max. amount of Lithium batt. in parallel

[T1 Terry]

There really is a limit to the number of cells in parallel for an extra low voltage battery like 12v or 24v. 8 cells in parallel is getting to about the limit where the resistance between cell links starts to become an issue as well as complexity of the battery build.
If you wanted an 800Ah 12v battery, either 8 x 100Ah cells in parallel or 4 x 200Ah cells in parallel would both be suitable, room to actually site the cells can have a big part in just what cell size you use. In reality, compressing and strapping an 8 cell pack isn't that difficult, it's picking it up and moving it that becomes the difficult part. The base would need to be supported to stop a cell slipping out in the centre and the whole lot tumbling out like a Kenga tower. We generally limit the packs to a max of 6 cells, just for ease of handling.

T1 Terry

[CruiseN]

Using series, higher voltage reduces current for usage because Watt is a multiple of voltage with current. Twice the voltage is half the current to maintain an equal Wattage.

Switching is relatively easy.
Advantages can include the mixture of AGM banks with Lithium banks because each vehicle of energy storage is merely sharing the same highways and isolated from one and other.
Pic isn't a recommendation, merely a cheap yet intelligent from mains charger. Will charge lithium ion, AGM, lead acid, gell.
More importantly, I haven't looked but there'd be solar, wind ,water chargers on market that'd automatically select requirements of battery at not a huge price. Bigger cost would be the batteries and energy supply. Mains is free and pay as you go, solar need panels, wind turbine, water paddle..

Hence, it'd make sense to some, not all. To bank energy via a switched system.

Whether conditions change and higher nots of availability become whilst out playing around in stranger environments, such system would allow a higher point of mix. Eg when able to get Watt you can get situations occur.
Plus.. additional systems can be supported easier. How much power do you need?

[StuM]

Originally Posted by Anders

Every time you posted this you have been told that boats use LiFePO4 batteries and NOT lithium ion.

Yep, in the six months he's been on CF, he's posted the same nonsense 6 times and despite his error being pointed out on every previous occasion by different members, still hasn't learnt.

To be accurate: LIFePO4 are "Lithium Ion" batteries. They are one of many types of battery built using various Lithium Ion chemistries.
However all of the scare mongering is about other, much less safe Lithium Ion chemistries and technologies.
LiFePO4 does not have the same risks as the types of Lithium Ion batteries used in EVs or consumer electronics.

[s/v Jedi]

Originally Posted by StuM

Yep, in the six months he's been on CF, he's posted the same nonsense 6 times and despite his error being pointed out on every previous occasion by different members, still hasn't learnt.

To be accurate: LIFePO4 are "Lithium Ion" batteries. They are one of many types of battery built using various Lithium Ion chemistries.
However all of the scare mongering is about other, much less safe Lithium Ion chemistries and technologies.
LiFePO4 does not have the same risks as the types of Lithium Ion batteries used in EVs or consumer electronics.

It’s a troll, maybe even a bot.

[more]

Originally Posted by s/v Jedi

It’s a troll, maybe even a bot.

yes AGM battery manufacture troll or bot. this industry is on road to downhill.

[CruiseN]

Infinite if isolated.


I don't know batteries. BMsomething device reads like that'd do job of balance.

Growing up in an automated house using a PC to switch electrical systems with manual overrides meant that systems would drain, trigger, recharge etc and do such with optimum minimal maintenance the goal whilst using'free' energy.
But balance is key.. our vessel 'Henry D' in the same conditions would balance a storm jib and 2nd reef on main OR full sail because leading edge of propulsion was a torqued luff similar to a square riggers; spinnaker.

Thus.. I'd think it easier to switch banks but I don't know how neither.
My thoughts for my future vessel are...

Isolated throw switches; each bank never sees the other banks.
24 volt to reduce current losses.
Accommodation of as many banks as whatever they are, it's just additional switches triggered by a brain.
If brain fails, switch them manually, just be like having a single bank yet visual on individual banks would determine which bank gets load, which bank gets charge. If I got smashed or something could always motorsail during sleep to keep proximity alarm active if out sailing.

Brain does control of Watt
Disables need to balance banks.
Enables use of bank until low storage triggers switch to next one.
Enables charging of bank until full then charges next bank. If all full it can top one up at a time on delayed hold.
If all full besides withdrawal bank, switch to full bank and recharge withdrawal.
On isolated throw switches flipping faster than electronic systems recognition keeping electronics and banks safe from confused currents.

Is simply what I use in land house, light weight yet robust. Banks can be a mix of lipo, AGM, gel cells, etc. Automatic with manual override.
But it ain't easy because boats have water, confined conditions, plumbing. I wouldn't have a clue because I don't have a boat hence wouldn't know where to place stuff.
I like the idea of glassing battery holders down near the bilge, enclosed from flooding yet breathable. Makes sense to honour vessels natural handling first seeing sea is natures way.

I know that's an easy system for some of my friends I haven't seen in years to build. I can't help, I haven't done enough homework.
But looks easier than parallel balancing in terms of reliability and hence robustness. Weights in the batteries.
AGM not trolling heavier conditions bro. Just ploughing through with a heavy keel son.

[Sailmonkey]

Originally Posted by CruiseN

Infinite if isolated.





I don't know batteries. BMsomething device reads like that'd do job of balance.



Growing up in an automated house using a PC to switch electrical systems with manual overrides meant that systems would drain, trigger, recharge etc and do such with optimum minimal maintenance the goal whilst using'free' energy.

But balance is key.. our vessel 'Henry D' in the same conditions would balance a storm jib and 2nd reef on main OR full sail because leading edge of propulsion was a torqued luff similar to a square riggers; spinnaker.



Thus.. I'd think it easier to switch banks but I don't know how neither.

My thoughts for my future vessel are...



Isolated throw switches; each bank never sees the other banks.

24 volt to reduce current losses.

Accommodation of as many banks as whatever they are, it's just additional switches triggered by a brain.

If brain fails, switch them manually, just be like having a single bank yet visual on individual banks would determine which bank gets load, which bank gets charge. If I got smashed or something could always motorsail during sleep to keep proximity alarm active if out sailing.



Brain does control of Watt

Disables need to balance banks.

Enables use of bank until low storage triggers switch to next one.

Enables charging of bank until full then charges next bank. If all full it can top one up at a time on delayed hold.

If all full besides withdrawal bank, switch to full bank and recharge withdrawal.

On isolated throw switches flipping faster than electronic systems recognition keeping electronics and banks safe from confused currents.



Is simply what I use in land house, light weight yet robust. Banks can be a mix of lipo, AGM, gel cells, etc. Automatic with manual override.

But it ain't easy because boats have water, confined conditions, plumbing. I wouldn't have a clue because I don't have a boat hence wouldn't know where to place stuff.

I like the idea of glassing battery holders down near the bilge, enclosed from flooding yet breathable. Makes sense to honour vessels natural handling first seeing sea is natures way.



I know that's an easy system for some of my friends I haven't seen in years to build. I can't help, I haven't done enough homework.

But looks easier than parallel balancing in terms of reliability and hence robustness. Weights in the batteries.

AGM not trolling heavier conditions bro. Just ploughing through with a heavy keel son.

Why even post this? You admit you don’t know batteries!!!! Then follow with useless babble.

And here I am replying to it....which pisses me off......

[T1 Terry]

The thing to keep in mind regarding switching DC current, you can not use AC switches to switch high DC current, a fire will be the end result.
Why? AC passes through zero volts twice in each wave, so any arc that starts soon goes out because the voltage wasn't enough to sustain the arc.
DC holds voltage so the arc is maintained. The air between the two points the arc starts and ends becomes ionised so it is easier for the arc to pass through, so the arc can get longer and longer. This creates serious heat, melts copper contacts and that melts the plastic around them and next thing you know, you have a melted switch or a fire ...... so best to understand just what you are playing with before you think about switching high current DC

T1 Terry

[CruiseN]

Originally Posted by Sailmonkey

Why even post this? You admit you don’t know batteries!!!! Then follow with useless babble.

And here I am replying to it....which pisses me off......

You know batteries aye?
That's a technology that is changing quick at moment.

Ain't babble to another whom can physdo code that and build himself a nice cheap yet high quality system. Half the time they just need an idea

[Moontide]

To answer the original question for the OP. Need to contact the specific battery manufacturer to see what they recommend. Some have a limit on number in parallel (have seen 4 a lot) while others may not. Will Prowse on Youtube has a good channel with lots on lithium and solar.



I disagree with T1 Terry and others who say make it one large battery. With one battery if one cell goes bad you lose the entire battery. With multiple batteries in parallel the loss of one cell means you only lost a portion of your battery power. I especially want redundancy/flexibility for when s___ happens at sea/away from services.



The other comments about burning out alternators and not letting lithium go into float are spot on.

[Moontide]

But T1 Terry is absolutely correct about using DC switches, not AC.

[Hermia II]

Originally Posted by henryk

I'm getting a 'drop in' boxes with BMS built in. Electrical and electronics are not my forte , so i would like to make it as simple as possible. So, getting to my first questions. If I will get 6 batteries, 12 V, 100 AH each and connect them in parallel,would BMS take care of even charging distribution ?

I have installed 8 Victron LiFePo4 12v 200AH, 2 in series and four such in parallel = 24v 800Ah, this works very well. They are all connected via a data bus to a VE-Bus BMS that also controls a BatteryProtect which will cut load if more than 200A in more than 30 sec (my bow truster uses 540A, but I will run it only for short stints). The BMS is in one direction connected to the Victron MultiPlus Charger 24v/300W/70Amp which controls the whole system. The MultiPlus is then connected to the Victron ColorControle GX. In the other direction the BMS is linked to the MultiPlus Remote Panel (it does not work in any other sequence).

1. First you have to log in with bluetooth into each battery and update firmware.
2. Then, when everything is connected, you have to connect your lap top (windows) with a special cable to the BMS, download a special application and ask Victron support to go in via Team Viewer to program the whole system (they install "assistants" and set other parameters in the MultiPlus).
3. You have to do a simple setting in the Battery Protect.

Phew, so far so good! This to me indicates, don't fiddle with your own BMS solution!

Now comes the charging! LiFePo4 will suck every piece in the charging infrastructure dry, at full capacity. For this reason it is very important to use a suitable charger. The MultiPlus is the best since it is programmed for this specific purpose. I have also used a Victron Skylla i, and it works fine but is not programmed so I would not use it unattended. These chargers can be set for a maximum amp of shore power. Again, with no limitation, they will suck att maximum capacity (like 32 amps /120v AC).

Next is your alternator and for this bank Balmar says that maybe a big body 200A/24v alternator would do, but no less. That one does not fit on my 110hp Yanmar, it is too large. Also, you need very good ventilation in your engine room. I chose to use my existing Mastervolt 75A/24v. After checking that the regulator current is limited to 28,5V (up to 28,8 could be accepted but 28,4 is recommended)Ii started using it. It charged at 60A and after 1 hour i checked the temperature of the alternator body...it was 270°F (130°C).
What you can do is to get a pair of 12v lead/gel batteries to use as "dump" and use the Mastervolt Charge Mate Pro, that limits the charging to 40 or 90 amp. It will not work without the lead batteries (I have tried). On the other hand, at this stage I think I will be happy to have a pair of leads as emergency (starter battery is 12v). If you have a 12v system you should keep the lead starter batteries and use the Charge Mate Pro, then it is quite practical.

Now comes the Panda 400 AGT diesel generator which is 120A/24v. Haven't sorted that one out yet.

In short, this is not simple. I'm not even sure that it is a suitable system for marine application. What happens if a bolt of thunder strikes a couple of hundred yards away? It has happened to me earlier and a bunch of electronics were wiped out.

If you do it, get the best stuff, otherwise it may never work properly and it will in any case cost a load of money.

Let's wish us luck!

[JimmyDarci]

The post asked a very specific question and I see no answer so far.
Question: “can you parallel wire MORE than four LI batteries??? (presumably
Drop in and with individual latest tech BMS.

I too read somewhere in the internet universe that four batteries was the limit for wiring. So here is my shot at an answer to the actual question as answered by my electrician when inset up four LI drop in batteries but wanted six.
... “ Best result is create a parallel of no more than four LI batts ... but you can have several banks of batteries on board. So, for example, you want six LI batteries, create two banks of three and three. Switch between banks or split the working load among appliances and various boat needs.”

Electrician did not supply reason for this but I suspect it had to do with balancing charges between more than four batteries even with high tech Internal BMS in each battery. I ended up getting four BattleBorn LofePo4 100ah batts with a Victron smart charger from six panels of solar. Works great and keeps it simple.

[SV Pegaso]

Originally Posted by henryk

I'm getting a 'drop in' boxes with BMS built in. Electrical and electronics are not my forte , so i would like to make it as simple as possible. So, getting to my first questions. If I will get 6 batteries, 12 V, 100 AH each and connect them in parallel,would BMS take care of even charging distribution ?

I am not sure if you can find a cable connect pattern for 6 batteries unless you are using a bus. All cable lengths (+) to your main (+) and (-) to your main (-) must be of equal length otherwise the batteries in the block get different resistance and charge differently. You can google some connect patterns to various numbers of batteries. I haven't seen one for six but 8 e.g. would be two blocks of 4 in parallel. Be aware that your main cables to and from the batteries need to be able to handle some serious DC power and the Lithiums are happy to process 400+A@12V if you give it to them.

[The Sun King]

Batteries in any chemistry are best not run in parallel. In large systems, the fewer the parallels the better. If you need a lot of power, go UP in voltage. I am currently putting together a 300 amp, 48v LiFePO4 system. That's roughly equal to 12 parallel 100ah@12v batteries in lithium or over 20 lead acids. I MAY go with a second set for redundancy, as I would hate to get shut down, late at night and a long way from home. My power doesn't just run lights and electronics, it drives the motor.


Charging a large 12v bank of any chemistry is likely to upset an ordinary alternator. You'll need one that can limit current or it will overheat.


The thing I don't like about lithium is that when the BMS turns off, you go dark. No more squeezing out a few more hours by dropping below the lead acid's 50% level. Hence, my redundancy plan.