Finally going off grid, need a bunch of help

offgriddave

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Feb 14, 2020
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79
Hi I haven't bought my property yet, waiting for my offer to be accepted. But I sold my farm and moving.... somewhere. I am setting up my solar the month of May! Let's have fun building a solution!

I have been building an arsenal of off grid parts. Eventually the goal is 10kwSolar+500w microhydro with 20kwH Lithium Phosphate. I do not have Lithium Phosphate. But for now, I just need something that works. I invested into Lithium Ion 18650.

I have not yet purchased my solar panels, but I have 4x 250w 37v for testing.

This is what I have

Batteries
13x 748wh 48v ebike batteries with BMS and 30 amp fuses, 100% tested. 1x bad one with BMS. 18650 based. Total 10kwh.
50x 14v medical 95kwh 18650 packs, each 18650 2200mah. I split one open so make it 49 still in pack. Total 5kwh
6x 36v bad BMS e-bike batteries with 18650 that rate at an amazing 3500mah each (tested). Total 4kwh
1x 48v nissian leaf battery unit with BMS. 500 watts. Not sure why I bought this.


Inverters
Hybrid 240v split phase LV5048, originally bought to run my 3/4 hp well pump last year. Unopened new in box. 150 VOC, 8000 watt total solar split 4k on each side. Pure sine wave.
Hybrid 120v 1200 watt 24v Giandel with non-mpp charge controller. Bought after power outage and used for a few days a year. Not pure sine wave.
Hybrid 120v 600 watt 12v Giandel with non-mpp charge controller. Bought as a backup to above
Some harbor frieght 1200 watt inverter that refuses to die.
Half a dozen 100-150 watt 12v inverters. None pure sine wave.
Half a dozen UPS/APC battery backup 500-750 watt computer, I cut the cables and put alligator clips and use them for lights and computer devices so they don't go down

Solar
- I only have 4x 250 watt 37v panels right now, but I want to order a pallet (27-29) for 350+ or 400w panels. (Any suggestion)? I want 10kwh. The property gets a lot of fog so I need to build it out four times the capacity I need. The panels aren't compatible with the Giandel because of the voltage, but somehow they work. Huge loss in effiency.

Microhydro
There's stream on the property. The property gets a lot of fog which will probably cause the solar panels to not work all the time or at 20%. In the winter, there is no sun at all. But there's massive potential for hydro

This is what I want to buy:

500 watt 120v AC. Send the AC 500ft on 12awg (voltage drop isn't bad at 500 watt), then run it into a 350w 48v-60v adjustable power supply, some how feed it into my inverter (?). 350w 24 hours a day is 8400 watts. This seems to be incredible. If the stream ran all year, I wouldn't need solar at all. But it doesn't apparently it dries up.

Tools:
-Clamp on meter with DC/AC in-rush, on order
-I bought two spot welders for 18650 and haven't built them yet
- charger: RD6012W step down power supply, will get today. No power supply or case
- charger: RD6018W full kit step down power supply with case and power supply, ordered from aliexpress will be here in 6 weeks...
10x dewalt 20v battery kits (no battery included) for my tools.. not to be split. For building. Will be breaking down the medical packs and building enough power packs to run all my tools all day.
- A bunch of no-name solar charge controllers that I bet are fake.

Generator
240 split phase 4750 propane electric start. Has a manual choke so I can't set it up on the alarm circuit on the LV5048 to auto-start, but maybe one day I can setup an Arduino with a servo to move the choke. Also unsure how dirty the power is, the LV5048 will reject bad power apparently. I have never hooked it up to a scope yet to see if the sine wave is clean, praying it will just work. Don't have a scope.


The challenges:
Summers are sunny, but a bit of foggy. There's a creek, and there's 40ft elevation. But it dries up. The owner says it doesn't the neighbor says it does. Who knows.
Winters are always foggy. Very poor solar. However, the creek gets 4ft wide massive amount of water.
If all else fails, I want to charge my battery packs through the LV5048 with the propane generator.

Anyway the plan is, ...

Step 1: first get something working, to charge my tools and run basic stuff. Radio, internet, dewalt battery chargers, lights.
4x 250w solar panels, total of 1000 watts. Four hours a day, 4000 watts
40x 14v 95wh medical battery packs, total of 40x95wh, 3800 watts
... first I will try the 24v Giandel inverter... at two 14v packs in series. so i'd be running it at 28v.... maybe might work
... if that fails, I'll try running 14v on the 12v Giandel inverter
.. yes if these work, they won't fully charge the batteries. Oh well

Step 2: Get my cabin/house built with above in 2 months, and have a better long term solution
27x 300-400 watt panels, to be bought. 9000 watts. Due to the fog, 20% in the winter efficency at 4 hours. Or only 3000-4000 watts of solar a day. Summer full 9000 watts 6-7 hours a day.
14x 748wh ebike batteries. I have not purchased any breakers, fuses, switches, indicators, etc. Will need to do this.
the LV5048. With the generator as backup

Step 3. Microhydro. This I don't know much about, and is really a hack
1x 500w microhydro , 120v
500ft of AWG 12
350watt no-name brand 48 or 60v .. or adjustable switching power supply. Hooked up to a MPP or into a hybrid inverter


I have a bunch of questions but what do you think, thanks
 

offgriddave

Solar Enthusiast
Joined
Feb 14, 2020
Messages
79
SanTan Solar has good deals on panels, new and used. I have no ties with SanTan but I am a repeat customer.

Thanks great! I sent a quote request to SunElec but SanTan has a way to calculate shipping.

Looks like I can get
20 used 385w Jinko 386W panels and max out my LV5048 at 8000 watts for $2600 shipped. VOC 49.1V, my LV5048 is 150v so it would be 2-3 panels in series.

They say "low light performance", I wonder what that means? I google these panels and nothing really showed up

Hell I might just buy this right now


There are other panels 250W for $42.50, 250w with snail trails for $38.25, and cracked 240W for $29.75.

But I figure with the 385w I would have less connectors, less mounting, and cheaper shipping (about $100). The mounting, bus bars, breakers, switches, cost will kill me. I bet I'll be spending several grand on just that going off grid. Better to buy bigger stuff

Anybody see anything wrong with this?

Buy? No Buy?
 

DThames

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Joined
Nov 22, 2019
Messages
1,440
Thanks great! I sent a quote request to SunElec but SanTan has a way to calculate shipping.

Looks like I can get
20 used 385w Jinko 386W panels and max out my LV5048 at 8000 watts for $2600 shipped. VOC 49.1V, my LV5048 is 150v so it would be 2-3 panels in series.

They say "low light performance", I wonder what that means? I google these panels and nothing really showed up

Hell I might just buy this right now


There are other panels 250W for $42.50, 250w with snail trails for $38.25, and cracked 240W for $29.75.

But I figure with the 385w I would have less connectors, less mounting, and cheaper shipping (about $100). The mounting, bus bars, breakers, switches, cost will kill me. I bet I'll be spending several grand on just that going off grid. Better to buy bigger stuff

Anybody see anything wrong with this?

Buy? No Buy?
Mounting costs do come into play with more panels of less power. I have some of those used "poly" type and some new "mono" type. Before the sun is on the panels those with better low light performance will make a little power with less direct sunlight. The difference is minor but might matter if you were overcast most of the time.
 

offgriddave

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Feb 14, 2020
Messages
79
Hey I bought the 20x 385w Jinko Panels. They will be freight delivered about 60 miles away where I can pick them up. I have a contractor's flatbed truck and a fork lift, so this is great. Having a fork lift where I am staying at has been great. There's no fork lift at the property I want to buy, but by then I'll be ready to unload it directly from the truck to install it.

Thanks @DThames!
 

mike95490

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Joined
Apr 16, 2021
Messages
74
I personally don't like welding tabbing onto dozens of cells to make a battery. To get yourself up and running, simple golf cart batteries ( GC-2 ) are fine, 4 will get you 28V at 200ah for $400, and you are on line. Doesn't need a BMS and all the wires for them.
Don't rush it - do it right, don't buy stuff 'cause it was on sale
Cracked panels are dead panels within a year or two.

Really examine the requirements for your micro hydro to work. Elevation and Flow ! does it cost as much as a generator ?
 

Hedges

I See Electromagnetic Fields!
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Mar 28, 2020
Messages
9,137
Inexpensive water turbine, don't know how well it will hold up.
Watch this guy's video on one he built:

 

DThames

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Nov 22, 2019
Messages
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Regarding this statement, "
Step 1: first get something working, to charge my tools and run basic stuff. Radio, internet, dewalt battery chargers, lights.
4x 250w solar panels, total of 1000 watts. Four hours a day, 4000 watts
40x 14v 95wh medical battery packs, total of 40x95wh, 3800 watts
... first I will try the 24v Giandel inverter... at two 14v packs in series. so i'd be running it at 28v.... maybe might work
... if that fails, I'll try running 14v on the 12v Giandel inverter
.. yes if these work, they won't fully charge the batteries. Oh well"

If the 14v packs are 4 series Li-ion, you will want to keep the max charge under the inverter max voltage. I tested this with a 12v inverter and I recall anything over 16.0v would shut that specific inverter down. But 4.0v per call isn't all that bad.
 

offgriddave

Solar Enthusiast
Joined
Feb 14, 2020
Messages
79
So yesterday I bought 20 385 watt panels
Today I bought this:


"This is a DC PowerStrip for Jehu's PCB DIY Powerwall Build. This is the fully populated version. Many battery packs have xt60 connectors, this PowerStrip allows you to connect many battery packs in Parallel to build a bigger battery system. It uses 2oz copper traces on both sides of the PCB board, good for up to 80A and 160A."

To connect the 14 48v ebike batteries to my LV5048. Each ebike battery has a BMS and a 30 amp fuse.

I will need a cut off switch and a 200 amp fuse.

The price on everything has gone crazy. The cut off switch I want is $40. The SB120 female connector for this board is $17!
Is there any cheap solution for buying the connectors, switches, fuses, breakers? Or am I really looking at $200-300? What about car audio, golf cart, or tractor electronic parts? I'm going to go broke buying this stuff. Its enough to buy another inverter or more panels.

Any suggestion on saving money on hooking this up is appreciated. Also did I do good buying the SB120 version of Jag35's connector?
 

Supervstech

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I am not a fan of jehu’s stuff.
Sure, it makes assembly quick, but just look at his specs...
10 xt60 connectors on a pcb...
Xt90 male and female with #10 30A ampacity wires...
it is all too small for sustained use...
a5000W inverter can draw 105AMPS easy, on surge it can draw 200+ for a small time. Will #10 handle that load? Will the solder fail from heating?
 

offgriddave

Solar Enthusiast
Joined
Feb 14, 2020
Messages
79
Yes I had some serious problems with his setup, using zinc plated bus bars and no safety equipment. He gets a lot of views on youtube and is pretty trendy.

I bought the PowerStrip 160A-SB120 Anderson connector version with xt60. I will be running 15 amps through the xt60. On this version it has four layers of copper, it claims 2oz. I figured that's enough,
 

DThames

Photon Sorcerer
Joined
Nov 22, 2019
Messages
1,440
So yesterday I bought 20 385 watt panels
Today I bought this:


"This is a DC PowerStrip for Jehu's PCB DIY Powerwall Build. This is the fully populated version. Many battery packs have xt60 connectors, this PowerStrip allows you to connect many battery packs in Parallel to build a bigger battery system. It uses 2oz copper traces on both sides of the PCB board, good for up to 80A and 160A."

To connect the 14 48v ebike batteries to my LV5048. Each ebike battery has a BMS and a 30 amp fuse.

I will need a cut off switch and a 200 amp fuse.

The price on everything has gone crazy. The cut off switch I want is $40. The SB120 female connector for this board is $17!
Is there any cheap solution for buying the connectors, switches, fuses, breakers? Or am I really looking at $200-300? What about car audio, golf cart, or tractor electronic parts? I'm going to go broke buying this stuff. Its enough to buy another inverter or more panels.

Any suggestion on saving money on hooking this up is appreciated. Also did I do good buying the SB120 version of Jag35's connector?
Many use a breaker as their switch. Not often is there a need to switch the battery off. I breaker that you can manually open should be fine for any time you want to open the circuit.
 

offgriddave

Solar Enthusiast
Joined
Feb 14, 2020
Messages
79
Here's my current shopping cart on Amazon

I opted for the digital meter, and a 48v-to-12v converter to power it
A breaker, a fuse, and a switch
No bus bar (cheapest was $39? really?)
Some spare parts and tools


Any suggestion for a box? What type of box do you recommend?


Screenshot from 2021-04-24 15-16-21.png
 

Hedges

I See Electromagnetic Fields!
Joined
Mar 28, 2020
Messages
9,137
We don't trust that style breaker unless from a name brand.
Especially $20 for 200A

ANL fuse - may be appropriate. The question is short circuit capability of your battery vs. AIC rating of fuse.
What is your battery?

Busbar, you can buy copper (bare or plated) from McMaster or Online Metals, drill holes, use stainless bolts. Plastic standoffs are available.

You're looking at lugs. Got a crimper? There are cheap hydraulic crimpers from Harbor Freight and others that sometimes work OK if the die sizes happen to fit well.

Battery switch - some people use a 2-position switch to precharge capacitors though a resistor.
Price $15 - is it really able to carry your current?
 

Supervstech

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Agreed! Get that breaker off your list. It is not reliable... either it will trip under light load, or it won’t trip at any load... don’t trust it.
 

offgriddave

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Feb 14, 2020
Messages
79
I removed the breaker

I checked and the switch isn't rated for 48v 200 amp.

I found this switch for $35 on a separate site: https://www.victronenergy.com/upload/documents/Datasheet-Battery-Switch-275-A-EN.pdf
48v 275a. I can't find a two way version of this switch.

Got a recommendation for a two way switch? Also I never knew which resistor to get, I know the one you are talking about -- David Poz uses them in his videos but never says what it is. Where can I get a resistor like that? He calls it "a little resistor" but obviously its the biggest one I've seen.

Regarding batteries, here is a picture of the battery. 48v battery packs with a 30a BMS and 40a inline fuse, 78 K-tech INR18650E 2600mah cells in 13s6p configuration,
14awg wires.
Fully charged pack is 54.6v (4.2v per cell)
Fully discharged pack is 36.4v (2.8v per cell)
Max continuous discharge is 30a
Max continuous charge is 15a

14 of them

IMG_20210424_170241831.jpg
 

Hedges

I See Electromagnetic Fields!
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Mar 28, 2020
Messages
9,137
Battery - do I read, "48V 15.6 Ah"? That would be pretty small.
Most people are using 100 to 300 Ah, and their batteries can put out considerable current so the fuse/breaker needs high ratings.
Don't know anything about what your batteries can deliver. "INR18650E" seems to be a format for cells with a variety of current characteristics.
Lithium Ion (not LiFePO4) so greater risk of fire. Make sure nothing overheats them, and that the BMS keeps voltage within limits. Charger and inverter settings also.

30A BMS - so about 1500W max at 48V is what you plan for?

You can also use a small pushbutton for the "little" resistor, together with a high amperage SPST switch.
You can use a lightbulb for the resistor.

Other battery switches:

You can use a switch and a suitable fuse, or you can use a breaker.
A fuse like "class T" can interrupt 20,000A at up to 125VDC.

BlueSea and other good names have these style breakers with moderate short-circuit interrupt ability (2000A to 5000A depending on voltage)


Midnight has some heavy battery breakers:

 

Hedges

I See Electromagnetic Fields!
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Mar 28, 2020
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9,137
Oh, "14 of them" meaning 14 of these 48V batteries in parallel, 14 x 30A = 420A available, and 10kWh or so?
That's a more usable amount of power, and a fairly high rated discharge, should be plenty for the inverter.
I'd recommend a class T fuse, or even something rated 50kA interrupting.
It would be good to find out what the short circuit current capability of the cells is. Might want wire it is groups of batteries each sharing a fuse, depending on what provides enough protection.
 

offgriddave

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Battery - do I read, "48V 15.6 Ah"? That would be pretty small.

Yes but I have 14 of them. See picture

Most people are using 100 to 300 Ah, and their batteries can put out considerable current so the fuse/breaker needs high ratings.
Don't know anything about what your batteries can deliver. "INR18650E" seems to be a format for cells with a variety of current characteristics.
Lithium Ion (not LiFePO4) so greater risk of fire. Make sure nothing overheats them, and that the BMS keeps voltage within limits. Charger and inverter settings also.

INR18650E is the name of the 18650 batteries inside


30A BMS - so about 1500W max at 48V is what you plan for?

They each have a 30A BMS. So 14 * 1500 = 21,000W. The LV5048 can only do 5000 watts.


You can also use a small pushbutton for the "little" resistor, together with a high amperage SPST switch.
You can use a lightbulb for the resistor.

Can you show me a picture or a link?

Other battery switches:

You can use a switch and a suitable fuse, or you can use a breaker.
A fuse like "class T" can interrupt 20,000A at up to 125VDC.

BlueSea and other good names have these style breakers with moderate short-circuit interrupt ability (2000A to 5000A depending on voltage)


Midnight has some heavy battery breakers:

IMG_20210424_181302471.jpg
 

Hedges

I See Electromagnetic Fields!
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Mar 28, 2020
Messages
9,137
This link has pictures of rotary switch with resistor.
You can substitute a momentary switch for the second position of the switch.
You could substitute a light bulb (maybe same voltage as your battery, maybe 120V bulb), check with a meter to see how fast it charges.

There is also a link to a page with [Download] in upper right corner giving more details and parts list.
 
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