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Old 09-25-2016, 12:15 AM   #21
scooter1942
 
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Default Re: Another Electrical Thread: Don't let me catch it on Fire!

Alright...I really do appreciate all of the suggestions and advice. I'm learning a lot, but now I feel right back where I started...lost.

I believe I made some progress with my schematic...or at least one variation. Would somebody be so kind as to print out my "best" schematic, pencil whip it, take a picture of it and reload onto the forum with an explanation? Or if you have the means to modify the PDF directly...all the better.

Pretty please, with sugar on top.
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Old 09-25-2016, 01:44 AM   #22
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Default Re: Another Electrical Thread: Don't let me catch it on Fire!

You need to add every pin/connection/terminal per the manuals for these things. Then you need to draw a wire or a no-connect to every one of those points on every device. Then you'll have a something to look at.

For the various vehicle ground points, use the lugs near the seats. It's what they are designed for.

IMG_1524.JPG

Last edited by NBB; 09-25-2016 at 01:46 AM.
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Old 09-25-2016, 03:32 AM   #23
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Default Re: Another Electrical Thread: Don't let me catch it on Fire!

Holy Crap! That changes everything!

Ok, NBB...a couple of things...

1. How is the solar providing charge to the battery bank if there's no (+) wire going from the controller to the battery? Or, are you just using the fuse box "backwards" and running power from solar, through a 30A fuse and back to the battery?

2. So the MT-50 meter. It came with the charge controller as a kit...BUT, it measures voltage, current (amps) and state of charge (%). If the MT-50 is capable of doing that, why do I need to drop bucks on a battery monitor? And if it does, wouldn't that mean the charge controller would need a (-) wire going to the negative post of the battery so that it can measure current?

I'll draw up a new schematic in the morning with your suggestions.
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Old 09-25-2016, 05:45 AM   #24
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Default Re: Another Electrical Thread: Don't let me catch it on Fire!

Scooter,
I am not in a position to reply fully today but will PM you tomorrow. Please keep an eye top right where it says Welcome Scooter for the pm.

Cheers

Ross
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Old 09-25-2016, 04:00 PM   #25
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Default Re: Another Electrical Thread: Don't let me catch it on Fire!

1) Yes, the latter. My suggestion is the safest, most straight forward way to wire the controller, IMO. Consider you don't want nor need fuses and connections spread all over the place.

2) The controller and meter look like a fine product, just checked it out, but it does not measure current - it is only estimating it based on a bunch of "other stuff". The number will be beyond inaccurate, IMO, it will be useless. In fact, check the manual, the "State Of Charge" feature will be removed at some point, you may not even have it. The reason is likely too many customers calling and complaining about the useless number. If you add in alternator charging via an isolator, as you should, just forget it, the estimates of current will be 100% useless.

Definitely add all the terminals/pins/connections on everything you are going to install and get them on that wiring diagram. It needs to be buildable, and 10 years from now you will not recall which wire went where buried down in your van somewhere. For example, you had numerous wires going to the (+) side of the battery. How exactly are you going to build that? Are you going to buy a lug that accepts all these connections? What does that look like? Duct tape? You get the idea. At some point, all these little details need to be addressed - sooner is better than later - get it documented.

EDIT - just looked at that fuse box, looks like a negative bus is built in so you do not need to buy one per my sketch. Connect the negative side to one of those ground lugs near the seats. There are 4 each seat - 2 outside the pedestal, 2 inside.

You definitely want that switch I indicated between the shunt and a ground. You need to be able to easily, safely and quickly cut off power to everything, this is the switch you do that with. The start battery to the vehicle is wired essentially the same way - that disconnect is on the floor near the gas pedal.

Last edited by NBB; 09-25-2016 at 04:13 PM.
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Old 09-26-2016, 01:25 AM   #26
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Default Re: Another Electrical Thread: Don't let me catch it on Fire!

Here's a quick question...If I'm using two 6V batteries to make 12V, will I still use a battery monitor that measures only one battery at 12V? There are some models that measure two batteries, but I believe it is intended for starter and house monitoring each at 12V.
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Old 09-26-2016, 02:48 AM   #27
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Default Re: Another Electrical Thread: Don't let me catch it on Fire!

The shunt is simply a current sensor. It shouldn't really care about the voltage of the battery or how many batteries make up the system. You could have 1 battery or 12 at who-cares what voltage. You tell it how many Amp-Hours the battery (or batteries) hold, and it sits there and looks at how much current is going in and out, and it tells you what percent that is of the total you programmed in there.

Models that say they measure both a start and house - they either have 2 shunts (less likely) - or they are simply giving you the voltage of that second battery system - ie, the start battery.

No shunt - no battery monitor.
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Old 09-26-2016, 12:48 PM   #28
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Default Re: Another Electrical Thread: Don't let me catch it on Fire!

Sorry, unable to get NBB's suggestions sketched out yesterday...looks like a new home computer is on my horizon. NBB...thank you for taking the time to print out and pencil whip my schematic. Now that I'm back at the office, so here's the latest schematic...


Last edited by scooter1942; 09-27-2016 at 02:15 AM.
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Old 09-26-2016, 03:45 PM   #29
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Default Re: Another Electrical Thread: Don't let me catch it on Fire!

Looks a lot better to me. For the solar controller, connection is likely a +/- 10 gage wire pair, wired into the fuse box no different than the fridge, lights, etc, don't need a separate ground lug there.

Also suggest per my comment upthread to keep it simple with wires and fuses - I used 14 guage wire on 15A fuses, and 10 guage wire on 30A fuses for everything. Buy a bunch of each wire in 2 conductor form - minimize cost, waste, confusion, etc, as you are putting it all together.

Some of your circuits can be combined as well. You don't need 2 10A (or 15A) circuits for a bunch of LED lights. Slots on your fuse panel should be consumed wisely.
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Old 09-26-2016, 09:44 PM   #30
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Default Re: Another Electrical Thread: Don't let me catch it on Fire!

Hi Scooter,

Your latest drawing shows three ground points (apart from the engine battery). There should be only one ground point which the one at the switch. Otherwise there will be ground path through the battery monitor despite the switch is off.

I have added a revised drawing which embodies all the changes I have suggested so far.

Please note that I have changed the polarity of the two batteries just to make the drawing clearer by removing some of the wires crossing each other.
A note about the Tracer solar controller:
These units were designed and are produced in China to provide battery charge control for solar powered street lighting. There must be many thousands used in China alone. I have installed many of them in Motorhomes and caravans here in NZ. They are well made and very reliable.
However your controller is current capacity limited to 20 Amps charging or discharging. The alternator, when charging a discharged battery could easily provide much more than 20Amps, and on discharge possibly more then 20 Amps .
That is why you need a separate battery monitor which will handle the higher current during charging and discharging. The Tracer controller has a built in shunt which can only be used when the load circuits are connected to it directly. You will not be using the load circuit as it is limited to 20Amps, so hence the need for a separate battery monitor.
If you want an isolating switch then it would be placed between the battery neg terminal and the shunt.

Cheers

Ross
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