bussbar versus daisychaining to increase capacity

[PaintBrush]

Is it advisable, or not, to connect two 100ah 24v batteries in parallel (negative to negative bussbar, positive to positive bussbar) at the bussbar level instead of daisychaining only the batteries in parallel to increase battery bank capacity?

 

[pollenface]

I don't see a problem if there are equal cable lengths from the bussbars to each battery.

 

[AHTrimble]

Is your system 24v or 48v?
My experience points to each battery to a busbar for parallel operation. Helps balance the batteries.
A great and clean option would be a Victron Energy Lynx PowerIn box as the busbar...really nice! https://www.victronenergy.com/dc-distribution-systems/lynx-power-in
Make sure your battery-to-busbar cables are same lengths for each battery.
And of course I like a good DC breaker or battery switch for each battery.
Add the Lynx Shunt to it and you are ready to go! https://www.victronenergy.com/dc-distribution-systems/lynx-shunt-ve-can

 

[PaintBrush]

Is your system 24v or 48v?
My experience points to each battery to a busbar for parallel operation. Helps balance the batteries.
A great and clean option would be a Victron Energy Lynx PowerIn box as the busbar...really nice! https://www.victronenergy.com/dc-distribution-systems/lynx-power-in
Make sure your battery-to-busbar cables are same lengths for each battery.
And of course I like a good DC breaker or battery switch for each battery.
Add the Lynx Shunt to it and you are ready to go! https://www.victronenergy.com/dc-distribution-systems/lynx-shunt-ve-can

24 volt. I have the Victron 500amp shunt, Victron MPPT 100/50, and Giandel 2000/4000 inverter. I was thinking about adding the Victron battery balencer but it is not bluetooth enabled so I'm waiting to see if they come out with a "smart" version. I would put a DC breaker on each battery (would 100 amp be high enough or would it need to be higher?).

 

[AHTrimble]

24 volt. I have the Victron 500amp shunt, Victron MPPT 100/50, and Giandel 2000/4000 inverter. I was thinking about adding the Victron battery balencer but it is not bluetooth enabled so I'm waiting to see if they come out with a "smart" version. I would put a DC breaker on each battery (would 100 amp be high enough or would it need to be higher?).

Your shunt could hang off the PowerIn just fine.
The size breaker or fuse is dependent on the size of wire between the battery and the busbar. Your battery manual should have recommendations for wire size or this is a good tool to calculate that
FWIW I like to go one size up on the wire whatever the recommendation is.
Why the balancer?

 

[PaintBrush]

You shunt could hang off the PowerIn just fine.
The size breaker or fuse is dependent on the size of wire between the battery and the busbar. Your battery manual should have recommendations for wire size or this is a good tool to calculate that
FWIW I like to go one size up on the wire whatever the recommendation is.
Why the balancer?

The balancer would just be for added protection to keep the two batteries balanced. My understanding is that it doesn't even start up unless there is a large imbalance.

 

[Bud Martin]

Is it advisable, or not, to connect two 100ah 24v batteries in parallel (negative to negative bussbar, positive to positive bussbar) at the bussbar level instead of daisychaining only the batteries in parallel to increase battery bank capacity?

1) Battery bank capacity is not affected by parallel or series (daisy chain) connection.
Two 24V 100Ah batteries connected in parallel you will have 24V battery bank = 24V x 200A = 4800Wh capacity.
Two 24V 100Ah batteries connected in series you will have 48V battery bank = 48V x 100A = 4800Wh capacity.

2) Victron battery balancer is made to balance batteries connected in series, in your case you have two batteries connected in parallel only so it is not for your setup..
The Solution: battery balancing: The Battery Balancer equalizes the state of charge of two series connected 12V batteries, or of several parallel strings of series connected batteries. When the charge voltage of a 24V battery system increases to more than 27,3V, the Battery Balancer will turn on and compare the voltage over the two series connected batteries. The Battery Balancer will draw a current of up to 0,7A from the battery (or parallel connected batteries) with the highest voltage. The resulting charge current differential will ensure that all batteries will converge to the same state of charge.
Victron battery balancer: https://www.victronenergy.com/upload/documents/Datasheet-Battery-Balancer-EN.pdf

 

[AHTrimble]

The balancer would just be for added protection to keep the two batteries balanced. My understanding is that it doesn't even start up unless there is a large imbalance.

The parallel batteries will balance themselves (micro-cycles) via their BMS and natural flow in and out of current.
FWIW reconsider a balancer.