24v - 16 Calb cells

Miketcq8

New Member
Joined
Jun 21, 2021
Messages
4
Guys, I'm new here and need to learn a lot quickly. I'm helping a buddy with his boat setup.
Background:
* Marine sailboat application with 24v gear and old lead acid (4x115 a/hr I think) batteries. Victron multi plus, Victron 12v to 24v DC to DC charger from the Starter battery to the house bank. Victron 24v to 12v Dc convert to the 12V busbar. The boat has an old Solar array.

** I would also like add a Honda 2000w charger to help with off grid charging.
** I have 16 Grade A 100amp Calb cells to use to build a 24V battery.
** (Future project, to double the battery capacity again.)

So my question is should I build 2 packs of 8S cells and buy two Daly BMS's? Or is there a better way to do it?
 

Steve_S

Offgrid Cabineer, N.E. Ontario, Canada
Joined
Oct 29, 2019
Messages
5,609
Location
Rural NE Ontario Canada
I look at Botas as a Risky Business because as well know things can happen out on the water and the consequences can be dire, quite quickly.
My suggestion is always to go for Fault Tolerance & Fallback / Failover because when Murphy wants to apply his Laws you want to kick him down the drain.

2x 8S packs for 24Volts, each with an 8S BMS and fused accordingly.
Word of Caution, it is best to oversize the BMS simply as a safety factor to provide margin so as to not reach Max Thresholds.
The CALB 100AH cells can output up to 100A for 1 Hour and take 50A Charge for 2 hours.
Fuse should be 100-125A and BMS also should be rated for at least 120A to 150A.
A SmartBMS is HIGHLY RECOMMENDED so it can be programmed & tweaked.
Optionally an Active Balancer (If these are not Grade-A & properly Matched & Batched cells *).

Adding packs later in Parallel with LFP is NO PROBLEM unlike the Lead Acid's. BUT be aware that having a large disparity between packs, ie: 100AH to 280AH is TOO MUCH and will result in the 100AH underperforming and drawing down the 280. It is best to keep packs closer together for Battery Bank Balance, over 100AH difference and issues start to arise which have to be dealt with.

* MOST Vendors sell "bulk" cells as Matched, They are ONLY Voltage & IR Matched at their static storage voltage. These are NOT MATCHED by any stretch of the imagination. Properly matched cells come with cell reports & cost on average between 30-50% more than Bulk Commodity cells.

Many FETbased BMS' such as the JBD or Heltec's will do just fine.
NB: Passive Balancing is of little use on Bulk Cells (too much differential) and the Capacity of the cells is too great. Active Balancers above 5A capacity do work with these larger cells.

REFS:
JBD BMS' 24V Models (dbl check for LifePo, communications you want etc)
HelTec BMS (8S-LifePo4 offerings, BMS, Active Balancers & BMS with Active Balancing.
Chargery BMS8T-300 (Relay/Contactor) controlling BMS: (Available with 200A BMS & DCC {Passive balancing only} )
QNBBM-8s Active Balancer by DeliGreen

BTW: I have a Chargery BMS8T-300 with 300A DCC and a QNBBM Active Balancer on all my packs. 2x 24V/280 Bulk Cells, 1x 24V/280AH Matched & Batched, 2x 24V/1750AH EV-Grade LFP packs in my bank.

My details and information in my signature which will be helpful to you as well.
Hope it helps, Good Luck.
Steve
 

Miketcq8

New Member
Joined
Jun 21, 2021
Messages
4
I look at Botas as a Risky Business because as well know things can happen out on the water and the consequences can be dire, quite quickly.
My suggestion is always to go for Fault Tolerance & Fallback / Failover because when Murphy wants to apply his Laws you want to kick him down the drain.

2x 8S packs for 24Volts, each with an 8S BMS and fused accordingly.
Word of Caution, it is best to oversize the BMS simply as a safety factor to provide margin so as to not reach Max Thresholds.
The CALB 100AH cells can output up to 100A for 1 Hour and take 50A Charge for 2 hours.
Fuse should be 100-125A and BMS also should be rated for at least 120A to 150A.
A SmartBMS is HIGHLY RECOMMENDED so it can be programmed & tweaked.
Optionally an Active Balancer (If these are not Grade-A & properly Matched & Batched cells *).

Adding packs later in Parallel with LFP is NO PROBLEM unlike the Lead Acid's. BUT be aware that having a large disparity between packs, ie: 100AH to 280AH is TOO MUCH and will result in the 100AH underperforming and drawing down the 280. It is best to keep packs closer together for Battery Bank Balance, over 100AH difference and issues start to arise which have to be dealt with.

* MOST Vendors sell "bulk" cells as Matched, They are ONLY Voltage & IR Matched at their static storage voltage. These are NOT MATCHED by any stretch of the imagination. Properly matched cells come with cell reports & cost on average between 30-50% more than Bulk Commodity cells.

Many FETbased BMS' such as the JBD or Heltec's will do just fine.
NB: Passive Balancing is of little use on Bulk Cells (too much differential) and the Capacity of the cells is too great. Active Balancers above 5A capacity do work with these larger cells.

REFS:
JBD BMS' 24V Models (dbl check for LifePo, communications you want etc)
HelTec BMS (8S-LifePo4 offerings, BMS, Active Balancers & BMS with Active Balancing.
Chargery BMS8T-300 (Relay/Contactor) controlling BMS: (Available with 200A BMS & DCC {Passive balancing only} )
QNBBM-8s Active Balancer by DeliGreen

BTW: I have a Chargery BMS8T-300 with 300A DCC and a QNBBM Active Balancer on all my packs. 2x 24V/280 Bulk Cells, 1x 24V/280AH Matched & Batched, 2x 24V/1750AH EV-Grade LFP packs in my bank.

My details and information in my signature which will be helpful to you as well.
Hope it helps, Good Luck.
Steve
Thanks Steve, very helpful insights and useful information for me.
 

Miketcq8

New Member
Joined
Jun 21, 2021
Messages
4
hi, Mike,
if you haven't bought the cells, I recommend you with Narada LFP cells. They are all brand new, high rate, great discharge performance, and has warranty life, can be delivered right away from the warehouse in CA, USA. And it is a phone call's reach, call 213.797.7727. Hope it is helpful.
Thanks for your feedback, but I'm in the Europe..
 

Quanifi

New Member
Joined
May 10, 2021
Messages
4
Is there a way to make 16s 3.2v Lithium batteries into a 24v setup...without running two separate 8s setups...???
 

smoothJoey

Hoop Dee Doo!
Joined
Nov 30, 2019
Messages
9,995
Is there a way to make 16s 3.2v Lithium batteries into a 24v setup...without running two separate 8s setups...???
8s2p is 2x 24 volt batteries.
2p8s is 1x 24 volt battery which is 8 pairs of cells connected in series.
 

wholybee

Solar Addict
Joined
Feb 11, 2021
Messages
427
Is there a way to make 16s 3.2v Lithium batteries into a 24v setup...without running two separate 8s setups...???
Yes. Parallel pairs of cells together. So you have 8 pairs. Then Build the battery as if each pair was a single cell. Often referred to as 2p8s.
 

Quanifi

New Member
Joined
May 10, 2021
Messages
4
Okay great, thank you so very much for this, really helps....

Now the question of all questions for solar power and the sun. Who can explain why my 4 x 250v panels, 1000w total and the day is the same as the day before, no clouds, perfect sunlight hitting the panels pulling in over 1000w up to like 1236-1279w at 10am PST and the system is charging great, a little hot but great with fans running its doing great. Then the next day same sun, no clouds and the panels are barley pulling 700w at 10am PST. How is this possible....??? Also to add the day it was pulling over 1000w the outside temp was around 70-80 degrees and the day it was 700w or lower the temp was around the high 90's to 100.
 

Quanifi

New Member
Joined
May 10, 2021
Messages
4
Do I use a 16s BMS for the 16 batteries made into the 2P8S Block for 24v on each of the 16 batteries, or just use an 8s BMS for this on every two batteries connected as one....???
 

Steve_S

Offgrid Cabineer, N.E. Ontario, Canada
Joined
Oct 29, 2019
Messages
5,609
Location
Rural NE Ontario Canada
Do I use a 16s BMS for the 16 batteries made into the 2P8S Block for 24v on each of the 16 batteries, or just use an 8s BMS for this on every two batteries connected as one....???
24 Volt LPF is based on 8 LFP Cells @ 3.2Vpc. If you parallel cells within the pack as you intend, they are then viewed as "one cell" regardless if it is 2 or 4 cells sitting in parallel. This does NOT allow you to view, monitor and manage "individual cells" as whatever is paired up is only seen as one.

We NEVER Recommend anyone parallels unmatched Bulk Cells because of the inherent issues with cell deviation & differential. Full Matched & Batched cells that perform exactly the same throughout the entire voltage curve are what are typically used for paralleling cells. For example, EV's (which are very finicky) use ONLY fully Matched & Batched cells. MANY people have assembled Paralleled cells in packs using Bulk Cells and "hit the wall" and had to convert to standard simple Straight S configs. BTW: That costs even more money having to do it over again....

If you built TWO 24V/8S packs instead of one ONE 24V/2P8S, you would be able to manage "each cell". Both packs in Parallel would divide Load & Charge equally (less demand hit) and this improves Fault Tolerance because IF one pack cuts off for any reason the other can keep operating (with properly configured BMS').

See the Second Link in my Signature for more extended details on assembling your packs, voltage charts etc are all in the PDF doc.
Hope it helps, Good Luck
 

toms

Photon Sorcerer
Joined
Jul 24, 2020
Messages
818
Curious as to why there are two series bars between pair #4 and pair #5?

You only require one link there.

And the disadvantages of using parallel pairs have been greatly overstated in this thread. Some people don’t understand the cells very well. You will always get greater capacity out of a pack by matching your weakest and strongest cells in a parallel pair.

eg: if the weakest cell you have is 95ah, the strongest is 105ah, and the rest are 100ah:

In a parallel pair pack if you match the 95 and 105, all the cells end up at 200ah.

In two series packs, the packs will be limited by the weakest cell in each pack which is 95ah + 100ah.

The advantages of a multiple battery system are battery redundancy, and in some cases lower price.

The advantages of a single battery system are less failure points, and in some cases lower price.

If redundancy is an issue i use multiple complete systems. (not much point having redundant batteries feeding a single inverter if the inverter fails!)
 
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