New here. What a fantastic source of info. A battery question if I may.

[Bocas DT]

I am an old oilfield engineer so bare with me. I have a completely off grid Cabin and my Trojans finally bit the dust, You are lucky to get 3.5 years out of them here in the tropics with perfect maintenance because of the heat and weather conditions here on the Island. I am new to Lithium's and purchased 6 12v 100ah Mini's (4 in parallel for the cabin and 2 for starlink in a separate setup). I currently do not have a huge power demand here but would like to upgrade with a few additional small appliances if possible. I am using a Renogy 60 charge controller and have 3 older 275w panels in parallel. I am upgrading to some fresh panels and wanted to add some battery power storage due to the crazy tropical weather patterns on the island. Everything that I have read most everywhere about the batteries, including the manufacturers instructions are 4 max in parallel. This is what I wanted to run by you pro's to see if this is possible or if I should just be committed.

I was thinking of running 2 Renogy 40a charge controllers, one with my new 505 panel, and the other Renogy 40a with a new 575 panel that I just picked up from a friend. Run both of these into a modified Victron Lynx Power in (internal 4 fused lugs now). I know this is possible as there are numbers of youtube and other sources, but my big question is about the batteries. Is it at all possible to take my 6 12v mini's (all 6 purchased at the same time) and make two strings of 3 batteries each in parallel and wire them into a bus bar set ups then wire the 4 bus bars into the Victron Lynx Power In for charging and possibly the extra power storage that I am seeking? I was told by somebody here on the Island that it could be possible. Not sure if that was the beer talking, but after reading a lot of these post, I felt it would be better to run this by the great people on this forum. Standing by, and thank you in advance for any input, ideas or recommendations. Keep in mind that all proper fusing and breakers being used in this potential design.

PS If this is possible, my next question will be about hooking up the inverter.

 

[mikefitz]

two strings of 3 batteries each in parallel and wire them into a bus bar set ups then wire the 4 bus bars into the Victron Lynx Power In for charging and possibly the extra power storage that I am seeking?

Bit confused here, a string of 3 batteries is 36 volts. Can I assume you mean 3 batteries connected in a parallel pack, connected to a further 3 battery pack, giving a 12v setup with 6 batteries in parallel.
The 6 batteries could , with careful connecting up using buss bars, be used as a single pack.

 

[Bocas DT]

Good morning and thank you for this information. Yes, 12v, 2 strings, 3 in parallel (top wiring set up in the photo that you sent with one of the batteries cut out) and another 3 in parallel wired into the modified Victron Lynx Power In (basically a fancy 1000a bus bar), with the dual Renogy 40a charge controllers (I believe similar to the top configuration in the photo that you attached). So, now that I know this is possible, where or how do I connect the inverter? Several examples that I have seen on line suggest wiring it into the far end of the Lynx just past the dual string of batteries and the Charge Controllers. Something about this just doesn't seem efficient as with this set up on line the controllers are bringing in the power to charge the batteries, but the inverter is drawing power at the same time. Thanks again for replying. Pictured with the ground connected.

 

[Bocas DT]

NOT PRETTY BUT THIS WAS THE IDEA. Of course with appropriate fusing, breakers and matching wire lengths.

 

[Reed Cole]

Most people would connect the inverter to Lynx bus bar. If you are running any kind of load while charging some of, and as much as all of the power being delivered by the charger will be used to power the load. Nothing you can do about that and and it's not like you earn interest on it if you save it in a battery. It's actually more efficient to use the power as it's being generated, lithium batteries have low internal resistance but if I understand correctly you're still losing a small percentage of the power you charge them with.

 

[Bocas DT]

Thanks for getting back with me. Those shakey lines (red and black) in the bottom right of my 1st time art work are actually the +,- from the 2 charge controllers. There are quite a few duel CC vids on line and most of them show the inverter mounted right into the mix of connections (mostly on the end where the red and black caps are) on the Lynx power in. For some reason it still doesn't set well, but with more experience and hours in I'll come around. Again, thanks so much for the info and taking the time to reply.