robbob2112
Doing more research, mosty harmless
Just putting this thread together as a place for me to post answers to common questions I see over and over.
Whatever you read below is my opinion - read at your own risk -
I found all the answers in the cellar at the end of the hall in the bottom of a locked filing cabinet stuck in a disused lavatory with a sign on the door saying 'Beware of the leopard.'
If you are new and reading this and have question - please post a new thread.
If you are more experinced and have a correction or disagree with what I have here - post and I'll make the correction if it makes sense.
Rules to live by -
Last one - Everyone has an opinion - the hard part is deciding which one is worth listening to
Links in this thread
#1 - how to decide battery voltage and also figure how many panels you need.
#2 - Sample system - off grid cabin - 24v - 4 panels - bougerv mppt -
#3 - My CPAP backup unit
#4 - Sample system - 4 x 12v parallel off grid - don't use
#5 - Tools - Things I have and use - YMMV
#6 - Ferrule usage
#7 - Do you need an equalizer/active balancer with series strings of batteries
diysolarforum.com
diysolarforum.com
#8 - How to choose system voltage
#9 - What are common types or wire and usage
#10 - Buried conduit - NEC and rules
#11 - Wires on a rooftop
#12 - Fuses, disconnects/isolators, and breakers on PV lines
#13 - Attaching the battery negative to ground
#14 Batteries for perfect balance without the math - a practical example
#15 24v UPS - outputs 240 split-phase
#16 - Link to my 4 panel trial build thread
Trial build thread
#17
#18 - Some info on SPD
SPD information and recommendation
#19 - PV wire in or on a building
PV wire in conduit
More on EGC and grounding
Good links to read not by me
opening 12v batteries without damage
Hooking multiple batteries in parallel and where on the bus bar to place the uplink cables.
Gasses released by LiFePO4 batteries during a cell vent. I have this one as a PDF, but it is to large to post -- just in case it disappears
Probably the neatest DIY Battery rack I have ever seen
Shading, bypass diodes, and optimizers
External links I want to remember -
Raw copper bus bar material
Custom bent/cut/punched/plated busbar assemblies
No-OX-id Special A grease - use it on all contact surfaces
EM radiation song - very funny
Topics to master:
Wire - what is good and bad. CCA vs pure copper, Temperature
Wire - sizes, strand count, sheath materials, ampacity and voltage
Tools. - list of essential tools for crimping, torquing, striping, etc
Tools - general torque specs for bolts and connectors
Lugs - material, plating, good and bad brands, what to look for
Fuses - DC arc breaking, sizes, types, where needed type to use
Switches - dc disconnect, ???
Inverters - how sized? Good brands? What to look for?
MPPT. - what to look for ?
Solar panels - ???
Battery options- rack mount vs home built vs ?
Balancers - what they do and what to look for
BMC - how to use them to control the battery charge states?
Conduit - what goes where and how to pull cables
Bus bars - what to look for, what works
SME list - These guys can answer any question - they parse through the listings and pick what they want that is general or in their area.
This is by no means comprehensive, it just covers the folks I see all the time.
@Hedges - 3 phase - sunny island inverters - transformers and the like
@timselectric - Mr Grounded - i.e. all things grounding - all things electrical as well
@sunshine_eggo - Grand Pa smurf - all things Victron
@Brucey - his blood runs blue as well
@Rednecktek - has a different take on doing things on the cheap verse
@12VoltInstalls - lower voltage stuff
@Mattb4 - Generalist - low voltage stuff
@BentleyJ - Schneider expert
@BKY2003 - Schneider expert
@400bird - Schneider expert
@GRMRC - Schneider expert
@Daddy Tanuki - we keep him around for the crude comments and sense of humor
@FilterGuy - expert at most things - DIY batteries especially
Sellers and vendors
@EG4TechSolutionsTeam - anything EG4 related
@SignatureSolarJess - Anything related to signature solar
@HighTechLab - Current connected owner
Whatever you read below is my opinion - read at your own risk -
I found all the answers in the cellar at the end of the hall in the bottom of a locked filing cabinet stuck in a disused lavatory with a sign on the door saying 'Beware of the leopard.'
If you are new and reading this and have question - please post a new thread.
If you are more experinced and have a correction or disagree with what I have here - post and I'll make the correction if it makes sense.
Rules to live by -
- If it seems to good to be true, it is..people lie to make a buck
- There can be only one - this is when talking about grounding - one rod - one grounding system - one ground potential for all equipment
- Never stack lugs - You can get away with a lug and a ring terminal on top, but never stack larger lugs
- You can do it right, or you can do it over, once it burns down
- Buy cheap, buy twice, or three times depending on how long it takes you to learn
- Fuse EVERY live positive wire
- Use the right type and amperage of fuse
- Class T fuses are expensive but if sized right they only blow when they save your butt.
- Buy the voltage battery you need, don't try and string them together for higher, it causes problems
- Trying to reuse your old equipment in your new design will cost you in the end - money or efficiency
- If you didn't listen to #10 & #11 use an active equalizer/balancer to keep them in balance.
- Use a MRBF fuse with holder on each battery post at 12v with 4 or less
- Use bus bars with more than two batteries or if you can't land all the large lugs without stacking
- Use a class T between the bus bar and inverter
- Do use rubber boots to insulate the cable ends and bolts they are on.
- All wires and fuses are sized 1.25% higher than max expected current.
- Try to use pure copper bus bars verse brass. Ensure you know the metal then you can do the math to figure the capacity
- Carefully read and understand any ad selling things - you usually get exactly what you order - and it is on you if you don't vet the ad.
Last one - Everyone has an opinion - the hard part is deciding which one is worth listening to
Standard Blurb
Don't spend any money, until you have planned out the entire system. An eraser is cheap, but returns can be costly.
Planning
Don't spend any money, until you have planned out the entire system. An eraser is cheap, but returns can be costly.
Planning
- Energy Audit - what do you have to power?
- Size the inverter for your maximum instantaneous demand (including surges).
- Size the battery for how long you want power, when the sun isn't shining.
- Size the PV to cover the loads and recharge the battery, when the sun is shining for your area - most in the US use 4hrs or 5 hours a day of sun
- Trying to use old equipment you already have usually costs more in design compromises than just...
Links in this thread
#1 - how to decide battery voltage and also figure how many panels you need.
#2 - Sample system - off grid cabin - 24v - 4 panels - bougerv mppt -
#3 - My CPAP backup unit
#4 - Sample system - 4 x 12v parallel off grid - don't use
#5 - Tools - Things I have and use - YMMV
#6 - Ferrule usage
#7 - Do you need an equalizer/active balancer with series strings of batteries
It is ALWAYS better to have the correct voltage of battery, it will save you trouble in the end. If you don't and have a series string see below
Running strings of 2 and 4 batteries - do you need an equalizer - it depends - if you charge discharge the same amount day after day you need an equalizer - if you run totally random patterns that are from 20 to 80% usage every day you don't. BUT, very few actually run a totally random pattern day after day. The sun rises and sets, the ac cycles on and off, etc. So random in the day will delay the batteries but they will get out of sync and require being put in parallel or disassembly and charging individually.

Do I need an Active balancer for two 12.8v 100ah in series?
Easy to add later if an issue develops. Not a permanent skip feature on a large component.


Do I need an Active balancer for two 12.8v 100ah in series?
Easy to add later if an issue develops. Not a permanent skip feature on a large component.

#8 - How to choose system voltage
#9 - What are common types or wire and usage
#10 - Buried conduit - NEC and rules
#11 - Wires on a rooftop
#12 - Fuses, disconnects/isolators, and breakers on PV lines
#13 - Attaching the battery negative to ground
#14 Batteries for perfect balance without the math - a practical example
#15 24v UPS - outputs 240 split-phase
#16 - Link to my 4 panel trial build thread
Trial build thread
#17
#18 - Some info on SPD
SPD information and recommendation
#19 - PV wire in or on a building
PV wire in conduit
More on EGC and grounding
Good links to read not by me
opening 12v batteries without damage

Grounding Requirements for Portable Generators | JADE Learning
Portable generators are useful for when temporary or remote power is needed. Knowing when to ground a generator is critical for operator safety.
www.jadelearning.com
Hooking multiple batteries in parallel and where on the bus bar to place the uplink cables.
Gasses released by LiFePO4 batteries during a cell vent. I have this one as a PDF, but it is to large to post -- just in case it disappears
Probably the neatest DIY Battery rack I have ever seen
Shading, bypass diodes, and optimizers
External links I want to remember -
Raw copper bus bar material
Custom bent/cut/punched/plated busbar assemblies
No-OX-id Special A grease - use it on all contact surfaces
EM radiation song - very funny
Topics to master:
Wire - what is good and bad. CCA vs pure copper, Temperature
Wire - sizes, strand count, sheath materials, ampacity and voltage
Tools. - list of essential tools for crimping, torquing, striping, etc
Tools - general torque specs for bolts and connectors
Lugs - material, plating, good and bad brands, what to look for
Fuses - DC arc breaking, sizes, types, where needed type to use
Switches - dc disconnect, ???
Inverters - how sized? Good brands? What to look for?
MPPT. - what to look for ?
Solar panels - ???
Battery options- rack mount vs home built vs ?
Balancers - what they do and what to look for
BMC - how to use them to control the battery charge states?
Conduit - what goes where and how to pull cables
Bus bars - what to look for, what works
SME list - These guys can answer any question - they parse through the listings and pick what they want that is general or in their area.
This is by no means comprehensive, it just covers the folks I see all the time.
@Hedges - 3 phase - sunny island inverters - transformers and the like
@timselectric - Mr Grounded - i.e. all things grounding - all things electrical as well
@sunshine_eggo - Grand Pa smurf - all things Victron
@Brucey - his blood runs blue as well
@Rednecktek - has a different take on doing things on the cheap verse
@12VoltInstalls - lower voltage stuff
@Mattb4 - Generalist - low voltage stuff
@BentleyJ - Schneider expert
@BKY2003 - Schneider expert
@400bird - Schneider expert
@GRMRC - Schneider expert
@Daddy Tanuki - we keep him around for the crude comments and sense of humor
@FilterGuy - expert at most things - DIY batteries especially
Sellers and vendors
@EG4TechSolutionsTeam - anything EG4 related
@SignatureSolarJess - Anything related to signature solar
@HighTechLab - Current connected owner
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