solar build near completion

[chriscowles]

I finally have something to show for all my inane questions in the past months. I have yet to install this in the front outside cabinet but it's substantially complete. The terminal lugs may seem uninsulated because the shrink-wrap is clear.

The panels are not yet installed. Right now I have 2 in series leaning on the wall outside the back door. Of course, it's a gloomy day. When installed there will be 4 x 180W Newpowa panels mounted flat on the roof in a 2S2P array. An 8AWG cable will travel down inside the front frame of the left front closet to the controller.

Smaller cables going down to the right will connect by a single 4AWG cable to the OEM converter. The black will go to a chassis ground immediately below the cabinet. I also upgraded the chassis ground to the power center to 4 AWG. I'm not upgrading the WFCO charger/converter, instead depending on the solar system to charge the LFP batteries fully.

2/0 cables going up to the right will connect to a 2000W PSW inverter, about 1' away. It will connect to a 30A WFCO auto-transfer switch (below). It fits on the back of the power center making for an easy install and compact package.

The inverter remote switch will be close by. When the inverter is on, the AC and converter breakers will be off, so it will be well within the inverter limits. I also added a 15A circuit with a new outlet in the solar cabinet. If I upgrade the converter later, that circuit will be the power source.

The Bluesea disconnect switch (I repurposed one I had) has 4 positions. I can cut off the inverter separately from the house/converter. The lower breakers isolate the SCC from the panels and battery.

Edit: batteries are SOK 12V 100A LFP. In parallel, max sustained discharge is a 200A. They'll tolerate higher surges longer than the inverter does.

[Relaxin in the woods]

This isn't feedback, I'm just here to learn. Looks great.

[chriscowles]

Another edit: the metal screen under the solar controller is an 8.5 x 12 cooling rack from Amazon. It provides a standoff from the flammable plywood and, not being solid, should aid in cooling. It was also easy to mount the controller to the wood behind it since I didn't have to drill any holes. The inverter will be mounted on a 12 x 17 cooling rack for the same reason.

[chriscowles]

I'm now powering my Weber outdoor electric grill with the 2K inverter. It's supplying a continuous 167A. It's a horrible waste of energy but it's just a test. I also want to deplete the batteries completely so I can put them through a full discharge/recharge cycle.

[jimmoore13]

This forum tool needs a thumbs up like button. 👍

[rk06382]

Originally Posted by chriscowles

I finally have something to show for all my inane questions in the past months. I have yet to install this in the front outside cabinet but it's substantially complete. The terminal lugs may seem uninsulated because the shrink-wrap is clear.

The panels are not yet installed. Right now I have 2 in series leaning on the wall outside the back door. Of course, it's a gloomy day. When installed there will be 4 x 180W Newpowa panels mounted flat on the roof in a 2S2P array. An 8AWG cable will travel down inside the front frame of the left front closet to the controller.

Smaller cables going down to the right will connect by a single 4AWG cable to the OEM converter. The black will go to a chassis ground immediately below the cabinet. I also upgraded the chassis ground to the power center to 4 AWG. I'm not upgrading the WFCO charger/converter, instead depending on the solar system to charge the LFP batteries fully.

2/0 cables going up to the right will connect to a 2000W PSW inverter, about 1' away. It will connect to a 30A WFCO auto-transfer switch (below). It fits on the back of the power center making for an easy install and compact package.

The inverter remote switch will be close by. When the inverter is on, the AC and converter breakers will be off, so it will be well within the inverter limits. I also added a 15A circuit with a new outlet in the solar cabinet. If I upgrade the converter later, that circuit will be the power source.

The Bluesea disconnect switch (I repurposed one I had) has 4 positions. I can cut off the inverter separately from the house/converter. The lower breakers isolate the SCC from the panels and battery.

Edit: batteries are SOK 12V 100A LFP. In parallel, max sustained discharge is a 200A. They'll tolerate higher surges longer than the inverter does.

Looking good.

Did you get the bluetooth to work?

[chriscowles]

Originally Posted by rk06382

Looking good.

Did you get the bluetooth to work?

Yes. It works easily, but only for the phone app. The PC software requires the cable. Either version isn't very slick but does what you need.

[chriscowles]

Running the grill for 20 minutes revealed some hot connections. All lugs are sized to the terminal post and torqued to manufacturer specs, so I seem to have some bad crimps.

I had resorted to a hammer crimper because the cheap manual squeeze-type crimper I bought doesn't go up to 2/0. Not all of the 2/0 crimps are hot, so it works some of the time. Being metric, the cheap crimper doesn't work well on all others, either. The 2/0 lugs are high quality. Others vary.

I bought a refurbished hydraulic crimper from Temco. It has a range of 12AWG to 2/0 and is supposedly improved in some ways from their original version. An advantage of that tool is that it's short. I'll be able to use it in some tight spaces where circumstances prevent moving the cable outside to use other methods. Unfortunately, it won't be delivered until the end of next week so further work is on hold until then.

[Hclarkx]

Originally Posted by chriscowles

I'm now powering my Weber outdoor electric grill with the 2K inverter. It's supplying a continuous 167A. It's a horrible waste of energy but it's just a test. I also want to deplete the batteries completely so I can put them through a full discharge/recharge cycle.

Chris, I'm sure you know this, but you don't want to discharge the batteries "completely". In Battleborn specs that means 8.8V (2.2V per cell). At least IMHO that's asking for trouble. I don't know that I've seen discharge curves on the SOK, but my inclination would be a discharge down to about 12V. That's on the knee of the discharge curve and is usually around 10% SOC. Going lower should just mean a bit of extra loss-of-life, but you never know.

[Hclarkx]

Chris, Nice progress, nice job.

My only quibble would be the red wire that passes under the negative lug sleeves about half way up near the right edge of the board. If the red wire is welding wire, the insulation is flexible but not all that sturdy. I'd worry about abrasion there over the long term from RV shaking. My preference is to have the positive and negative wires separated as much as possible, half inch or more where feasible.

[TitanMike]

Originally Posted by Hclarkx

Chris, I'm sure you know this, but you don't want to discharge the batteries "completely". In Battleborn specs that means 8.8V (2.2V per cell). At least IMHO that's asking for trouble. I don't know that I've seen discharge curves on the SOK, but my inclination would be a discharge down to about 12V. That's on the knee of the discharge curve and is usually around 10% SOC. Going lower should just mean a bit of extra loss-of-life, but you never know.

One would certainly hope that the battery's BMS would shut it down before it got discharged to deeply. Only caution really would be to recharge fully to balance cells and also prevent the BMS from drawing the battery below it's safe voltage due to the current the BMS draws while doing it's job. Not something that would happen in a day or two but worth mentioning.

One of the GREAT features of LiFePo4 batteries is the fact that they take care of themselves through the BMS (at least the good ones do). Use them, charge them, enjoy the convenience. The obsession with proper voltages, DOD anxieties, etc, all belong in the world of Lead/Acid batteries which we left behind. Now if you are building your own LiFePo4 batteries from kits, one needs to pay attention if using a "budget" BMS.

[Hclarkx]

Originally Posted by TitanMike

One would certainly hope that the battery's BMS would shut it down before it got discharged to deeply. Only caution really would be to recharge fully to balance cells and also prevent the BMS from drawing the battery below it's safe voltage due to the current the BMS draws while doing it's job. Not something that would happen in a day or two but worth mentioning.

One of the GREAT features of LiFePo4 batteries is the fact that they take care of themselves through the BMS (at least the good ones do). Use them, charge them, enjoy the convenience. The obsession with proper voltages, DOD anxieties, etc, all belong in the world of Lead/Acid batteries which we left behind. Now if you are building your own LiFePo4 batteries from kits, one needs to pay attention if using a "budget" BMS.

I think you overstate what most BMS's do. I'm not comfortable letting my $2700 battery get down to the BMS discharge cut-off voltage. Or up to the 16V charge cut-off voltage some apply. BMS are there to avoid catastrophic damage, not to ensure a long life.

It's buyer beware in the DIY market, but some are superior to what comes in the black box, especially if one wants to be a bit more conservative in the damage protection.

[TitanMike]

Originally Posted by Hclarkx

I think you overstate what most BMS's do. I'm not comfortable letting my $2700 battery get down to the BMS discharge cut-off voltage. Or up to the 16V charge cut-off voltage some apply. BMS are there to avoid catastrophic damage, not to ensure a long life.

It's buyer beware in the DIY market, but some are superior to what comes in the black box, especially if one wants to be a bit more conservative in the damage protection.

It's really going to depend on the manufacturer and what rhey design into their BMS. Battleborn shuts down at an upper limit of 14.7 volts (3.675 volts per cell) and a low voltage of 10 volts (2.5 volts per cell).

Max voltage recommended for a LiFePo battery (cell) is 3.5V-3.6V (absolute max 4.2 volts per cell).

Lower limit is 2.0 volts per cell so BB's setting of 2.5 V is well above this lower limit.

I can't speak for other brands but I am very confident that Battleborn has put plenty of research, development, and testing into all aspects of their battery, especially their BMS, in order to make it as "user-proof" as possible.

Perhaps I am overstating what SOME BMS' do but not the Battleborn's.

Battleborn even advises to just let the BMS do it's job.

[chriscowles]

Originally Posted by Hclarkx

Chris, Nice progress, nice job.

My only quibble would be the red wire that passes under the negative lug sleeves about half way up near the right edge of the board. If the red wire is welding wire, the insulation is flexible but not all that sturdy. I'd worry about abrasion there over the long term from RV shaking. My preference is to have the positive and negative wires separated as much as possible, half inch or more where feasible.

Thanks, Harrison. The red wire you refer to is 2/0 welding cable to the inverter. It's really not hooked to anything in the picture. I jammed it under the negative to hold it in place for the picture, as much as anything else. When in place, it will loop over it a little more gracefully with a bit more distance between. I'll take your advice about abrasion and secure it to to reduce that risk.

[chriscowles]

Originally Posted by TitanMike

It's really going to depend on the manufacturer and what rhey design into their BMS. Battleborn shuts down at an upper limit of 14.7 volts (3.675 volts per cell) and a low voltage of 10 volts (2.5 volts per cell).

Max voltage recommended for a LiFePo battery (cell) is 3.5V-3.6V (absolute max 4.2 volts per cell).

Lower limit is 2.0 volts per cell so BB's setting of 2.5 V is well above this lower limit.

I can't speak for other brands but I am very confident that Battleborn has put plenty of research, development, and testing into all aspects of their battery, especially their BMS, in order to make it as "user-proof" as possible.

Perhaps I am overstating what SOME BMS' do but not the Battleborn's.

Battleborn even advises to just let the BMS do it's job.

The low voltage disconnect for my SOK batteries is 10.4V.

They're rated for > 3,000 cycles with 100%* charge/discharge cycles. (*100% of what the BMS allows.) I measured capacity with a cheap tester and got 108Ah.

With a narrower range of charge and discharge it would last longer but 8 years is plenty for me, and that assumes depleting it every day.

[rk06382]

Originally Posted by chriscowles

Running the grill for 20 minutes revealed some hot connections. All lugs are sized to the terminal post and torqued to manufacturer specs, so I seem to have some bad crimps.

I had resorted to a hammer crimper because the cheap manual squeeze-type crimper I bought doesn't go up to 2/0. Not all of the 2/0 crimps are hot, so it works some of the time. Being metric, the cheap crimper doesn't work well on all others, either. The 2/0 lugs are high quality. Others vary.

I bought a refurbished hydraulic crimper from Temco. It has a range of 12AWG to 2/0 and is supposedly improved in some ways from their original version. An advantage of that tool is that it's short. I'll be able to use it in some tight spaces where circumstances prevent moving the cable outside to use other methods. Unfortunately, it won't be delivered until the end of next week so further work is on hold until then.

I purchased a 16-ton crimper from Amazon to do my 4/0 cables. I had over twenty crimps with my six Battle Born batteries, fuse, switches, & shunt. I also had to redo some bad OEM FR3 cables with a bad crimp.

It was worth the $60 I spent on it because each one was done right.

[Hclarkx]

Originally Posted by TitanMike

Perhaps I am overstating what SOME BMS' do but not the Battleborn's.

Battleborn even advises to just let the BMS do it's job.

Sure they say that. Most manufacturers do. But, they aren't saying you can through anything you want at it and it will have a nice long life.

If what you say is true, BB should correct their web site and battery specs. Because from the very limited data they provide, their BMS is very standard. Or maybe substandard in that they do not limit charge current at all. They apparently limit charging only on total voltage, not excessive individual cell voltage. And likewise they don't limit discharge based on individual cell voltage. You can damage this battery. The BMS helps but is far from complete protection.

The only plus I would give Battleborn is that they limit total charge voltage to 14.7V. Some others allow 15V or more.

And a minus for not including Bluetooth.

https://1t1pye1e13di20waq11old70-wpe...n-Manual-1.pdf

If you want to compare BMS, look up the Overkill BMS. It's much more complete protection. BB could use it. Some others do.

[TitanMike]

[QUOTE=Hclarkx;2491095]
If what you say is true, BB should correct their web site and battery specs. Because from the very limited data they provide,--------------


Many manufacturers limit the amount of data provided for several reasons.

One is that it could be proprietary. Why tell their competitors how to improve their product.

Second, why overload the public with data that only confuses their understanding of the product. They tell you what they feel you need know.

You may want it, I don't particularly do.

I have every confidence that the Battleborn BMS is more than adequate to protect my batteries With two batteries in parallel and a 60 amp converter I am well within charging current limits. Discharge current is limited to the fuse installed and it's well within Battleborn's recommendations for max discharge rate.

As for how long my Battleborns will last? I guarantee they'll be around when the executor of my estate has to decide what to do with them and there's no indication I'll be checking out before their warranty expires.

For those who are unaware, Battleborn is the "Retail" arm of Dragonfly Energy. A company that is deeply involved in R&D for LiFePo4 batteries. I think they know what they're doing.

[TitanMike]

Originally Posted by Hclarkx

Sure they say that. Most manufacturers do. But, they aren't saying you can through anything you want at it and it will have a nice long life.

If what you say is true, BB should correct their web site and battery specs. Because from the very limited data they provide, their BMS is very standard. Or maybe substandard in that they do not limit charge current at all. They apparently limit charging only on total voltage, not excessive individual cell voltage. And likewise they don't limit discharge based on individual cell voltage. You can damage this battery. The BMS helps but is far from complete protection.

The only plus I would give Battleborn is that they limit total charge voltage to 14.7V. Some others allow 15V or more.

And a minus for not including Bluetooth.

https://1t1pye1e13di20waq11old70-wpe...n-Manual-1.pdf

If you want to compare BMS, look up the Overkill BMS. It's much more complete protection. BB could use it. Some others do.

Interesting. From the copy of the manual you linked:

If an individual cell falls below a prescribed threshold during discharge, the BMS will prevent
further discharge

As for bluetooth, I like many others get that service from my Victron Monitor along with a lot of other data. Don't need another app that way.

[chriscowles]

I tweaked the setup by removing an unnecessary terminal post. That bought me some space. I'm able to make those same connections on other posts and only one of them has three wires, the max according to ABYC standards. If stricter standards don't allow that, please educate me.

The two red wires coming down from the top are an uninterrupted 4 AWG to the power center and 8 AWG to the junction box under the trailer. The latter powers the jack and slide motors. If I zip-tie them to the rack, I'll put them in a sleeve of some kind.

The jack and slide have a Type I circuit breaker but there would be no OCPD between the terminal here and the breaker there, so I attached it to the breaker here. I may move the Type I breaker up to this panel area instead. In that case I'll move the connection to the bottom of this breaker.

The black wire coming down from the top is 4 AWG to a chassis ground directly below.

The 2/0 cables to the inverter will be secured so they're not rubbing on anything.

The 4 AWG travels the length of the trailer to the power center. In the OEM configuration there is a Type I breaker close to the battery; in this configuration, there is not. Do I need one? If so, is 40A enough? I have a small 40A Type III breaker I could use for the fuse block and repurpose the one seen here on the power center line.