I have a 4 battery bank in paraelle, 4 ea 24v 100ah lithium ampretime. I need to double capacity most econimicial way, Im told I can only run 4 of these in a bank. They suggested replacing with 24v 200ah batterys, but that is major expens and elenamiates the bank I already have. Is it possible to have a switch that can change to another bank of battery's , manual or automatic. Ant suggestions will be appreaciated.Thanks
Need to increase capacity.
- Thread starter kowboy
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MisterSandals
Participation Medalist
A quick search shows the max per bank is 4P2S which would be 2 banks like you currently have, connected in series to make a 48V battery bank.
This of course would obsolete your 24V equipment.
In regards to "switching" between 2 different battery banks, this is possible. It would pretty much require a disconnect (loss of power) and then a reconnect to the second bank.
There are a few issues with this, a couple are:
Disconnecting a battery from SCC while being powered by a solar array is bad.
Reconnecting a battery to an inverter, if not done quickly would require a capacitor pre-charge.
You could not connect the two battery banks together with different voltages because the current between them may be too great (huge spark, possible BMS cutout,...).
Brucey
Solar Wizard
You can create another bank of four 24V 100Ah batteries to run in parallel with your existing bank. Prob easiest to connect both to a common bus bar.
MisterSandals
Participation Medalist
I am guessing that the 4 in parallel limit is not avoided by putting a bus bar between the 2 sets of 4 in parallel.
Brucey
Solar Wizard
Well they show parallel in 4 in their advertising, once both parallel strings of 4 are on a bus bar they are effectively separate, in terms of current passing through them? The difference in this case is basically that he isn't going to series pairs together to get 48V.
That is what I am afraid of.......Thanks for info
MisterSandals
Participation Medalist
No! 4 batteries in parallel connected in parallel to 4 more batteries connected in parallel is 8 batteries in parallel.
They may be physically separate but electrically is 8P (forbidden by manufacturer).
This is very helpful, Thank you
Brucey
Solar Wizard
There will be his existing parallel set of four batteries, 24V, 400Ah.
They connect to bus bar connected to inverter.
Then he assembles another parallel set of four batteries, 24V, 100Ah. That will also connect to bus bar, connected to inverter. As far as the batteries are concerned, they are connected in 4P, but there's no parallel connection between the arrays that would make it 8P.
Solarcabin Channel
Solar Addict
Yes, it is called a dual battery switch.
You can also put a switch on your controller leads to the battery so you can divert the solar power to either bank.
Hedges
I See Electromagnetic Fields!
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Why should anything care if there are eight batteries in parallel?
There could be higher fault current available, use multiple fuses.
If resistance is imbalanced they will charge/discharge at different rates, available current doesn't add. But for capacity, they will catch up at upper and lower knees of curve.
With a power of 2 such as 8, you can use cables to fan out in a way that matches resistance exactly.
Or use large busbars, or cables to busbars.
Rules are guidelines, really. A challenge to break them.
Think this guy was supposed to wire batteries 1s100p, or 4s25p?
diysolarforum.com
There could be higher fault current available, use multiple fuses.
If resistance is imbalanced they will charge/discharge at different rates, available current doesn't add. But for capacity, they will catch up at upper and lower knees of curve.
With a power of 2 such as 8, you can use cables to fan out in a way that matches resistance exactly.
Or use large busbars, or cables to busbars.
Rules are guidelines, really. A challenge to break them.
Think this guy was supposed to wire batteries 1s100p, or 4s25p?
So… what’s 100 batteries in parallel do?
diysolarforum.com
Last edited:
MisterSandals
Participation Medalist
I was wondering the same thing.
Marketing confusion?
This is also odd, confusing 2S4P and 4P2S in the same ad (link below):
"• ...It is allowed to be expanded to max 2S4P as 51.2V 800Ah battery system with around 41kWh energy..."
This is the reply from Manufacture, I guess they are saying its ok?
New message from: amperetime_us (691 | |
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)Th
This is from Manufacture. I guess saying it is ok?
New message from: amperetime_us (691 | |
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