - don't do it, you could end up with toast or worse!

[@marcomattio1230]

Well explained, thank you.

[@ALLERTY]

Great explanation. Can I connect different voltage in parallel for example with charging controller?

[@desrender4893]

I am a cheap Charlie. My camper truck has 2 starter batteries and 2 deep-cycle batteries, all wired in parallel, off different capacities and ages. My feed to my inverter goes off the biggest deep-cycle battery. My oldest battery is coming up 5 years old and still good. My deep-cycle batteries alone cannot run my microwave, but with the starter batteries in the circuit, I have no problem. The only issue I have is to regularly clean the terminals, but I do monitor their voltage and condition. I now rely on cheap reconditioned batteries and have found they work well. I am sure a lot of the crap about using the same capacity and age batteries is a sales gimmick

[@HughCStevenson1]

Using the starter batteries in parallel with the deep cycle batteries is not ideal since, to get the capacity from the deep cycle batteries, you need to run the voltage down quite low but this will ultimately damage the starter batteries, which need to be used at full voltage most of the time. With your configuration you would need to keep the voltage high - in the top 10% of charge. There isn't really a good way around this that I can think of. Starter batteries and deep cycle batteries are not really the "same chemistry" just as flooded lead acid and VRLA (sealed) lead acid batteries are not. Getting a bit nit-picky...but it could affect the life. Not really the safety, though. Parallel is pretty good that way.

[@desrender4893]

@@HughCStevenson1 Mate, my main big starter battery is my oldest battery, but as soon as the voltage running my fridge etc drops below 12volts. I manually isolate my starter batteries. But I have too say, you can paye megabucks for auto systems but a little bit of knowledge and physical presence saves you lots

[@Murtahz]

Great video thanks. Exactly what I wanted to know.

[@RobbieLValentine]

WOW! This is the first video I've watched that's very easy to understands. I have one question though as I have heard conflicting info. Can I connect two 130 ah Lead Acid with a 105 ah Lead Acid battery to have a total of three batteries with a combined amperage of 365?? Thank you so much!

[@AKIOTV]

you probably could so long as they're all in parallel and have the same voltage

[@VINTAGERENEWABLEENERGY]

Good explanation❤❤❤

[@masterdrake6192]

Nice info to know now that I'm planning to do the same thing.

[@alaricace8118]

Thank you for this great content! I have questions, Would that be okay if I connected 12v 35ah car battery with 12v 8.2ah ups battery? I'm asking that because my smaller battery is already degraded even though it has 12v it doesn't have the capacity, So even though I said 8.2ah according to the sticker it may only have around 5ah I guess. Thus if I don't mind about this smaller battery's health would that be okay to connect 35ah battery to this combination? I'm connecting these to a 1.2kv computer ups.

[@swarfegakid]

Excellent, thanks.... I'll get connecting my 12v lead acid batteries in parallel.....

[@deudorix3802]

Great job.

[@mikesenior1333]

I have a lift that uses a 24v system, it runs off 2 x 7ah batteries sealed lead acid. The charge board on lift is faulty so i have installed a 24v 5ah charger to the batteries. It trickle chargers but i can switch the charger off when its been on overnight. Will leaving the charger on constantly damage the batteries... and by using the lift motor with the charger turned on, is this going to damage the charger? Using 3way wago connecto to put charger in the system.... red on1st batt and black on the 2nd

[@givenmagopa1946]

Hi please help me out, i have a 24v battery and 2×12v batteries which are connected in series, So i want to know if i can be able to connect them together parallel as 2×24v batteries to a 3kva inverter?

[@MDogg1960]

Hi, will a 6V 208Ah battery and 5- 6V 225Ah battery connected in series for 36V be a big problem? I'm having trouble getting a direct replacement for a bad battery on my golf cart, and I don't really want the expense of having to by all new batteries. I know you said capacities should be the same in series, but I'm thinking the older 225Ah batteries may have some degradation any way. Thanks

[@HughCStevenson1]

Ughhh! Did you try it out?? :) It could work. Are they flooded wet-cell lead acid or "sealed" VRLA cells? The wet cells are more tolerant of overcharging - they will boil off electrolyte (actually water) and need topping up with distilled water. "sealed" cells struggle and get hot when overcharged...

[@jennycorcuera56]

Sorry I have a question, I need to kee my truck battery charged, but in that truck I also have a tennis ball machine that has a battery if different size but both have the sane chemistry. Would this method work to keep not betteries charged with one solar panel Thank you

[@AKIOTV]

If they're both 12v lead acid it should be fine. I'm not sure if I'd also keep the batteries in parallel while starting/driving the truck. Perhaps also put a fuse between them so a short on the tennis ball machine won't short out the (big) truck battery.

[@Powerstroke431]

When doing 12v in parallel, how close do the charges need to be? Say one battery holds at 12.4v and the other holds at 12.8v, would that work or be too much of a difference?

[@AKIOTV]

@@Powerstroke431 Ideally very close. Especially if it's li-ion/li-fe it's important. With lead acid, less so. Lead acid batteries can very easily increase/decrease in voltage regardless of their charge level, making them quite forgiving in this aspect. That's why you can hook up jump leads to start a vehicle without measuring voltages first.

[@Powerstroke431]

@@AKIOTV I have a 12v 90 minute reserve, 675MCA lead acid right now and just looking for another good working used lead acid to run in parallel with it and just want to make sure I buy the correct battery. Thanks for your help brother :)

[@SEaudiofan]

Is there a battery isolator?

[@gardenwaster]

Good explanation very helpful, may I ask what is the yellow inline fuse you are using in your system ?

[@AKIOTV]

It's a 100A fuse. Not sure what the official name for this size/shape is. It's mainly there just in case I accidentally short circuit the battery pack.

[@علاءالطحان-ب1ف]

Thank you for greet content

[@natemiller6389]

so im building a 6s 24v battery bank and each of those batteries in series will have batteries connected parallel to them would it be ok than to use batteries of different capacity in the parallel array? whatever its called.... i was going with a 6s but 6 in p as well but messed up and bought 2 different capacity batteries. as long as i keep each array in parallel the same capacity as each other i should be good right? be just one battery of much lower capacity at the end of each.... like a 5kma difference. Its my first time..... if the explosions is worth the risk you take it. for science.

[@AKIOTV]

I assume you are going to use some sort of balancing system/balance charger to keep the series groups at the same voltage? What you have in mind should work given your series groups have the same capacity.

[@natemiller6389]

@@AKIOTV perfect than lol thanks alot. This stuff is not cheap is it? im back into the mountains to get things done than. Take care and thanks again for the help.

[@FrankLowe1949]

Very nice thank you so much❤❤

[@humandisorder3962]

Hi. Soooo can I mix AGM and lifepo4 or not?

[@rudy8357]

Your question was answered in the first minute

[@MichaelsKarish]

@@rudy8357yes you but using bank managers There was a guy I watched today who makes battery bank managers for exactly that reason But without those I don’t think it is a good idea

[@laurentsosson1739]

Good morning I have 2 packs of Lifepo with the same voltage but 1 is 24 volt 1120 AH and the other is 24 volt 200AH I would also like to put // both I don't know if a fuse is needed between the two? otherwise my converter is a 4000 watts to 24 volts what do you think about implementing // the 2 packs? busbars between the 2? THANKS laurent

[@HughCStevenson1]

Should work. No extra fuse - put one in series with the combined battery combo, unless they are physically separate and a fault could occur between them.

[@bkokenge]

I currently have 4 x 300ah LFP in series (48 volts). They are 9 months old. I would like to add another 4x300ah (same voltage and ah). Should i wire it: new+old in parallel (so they stay equalized) and then 4 of those in series, or should I leave the existing old four in series and add the four new in series and parallel new to old. Option 1: (old + new)P x 4 in Series, OR Options 2: [4S(old) + 4S(new) in parallel]? I am concerned about charging.

[@AKIOTV]

@@bkokenge Although arguments could be made for both options, parallel groups in series is usually preferred over series groups in parallel.

[@bkokenge]

@@AKIOTV I believe there is also concern over the length of the cables - that is, we want them all same length to prevent voltage drop.

[@p.r.960]

Great vid! Easy to understand. Q… Can I connect 2 12v 50Ah Li-ion batts in Series/Parallel (24v 100Ah total) or is there a min # of batts (ex. 4 or more)? Pros and Cons please 😁

[@HughCStevenson1]

If you have two identical batteries you can connect them in parallel to get 12 V 100 AH or in series to get 24 V 50 AH. Parallel is preferable because the batteries will automatically share. in series you would need to check over time that the voltage on each is staying close to the same. If you want 24 V 100 AH you need 4 batteries in series/parallel. You can connect the center terminals together.

[@gabrielkrolczuk4596]

Is it possible to connect three strings of batteries in parallel (all AMG) 2x100Ah (24 Volts together) in series plus 2x150Ah (24 Volts) in series plus 260 AH (24 Volts) in series. I would like to equip each row of batteries with a voltage balancer. Is this a good idea for a photovoltaic energy bank? Best regards, Gabriel

[@owenbruce4120]

I do this using a switch between each size else the smaller capacities fill first and overcharge...you can use separate solar controllers on each battery bank which overcomes this issue...pwm controllers are cheap and good enough 👍

[@Zapgod]

I have a mightymax 100ah battery paralleled to a group 35 optima yellowtop. Its connected to my car stereo with a battery switch between the amp and the group of batteries. Been working for over a year and a half with the occassional charging in my garage. The problem is if i dont drive it for more than 4 days, voltage gets to 12v. Is it because the mighty max or the yellowtop is charging each other? The mightymax is nearest to my amp and the yellowtop is in the engine bay for starting. Does starting the car drain both batteries?

[@coeniejvr]

if it's connected in parallel then yes it would. Don't connect the car starting battery to the other battery. if you want them both to charge at the same time from the alternator then get a dc to dc charger that runs from the split way of your alternator to both batteries. You need to know the amps of your alternator before buying a dc to dc charge to get the right size. Remember starting batteries use high amps for a few seconds when starting your car then get boost up again once the alternator is running.

[@yusufhaliluzakari]

Great content! However, my question is: Would there be problems if I connect an AGM 180AH 12V lead acid battery with a GEL 100AH 12V lead acid battery in SERIES (to give me 24V) then connect a battery equalizer/balancer to ensure that they charge and discharge at equal voltage?

[@AKIOTV]

Maybe you'd get away with it, but you need to make sure the charge/discharge current stays within the limit of both batteries. Also, you're not making optimal use of the larger battery. I'd say its far from an ideal setup.

[@236vic]

That had to be the best explanation. I just want to be sure for my situation. So I have 2 acid batteries at 12 volts one is a car battery with 45 ah the other 190 ah I want to connect in parallel which I already have done before. But I had only being drawing from the 190ah battery. The question is is I draw from both batteries by take a positive lead from one battery and negative lead from the other does it matter which is the positive lead and negative lead taken from ?

[@hodgo1981]

Technically you are drawing from both unless you have some sort of isolator on the positive wire joining the 2 batteries. Can be as simple as a manual isolator switch or disconnecting the terminal, or more advancved methods. Vehicle dual batteries systems have been using isolators for decades to "protect" the starter battery from drawing. Most commonly there are isolators which connect via a switch (eg your ignition key) or there are "smart" Voltage sensing relays (VSR), these connect and disconnnect at preset voltages. for example connect when an alternator or other charger is providing 14v to the starter battery, and disconnect when the starter battery dorps to 12.8V (approximately float voltage of lead acid)

[@JahnDough]

All the batteries I have are 12 volt lead acid, and i ha e some that are 12ah and 18ah, do yall think it would be good?

[@BobJones20001]

This explains why I'm getting hot batteries in the solar setup. This is a 5 year old install. 2 strings 8 x 6 volt deep cycle flooded lead acid batteries making 1 array of 16 6 volt batteries at nominal 48 volts. The "hot" batteries capacities are now very low and are discharging and rechargimg at a much greater percentage of their true capacity than the others in the string. The 2nd string was unable to support any load. Dropping from resting voltage of 52volts to zero in seconds the moment a load was applied

[@aaronsmith593]

Ive heard you can wire 2 lifepo4 batteries in parallel, but wired in series is problematic for keeping the 2 batteries balanced to each other. Also best to even use same capacity batteries together in parallel.

[@HughCStevenson1]

No, in parallel it doesn't matter, so long as the voltage vs state of chrge is the same for both - hence the need for the "same chemistry".

[@EE-Z]

As someone who has no clue about this stuff, I have queries that I would be grateful for answers to. I have a motion sensing light that requires 4x AAA batteries mounted in a single line. As it's not an important light to have, I just use old 1.2v Ni-MH batteries of varying mAh ratings (mostly 900 with a couple 500) that don't last long in the home phones anymore. Based on your explanation, am I correct in saying these are connected in series and therefore is not recommended to mix capacities? Having put 900mAh cells on each end with two 500's in the middle, the light flickers. However if I put the 500's on the ends and the 900's in the middle or alternate with 900, 500, 900, 500 (also 500, 900, 500, 900), the light is stable. I assume this makes no difference to the damage it could do to the cells?

[@HughCStevenson1]

Correct. Nasty idea! :)

[@jackfarrell4727]

Thank you for the information

[@NerdThingsAndMore]

Thanks for the info

[@sapere-m1p]

Obrigado, você eliminou todas as minhas dúvidas.

[@CR8VE]

So is lead acid the same chem. As gel lead acid?

[@HughCStevenson1]

Not really but you can probably get away with it. Professionally it would not be done because they want to get the absolute maximum life out of the batteries. Decades...! If you don't need that, it will work ok.

[@kaapuutt]

Awesome!!

[@Leo-yy4zt]

I have a 120 ah and a 130ah batterys can i hook those up

[@SacredHeart0520]

You most def can mix lead acid and lifepo . Ive done it and the neg performance is minute

[@danielristov736]

lets say i have old batteries.... they both on label are 12v 50AH.... but one of the batteries from using have loose the capicity... can i wire them in series because on label are printed 12v 50ah on both batteries?

[@AKIOTV]

not a good idea. The actual capacity can be very different

[@bobotubeful]

Hi, so useful. In case we have the Active Balance, can we connect series 50Ah 12V with 100Ah 12V for real life using?

[@AKIOTV]

If you have active balancing, connecting different capacities in series may be safe, but it's still a waste of capacity. With 50 and 100Ah in series, the usable capacity will be 50Ah.

[@bobotubeful]

@@AKIOTV thank you so much

[@zachariamusau3136]

Can lead acid battery be connected together with a mantainace free battery in parallel?

[@HughCStevenson1]

Not really but you can probably get away with it. Professionally it would not be done because they want to get the absolute maximum life out of the batteries. Decades...! If you don't need that, it will work ok.

[@shukry0115]

Sealed lead acid battery and flooded lead acid battery can mixing them together in parallel?

[@HughCStevenson1]

Not really but you can probably get away with it. Professionally it would not be done because they want to get the absolute maximum life out of the batteries. Decades...! If you don't need that, it will work ok.

[@parzival4593]

ty i got 120 ah want to put a 100 ah to gether both 12 v same brand so you saying i can conetted it to gether to make 220 ah battery

[@devinpatterson2185]

What if you have 2 slightly different capacity batteries in series but you only charge through the smaller one?

[@AKIOTV]

slightly different capacities in series could be done safely if you have active monitoring/balancing during charging and discharging to keep both batteries at safe voltages. It's complicated and messy so I'd avoid it.

[@mannynoleal7521]

How bout low voltage battery mix in new one?

[@bacasholimited2617]

Awesome

[@adrianfoster4899]

If you think about it you are wrong!! You can connect different types together!! Everyone knows you can connect a power station which is lithium to car battery which is LEAD! I have been doing this for years connecting a lithium battery to LEAD!. It can be done with a solar controller! Connect the reception battery first to the controller battery terminals! Then connect the other battery to the solar input connectors! Flow will only go one way from the solar input controller to the battery controller!

[@AKIOTV]

@@adrianfoster4899 I can combine any two batteries if I use some sort of electronic equipment. Surely then the video is also "wrong" because with a bidirectional dc converter you could connect a 500V battery and a 3V battery in parallel.

[@adrianfoster4899]

Surely by definition a battery is electronic equipment so now u r saying by connecting 2 batteries (electronic equipment) meets your criteria which is obviously wrong!

[@D-365]

What if the second battery is a supercapacitor?

[@AKIOTV]

@@D-365 It'll work but: - it's virtually pointless, the battery will almost always have far, far more capacity than the capacitor. - you need to be careful connecting a battery in parallel to an empty capacitor, it will cause a massive surge of charging current that could damage the battery or the capacitor. Before connecting them directly the first time, you could use a resistor between them to limit the current.

[@D-365]

@AKIOTV Tjank you brother! :D

[@Yaadtech]

I have connected agm batteries @48v parallel to lifepo4 batteries which Re the same 48v and have had them working for 3yrs now, I've also recently seen video from the off grid garage where he paralleled a 100ah(5kw) and a 280ah(14kw) and both ran successfully, what u people should explain is that if ur a novice at this stuff and don't understand batteries it's wise to leave it to the pros

[@dip-tree]

Not a good engineering practice to connect batteries in parallel for low internal impedance batteries. It is not easy to ensure that the two batteries are in identical state of charge or voltage at any time.

[@AKIOTV]

Depends on the use case. Take my battery pack as an example: Could the voltage be different when discharging at 150A continuously? Yes, probably. Will the battery pack be discharged at that rate for long periods of time without interruption? No, typically the load is

[@dip-tree]

@@AKIOTV As an engineer with four decades of experience in this field, my suggestion to you is not to violate a standard rule in engineering practices. You may get by on occasions, but sooner or later Murphy will play an ugly trick. So standard operating procedure is to stay away from paralleling low impedance batteries (or any voltage source for that matter). Just to indicate a potential pitfall (of many), say one of the batteries develop a shorted plate in one of the cells. So suddenly you will have a huge imbalance and a 2V odd difference sees an impedance of milli ohms. You can conclude that the result would be catastrophic - potential fire and explosion not ruled out. All the best and be safe.

[@northernboy1]

as long as your bms is appropriate, and all the batteries are of same capacity and make. There is no such harm. If he bounds himself with standards how he can try on new ideas...

[@dip-tree]

@@northernboy1 With respect, professionally I disagree with your suggestions. There is a difference between engineering professionalism and amateur practices. Think about this, why do pilots go through an extensive check-list of pre-flight tests, and do not go by their 'gut-feel'. It is because the consequences of an error is very large, and therefore you do not take any chances. Have you not seen countless videos of batteries bursting into flames on youtube? So if you are just experimenting to study the consequence of a topology, or perhaps just dealing with a temporary but emergency situation you can sometime take liberty with these standard practices. As I said, anyone who has even done basic electrical / electronics engineering studies (properly) will advise you to not connect low impedance sources in parallel. Hope this helps and be safe.

[@northernboy1]

@@dip-tree if you carefully read my comment,,, I used word BMS ( Battery management system) will cover safety and SOP's must carefully be tackled. Now coming to the point, in order to understand the phenomenon, nature and working of any product it is very important to implement the ideas on small scale. Yes, you are right the safeties and SOP's should not be ignored. But there is a saying we learn from mistakes. And great ideas comes trying stupid things.

[@dnaomondi]

Cool

[@emmavanderniet2847]

Wat een cutie 🥰

[@mikewarren7855]

The internet tells me you can not do this. the smaller battery will drain faster than the higher capacity. itl go empty while you still draw from the higher one. and then over charge.

[@glennmccorquodale8599]

The internet is full of both truth and nonsense but hard to tell apart. The author is correct.

[@leetwovilaghazudosa]

gratulalok a videohoz de lenne kerdesem hogyan kell bekotnom /// szabalyosan /// 1 darab 16v supercapacitor baterry es 1 darab 12 v gel baterry koszonom a valaszt

[@mannynoleal7521]

Dead battery

[@playaj320]

🤣 whole video started off with a strt8 up lie, plenty of videos on here with batteries with different chemistry. I have a flood lead acid and agm and lithium all in da same battery bank.

[@ChrisInShorts]

bro what if we have same lead acid batteries with same amp and volts but the one is old(almost 2 years old in using but still have good backup) and the other one is new can we still connect both in series?