High voltage DC inverters?

[timselectric]

Here's the video where the gentlemen designs his own bms to identify individual cells via a led light, it also controls a relay or something in the power panel to cut off power if there's a issue. I'd like to learn more about that.

We have several members using a Batrium BMS. That's how it works. I don't remember if that's what is in that video. But, you should be able to search for Batrium in this forum for more information.

 

[realpinochet]

We have several members using a Batrium BMS. That's how it works. I don't remember if that's what is in that video. But, you should be able to search for Batrium in this forum for more information.

Thanks bro. Also, on the sandi website they sell battery banks ready to go with all the built in breakers, fuses etc. Looks like you just connect it and turn it on. Like we were discussing it should make HV much safer than diy battery banks. Seems some are using tesla packs the same way.

https://www.sandielectric.com/battery-management-systems.html

 

[timselectric]

Thanks bro. Also, on the sandi website they sell battery banks ready to go with all the built in breakers, fuses etc. Looks like you just connect it and turn it on. Like we were discussing it should make HV much safer than diy battery banks. Seems some are using tesla packs the same way.

https://www.sandielectric.com/battery-management-systems.html

Right
I have been following that market, as well.
My issue with high voltage batteries is the loss of redundancy in my system. But, I am entertaining the idea of a high voltage inverter for my EV build. As a vehicle to home option. And also for charging the vehicle. A high voltage AIO would cover all of my needs for the project.

 

[Ampster]

I did not get much information about the BMS from the video. It looked like a distributed system with individual modules on each cell. I have seen that type on EV conversions because they are scalable as the voltage and number of cells increases.

 

[realpinochet]

Right
I have been following that market, as well.
My issue with high voltage batteries is the loss of redundancy in my system. But, I am entertaining the idea of a high voltage inverter for my EV build. As a vehicle to home option. And also for charging the vehicle. A high voltage AIO would cover all of my needs for the project.

Say your voltage is 300V. You can parallel two 300V battery banks so should one fail you still have power. Are you saying you're wanting to use the car's battery to run the system to? I thought manufacturers stop allowing this?

 

[realpinochet]

I did not get much information about the BMS from the video. It looked like a distributed system with individual modules on each cell. I have seen that type on EV conversions because they are scalable as the voltage and number of cells increases.

I think he gave a website or contact info for them. Anyways ..why do people use ratchet straps to hold the batteries together? I've heard you're suppose to compress them, is this to keep them from bloating?

 

[Ampster]

I think he gave a website or contact info for them. Anyways ..why do people use ratchet straps to hold the batteries together. I've heard you're suppose to compress them, is this to keep them from bloating?

The link was to a Chinese manufacturer who makes a BMS but no details. Ratchet straps are a shortcut but put too much stress on the corners when there is expansion. They also do not prevent swelling of the end cell. You need a board or stiff piece of metal at the end.

 

[hwy17]

APC UPS use high voltage inverters. Our old 3kva 120v lead acid models use a 120v battery.

Might be a cheap way to do testing if you can find them on craigslist.

 

[Hedges]

There's was to mitigate some of this right? I believe you're an electrician. There's protective gear I see them wearing on youtube for arc flash...like face shields and gloves. But, to your point is exactly why I wanted a battery professionally made where It's plug and play not a diy one. Just plug the battery in via a Anderson pole or something. But also, we're playing with 500-600 VDC from the solar panels into the charge controllers right? Isn't this similar.

Difference is current, as Tim said. PV is still plenty of current for shock hazard, and will pull a long flame.
Battery will dump massive amount of energy, splatter metal. One guy had a fault in his LiFePO4 golf cart. Didn't even blow fuse, but splattered a poorly connected busbar. At 600V vs. 48V I think true arc-blast shock wave more possible with 600kW ~ 6MW or so delivered. 600V x 10,000A x 0.01 seconds = 60kJ, similar to an entire carton of ammo.

Just having the series connected batteries isolated by pull-out connectors (Anderson), while current flow stopped, would make them safe to work on. Just like 600V or 1000V PV strings with MC connectors.

(Those guys who say they cut off MC4 connectors and solder or crimp splices - what is their practice for electrical safety while making such splices??)

BYD sells batteries that are part of UL listed ESS for Sunny Boy Storage. Two to four boxes of cells stack on top of each other, connecting in series.

I'm still dreaming of DIY HV battery (maybe REC BMS), or series connected server rack batteries (would likely require occasional balancing, possibly 48V charger which could be AC or PV powered, relays or just pluggable connectors.)

 

[Hedges]

My issue with high voltage batteries is the loss of redundancy in my system. But, I am entertaining the idea of a high voltage inverter for my EV build. As a vehicle to home option. And also for charging the vehicle. A high voltage AIO would cover all of my needs for the project.

The HV inverters I've seen specs for work from 100V to 500V (limited wattage at lower voltage).
Your redundancy would just be unplugging bad pack and jumpering around it.

 

[timselectric]

The HV inverters I've seen specs for work from 100V to 500V (limited wattage at lower voltage).
Your redundancy would just be unplugging bad pack and jumpering around it.

That is a solution. But you would have to be present to implement it. And the system would be down until it was done. Whereas a BMS, breaker, or fuse can automatically remove a battery from the bank. And the system would continue functioning.