Victron Power In necessity

[SHTF Power Anyway]

We recently built a 10kwh system with a Sol-Ark 12 and 4 eFlex batteries. This was a DIY project using equipment put together by NAWS. My husband and his two other electrician friends did not install the Victron Lynx Power In modules (2) that were included in the original order. I did not discover this until we decided to add more panels and batteries. The system has been running just fine without these installed but I'm concerned that they should be there. Thoughts?

 

[John Frum]

It's a question of topology.
Please post a photo of the system core including the batteries.

 

[John Frum]

What is Naws?

 

[SHTF Power Anyway]

It's a question of topology.
Please post a photo of the system core including the batteries.

 

[SHTF Power Anyway]

What is Naws?

Northern Arizona Wind & Sun

 

[John Frum]

I see what appears to be 5 server rack style batteries.
4 of which appear to be connected in parallel.

The sol-ark 12k inverter can do 9000 watts continuous discharge.

9000 ac watts / .85 inverter efficiency / 48 volts low cutoff = 220.588235294 service amps.
220.588235294 service amps / .8 fuse headroom = 275.735294118 fault amps.

That means 2/0 awg minimum for the main wire between the inverter and the battery bank.

If any connection in the battery bank fails the whole bank goes offline.
Also each connection point along the current path adds to the resistance of the circuit.

I would have used 1 power-in and connected each battery to a separate branch.
Each battery would have its own circuit to the busbar using 4 awg wire.
I would have then connected the sol-ark to the backplane of the power-in using 2/0 awg or better.
That way if a single battery has a failure, or administrative disconnect the rest can keep on working.

 

[SHTF Power Anyway]

I see what appears to be 5 server rack style batteries.
4 of which appear to be connected in parallel.

The sol-ark 12k inverter can do 9000 watts continuous discharge.

9000 ac watts / .85 inverter efficiency / 48 volts low cutoff = 220.588235294 service amps.
220.588235294 service amps / .8 fuse headroom = 275.735294118 fault amps.

That means 2/0 awg minimum for the main wire between the inverter and the battery bank.

If any connection in the battery bank fails the whole bank goes offline.
Also each connection point along the current path adds to the resistance of the circuit.

I would have used 1 power-in and connected each battery to a separate branch.
Each battery would have its own circuit to the busbar using 4 awg wire.
I would have then connected the sol-ark to the backplane of the power-in using 2/0 awg or better.
That way if a single battery has a failure, or administrative disconnect the rest can keep on working.

Thank you so much for the explanation. We had started with 4 batteries before ordering 6 more that have not yet been installed (hence you see the one not yet connected). We're about to hang another Sol-Ark 12 above a 2nd rack of batteries so now is definitely the time to configure correctly.

 

[John Frum]

Thank you so much for the explanation. We had started with 4 batteries before ordering 6 more that have not yet been installed (hence you see the one not yet connected). We're about to hang another Sol-Ark 12 above a 2nd rack of batteries so now is definitely the time to configure correctly.

2x sol-arks and 10x batteries requies 3x power-ins

 

[John Frum]

Do the batteries have built-in over-current protection?

 

[rhino]

Do the batteries have built-in over-current protection?

Looks like it is this one: https://www.solar-electric.com/fortress-power-eflex-5-4-kwh-lithium-battery.html and I'm not seeing any built-in circuit protection? Pretty pricy for what you get.

 

[SHTF Power Anyway]

Looks like it is this one: https://www.solar-electric.com/fortress-power-eflex-5-4-kwh-lithium-battery.html and I'm not seeing any built-in circuit protection? Pretty pricy for what you get.

Those are the batteries. Yes, pricey. Good support from Fortress so far but if I had to do it all over again, I'd likely have installed the Sol-Ark 15 and EG4s. The 15 wasn't available when we started this project and I was so green, I'm not even sure how I picked the batteries. The Fortress eVault would have been a better option from Fortress too but... it's done so... sigh. We're financially in as deep as we can go so we're making the most out of the choices made.

 

[jrcromer]

Fortress here. We got circuit protection up the wazzoo. SHTF - no other battery on the market has a 1/4” aluminum case like the eflex. Your cell temps will remain nice and uniform - and that’s my biggest “unknown gotcha” that I think the battery industry will face down the road (think “snail trails” but for batteries not solar panels). There are some upfront cost advantages for the eVault but you’ll get that extra eflex expense back when disposing of the eflex down the road. You get what you pay for and some items like that aluminum case increase the cost per kWh of the battery for advantages that aren’t readily apparent to anyone who isn’t milking the cow themselves. The eFlex is our staff favorite - there are no master/slaves and you might find that puts you ahead down the road as the batteries age. Happy travels.