Wiring/Electrical tips from a pro.

There is a lot of discussion here about wiring and battery banks ect. I have found this guys tutorial or illustrations to be very helpful. It is my goal to make it look as good as he does. If you have links that have helped you, feel free to add.

This is the main page, you have to scroll down a bit past boat related stuff (though the sealants link is good) to pick out the electrical stuff (is worth it)

https://marinehowto.com/

With some good stuff pulled out: I was looking for a way to calibrate my Victron battery monitor. Turns out it can be pretty important.

https://marinehowto.com/programming-a-battery-monitor/

https://marinehowto.com/making-your-own-battery-cables/

http://www.pbase.com/mainecruising/battery_cables

http://www.pbase.com/mainecruising/inverter_inefficiency

http://www.pbase.com/mainecruising/wire_labeling

http://www.pbase.com/mainecruising/battery_fusing

Much more (along with boat stuff) but I like his style.

Jmolan said:

There is a lot of discussion here about wiring and battery banks ect. I have found this guys tutorial or illustrations to be very helpful. It is my goal to make it look as good as he does. If you have links that have helped you, feel free to add.

This is the main page, you have to scroll down a bit past boat related stuff (though the sealants link is good) to pick out the electrical stuff (is worth it)

http://www.pbase.com/mainecruising/boat_projects

With some good stuff pulled out: I was looking for a way to calibrate my Victron battery monitor. Turns out it can be pretty important.

http://www.pbase.com/mainecruising/programming_a_battery_monitor

http://www.pbase.com/mainecruising/wire_termination

http://www.pbase.com/mainecruising/battery_cables

http://www.pbase.com/mainecruising/inverter_inefficiency

http://www.pbase.com/mainecruising/wire_labeling

http://www.pbase.com/mainecruising/battery_fusing

Much more (along with boat stuff) but I like his style.

Click to expand...

BMV 700, when 1st installed set up for 450 hr pack, read the manual seemed important, after a few factory set points reset’s, only care about voltage readings.
Set up, set points changed from default 12 = ON, 14 = 3 min, 18 = 12. 1vdc, 19 = 12.2vdc.
With above listed and the relay wired to a simple relay, all loads are disabled when SOC is <= 12.1 for 3 min. When a large load (microwave) is on voltage will drop below 12 v when pack is not near SOC 12.75 (batt type listed full SOC dependent).
One could use like to disable the charger ( relay or Sterling etc), use function 20, 21 . 14, time may be needed??? Some batteries must not float, charge once full state of charged is reached.
I do use the instantaneous amp reading’s, but not for control or battery health. Batteries get weaker/less amp hr from day one, small unless one leave’ the light’s/etc on and allows SOC way low.

Jmolan said:

There is a lot of discussion here about wiring and battery banks ect. I have found this guys tutorial or illustrations to be very helpful....
...
Much more (along with boat stuff) but I like his style.

Click to expand...

good find, J!

especially with all the (arguments) discussions re: van+rv electrical 'modifications' and 'customizations'.

people here would do very well, be very well served to pay attention to the stuff boaters have learned
(mostly the hard way) about HOW to build a REAL electrical system on their sprinters.

mostly since land vehicle electrical systems are built with one thing in mind:
'how can we design this thing for mass production, with the lowest-cost outcome'
note that this typically does NOT mean 'lowest price' outcome - it means HIGHEST PROFIT
for both the selling dealers as well as their 'service' depts.

with the implication or rather REALITY that if something fails, the typical land motorist
can simply pull over, look under their hoods and maybe try fix something...

or, worst case scenario?
have to call for a tow to the nearest 'qualified' service bay.

vs boats - particularly blue water cruisers - where the operators know that if they're 1000 miles from land,
and something causes their electrical system to crap out?

they might never be seen or heard from again.

why i've oft noted that airline pilots tend to be my best customers - why?

because they know all too well if something goes wrong at 38000feet,
going 500-600MPH in a pressurized aluminum tube?

it's good night irene.

just my

I found this site when doing my 34' trimaran in Mexico. Of everything I've seen he helped me the most.

I am a professional boat driver guy, and cannot help but bring that to my Sprinter. I may not know how to do, but I can tell if it looks cheap or cheesy.

Believe me, Bering Sea crab boats do silly things like cook 8D batteries with old school constavolt chargers. I finally persuaded the owners to get smart chargers for the wheelhouse electronics. Change is not easy for many.

WOW! I am impressed. Finding someone like you on a van site is great! I have always thought that 'boat' stuff is perfect for land vehicle use too. Not as important, but nice is the normal use of wood in a Yacht too. The beautiful woodwork seen in some water craft just doesn't seem to make it to the land yachts. Adding proper low voltage electrical gear of good design just makes sense.

I've been reading this guy's stuff for some time. Just never thought to post it.

http://www.pbase.com/mainecruising/battery_cables&page=4

The crimper he describe at the bottom as "The tool on the right, I had the most hopes" is the one I have (see above link). When I went to buy one (long ago and before reading his blog) it was down to the one he recommends and this one which was half the price. The tool he recommends does look less clunky. The one I have is tremendously a PIA to use but it does make good 4/0 crips. It's more of a two person operation. I use the die that is labeled 95mm.

I did not do a pull test like he did but I did try to disassemble a connection. I put the lug into a vice and tried to pull the wire out. That was a nogo. The entire 500 pound workbench moved and acted like it wanted to tip over. I cut the lug from the wire with about 2" of wire, stripped off the insulation and tried to pull the strands out with pliers with the lug held in a vice. The strands did not pull out. They did break off if I pull on too few. I cut through the lug to see if there were any voids. There didn't appear to be but unfortunately I did not have anything better than a hack saw. So take it for what it's worth.

I probably would have spent the extra money had I read his blog first. As it is the one I have works.

Thanks for posting Mainesail's stuff. I too have been going to this site for a long time as my husband and I are helping our son restore a 40' wooden schooner and the project involves completely redoing all electrical and plumbing on the boat. He has been posting on boating forums for years and his experience and advice is highly valued.

Take a look at his piece on shore power inlets - especially the ones that fail. This is what convinced us to go with the SmartPlug.
http://www.pbase.com/mainecruising/installing_a_smart_plug

And, for those considering lithium (lifepo4) batteries, he has built his own battery with lithium cells and has quite a lot of documented testing and experience with it to share.

http://www.pbase.com/mainecruising/lifepo4_on_boats

Finally, the last three pieces on maintaining AGM batteries and alternator charging are full of tested & documented information. If you have AGMs or are considering them, definitely worth a read.

Great thread with some good information. I also have quite a few articles and installation videos on lithium batteries for B-B+-C and A RV's on my personal web site also enjoy!

www.rvvolt.com

Stay Safe- Mike

Isn’t a

outbound said:

good find, J!

especially with all the (arguments) discussions re: van+rv electrical 'modifications' and 'customizations'.

people here would do very well, be very well served to pay attention to the stuff boaters have learned
(mostly the hard way) about HOW to build a REAL electrical system on their sprinters.

mostly since land vehicle electrical systems are built with one thing in mind:
'how can we design this thing for mass production, with the lowest-cost outcome'
note that this typically does NOT mean 'lowest price' outcome - it means HIGHEST PROFIT
for both the selling dealers as well as their 'service' depts.

with the implication or rather REALITY that if something fails, the typical land motorist
can simply pull over, look under their hoods and maybe try fix something...

or, worst case scenario?
have to call for a tow to the nearest 'qualified' service bay.

vs boats - particularly blue water cruisers - where the operators know that if they're 1000 miles from land,
and something causes their electrical system to crap out?

they might never be seen or heard from again.

why i've oft noted that airline pilots tend to be my best customers - why?

because they know all too well if something goes wrong at 38000feet,
going 500-600MPH in a pressurized aluminum tube?

it's good night irene.

just my

Click to expand...

Sprinter (or any other vanlife build) nothing more then a boat on wheels?

IdleUp said:

Great thread with some good information. I also have quite a few articles and installation videos on lithium batteries for B-B+-C and A RV's on my personal web site also enjoy!

www.rvvolt.com

Stay Safe- Mike

Click to expand...

Sorry/ Off topic. Hi Mike, I see you fly Helicopters also. I have been flying since the '90s. Fun stuff.

Any probs for me using Blue Sea 2151 dual terminal (ea fuse diff A)? I plan to use 1-300A and 1-30A?

Terminal fuses as good as ANL fuses?


THANX

2019 Sprinter Cargo 144 low 4x4
Starting to understand the wiring. And I have a relatively simple system. Stand-alone 3 belt, 2-6v, 1500w inv, leds, fridge, fan, waterpump, usb. I can't imagine integrated system with vehicle elect,and solar.

You guys are great!! Thanx
Loren N MN -36 last nt.

MRBF fuses like the Blue Sea are a good choice, better than ANL.


Regards,

Mark

Mark

Thanx for guidance.

Should I have a fuse on the negative fr inverter in addition to the positive.?

I have read once to chassis ground the inverter also.???

Do I also chassis ground my 2nd alt? It is NOT hooked into any of my starter battery or vehicle.

Loren

ljks said:

Mark

Thanx for guidance.

Should I have a fuse on the negative fr inverter in addition to the positive.?

I have read once to chassis ground the inverter also.???

Do I also chassis ground my 2nd alt? It is NOT hooked into any of my starter battery or vehicle.

Loren

Click to expand...

You don't fuse the negative leads.

Whether to ground the negative on the house 12V system depends on a whole bunch of things. If you are not an expert, it is probably safer to ground the negative of everything on the DC side to the chassis. The inverter should describe how it should be wired. Mine has a negative and positive input from the batteries and an additional chassis ground. Both the negative and the chassis ground go to ground.

The MRBF fuses fit on battery terminals. I have a lower amp one on each battery to protect the wiring, as my batteries are not together.

Search in this forum for alternator threads. There are many long ones with lots of info. I don't have a second alternator and am not an expert on them.

Regards,

Mark

Thanks-all of you people. This is a great thread and I will read and learn. And maybe I will try to get a consultation with the guy up in Cumberland Maine, when we return to Penobscot Bay this May. Roger Eaton

I'm trying to remember where it is critical to have the shortest cable/s (voltage drops) on an RV solar system. Is it between the panel and the charge controller? Or between the charge controller and the batteries?

The length of the wire does not matter if you size it correctly. Obviously shorter wires will allow you to use smaller gauge as long it is still within the voltage drop guidelines. But basically, the higher amps will require a larger wire. So the wire from the charge controller to the batteries will carry more amps and needs to be larger and preferably shorter.

Think of it this way. If you panel puts out 400W at 50V, that is 8A of current between the panel and the charge controller, that would equate to a 14 or 12ga wire, depending on length. Assuming perfect efficiency and no loss, that same 400W at 12V is now 33A, requiring a much larger wire. 8ga or larger, depending on the length of the wire.

Hope that helps.

I just realized you may be able to answer a question I've had about my batteries. I planned to install lithium cells laid flat in my subfloor (inside the cabin) but a pro in that field prefers to use buss bars for the poles of each cell and of course that wouldn't work in a horizontal configuration so I suggested good marine cables since (it's my understanding) electrons prefer the outer surfaces for travel and there is obviously more surface area in those than a bar. Am I correct? If not, please explain if you know.

Skin effect doesn't really play into a DC circuit.
The "penetration depth" is infinite ... the entire cable/bar is carrying current.
All that matters for "Sprinter-length" wiring is cross-sectional area.

But, since you asked, a cylindrical cable has less exterior surface area than a same-area rectangular bar.
If you consider each strand of a flexible cable as a carrier, then their summed area would be greater than the bar's, but since they're in intimate contact i'd hate to try to figure the effective area. (i'm sure there are handy web-based calculators)

--dick

autostaretx said:

Skin effect doesn't really play into a DC circuit.
The "penetration depth" is infinite ... the entire cable/bar is carrying current.
All that matters for "Sprinter-length" wiring is cross-sectional area.

But, since you asked, a cylindrical cable has less exterior surface area than a same-area rectangular bar.
If you consider each strand of a flexible cable as a carrier, then their summed area would be greater than the bar's, but since they're in intimate contact i'd hate to try to figure the effective area. (i'm sure there are handy web-based calculators)

--dick

Click to expand...

I remember you from way back. Thanks! yeah, that 'intimate contact' is the killer I suspect.