2015 170” DirtDevil Build

casmith32

Member
2015 170” DirtDevil Build - Insulation

Insulation and Sound Dampening

Finally got around to adding sound dampening and insulating the rear of the van. After some serious thought and consideration as to what I’m going to be using the van for, I’ve decided to run with rattle trap and roadkill for sound dampening. And a combination of Low-E for reflective insulation, and Thinsulate and RMax R-Matt Plus-3 rigid polyiso foam.

Used the rattletrap because a friend had some left over from his build. That got me pretty much good for the entire van except the roof and wheel wells. I ordered RoadKill to finish things off. If I had to do it again, I’d use RoadKill for it all - nice stuff, cheaper I think, and no asphalt. It all came out well though. No need to cover the entire surface area of the van with the stuff though.

Insulation will be a multi-stage deal. After dry testing some combinations, looking at R-values and also looking at where I needed rigidity or not, I decided to go with the following, in order, from the outer van walls toward the inside; will finish off with wall panels as well later:

Upper recesses: rattletrap + 1 layer of 2” thick thinsulate + Low-E
Middle window recesses: rattletrap + 1.5” of RMAX PolyIso rigid foam + Low-E
Bottom recesses: rattletrap + 2 layers of Thinsulate
Roof: 1 layer of RoadKill + 1.5” of RMAX PolyIso rigid foam + Low-E

The walls are pretty much done, except for the fact that I am leaving the Low-E off until I get all my electrical run and situated...

Went ahead and put a double layer of 2" wide thinsulate in the middle channels; Just snaked them through the oblong holes and pulled them the length of the run. Pretty much put thinsulate in all the nooks and crannys I could.

Rear and slider doors got a healthy dose of thinsulate as well - I spend a lot of time working it in those things !! but happy how it turned out. I get a good "thump" when closing them now. Solid sounding!

For the bottom recesses I determined that there was enough room to put two layers of Thinsulate and not really compress it! - So that gives an estimated R-value of about R10 - give or take. Couple that with the Low-e, I think it will be really good. I’m happy with how it’s looking so far.

For the Middle window recesses, I decided to go with the RMax Polyiso because I want some rigidity in those areas since I’ll be running some L-Track and other things along the wall. I’ll be reinforcing the walls and roof in some parts with some metal sheeting of some flavor (SS, or painted steel, etc), so the foam will give a nice firm area to play with, while giving an estimated R-value of close to 10+ with the Low-E.

Lastly, the Roof - I want the most reflective insulation possible; I’m struggling on whether to run with the 1.5” Rmax to get an Rvalue of R13, followed by the Low-E (R6). OR go with the Thinsulate (R5) and the Low-E (R6) - I can get approx R11 with the proper small airgap (specs say that Low-E in horizontal applications gets R6 mostly).

I’m going to be shimming out the roof with some 1/4 boards to provide a surface for the roof panels to mount on, as well as give me just a little bit more gap between the insulation and the Low-e.

Given I have a lot of leftover Thinsulate, ponder if R11 is good enough for me; also considering it won’t cost me any more money. Although, the RMAX isn’t too bad in terms of cost for the amount I’ll need. However the other option could yield upwards of R19 combination with the right air gap. That’s pretty significant. I’m also thinking of the fact that I’ll have upwards of 300-400 watts of Solar on the roof, collecting the sun at times.

Before I seal it all up with Low-E, I need to go and seal the side trim mounting tabs on the inside, everywhere I can - with some sealant. Or do folks think it's overkill ? The thinsulate is hydrophobic after all...

Interested in everyone’s thoughts.
 

ryneodonnell

New member
Re: 2015 170” DirtDevil Build - Insulation

Insulation and Sound Dampening

Finally got around to adding sound dampening and insulating the rear of the van. After some serious thought and consideration as to what I’m going to be using the van for, I’ve decided to run with rattle trap and roadkill for sound dampening. And a combination of Low-E for reflective insulation, and Thinsulate and RMax R-Matt Plus-3 rigid polyiso foam.

Used the rattletrap because a friend had some left over from his build. That got me pretty much good for the entire van except the roof and wheel wells. I ordered RoadKill to finish things off. If I had to do it again, I’d use RoadKill for it all - nice stuff, cheaper I think, and no asphalt. It all came out well though. No need to cover the entire surface area of the van with the stuff though.

Insulation will be a multi-stage deal. After dry testing some combinations, looking at R-values and also looking at where I needed rigidity or not, I decided to go with the following, in order, from the outer van walls toward the inside; will finish off with wall panels as well later:

Upper recesses: rattletrap + 1 layer of 2” thick thinsulate + Low-E
Middle window recesses: rattletrap + 1.5” of RMAX PolyIso rigid foam + Low-E
Bottom recesses: rattletrap + 2 layers of Thinsulate
Roof: 1 layer of RoadKill + 1.5” of RMAX PolyIso rigid foam + Low-E

The walls are pretty much done, except for the fact that I am leaving the Low-E off until I get all my electrical run and situated...

Went ahead and put a double layer of 2" wide thinsulate in the middle channels; Just snaked them through the oblong holes and pulled them the length of the run. Pretty much put thinsulate in all the nooks and crannys I could.

Rear and slider doors got a healthy dose of thinsulate as well - I spend a lot of time working it in those things !! but happy how it turned out. I get a good "thump" when closing them now. Solid sounding!

For the bottom recesses I determined that there was enough room to put two layers of Thinsulate and not really compress it! - So that gives an estimated R-value of about R10 - give or take. Couple that with the Low-e, I think it will be really good. I’m happy with how it’s looking so far.

For the Middle window recesses, I decided to go with the RMax Polyiso because I want some rigidity in those areas since I’ll be running some L-Track and other things along the wall. I’ll be reinforcing the walls and roof in some parts with some metal sheeting of some flavor (SS, or painted steel, etc), so the foam will give a nice firm area to play with, while giving an estimated R-value of close to 10+ with the Low-E.

Lastly, the Roof - I want the most reflective insulation possible; I’m struggling on whether to run with the 1.5” Rmax to get an Rvalue of R13, followed by the Low-E (R6). OR go with the Thinsulate (R5) and the Low-E (R6) - I can get approx R11 with the proper small airgap (specs say that Low-E in horizontal applications gets R6 mostly).

I’m going to be shimming out the roof with some 1/4 boards to provide a surface for the roof panels to mount on, as well as give me just a little bit more gap between the insulation and the Low-e.

Given I have a lot of leftover Thinsulate, ponder if R11 is good enough for me; also considering it won’t cost me any more money. Although, the RMAX isn’t too bad in terms of cost for the amount I’ll need. However the other option could yield upwards of R19 combination with the right air gap. That’s pretty significant. I’m also thinking of the fact that I’ll have upwards of 300-400 watts of Solar on the roof, collecting the sun at times.

Before I seal it all up with Low-E, I need to go and seal the side trim mounting tabs on the inside, everywhere I can - with some sealant. Or do folks think it's overkill ? The thinsulate is hydrophobic after all...

Interested in everyone’s thoughts.
Thank you for the details on your build!

Curious, how many labor hours did it take for the following casmith?

- Front Cab Insulation & Stereo Install
- Rear Cargo Area Insulation & Stereo Install
- Fan Install

Trying to gauge what it will be like labor wise for my upcoming build.

Thank you!

-Ryne
 

hein

Van Guru
Thank your for sharing your impressive insulation strategy. Rain on a metal van roof can be pretty loud. Thinsulate(TM) could let you sleep though it.
 

casmith32

Member
Re: 2015 170” DirtDevil Build - Insulation

@ryneodonnell

I'm pretty mechanically and technically inclined (engineer), so I'm a bit methodical and cautious in my planning - sometimes to a fault...so things took longer than I'd like for the simple fact that I pondered materials, methods, usage, etc.. but in terms of estimated hours of actual "work" time vs planning, etc:

Probably a total of 8-10 hrs for the front cab stereo and insulation on the headliner/doors

About 8 hrs total for the rear insulation- including working things into the nooks and crannys

Fan Install - probably a total of 6 hours of actual work over 3 days. There is a certain pucker factor when cutting into a brand new 2015 van when you've never done it before; thus lots of time measuring, making template, remeasuring, dry fitting, etc...

For me, the first time of doing something always takes longer because I'm very cautious and methodical to make sure I'm doing a quality job. So now that I know how all this stuff works, and how things pop off, connect, etc, I can do it much faster with much more confidence...

For example - now I could knock out the two fan installs easily in a half a day I think... as in most things..preparation is what take a lot of the time..

Thank you for the details on your build!

Curious, how many labor hours did it take for the following casmith?

- Front Cab Insulation & Stereo Install
- Rear Cargo Area Insulation & Stereo Install
- Fan Install

Trying to gauge what it will be like labor wise for my upcoming build.

Thank you!

-Ryne
 

casmith32

Member
Thank your for sharing your impressive insulation strategy. Rain on a metal van roof can be pretty loud. Thinsulate(TM) could let you sleep though it.
Thanks Hein - my thought is that I like the idea of a bit more rigidity / solid backing in the larger voids of the van ; window recesses, and ceiling recesses. Mainly because I'll be hanging things and running l-track on the walls. That said, I'm planning on running strips of 6" wide aluminum or SS sheet/plating to reinforce the walls behind the wall panels to add a larger spread of support for wall panels, and L-track that will run on the walls; So maybe the 4" of thinsulate will work just fine.

For the ceiling, I may just use the thinsulate I have left over on the ceiling as well with the Low-E - should get a pretty good high R value yes ? thinking 10-15 with the proper air gap. I may run 1/4" furring strips lengthwise on the ceiling for mounting the ceiling panels easily and give a slight air-gap but I think the Thinsulate is enough airgap...
 

casmith32

Member
DirtDevil Build Electrical system critique requested

Finally got the draft of my proposed electrical plan together. Looking for some input from the forum to see what is good, and what's not. I've attached both pdf and dwg files - but I built the diagram in microsoft visio - so not sure if the dwg exported well or not.

On the diagram I've got some yellow boxes indicating some questions I have in particular. Everything outside the seat pedestals will be located near roughly behind the driver's seat / driver side window; either down low or up high in overhead cabinet.

Running a MS2000 inverter/charger to support brief use of induction hotplate, elec. tea kettle, and a nespresso machine (yes I said it !)...

I've indicated some rough distances on the cable runs as well. Interested in any feedback for sure.
View attachment Sprinter-ElecSys.pdf
 

Attachments

Last edited:

casmith32

Member
DirtDevil Build Electrical system critique requested

Thanks @ Midwestdrifter ! much appreciated. Have a couple follow ups....

1 - "10/3 is not needed for max 15A outlets"
==> I apologize for the confusion; That was intended to mean "3-conductor wire"; so if I was using house wire - yes it'd be 10/2 technically - marine wire seems to not "imply" a third wire exists like house wire - so I was just being explicit here as I may use marine wire...

2 - "Ground and AUX negative should be bonded, so either is acceptable. "
==> Not quite clear as to what the answer here is - do you mean that is okay to ground the battery isolator/charge relay to the chassis ground OR the house/aux neg busbar ?

3 - "Consider connecting inverter directly to shunt."
==> interested in the reasoning for this just for my education - I can see the advantage of one less hop in the path, but the positive is still going through the busbar. Is the idea to keep the number of "hops" in the path equal ?

I've also had suggestions to run the inverter pos+ straight to the battery, as well as the solar charge controller, for best charging performance. Does that jive ?

My goal was to have the busbars and shunt in the driver seat, to leave room to expand my battery bank in the future ; either adding two more in the passenger seat, or moving the battery bank in the future if needed. My thought was that it would be easier from a connectivity standpoint, minimizing the large runs to the batteries; thoughts on that ? Is also terminating the Solar charge controller to the busbars detrimental ? I realize it's sub-optimal.

4 - "You need a Chassis ground connected for Alternator charging. "
==> Are you implying that the Neg Busbar for the house/aux system needs to be grounded to the chassis ? I thought that would lend potential for grounding loops ? I want to keep the vehicle and house systems separate.

Another question around the alternator charging is how various charge relays/isolators deal with the flat voltage curve of the LifePo4 battery with respect to charging? I'm trying to find one that's compatible...

5 - " Move to other side of shunt" - not quite clear as what you are referring to ?

6 - Breaker for Solar feed from MPPT controller - "Closer is better, as unprotected wire is undesirable. I think AYBC allows for 2ft? If you sufficiently protect the wire from possible damage you can go farther. You might consider attaching the + cable after the disconnect switch. "
==> Understood ! However I thought this is okay since the majority of flow is charging the battery, vs drawing from the battery. Thus I'd want to protect closer to the MPPT controller since it's sending potential large loads.

7 - Portable Solar connection - See your point. I'd be potentially be using the flexible version of the 100W panel, which is close in specs. OR I may just move the connection to terminating directly on either the batteries or busbar in the driver seat; and use a zamp solar portable unit with controller. I'm assuming there won't be any "fighting" going on between the two solar charge controllers if they are both actively charging ? Has anyone seen any issues with that ? My preference is to have one controller in the mix...

8 - "For best charging connect as close to alternator a possible. Fuse to protect your wiring. Choose wiring for expected load and desired voltage drop. 150A works for 2 gauge and should handle any expected alternator charging load. "
==> perfect thanks - my intent is to come off the same terminal 4 on the pre-fuse block, similar to what the aux battery retrofit says. And obviously fuse it as suggested.


Great comments - thanks again !!


I have reviewed your diagram. Attached is a markup with my suggestions. :cheers:
 

Midwestdrifter

Engineer In Residence
Let me explain my notes further.

1. I was referring to the wire size. For 15A service 14 or 12 gauge is the most you would need. For runs under 20 ft 14 gauge would work fine. If you are using 15A outlets and appliances you should have a 15A breaker or fuse for them. Blue sea has a nice 3 circuit 15A/120v breaker panel.

2. If you intend to charge from your alternator you MUST have the chassis and AUX grounds connected. You wouldn't only connect the positive cable on a battery charger and expect it to work?

3.For high current users you want to reduce the resistance of the DC wiring as much as is reasonable. This means reducing both wire length AND connections. Each connection/termination/splice add a small amount of resistance. There is no reason to go directly to the battery unless it substantially reduces your cable length or removes a number of connections. The reason I suggested going directly to the shunt is that it MIGHT remove a connection. If your shunt is not close to your buss bar, then its a moot point.

Since you are using properly sized cables, there is no need to run your solar charger directly to the battery unless it substantially reduces cable resistance/length. Even then, its a reducing returns situation as the 4/0 cable is very low resistance. For example I have 4ftx2 of 4/0 cable between my batteries and my chargers/consumers. This is due to my batteries be underbody mounted. My solar controllers and inverter are connected to the shunt/buss-bar.

4. Yes See item 2. You cannot use alternator current without a path to the vehicle ground. Regarding charging due to the higher voltage of lithium batteries, your isolator may not open until they are discharged somewhat. This probably wont be an issue, but again I have never used lithium packs like yours. Does your battery monitor have a programmable output? If you so you could use it to trigger an isolator on/off based on voltage or SOC setpoints.

5. All current on the negative side MUST go through the shunt. Your solar negative wire bypasses the shunt, so you battery monitor cannot see the charging current.

6. You have 2 sources on this wire. However the batteries are by far the highest current source. The fault current for the solar controller is not very high. But the batteries is VERY large. If the wire faults to ground between the breaker and the battery a fire could result. The breaker is designed to protect the wire. Having lots of unprotected wire on the battery side of the breaker is not good design practice.

7. The controllers wont fight each other any more than the alternator and the solar controller will. They should ideally have similar setpoints.

Another note, you might consider running your 2/0 isolator cable to the other side of your disconnect switch. The point of a disconnect is to remove all power from the system in an emergency or during servicing.
 

raisin

New member
i am working on an approach very similar to your elec system but will start a new thread so as not to encroach on yours. thanks for posting
 

casmith32

Member
Let me know your thread when you do - But I don't consider it encroachment at all !! the more collaboration the better IMO....

i am working on an approach very similar to your elec system but will start a new thread so as not to encroach on yours. thanks for posting
 

casmith32

Member
Once again - thanks for the explanations. I really appreciate folks taking the time out of their day to help review this !! Totally get what you are saying now...

On the chassis / AUX grounding question - I was mainly confused on when you said "either is acceptable" - but now I see you mean only if chassis and AUX grounds are connected. Assuming this implies grounding the Neg busbar to chassis ground ? Are there any significant risks or future complications, or what I like to call "Oh by the ways" - that I need to consider with bonding the chassis and AUX grounds ?

On the DC wiring issue - yea I see what you are saying - the most length I'd cut out is just the distance between the two seat pedestals - so approx 2ft or so... my shunt will be in the driver seat pedestal with the busbars - so this should be good then, I can remove one connection from the inverter neg lead. Now there will be the same number of connections points (pos+ on busbar, neg- on shunt) b/t the inverter and batteries...

I didn't catch the issue with connecting the solar charger behind the shunt; I was so focused on power draw, I forgot about being able to monitor charging current as well... thanks for resetting my thinking on that !

I'll make modifications to the design and repost later this evening for review. I wanna make sure this is right before starting anything. I've learned, that while it may extend out build time, taking the time to draw up, and validate a sound plan is crucial to mitigating issues down the road and more importantly, safer!!


Let me explain my notes further.

1. I was referring to the wire size. For 15A service 14 or 12 gauge is the most you would need. For runs under 20 ft 14 gauge would work fine. If you are using 15A outlets and appliances you should have a 15A breaker or fuse for them. Blue sea has a nice 3 circuit 15A/120v breaker panel.

2. If you intend to charge from your alternator you MUST have the chassis and AUX grounds connected. You wouldn't only connect the positive cable on a battery charger and expect it to work?

3.For high current users you want to reduce the resistance of the DC wiring as much as is reasonable. This means reducing both wire length AND connections. Each connection/termination/splice add a small amount of resistance. There is no reason to go directly to the battery unless it substantially reduces your cable length or removes a number of connections. The reason I suggested going directly to the shunt is that it MIGHT remove a connection. If your shunt is not close to your buss bar, then its a moot point.

Since you are using properly sized cables, there is no need to run your solar charger directly to the battery unless it substantially reduces cable resistance/length. Even then, its a reducing returns situation as the 4/0 cable is very low resistance. For example I have 4ftx2 of 4/0 cable between my batteries and my chargers/consumers. This is due to my batteries be underbody mounted. My solar controllers and inverter are connected to the shunt/buss-bar.

4. Yes See item 2. You cannot use alternator current without a path to the vehicle ground. Regarding charging due to the higher voltage of lithium batteries, your isolator may not open until they are discharged somewhat. This probably wont be an issue, but again I have never used lithium packs like yours. Does your battery monitor have a programmable output? If you so you could use it to trigger an isolator on/off based on voltage or SOC setpoints.

5. All current on the negative side MUST go through the shunt. Your solar negative wire bypasses the shunt, so you battery monitor cannot see the charging current.

6. You have 2 sources on this wire. However the batteries are by far the highest current source. The fault current for the solar controller is not very high. But the batteries is VERY large. If the wire faults to ground between the breaker and the battery a fire could result. The breaker is designed to protect the wire. Having lots of unprotected wire on the battery side of the breaker is not good design practice.

7. The controllers wont fight each other any more than the alternator and the solar controller will. They should ideally have similar setpoints.

Another note, you might consider running your 2/0 isolator cable to the other side of your disconnect switch. The point of a disconnect is to remove all power from the system in an emergency or during servicing.
 

Midwestdrifter

Engineer In Residence
Once again - thanks for the explanations. I really appreciate folks taking the time out of their day to help review this !! Totally get what you are saying now...

On the chassis / AUX grounding question - I was mainly confused on when you said "either is acceptable" - but now I see you mean only if chassis and AUX grounds are connected. Assuming this implies grounding the Neg busbar to chassis ground ? Are there any significant risks or future complications, or what I like to call "Oh by the ways" - that I need to consider with bonding the chassis and AUX grounds ?

On the DC wiring issue - yea I see what you are saying - the most length I'd cut out is just the distance between the two seat pedestals - so approx 2ft or so... my shunt will be in the driver seat pedestal with the busbars - so this should be good then, I can remove one connection from the inverter neg lead. Now there will be the same number of connections points (pos+ on busbar, neg- on shunt) b/t the inverter and batteries...

I didn't catch the issue with connecting the solar charger behind the shunt; I was so focused on power draw, I forgot about being able to monitor charging current as well... thanks for resetting my thinking on that !

I'll make modifications to the design and repost later this evening for review. I wanna make sure this is right before starting anything. I've learned, that while it may extend out build time, taking the time to draw up, and validate a sound plan is crucial to mitigating issues down the road and more importantly, safer!!
Regarding Chassis grounding; I cannot think of any downsides with one exception. Because your entire frame is grounded any positive wire shorting to the body will cause a fuse/breaker trip. Of course properly run/designed wiring essentially eliminates this issue. One positive of bonding the negatives/grounds is that you can use the chassis to carry negative current. This can be useful as do not need a negative return wire for some runs.

There is no reason/need to "balance" the number of connections on any DC run with one exception. The interconnect wiring between your 2 batteries should be the same total length and number of connections. This prevent uneven charging and loading of the batteries. You seem to have a good grasp of this as the negative/positive take leads are on different batteries.
 

casmith32

Member
Posting the latest revision with suggested updates.... still have some considerations to make but hoping this update is a bit more sound...

- Moved DC- of inverter directly to shunt
- Moved ext solar connection directly to batteries - will be located on right side of van
- Added 12v-led leads from Blue Sea AC breaker panel
- Added remaining DC neg leads for devices
- Added grounding from DC neg busbar to chassis ground to support alternator charging
- Updated AC outlets to include just one GFCI at beginning of string.

Still to do
==========
Still undecided on model of alternator battery isolator, and location, etc. Need to figure out options for charging LifePo4 batts...

Validate all wiring lengths and sizes for intended loads.

View attachment Sprinter-ElecSys-Rev2.pdf
 

Midwestdrifter

Engineer In Residence
Posting the latest revision with suggested updates.... still have some considerations to make but hoping this update is a bit more sound...

- Moved DC- of inverter directly to shunt
- Moved ext solar connection directly to batteries - will be located on right side of van
- Added 12v-led leads from Blue Sea AC breaker panel
- Added remaining DC neg leads for devices
- Added grounding from DC neg busbar to chassis ground to support alternator charging
- Updated AC outlets to include just one GFCI at beginning of string.

Still to do
==========
Still undecided on model of alternator battery isolator, and location, etc. Need to figure out options for charging LifePo4 batts...

Validate all wiring lengths and sizes for intended loads.

View attachment 71333
Looking good. Much better than the hand drawn Diagrams I did on scrap paper. :smilewink:

A couple of things I noticed.

1. The negative bus to ground wire should be sized to carry all of your alternator charging load. 16 gauge is definitely to small for the 150A fuse you have on that circuit.

2. You should have branch protection on your AC outlets. The 30A breaker and 10/3 are sufficient for main protection. However your outlets and the connected devices cannot handle 30A. You need at least one 15A breaker (or more if you want separate circuits). Optionally you could just install a 120V rated 15A fuse to save space.

3. It was probably a simple oversight, but your portable solar negative bypasses the shunt. :tongue:

4. With 10 and 8 gauge wiring connector your solar panels, I am not sure you need a breaker on the panel side of the controller. The reason for this is that the maximum fault current for your panels is 18A or so, which is not a problem for 10 gauge. If you want disconnect ability a switch would work just fine.

Regarding your battery isolator. Your lithium batteries have a built in BMS correct? If this is the case, an automatic/intelligent isolator may not be needed. Instead an isolator wired to close whenever the engine runs would probably work just fine. If you don't let your vehicle set for months at a time and you don't have any loads on your chassis battery, you mostly likely won't need the bi-directional operation of a smart isolator.
 

calbiker

Well-known member
You have a total of 100AH battery capacity and a 2000W inverter. That's not a good fit. Why do you need a 2000W inverter? Per your description, max continuous battery current is 50A, or 100A for two batteries. Yet the 2000W inverter will pull 166A max. The positive inverter output/input should go directly to the batteries.

Is your 2015 Sprinter alternator capable of supplying high currents to the house batteries? There have been some discussions that current is limited.

You have a 300A fuse connected to house batteries. Why did you choose 300A? Not all shorts are "hard shorts". A 200A fuse should be adequate.

Why do you have a 500A dc shunt? The batteries can only supply 100A. Is a 200A shunt more appropriate?

10/3 AWG for ac conductors is over kill. The ground conductor is also usually smaller.

Do you have a handle on your loads? What's your AH usage per day? What does the fridge take? How low can you take those batteries. Are they adequate?
 

casmith32

Member
DirtDevil Build - Electrical

Great questions - I'll try and answer the best I can:

2000W inverter was the result of wanting to run an induction hot plate, elect tea kettle, and coffee maker (not all at the same time). And for short periods of time - The hot plate will draw upwards of 1800W, thus the need for the 2000W inverter. I purchased from AM Solar, along with my solar setup. I'll probably be adding another 100W panel for a total of 300W of solar.

I'd done the calcs and spoken to multiple folks at Zamp Solar, and AM Solar who are familiar with these types of builds; they helped me spec things out based on my expectations. Max power draw will be the induction hot plate, and only at maybe 15-20 mins once or twice a day -

Batts are Lithium ion - I also went with 2000W inverter with the understanding that I have the option to expand my battery bank to 200Ah - all under the passenger seat, depending on how things go. Idea is that with 200-300W solar or shore power, LifePo4 batteries will charge faster and have more effective capacity than AGM banks. we'll see ! Beyond the induction hotplate and tea kettle, the fridge will be the constant draw, with the other consumers varying with weather, and day/night.

300A T-Fuse was both what AM Solar and Magnum recommends for this inverter; As well as the 4/0 cabling. I realize it's high, but it's the manufacturer's recs due to the 3300W surge capacity (275A). To your point, given the current max capable draw of 100A from my battery bank, I could use a 100A fuse, and bump it to 200A when I add to the battery bank? Or just go to a 200A fuse.

Assuming this would also allow me to use 200 - 250A busbars vs 300+ ones which I'm finding are way more expensive.

And if I do all that, I'd ask if you think that 4/0 cabling is overkill and I could probably go with 2/0 cabling which is rated to 200A up to 20Ft.; well beyond the length I need

Seems like the basic premise here is that it's safe to base fuse and cabling sizes off the Max battery discharge rate ? in my case 100A-200A ? and that manufacturer's specs are obviously based on theoretical maximums - for safety reasons..so my battery specs are what I should be basing sizing on ?

Shunt - same deal as with the T-Fuse - came with the inverter package - they go with max specs when determining the parts for the kits they sell.

AC output from the inverter - yep - that was a mistake on the diagram... that MidwestDrifter caught for me - switched it to a 15A breaker and 14AWG wiring for the 120v outlets.

As for the Neg bus Ground, yea that was based on if I needed to ground the neg busbar to chassis for the battery isolator/alternator charging to work properly - was matching up the wire size for expected 150A alternator output specs which I was basing off the MB Aux retrofit guide and the fact that they fuse position #4 on the pre-fuse block (in diagram) @ 150A. I'm fully aware that I could be way off base on my interpretation of that though - any help is appreciated.

I am questioning the need to bond the DC neg busbar to chassis - I'd prefer to isolate the two completely. It was suggested that the alternator charging setup (which I've not really ironed out completely for LifePO4 batts - questions around that), required chassis ground. But I'm not sure it needs to be both at the isolator/charge relay itself, and the DC neg busbar ?

Inverter leads - I was trying to minimize cabling to the battery bank/passenger seat pedestal; locating the busbars and other connectivity under the driver's seat makes it easier to relocate my battery bank in the future if I need / wanna go beyond 200Ah in the future. Thought was that with 4/0 cabling between the busbars and the batteries, there is minimal drop given the amperages I'd be pulling - 200A max - So not sure it's pivotal to terminate the inverter directly on the battery positive unless I'm missing something; added resistance should be minimal I'd think...even if I drop the cables to 2/0. I realize it's best practice to minimize hops / resistance on anything electrical though..so I'm interested in more thoughts on that.


thanks for your questions ! Appreciate the time to review this. Made me rethink and question some things - new diagram coming in a bit...for more critique...

You have a total of 100AH battery capacity and a 2000W inverter. That's not a good fit. Why do you need a 2000W inverter? Per your description, max continuous battery current is 50A, or 100A for two batteries. Yet the 2000W inverter will pull 166A max. The positive inverter output/input should go directly to the batteries.

Is your 2015 Sprinter alternator capable of supplying high currents to the house batteries? There have been some discussions that current is limited.

You have a 300A fuse connected to house batteries. Why did you choose 300A? Not all shorts are "hard shorts". A 200A fuse should be adequate.

Why do you have a 500A dc shunt? The batteries can only supply 100A. Is a 200A shunt more appropriate?

10/3 AWG for ac conductors is over kill. The ground conductor is also usually smaller.

Do you have a handle on your loads? What's your AH usage per day? What does the fridge take? How low can you take those batteries. Are they adequate?
 

casmith32

Member
Updated electrical design v3 - it's evolving !!! Appreciate everyone's input !! Digging the process here...

Changes:
- simplified DC connectivity to single fuse panel, with SPST switches
- updated AC output to 15A and 14AWG cabling
- Replaced breaker b/t PV and PV charge controller with on/off switch

Still some questions based on Calbiker's comments... mostly around sizing of cables and fuses given anticipated 200Ah battery bank in future vs going with all out full manufacturer's (Magnum Energy) recommendations based on max config.

Thanks!!

View attachment Sprinter-ElecSys-v3.pdf
 

Graphite Dave

Dave Orton
Updated electrical design v3 - it's evolving !!! Appreciate everyone's input !! Digging the process here...

Changes:
- simplified DC connectivity to single fuse panel, with SPST switches
- updated AC output to 15A and 14AWG cabling
- Replaced breaker b/t PV and PV charge controller with on/off switch

Still some questions based on Calbiker's comments... mostly around sizing of cables and fuses given anticipated 200Ah battery bank in future vs going with all out full manufacturer's (Magnum Energy) recommendations based on max config.

Thanks!!

View attachment 71476
Quick look.

Usually the battery connection has the fuse before the disconnect switch. Reverse the positions of the fuse and disconnect?

I have a single 300 watt high voltage solar panel with two roof holes. Eliminates the connector box and makes mounting easier. I retain the panel MP4 quick disconnects that are located between the roof penetrations and the panel. Bought a 15' solar extension cable with the male and female ends that I cut in two to get the cables that run through the roof holes. Disadvantage is more potential loss from shading.

Super nice job of documenting the diagram.
 

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