diy solar

diy solar

100Ah lifeP04 batteries

sunnyeveryday

New Member
Joined
Jan 18, 2020
Messages
22
So I've got 16 100Ah Life04 Calb batteries.

I will be using them for battery storage in a 12V nominal system. Charge, mainly with Solar, discharge using an inverter.

I've read that the parallel connections don't have to be too large, (whatever too large means), as the main current flows through the series connections, the parallel just keeping the parallel cells balanced.

So, the big question...what should I be using, cable size, for the parallel connections ? ADD: I will discharge them to 2.85V each before paralleling them.

I have the hunking big solid copper connections for when I start putting them in series.

I have to make up a little test bench to charge/discharge each set of 4 to verify capacity before I start assembling them in parallel, so I have some time.

I would appreciate any advice.

Thanks
 
Last edited:
Motorhome/travel trailer for extended off grid.

So I want to stay at 12V. Yes, I could down convert from 24V or even 48V for the 12V but I don't want to go there.

DIY Lithium batteries by Micah Toll says and shows a diagram to use the larger bus bars for the series and small for the parallel as they are self balanced, being in parallel and not much current flows.

Each Four set in parallel uses 6 busbars ( 3 on the negatives and 3 on the positives). That's 24 bus bars before I even put them in series.

Add another 4 to join each pack in series is another 12 bus bars for a total of 36.

That's a lot.

If I don't need the heavy duty ones in parallel, then it will be easier as I am finding it hard to get extra bus bars, unless I go through China with delays in delivery.

So I'm asking for more experiences peoples opinions and advice.
 
4p4s seems likes it's going to be a logistical challenge. If it was me, I would be making my own bus bars. Then again, I wouldn't be doing 4p4s if it was me. 2p4s is where I the design of my system started, but the eggheads here on the forum convinced me to go with 4s2p instead. A single 4s battery is dead easy to create. Make four of those is just more of the same. The downside is that you need to go with four BMS. The upside is that four BMS gives you four times the amp rating of a single BMS.

Moving/installing a 4s battery is fairly straightforward. It weighs about 45 lbs and can be put into a reasonably sized compression frame that isn't four foot long like your 4p4s battery would be.

I'm not sure that the idea that current flow is lower through the parallel connections than the serial connections. Maybe one of the aforementioned eggheads will have a better answer on this.
 
Ok - I found this. Reading it now.


Why would it be a logistical challenge ?

You measure the space in the motorhome/trailer

You measure the individual batteries.

You build a suitable box.

You test your batteries, charge, discharge etc.

You label and disassemble them and resemble them one by one, into the motorhome/trailer.

The calb 100Ah paralleled in groups of 4 are 10 3/4" x 5 1/2". 4 parallels in series together are about 10 3/4" x 23".

Not a particularly large size for 12V@400Ah aka 5.12Kwh
 
Logistics, not spatial. It sounds like you're having a tough time getting the bus bars you need.

The weight and measurements were for my 280 Ah cells. I forgot that you are using 100 Ah cells.
 
Back
Top