Hi guys,

Been using this forum for guidance on my system, so thanks for all the information shared. 

Today I expanded the existing 4 x 12v in series, 48v bank into two 4 x 12v strings connected in parallel to each other. All new 100ah batteries were used. 

From these I have connections to a Victron controller and a Cotek inverter. This is all good.

My question relates to a 48v to 24v converter that was originally attached across the one 48v string of 4 batteries. This was used to run all the LED lighting in the place (a very small place so not a huge amount of lighting). How would I now connect this to my current set up of two 48v strings connected in parallel to ensure a balanced load on the batteries? 

Thanks in advance. 

As soon as I fathom how to load images on this forum I'll upload my very rough diagram 😊

Welcome Clint.

37 minutes ago, ClintZA said:

How would I now connect this to my current set up of two 48v strings connected in parallel to ensure a balanced load on the batteries? 

You connect the 48v to 24v converter at the same spot as the inverter is connected to the batts.

Ensures a even draw over all the batts.

38 minutes ago, ClintZA said:

As soon as I fathom how to load images on this forum I'll upload my very rough diagram 😊

Bottom of the blcok where you type is a "

Drag files here to attach, or choose files... Drag files here to attache ... Max total size 3MB. Drag the file there or paste the image direct.

The @The Terrible Triplett

28 minutes ago, The Terrible Triplett said:

Bottom of the blcok where you type is a "

Drag files here to attach, or choose files... Drag files here to attache ... Max total size 3MB. Drag the file there or paste the image direct.

Let me try again ... posted too fast.

Bottom of the block where you type a reply there is a section for "Drag files here to attach ... Max total size 3MB"

Drag files there from your PC's file explorer to attach / or choose files OR copy paste a image taken and paste the image direct into the post.

See here: 

Edited August 27, 20196 yr by Guest

8 minutes ago, Energy said:

The @The Terrible Triplett

Site does not give us enough time to "fix" oepsies.

Can it be changed to say 5-10 minutes or some such?

Excellent, thanks. I was unable to post images I think as it was awaiting approval. I see the link now. 

Attached is the promised image. So just to confirm the 48v-24v DC-DC would be added to the "pile"* of connectors on the bottom left - ve and the top right +ve? 

 

* pile being parallel connection cable, cable to inverter and cable to charge controller - was already a squeeze so I hope I can get a fourth wire on. 

Edited August 27, 20196 yr by ClintZA

11 minutes ago, ClintZA said:

- was already a squeeze so I hope I can get a fourth wire on. 

To overcome that problem I use these fuses below.
You get them in single and double pole, with 30-300amps fuse blocks.
EDIT: And you can have like one 300amp and one 30amp fuse on the double pole ones.

Edited August 27, 20196 yr by Guest

12 minutes ago, ClintZA said:

So just to confirm the 48v-24v DC-DC would be added to the "pile"* of connectors on the bottom left - ve and the top right +ve?

Correct, use the 48v connection points for a 48v to 24v converter.

And don't be like me and connect a 24v device to a 48v battery bank. ☠️

9 hours ago, Energy said:

The @The Terrible Triplett

Haha sorry. I meant. 'Thanks so much for assisting the guys' fell asleep mid type! #trump

12 hours ago, ClintZA said:

I hope I can get a fourth wire on

If that is a challenge, you can also use the other diagonal pair. Eg:

Same balancing principle.

What is your experience with the LED lights running straight from the battery? It is presumably more efficient? I'm not sure it would be worthwhile to run in parallel with the 220V from the inverter?

I have one 12V LED on a switch on one battery so I can find my way around in the dark if the inverter goes off for whatever reason (usually low battery in winter). 

3 minutes ago, DeepBass9 said:

I have one 12V LED on a switch on one battery so I can find my way around in the dark if the inverter goes off for whatever reason (usually low battery in winter).

If it is not used permanently, there is absolutely no reason not to do that.

It is only when it is a permanent always on thing when that one batts may get affected ito charging / discharging not identical to the rest of the batts.

On 2019/08/28 at 11:39 AM, plonkster said:

If that is a challenge, you can also use the other diagonal pair. Eg:

Same balancing principle.

That'd be a lot easier! I (based on my inexperience and using Prof Google) thought that might not be perfect balance but, in thinking about it, it would obviously still travel through all 8 x 12v (or in this case probably more accurately 2 x 48v) batteries. 

On 2019/08/28 at 1:52 PM, DeepBass9 said:

What is your experience with the LED lights running straight from the battery? It is presumably more efficient? I'm not sure it would be worthwhile to run in parallel with the 220V from the inverter?

I'm only doing it this way as I already had the 48 to 24 DC-DC and the LEDs are all 12/24v. But I am a newbie so always open to advice.