18 replies to this topic

[buckland]

 (And Happy St Patricks day)

 

I have been doing searches looking for the thread on Victron Smart Shunt install. As usual I am probably over thinking it. I hate sparks!  I have two BB 100 lithium batteries in parallel.  The Victron DCDC charger. Victron 100/20 MPPT controller and a 1000 watt inverter.  

Basically just one question:

1) I am assuming I should simply leave all wires attached to the Positive on the battery.

2) Remove all wires to the Negative on the battery 

3) Attach a wire from Negative on the battery to the Shunt 

4) Attach all Negative wires (that were on battery) to the other side of the Shunt

 

Here's the question: With 2 batteries in wired together in Parallel, the batteries' negatives and positives are still still connected ? 

 

Thanks Rob

 

 

 

Attached Files

•  Parallel.jpg   60.28K   32 downloads

[pvstoy]

Yes. and Yes.  to your questions.

 

Battery #1 will have the positive input and a jumper to Battery #2. 

For the negative wire, take it off battery #2 and go to the shunt.  

Run the negative jumper from battery #2 to battery #1.

 

All negatives wires from the camper and inputs need to run through the shunt so it can measure how many amps are going in and out of the battery bank.

 

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 InkedParallel_LI.jpg   120.57K   29 downloads

Edited by pvstoy, 17 March 2022 - 06:23 PM.

[Vic Harder]

+1 to what Patrick said.  And his removal of the redundant +ve wire is a very good move.  You were on the right track Buckland!

[buckland]

Got it... and yet again a Lucky Irishman says thanks for the help. I have a strangely warm day forecast for tomorrow so will hopefully get this done and looking forward to the info the shunt will give about the combined 2 batteries. Thanks for your help and reassurance.

[Jon R]

The reason for the wiring arrangement Pvstoy recommended (batteries wired in parallel, but connection to the battery network done with positive from one battery and negative from the other) is to try to balance the current going in and out of the two batteries so they stay at the same charge state.

Also, one change I strongly suggest: a single large wire coming off the selected positve battery terminal should go to a main battery fuse or circuit breaker located as close as possible to the batteries, then all the chargers and loads should be connected to the other side of that fuse or CB. Size the fuse to protect the smallest connected wiring that is not already fuse protected. That fuse will help prevent a fire if your positive wiring shorts to ground somewhere.

[buckland]

Thanks for the additional info Jon.

Another question: I have a 1000W inverter currently wired positive and negative to battery#2 . Could I keep the positive on battery #2 (instead of moving to battery #1) and only move the inverter negative to the shunt? 

 

OR should all positive wires on the parallel batteries be on Battery #1?

[pvstoy]

Does not matter which battery is 1 or 2.  Just make it convenient for your wiring.  Just have positive on one battery and negative on the other battery.  And all negative on the input of the shunt.

 

I had to make a buss Bar for all the negative wires to assemble and then one wire to the shunt.  There is not much room to add too many wires on the shunt.

[buckland]

Thanks Patrick!... 

I got it all up and it seems A-ok. Below is a screen shot of the battery settings  for the Shunt. I changed the Peukert Exponent  to 1.05 as I have LiFePo4. Batteries' voltage were 14.19. Question Should I Calibrate and Synchronize ? And if so, I assume it is done when batteries are at 14.2?  

Attached Files

•  IMG_5488.jpg   97.86K   28 downloads

[Vic Harder]

Turn off the "Battery starts synchronized" function.  Calibrate is done when you have zero loads and zero charging, to set the current flow to ZERO.  You should not have to do that, but that is when it is done.

 

As for synchronize, yes, when you have had it on a charge and no load for days on end, you can synchronize.  

 

I'd consider setting the tail current to 2%.  In other words, when you get to 2% of max C it is "full" = 4A for a 200AH battery.

[buckland]

Thanks Vic,

I owe you a couple beers at least over the years for you help. I plan on getting out to BC in the next couple years... Maybe we can have a pop in and say hi over a pint or two.

I switched the setting but now I have to read up on what they mean! I recall I read about it before but I can't remember. I am finally at where I think I planned to be years ago. I want to enjoy getting back out there (wife just retired) and feel the camper is in tip top ready condition now. BC, AK (again), NV. UT, CO, YK, Mexico, TX, FL (to see a launch), Gulf coast etc.... IF the dreaded next wave of Covid doesn't happen (but I think it will). 

My truck has a small diesel so loaded I get 20mpg better at times. That will have to do. 

Thanks again Vic Jon Patrick!