[El Guapo]

Is it acceptable to connect a busbar to a ground wire that grounds to a pillar then run all other grounds in the van (battery, 12v fuse block, inverter, solar charger, etc) to the bus bar?

On the positive side, is it acceptable to run a wire from the positive terminal of the house battery to a busbar, then run all the positive loads (12v fuse block, positive to inverter, positive from solar charger, etc) to the busbar or should they all go directly to the battery?

If these are acceptable, if I go to a two batter system is it ok to wire both batteries to a common busbar or should they be wired directly to each other?

 

[RDinNHandAZ]

Ground bus bar- good, ground it directly to a heavy part of the vans ribs by removing paint, coating with dielectric grease and bolting. No reason to run a wire but a properly sized one is OK.

Positive bus bar good, wire from positive to busbar then to individual circuits with fusing.

Batteries should be in series and connected to each other if 6 volt and parallel and connected if 12 volt, no reason to wire each to a busbar when one properly sized wire will suffice.

Acceptable and best practice may not be the same thing.

 

[keeponvaning]

That's how I did it on my ground side.

 

[El Guapo]

Awesome, thanks you guys. I'm anxious to get this wiring finalized and start slinging wood.

 

[Hein]

Make sure to size the cables going from the buss bars to the chassis ground and battery positive large enough for all your combined loads and/or the max amperage supplied by your charge sources.

For safety, there should be a main large fuse or breaker at or near the positive terminal to protect the cable going to the positive buss bar. Many folks get a Bluesea fuse panel which serves as both positive buss and a place for the individual fuses.

Newer vehicles are put together with adhesives (not as much welding) so the chassis may not be the best low resistance path to the negative terminal on the batteries. Especially for high combined loads.

 

[GaryBIS]

Hi,

I think that the busbar for the positive loads with a heavy wire from the busbar to the + battery terminal is fine.

I'd do the same thing for the negative busbar. That is, run a heavy wire from the negative busbar directly to the negative terminal of the battery.

If you ground the busbar to the chassis, it needs to be a heavy wire capable of carrying the sum of all your loads, which could be well over 100 amps, and it needs a very careful connection to the chassis. Then you will need a similar connection from the negative terminal of the battery to the chassis -- again sized for the sum of all your loads and very carefully connected to the chassis. The alternative is to just run a heavy wire capable of carrying the sum of all your loads directly from the negative busbar to the negative terminal of the battery. The 2nd approach seems like less work to me and is less likely to fail over time. Chassis connections are notorious for failure over time due to corrosion where the wire to chassis connection is made. I never use chassis grounds except for the safety ground of the battery negative terminal to the chassis.

Bluesea.com sells some busbars that are popular.

Gary

Gary

 

[El Guapo]

And by "sum of all the loads" would that also include loads going from the battery to the inverter? A 2000w inverter could be pulling ~200 amps. Pretty big wire.

 

[GaryBIS]

And by "sum of all the loads" would that also include loads going from the battery to the inverter? A 2000w inverter could be pulling ~200 amps. Pretty big wire.

Right -- the BlueSea Circuit Wizard calculator will tell you the size:
http://circuitwizard.bluesea.com/

Looks like AWG 2 or AWG 1 if the wires are not too long.

Gary

 

[mikesee]

Hi,

I think that the busbar for the positive loads with a heavy wire from the busbar to the + battery terminal is fine.

I'd do the same thing for the negative busbar. That is, run a heavy wire from the negative busbar directly to the negative terminal of the battery.

If you ground the busbar to the chassis, it needs to be a heavy wire capable of carrying the sum of all your loads, which could be well over 100 amps, and it needs a very careful connection to the chassis. Then you will need a similar connection from the negative terminal of the battery to the chassis -- again sized for the sum of all your loads and very carefully connected to the chassis. The alternative is to just run a heavy wire capable of carrying the sum of all your loads directly from the negative busbar to the negative terminal of the battery. The 2nd approach seems like less work to me and is less likely to fail over time. Chassis connections are notorious for failure over time due to corrosion where the wire to chassis connection is made. I never use chassis grounds except for the safety ground of the battery negative terminal to the chassis.

Bluesea.com sells some busbars that are popular.

Gary

I bolded one sentence above ^ that is confusing to me. I have a BlueSea 6-slot busbar. Planning to install it this week. It has no negative lead.

This one.

It has a single post for the positive input, and 6 fused output circuits. When you look at the second picture on that page, it clearly shows a red positive cable coming into the busbar, and smaller wires going out to each circuit, but no negative.

If I'm running my solar power into my charge controller, and then to the batteries, should I ground the batteries directly to the chassis?

And if so, what then for the busbar that has no negative lead?

Be gentle, please. And thanks.

 

[Winston]

You don't literally need a negative buss bar. The issue often debated is whether to rely on the van chassis as your negative return to the battery from your various 'loads' or to have a separate ground wire return for each load (not providing a ground wire return is a common technique employed by auto manufacturers as it allows them to save by not putting in additional wiring for the negative lead/return). Our choice, and Gary's recommendation we believe, is NOT to rely on the chassis for ground current return, rather, to close the circuit 'back to the battery' with equally large negative conductors from your various loads . . . equal to the positive wires going to those loads. This does not mean you shouldn't ground the negative to the chassis at some point. But for technical reasons (often referred to as "ground loops"), it is not a good idea to ground to the chassis at more than one location. Therefore, we'd recommend you select your house battery mounting location as the point, and only point. to ground your negative to the chassis. (An alternative would be to ground where your vehicle battery is grounded, particularly if you're going to tie your vehicle battery/alternator into your house battery system for charging purposes. In this arrangement you'll maintain a single vehicle ground but, instead, it will be at the location of the vehicle battery.)

Looking at this from another perspective, pretend you don't have a Promaster, but are wiring everything out in your driveway. You'll need both positive and negative wires from your battery to your 'loads'. Again, make them all the same gauge. Now, pretend, further, that you're going to take all this wiring and place it in your van. It would operate correctly as re-positioned in the van without any further connection to the van chassis. But it is strongly recommended that it be connected to the van body, again, at one location.

As to a 'formal' negative buss . . . remember, you don't need any fuses in the negative side . . . so the 'so-called' negative buss is nothing more than properly 'connecting' all the negative wires to the battery - - you can do that anyway you want, you don't need a special 'buss bar'.

 

[mikesee]

You don't literally need a negative buss bar. The issue often debated is whether to rely on the van chassis as your negative return to the battery from your various 'loads' or to have a separate ground wire return for each load (not providing a ground wire return is a common technique employed by auto manufacturers as it allows them to save by not putting in additional wiring for the negative lead/return). Our choice, and Gary's recommendation we believe, is NOT to rely on the chassis for ground current return, rather, to close the circuit 'back to the battery' with equally large negative conductors from your various loads . . . equal to the positive wires going to those loads. This does not mean you shouldn't ground the negative to the chassis at some point. But for technical reasons (often referred to as "ground loops"), it is not a good idea to ground to the chassis at more than one location. Therefore, we'd recommend you select your house battery mounting location as the point, and only point. to ground your negative to the chassis. (An alternative would be to ground where your vehicle battery is grounded, particularly if you're going to tie your vehicle battery/alternator into your house battery system for charging purposes. In this arrangement you'll maintain a single vehicle ground but, instead, it will be at the location of the vehicle battery.)

Looking at this from another perspective, pretend you don't have a Promaster, but are wiring everything out in your driveway. You'll need both positive and negative wires from your battery to your 'loads'. Again, make them all the same gauge. Now, pretend, further, that you're going to take all this wiring and place it in your van. It would operate correctly as re-positioned in the van without any further connection to the van chassis. But it is strongly recommended that it be connected to the van body, again, at one location.

As to a 'formal' negative buss . . . remember, you don't need any fuses in the negative side . . . so the 'so-called' negative buss is nothing more than properly 'connecting' all the negative wires to the battery - - you can do that anyway you want, you don't need a special 'buss bar'.

Thanks for taking the time to 'splain. That did help, to a point, but my lack of basic understanding means that I was confused again before I finished reading.

I think the confusion stems from the fact that my batteries (2 x 6v) are wired straight into my charge controller, and then my charge controller is disbursing the loads. None of my loads are connected directly to the battery, and at this point (and for the last year) I haven't been grounded to the chassis.

But I'm adding LED lighting and some USB ports this week, and using a bus bar to disburse (and fuse) those loads. With that addition it finally occurred to me to ground the whole shebang.

At this point it'd be instructive for me to show you a chart with my whole setup, but I don't have one -- it lives in my head.

Essentially it goes like this: PV panels --> charge controller <-batteries, and then I'm disbursing loads from the charge controller to the busbar, which will then disburse it to the fridge, lighting, signal booster, USB jacks, etc...

Best I can tell, based on what I have and what I'm doing, is that I need to continue to run the PV leads into the charge controller and the batteries into the charge controller as I'm doing now. But then I need to run the negative lead *from* the charge controller to the chassis, the positive lead from the charge controller to the busbar, and then all of the positive leads from the busbar will be fused out to the loads.

Got that? Am I off base?

Thanks again.

 

[Hein]

Your DC loads should be connected to the battery. And the solar controller as well.

Battery > large main fuse/breaker > DC panel with multiple fuses > various loads
Solar controller> fuse/breaker > battery

You already have this from a functional perspective. But wire going from the battery
to the charge controller may be carrying more current than you want. What gauge is it?

Here is the diagram for our system. It might help to further illustrate what we are discussing.
http://www.impact3d.com/DC_charge+distribution_system_revE.jpg

 

[Winston]

Mike,

We tried to keep it simple . . . so when we spoke of 'battery' connected to 'loads' . . . we were referring to anything connected to the battery as a 'load'. In fact, your charge controller is a 'negative load' as it provides, rather than removes, energy from the battery and other loads.

Most focus on the battery as the 'center' of everything. Seems you're focused on the charge controller as the center of everything. Depending on wire sizes and current flow, it probably doesn't make any difference. In short, connecting your led's and other loads directly to the charge controller rather than the battery makes no functional difference so long as your cable from the battery to the charge controller is of sufficient size to handle all current heading to, and from, the battery.

And you can probably ground your system at any point you want - - you can ground it at the charge controller. If you do that, again, we recommend 'single point grounding', so recommend against grounding the battery directly - - it will be grounded essentially through the ground at the charge controller. But even if you use the charge controller as your 'focus' (i.e. where everything converges and is interconnected and where your buss bar is), we'd probably still use a solid, single ground at the battery.

The only other wisdom we can impart is that the battery is the 'big threat' when it comes to shorts . . . if your buss is at the charge controller and if all your fusing/breakers are on that buss, you should be sure to provide battery protection by having a fuse at the battery positive lead.

 

[RDinNHandAZ]

AND I would recommend a large quick disconnect at the negative side of the battery in case something goes amiss and you want to remove that big power pack from everything. It can be manual. I have used mine to work on wiring and want to be sure I cannot create a short. The ONE ground I have between the negative side of the battery and the chassis can be disconnected, meaning the battery cannot make a circuit, via a short or through an appliance. I used this one:
https://www.amazon.com/HELLA-002843...1499462593&sr=1-2&keywords=Battery+disconnect
But other like a different brand at more $:
https://www.amazon.com/Blue-Sea-Sys...499462583&sr=8-15&keywords=Battery+disconnect

 

[mikesee]

Your DC loads should be connected to the battery. And the solar controller as well.


You already have this from a functional perspective. But wire going from the battery
to the charge controller may be carrying more current than you want. What gauge is it?

I don't understand how I can wire the DC loads to both the batteries and the controller. I did look at your diagram but I still don't understand.

It's been a ~year since I did my initial setup with batts, PV, charge controller. I don't remember the gauge of the wire, except to say that a friend that is an HVAC tech supplied it after seeing what I was doing, and it's roughly as thick as my pinky finger.

 

[Winston]

I don't understand how I can wire the DC loads to both the batteries and the controller.

It's been a ~year since I did my initial setup with batts, PV, charge controller.

If it's been working for a year, why change it now?

You don't literally connect your loads to both the batteries and the controller. But since the batteries and controller 'are wired together', in one sense you are connected to both. The more 'normal' configuration is to literally connect the loads to the battery, but if you've done it otherwise, we wouldn't worry about it.

If you're really curious and want some additional 'feedback, find a good digital voltmeter (millivoltmeter) and connect the voltmeter, first, between your battery negative and your solar controller negative. Measure this voltage when your batteries are at low charge and at 'high noon' when your solar controller is putting out maximum wattage/current. Do this both with the other loads turned off and with them on at maximum. Do the same for the positive terminal of the battery and the positive of the solar controller. We bet, in both cases, you'll measure less than a half volt - - which we consider acceptable. If you measure substantially more than that, then maybe you should consider getting a bigger 'pinky'.

 

[mikesee]

If it's been working for a year, why change it now?

Because I'm adding the busbar, and it doesn't have a ground, and that doesn't seem safe, or right, to me.

 

[keeponvaning]

It has to be grounded somewhere or nothing would work! Perhaps you mean it doesn't have a good enough ground or you don't trust the ground?

 

[mikesee]

It has to be grounded somewhere or nothing would work! Perhaps you mean it doesn't have a good enough ground or you don't trust the ground?

My battery cables are run into the pos and neg terminals on my charge controller. That's it -- nothing is attached to the chassis.

As Winston (I think) noted earlier in the thread, I could take the whole system out and place it on my driveway and it would function exactly as it does now. And it's been functioning fine. But for the desire to add this busbar and take advantage of the free solar power being generated, I probably wouldn't feel compelled to change anything.

 

[keeponvaning]

Well, you get the ground from your solar panel(s). It obviously works as you have found out but I think a better system would be to also ground the house battery(s) to the chassis then you don't have to fool around with a grounding buss bar on the controller. I just screwed a buss bar to my body and connected all the ground wires to it then ran a #8 wire (I believe) to the negative post on my battery which is also grounded to the body thru a ground cable from the battery to a tie down bolt on the floor.

There are lots of ways to do it but you seem to want to power everything at your controller where most people simply do it at the battery itself and simply charge the battery from the controller.

It it works for you and you're happy just keep on doing it