Add new Pylontech US3000 to bank

Hi all

I currently have 2 x US2000’s.
Bought a new US3000.
I know I got to install the US3000 as the primary.

The seller agreed to have one of their techs sit with me now… and made sure i got gape between meetings today, but now no show… so need to consider doing this myself.

Can I simply replicate the wiring of battery one into 2…
basically move whats coming from inverter into the first us2000 into same spots on us3000 and then connect us3000 onto us2000 as us2000#1 is connected us2000#2 ?
or will there be more wiring/programming changes on the inverter.

And move the monitoring cable to the new battery (make it master).

ye, there is a can bus cable going from old primary that will go into new batter, and then the cable going from inverter into old primary will move to same port on new unit.


I did this the other day. Added a 3rd E-Tower. I prepared for sparks and all sorts of nasties but it went very well. Inverter immediately picked up the 3rd battery.

I initially got the dip switch settings wrong (only on the 3rd battery) because what I read didn’t make sense to me - binary or sum such. So just made a quick video of their positions, and installer told me what to flip on the last battery and all was well.

No extra programming needed save for the BMV that had to be told that there is now 300Ah’s available.

Those breakers on the batteries is really a nice feature. Had I done this with my previous lead acids, sparks all the way lol.

… what battery did you add? this is not sounding like a Pylontech that your talking about.

My dip switches on both my us2000’s are exactly the same atm.


I had 2 Freedom Won Etowers 5,2Kw and added a 3rd one.

Sorry yes not Pylontec, I’m just saying that it was basically plug and play with no extra programming needed. Pylons cannot be that much different?

But the Freedoms must have their dip switches configured, I suppose to make one the master, 1st slave, 2nd slave etc. Settings different for each one.

ye, i assume they could also potentially, but then looking at mine, they currently both the same, guessing the way the network cabling is between them and which one is connected to the inverter also defines master… but allot of can be this, can be that… so I’d just confirm before screwing something up, they not cheap… some patience can safe lots of $$$.

I know too little still about litium settings still, but my installer told me the different dip switch settings are specifically required to make them communicate better with each other in terms of their place in the food chain.

Please make sure about this as I share your sentiments. Lots of Randelas gone if we stuff something up.

Other than that, connecting the 3rd one was really simple and easy, not even a 10 minute jobbie. Literally just plugged all cables going into the 2nd battery (from Venus and Multi) into the new 3rd one, and added the extra data cable from 3rd to 2nd.

I’m thinking the same… pretty sure i have a good idea what needs to be done.
want to confirm, … other question of course is firmware, can’t see them all being on the same so how do i fix that…
especially since I use a MBP.


If you do the connections with the new battery as master you should be fine. Just make sure all the batteries and the inverter are off before you start and the DC Disconnect is open.

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i have a isolating switch… or another way is to switch all batteries off… and disconnect the positive cable… once all the other connections are done, connect pos and then flip the on switch and then press the on button… guess.

i’ve seen on YT movie demanding a battery balancing hour/2, but then saw a 2nd that says the batteries’ have a internal BMS ad it’s not needed, the BMS will sort everything out itself…

for now i can fw flash anyhow, between having to search for cables and using a MAC M1 I’m a bit strander on doing anything fw wise. so hoping i’m not sitting with a problem…

again… hoping someone with more Pylontech knowledge will chirp in here.


Really George??

Charge existing bank to 100%,
Shut down inverter
Shut down each battery
Disconnect battery isolator
disconnect existing bank and connect only new battery, move comms cable
Reconnect isolator
Turn new battery on
Turn inverter on
Charge new battery to 100%

Then shutdown inverter, turn off battery and disconnect isolator.
Add old batteries in parallel to new battery battery and reconnect isolator
Turn all batteries on. Sometimes you need to press the reset on the master.
Turn inverter on.

Cross your fingers and hope for no sparks or smoke.

Not sure what size inverter you have but if there’s a chance the battery current exceeds the 100A (or maybe 120, can’t remember), you need to add another set of cables.
If using just 1 set, I connect positive to top most battery and negative to bottom most.

I’ve added batteries to a bank over 2 years and didn’t have to change firmwares. If it ain’t broken, don’t try to fix it.

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So looking at your answer, are you responding specifically with knowledge of Pylontec connected to Victron or generally?

I’ve seen 2 ways to do it and you now added a 3rd.

looking for pylontec/victron specific knowledge/method.

way 1, disconnect all batteries from inverter, interconnect them and switch them on, they balance. Once balanced, switch off, connect to inverter, switch on.

way 2, simply connect and switch on, the internal BMS will sort itself out,

way 3, as per your above.


A fourth way is to switch off your MPPT and discharge your current bank to 50% overnight.

The new battery will ship at 50% SOC. In the morning, add the new battery as the master and turn on the MPPT and the bank will charge back from 50 to 100% with plenty of time to top balance on a sunny day.

If the bank has not been at 100% for a few hours and all the cells are balanced, set to ‘keep batteries charged’ overnight.

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hi hi, is what was done pretty much.
my bank, being 2 smallish US2000’s was pulled down to 50% quickly using a couple of loads, at max discharge rate that inverter could handle.
Battery was connected and all is back on.
Thanks to your suggestion and quick call with @mmaritz

My way is similar to option 1 except that it’s a lot quicker. Who has the time to wait for a few hours when we are on stage 6/7 if you do it during the day, you lose pv power, at night, you lose backup power.

I used to follow option 1 but it just took too long.

Option 2 is not as simple as it sounds. It will take time for the batteries to balance, possibly many days. Internal bms is different to the bms comms to the inverter. I don’t have victron but my brother and friends do and they also follow the method I’ve mentioned.

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Vassen, agree. my problem was I had to travel this morning (for wknd), and we sitting with stage 6 atm, so wanted to leave family in better state.