1Bus Bar

[kelsol]

My off grid system is currently being built:

6 130Ah lead acid 12v batteries
6 100W monocrystalline panesl
60 A (true) MPPT controller
12 x 1 ft 4/0 cables (post to 5/16)
4kw(8kw peak) inverter (2/0x2 each polarity)

Main issue now are fuses and busbar.

I assume a 4-500A busbar would be appropriate.
But I have no clue as to how to connect each battery to busbar through fuse.

Are there *affordable* busbars that include fusing provisions (assuming 150A slo-blo per battery) .

Or, if this is not practical, plans to build such a device?

I have found a :

Victron Energy® CIP050060000 - 500A 6-Way Fuse Block with Busbar​

On ebay, but is this acceptable? Post heights seem short.

Many thanks in advance. This is my first post here!


Also, and possibly OT to this thread:
Are there any plans out there to use battery temperature sensors per battery on an I2C arduino setup to disconnect the panels and load if charge/discharge becomes excessive?

 

[Rednecktek]

But I have no clue as to how to connect each battery to busbar through fuse.

It's not uncommon for people to bolt the fuse right to the Pos terminal of the battery and then run the wire from the fuse up to the bus bar. Many of the fuse holders out there will slide right over the battery posts on lead acid batteries and you just tighten the nut down.

 

[kelsol]

Many thanks!
Now the question is where to find these types of use holders that handle 4/0 AWG precut with 5/16 lugs and lead type posts.
The batteries are 6 1000MCA @ 135AH (FLA) . They will be in parallel. Is it safe to assume 150A slow blo?

 

[BigCharlie]

I like your question. I'm a newbie planning a similar setup with 6 FLAs.

In trying to figure out how to wire the batteries for balanced charging, it seemed to connect each battery individually to a large bus bar would be the best. Is that what you're doing here?

I'm surprised it's not the de facto way to do things.

I put my batteries on this shelf two rows of three batteries. I'm thinking of mounting a bus bar on each side of the middle rack.




About your Arduino idea. That's interesting, I want to monitor heat, too. Cutting off everything when out of range and alerting of issues. How would you do that? With a solenoid? Doesn't your MPPT monitor overcharging?


BTW, it looks like that CIP050060000 only connects 5 out of 6 posts

 

[kelsol]

The lil lady came across this today:

How to Charge Lead Acid Marine and RV Batteries in Parallel

How to Charge Lead Acid Marine and RV Batteries in Parallel Have you ever wondered why your batteries in parallel seem to fail sooner than you would expect? When asked how to charge batteries in parallel people commonly reply connect the positive to positive and negative to negative. Yep,

www.impactbattery.com

Now the question is - with short 4/0 connectors and wires whether a bus bar is needed at all.
The wires are expensive enough, but a 'standard' bus bar is outrageous for what is in essence a piece of copper with studs.

The issue about detecting imbalances in parallel connections is simple: current meters would be out of the question for individual batteries in parallel, as they would cause increased internal resistance merely from their presence. Perhaps hall effect sensors ?
The other possibility is the assumption that an unbalanced battery would simply run hotter. This can be detected with a multiple temp sensor:

For pi:

Connect multiple DS18B20 temperature sensors to a Raspberry Pi | Raspberry Pi Automation

How to connect multiple DS18B20 temperature sensors to a raspberry Pi and use them in Domoticz

raspberryautomation.com

For arduino

Multi Temperature Sensor

An Arduino based device to read multiple DS18B20 sensors and send the values through a RS232 connection to a domotica system. By WT040.

create.arduino.cc

Ultimately the question is what to use as a cutoff device. Ideally a solenoid DPDT switch that can handle a few kw (400+ amps), that is not absurdly expensive. Cut both MPPT and Inverter.

Perhaps something as simple as using a GFI type breaker to trip to ground?

From what I am seeing, it appears that off grid DIY circuitry development is still in a bit of a pioneer stage, with most experimenters designing with grid-tied systems. The system I am trying to build is a somewhat portable off grid system only to be used when the grid goes down (rolling blackouts, weather line damage, TSHTF, EMP, Armageddon, etc.). I would also like to use it on an off-grid camping property.

 

[BigCharlie]

LOL, I have a couple of posts about that. I started a similar thread here: https://diysolarforum.com/threads/c...erfectly-balanced-charging-discharging.41371/

Take a look at sunshine_eggo's post. His image suggested using a post. Which makes a lot of sense. A lot cheaper. But can a post handle the amperage? I suppose, TBD

Apparently, the Perfectly Balanced Charging method outlined in the Impact Battery article cannot be used for any more than four batteries. But you can group batteries.

I was thinking about temperature monitoring for safety, for imbalances is interesting.

Thanks for the Raspi link. That's my jam. I have a gaggle of them. I have an arduino but I haven't played with it.
The DS18B20 is what I need.

I was thinking about setting up the pi as a zabbix server and/or agent, there are templates for environmental monitoring.
Zabbix can push alerts to phone apps, email, XMPP, and SMS alerts too. Maybe APRS if you're hardcore, that's beyond me at the moment.
I thought about setting up Zabbix to alert me if the power goes down. It happens here on the island fairly frequently. A cloud VM to ping the local agent or firewall to monitor for blackouts and the local raspi agent to collect environmental for the server.
Zabbix can be setup to execute prescribed actions in specific events. If temp it out of range maybe execute a script that activates a solenoid.
I'd guess there are voltage templates, too.

Zabbix

Learn about Zabbix monitoring using the best and most comprehensive tutorials on the Internet!

bestmonitoringtools.com

Monitor Temperature and Humidity with Zabbix - Zabbix.tips

Hook up an DHT22/AM2302 sensor to a Raspberry Pi 3, and configure it to pull temperature and humidity data through a small Python script.

zabbix.tips

 

[BigCharlie]

... and check this out it's a hydrogen sulfide detector for arduinos and raspis.

https://www.amazon.com/SMAKN®-Hydrogen-Arduino-Mega2560-Raspberry/dp/B00S0CRNN2

 

[kelsol]

The MQ36 sensor is certainly made for H2S, but I always thaought that overheated batteries emit H2.
The H2 sensing MQ8 is only a fraction of the price!
(Plus I might have one lying around here....)

Basically - whats better to sense - H2 or H2S?

 

[BigCharlie]

The MQ36 sensor is certainly made for H2S, but I always thaought that overheated batteries emit H2.
The H2 sensing MQ8 is only a fraction of the price!
(Plus I might have one lying around here....)

Basically - whats better to sense - H2 or H2S?

I'm not certain but it's interesting.

Maybe the presence of one suggests the others are in excess, too.

Which Gases Are Produced In Battery Charging? - Battery Skills

Lead-acid batteries will produce little or no gases at all during discharge. During discharge, the plates are mainly lead and lead oxide while the electrolyte has a high concentration of sulfuric acid. During discharge, the sulfuric acid in the electrolyte divides into sulfur ions and hydrogen...

www.batteryskills.com

 

[BigCharlie]

Ultimately the question is what to use as a cutoff device. Ideally a solenoid DPDT switch that can handle a few kw (400+ amps), that is not absurdly expensive. Cut both MPPT and Inverter.

Here's a cheap answer. Create a solenoid and get a small motor, pully, and a knife switch

I saw this:

Pull Cord Switch : Construction, Working, Types, Wiring & Its Applications

This Article Discusses an Overview of What is Pull Cord Switch, Specifications, Construction, Working, Types, Wiring & Its Applications

www.elprocus.com

and it gave me the idea (the opposite of this) to have an actuator pull a plug. Rube Goldbergesque.