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Hey all,

I attached my draft for the electrical diagram on my current buildout of a 2016 159 HR. This part of the build boggled my brain more than all others thus far. Any comments/suggestions are greatly appreciated. We will be living in our van full time but our needs are quite basic. Some specific questions:

1. Is this a sufficient way to ground everything?
2. Are the circuit breakers I have picked out sufficient/excessive?
3. I want to have one 110v outlet connected to my inverter. Can I do this with a standard extension cord? DC research took all my brain power and I haven't figured out yet the easiest/safest way for this. I'd rather not hardwire the inverter and utilize the existing three prong outlets.
4. Any red flags with the wire sizing and configurations?

This forum as been a huge resource already! Prior to this project I've never picked up a power tool as an adult (I come from a long line of accountants). I have an electrician friend helping me install this in about five days; however, he specializes in very high voltage systems so not sure how much help he will be with the DC stuff. The van is coming along nicely so far but if it wasn't for this forum, YouTube and blogs I'd surely blow myself up by now.
 

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A few issues, 4 gauge is not sufficient for your batter connections to a 2000 w inverter. You need 1/0 or larger from the battery to the bus bar and the bus bar to the inverter. You should also have a 1/0 from the bus bar to chassis ground. (your friend the electrician will know this, as current is current regardless of voltage).

Second, I am not sure what your BMS is, or what it does?

IF it is monitoring battery state and current then all negative connections to the battery will need to go through it, so get rid of both the 4 gauge to the bus bar and the 8 guage through the BMS and just connect at least a 1/0 through the bms to the bus bar. This is assuming what you are calling a BMS is a monitor. I am not sure from either your description or diagram. If it is something else, I am not sure.
 

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3. I want to have one 110v outlet connected to my inverter. Can I do this with a standard extension cord?
A 2000 watt inverter at 110 volts supplies around 18 amps. If you use a 12 gauge extension cord you will be fine. However most Big-Box store extension cords are 14 gauge or smaller, so watch what you buy.
 

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Thanks and great points Jracca. The 4awg actually came with the inverter (Renogy) so should I ditch it for the stronger stuff? I’ll definitely get stronger wire for the grounding then.
And you are correct about the BMS. I’m not so happy with it (built in 8awg) and it’s a cheaper one. Will probably be returning. If not I’ll need to remove the battery to negative bus wire.
 

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A 2000 watt inverter at 110 volts supplies around 18 amps. If you use a 12 gauge extension cord you will be fine. However most Big-Box store extension cords are 14 gauge or smaller, so watch what you buy.
Thanks Larry. I’ll try and find one online.
 

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Hi,
What kind of 12 volt heater is connected to the DC fuse panel? All of your other 12 volt loads are pretty small, and if the 12 volt heater load is for (say) the fan on a propane or fuel heater, than the 4 AWG wires to the DC fuse panel seem large. You want to add up the 12 volt loads that could be on at the same time, add 20% or so, and then pick the wire and fuse size for the DC panel accordingly. The BlueSea Circuit Wizard makes it easy to pick the right size wires.

The only source of charging I see is solar? This will leave you with a flat battery whenever you are not getting good sun. Most people have at least the van alternator charging, and with these very expensive batteries, this probably means a battery to battery charger to lessen the chance of damaging the Li batteries. Charging with shore power is also commonly used, in which case you probably want to go from an inverter to an inverter/charger.

You also don't show any way to power AC appliances from shore power -- this is OK as long as you don't think you will want to do this.

This is just a caution and feel free to ignore it, but bear in mind that people (especially ones new to electrical systems) tend to end up destroying their first (and sometimes 2nd:) set of batteries -- this is not so bad if its a couple of $90 Flooded Lead Acid batteries, but would be kind of painful if they are $1000 each Li batteries. You might consider starting with a couple of golf cart batteries and then upgrade to the Li's after a while getting used to them. Just a thought.

Gary
 

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Thanks and great points Jracca. The 4awg actually came with the inverter (Renogy) so should I ditch it for the stronger stuff? I’ll definitely get stronger wire for the grounding then.
And you are correct about the BMS. I’m not so happy with it (built in 8awg) and it’s a cheaper one. Will probably be returning. If not I’ll need to remove the battery to negative bus wire.
I would be interested in knowing about that BMS, it sounds like junk (please don't take it as an insult since I am assuming you didn't make it). 8 gauge can't handle the load you will put on it, and it doesn't work right if you bypass it.

4 gauge wire with a 2000 watt inverter sounds like borderline negligence. 2000 watts of load will draw over 150 amps from the battery. 4 gauge is not reasonable for 150 amps. Perhaps renogy knows that their inverter can't really put out 2000 watts, in which case it is fraud rather than negligence.

I don't know what your usage will be like but if your only charging source is solar you are likely to be unable to charge your batteries if you have heavy use. If you don't have heavy use then 200 AH of ultra expensive lithium batteries is probably a poor choice. If you have heavy use, 300W of solar as your only charging source is not sufficient as Gary points out.

I am not against lithium batteries, I have a 600 AH set of lithium batteries in my van, but my use is heavy. I have battery to battery charging, 400W of solar on the roof, and the ability to charge at 120 amps from shore power. I have multiple battery protection systems to prevent low temperature charging, an active battery ventilation system to keep the batteries warm or cool, and an extensive system to monitor them. And even with all my planning and knowledge, I probably could have just had a 400AH system because I never seem to need the air conditioner as much as I thought I might. I am considering pulling one of my 3 200 AH batteries and using it for something else (can save me 70 pounds and free up a little space)
 

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To follow up on what Gary has said it is a good idea to divulge what all your uses will be and the time they will be used so we can give more basic advice. If lithium is your plan despite whether you need it’s capacity or ability to provide large loads then sizing is the only issue. Lithium set ups are becoming more plug and play but if you plan to adapt things like BMS and B to B etc. then I hope you have electrical design skills to avoid Gary’s concern about battery failure by unintended misuse. The sellers say lithium batteries will last 10-20 years but we have seen several failures on here already. Remember you can build a $700 complete electrical system, less than the price of one 100 A-H lithium battery. It depends on your needs and desire.
 

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One thing I don't see is any way the BMS can disconnect the batteries if there is a problem. If all your "BMS" is doing is monitoring state-of-charge, it's not really a BMS. If those batteries are "smart" batteries like the BattleBorn you are OK, but if they are discrete cells like what I put in my system, they need a true BMS with high-current contactors that can disconnect the batteries from charging if they overvolt or are too cold, and disconnect them from discharging if they undervolt or overheat. For your battery to ground connection - one, that wire is too skimpy; you are potentially running several hundred amps through it so it should be at least 1/0 (I used 4/0 in my system). If what you are calling a "BMS" is just the shunt for a monitor, the battery negatives go to it, and then it goes to the ground bus - all current through the batteries must pass through the shunt to be measured.
You may also want a disconnect switch somewhere that totally disconnects power, for storage and service. If the current limiting elements you show are actual breakers that can be turned off, that may suffice, but having an actual master disconnect is better.
Lastly, you may want to consider a charging path from the alternator to the batteries. At a minimum, it needs to be a high current contactor that switches on when the engine is running (not JUST in the run position, but actually running), and it probably should be an actual DC/DC converter rated to charge LiMnFePO4 batteries. When you are driving, you may as well use that power.
 

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Thanks and great points Jracca. The 4awg actually came with the inverter (Renogy)
According to the Renogy web site you should have received a negative cable made up of 2 short 4AWG wires in parallel and a positive cable made up of 2 short 4AWG wires in parallel.
 

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Wow, thanks for all the feedback guys. Some updates, you guys convinced me to connect the alternator. I'll also be returning the BMS as it clearly doesn't have the structure in place for this large of a system. I'll also get larger wires grounding lines. The Renogy cables are actually 4x2AWG. Is that sufficient? If not I will replace. Hoping to have an updated diagram to send out later today.

Honestly, figuring out solar overwhelmed me so I've been postponing looking at DC to DC system from the alternator. But you're right, it's there, I should use it. We are mainly off grid campers and I don't need to be at the mercy of the sky all the time. If you have one you recommend for my batteries (link below) I'd be all ears. My challenge has been and continues to be these batteries. I've debated trying to go with a simpler system but I guess I'm committed to making them work. I did spend $1100 for both, because a friend had them in storage, never used, because he'd overestimated his own needs. So at the time, when I was less researched, seemed like a worthwhile investment. Hopefully it will be down the road but the verdict isn't out. I need to check what size my alternator is. It's a 2016 2500 eco diesel but I bought it used so I'll have to investigate.


My Renogy charge controller seems to be able to tell me battery capacity and temperature from the app. However, it's not a BMS and can't control current flow, shut off, optimization. So trying to find something that I can connect with these batteries that doesn't break the bank. Especially to protect them if I also have power coming from the alternator. So anybody that enjoys solving these kinds of riddles feel free to speak up. Thanks!
 

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Hi,
What kind of 12 volt heater is connected to the DC fuse panel? All of your other 12 volt loads are pretty small, and if the 12 volt heater load is for (say) the fan on a propane or fuel heater, than the 4 AWG wires to the DC fuse panel seem large. You want to add up the 12 volt loads that could be on at the same time, add 20% or so, and then pick the wire and fuse size for the DC panel accordingly. The BlueSea Circuit Wizard makes it easy to pick the right size wires.

The only source of charging I see is solar? This will leave you with a flat battery whenever you are not getting good sun. Most people have at least the van alternator charging, and with these very expensive batteries, this probably means a battery to battery charger to lessen the chance of damaging the Li batteries. Charging with shore power is also commonly used, in which case you probably want to go from an inverter to an inverter/charger.

You also don't show any way to power AC appliances from shore power -- this is OK as long as you don't think you will want to do this.

This is just a caution and feel free to ignore it, but bear in mind that people (especially ones new to electrical systems) tend to end up destroying their first (and sometimes 2nd:) set of batteries -- this is not so bad if its a couple of $90 Flooded Lead Acid batteries, but would be kind of painful if they are $1000 each Li batteries. You might consider starting with a couple of golf cart batteries and then upgrade to the Li's after a while getting used to them. Just a thought.

Gary
Good point, it is a diesel heater so I'll look into the right wire size for the Blue Sea DC Fuse Panel.
 

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Wow, thanks for all the feedback guys. Some updates, you guys convinced me to connect the alternator. I'll also be returning the BMS as it clearly doesn't have the structure in place for this large of a system. I'll also get larger wires grounding lines. The Renogy cables are actually 4x2AWG. Is that sufficient? If not I will replace. Hoping to have an updated diagram to send out later today.

Honestly, figuring out solar overwhelmed me so I've been postponing looking at DC to DC system from the alternator. But you're right, it's there, I should use it. We are mainly off grid campers and I don't need to be at the mercy of the sky all the time. If you have one you recommend for my batteries (link below) I'd be all ears. My challenge has been and continues to be these batteries. I've debated trying to go with a simpler system but I guess I'm committed to making them work. I did spend $1100 for both, because a friend had them in storage, never used, because he'd overestimated his own needs. So at the time, when I was less researched, seemed like a worthwhile investment. Hopefully it will be down the road but the verdict isn't out. I need to check what size my alternator is. It's a 2016 2500 eco diesel but I bought it used so I'll have to investigate.


My Renogy charge controller seems to be able to tell me battery capacity and temperature from the app. However, it's not a BMS and can't control current flow, shut off, optimization. So trying to find something that I can connect with these batteries that doesn't break the bank. Especially to protect them if I also have power coming from the alternator. So anybody that enjoys solving these kinds of riddles feel free to speak up. Thanks!
You will need a sophisticated battery management system for those batteries. They are not drop in and they are not going to tolerate much abuse. They are not like the LiFePO4 batteries sold by battleborn and other companies for RV type use. They are a lighter weight (good) lower cycle life (bad) style of battery. Ultimately not the best choice for an RV system.

Because you have two 'batteries' you will need a BMS that can either handle cells in parallel or a BMS for each of the batteries. I would probably connect the cells in parallel and then in series and make one large battery if I was attempting to go forward with these batteries. I would not go forward with these batteries. The balance of the system to use these will cost more than buying some AGM batteries.

Setting these up and getting it right is not a job for a novice. It is a job for someone with a lot of knowledge about battery technology and electronics. I can't see a path where setting these up for an RV makes a lot of sense. Unless you are willing to either hire or study to be an expert in battery management systems and lithium batteries.

I have work experience as an electrician and an electrical engineering degree and I would probably NOT attempt to use these in an RV (I have LiFePO4 batteries, but I did not build the internal BMS myself and mine use cylindrical cells which are a bit more tolerant to abuse). These are simply four cells bolted together for you to build a battery out of. Not at all an impossible task, but based on your inquiries it does not appear you have the knowledge (you can certainly learn if you are willing). A lithium battery is nothing like a lead acid or AGM battery. Those batteries need very little external management because they have internal resistiance that self governs their currents, lithium batteries have almost none and need circuitry to manage and monitor their state of charge, temperature, and balance the cells.
 

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You will need a sophisticated battery management system for those batteries. They are not drop in and they are not going to tolerate much abuse. They are not like the LiFePO4 batteries sold by battleborn and other companies for RV type use. They are a lighter weight (good) lower cycle life (bad) style of battery. Ultimately not the best choice for an RV system.

Because you have two 'batteries' you will need a BMS that can either handle cells in parallel or a BMS for each of the batteries. I would probably connect the cells in parallel and then in series and make one large battery if I was attempting to go forward with these batteries. I would not go forward with these batteries. The balance of the system to use these will cost more than buying some AGM batteries.

Setting these up and getting it right is not a job for a novice. It is a job for someone with a lot of knowledge about battery technology and electronics. I can't see a path where setting these up for an RV makes a lot of sense. Unless you are willing to either hire or study to be an expert in battery management systems and lithium batteries.

I have work experience as an electrician and an electrical engineering degree and I would probably NOT attempt to use these in an RV (I have LiFePO4 batteries, but I did not build the internal BMS myself and mine use cylindrical cells which are a bit more tolerant to abuse). These are simply four cells bolted together for you to build a battery out of. Not at all an impossible task, but based on your inquiries it does not appear you have the knowledge (you can certainly learn if you are willing). A lithium battery is nothing like a lead acid or AGM battery. Those batteries need very little external management because they have internal resistiance that self governs their currents, lithium batteries have almost none and need circuitry to manage and monitor their state of charge, temperature, and balance the cells.
Really appreciate the expert advice. I'm a novice. I'd be an idiot to not admit that. So, I'm starting over with the batteries and looking into something better for a first timer. Thanks, feel free to suggest something budget friendly for me!
 

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Hi,
I think your best bet would be to go back to the beginning and add up all of your loads. There is a link to a spreadsheet to help you do that about half way down this page: Sizing the Electrical Components for Your Camper Van – Build A Green RV
Also some info on battery options on the same page.

It varies a lot of course, but a number of people have found that two 6 volt, 220 amp-hr golf cart batteries hooked in series to make a 12 volt battery is a good and cheap option. Costco and Walmart both sell them for about $90 each.

If you end up using FLA or AGM batteries you will have to decide how far they can routinely be discharged. I think a pretty good rule of thumb is that for a routine day/night, don't go much below 50%, but for the unusual or worst case day/nights its OK to take them down to 80% discharge -- they will still deliver several hundred cycles going down to 80% discharge.

Gary
 

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Really appreciate the expert advice. I'm a novice. I'd be an idiot to not admit that. So, I'm starting over with the batteries and looking into something better for a first timer. Thanks, feel free to suggest something budget friendly for me!
Gary's advice is very good. You can easily start with some flooded lead acid from walmart if you don't mind checking the water level in the batteries every month. Be honest with yourself, if you won't check the fluid and add ONLY distilled water when needed, then get an AGM battery. But if you can commit to the maintenance then 4 flooded batteries from walmart would be a huge 440 amp hour bank (2 in series, 2 series strings in parallel) for less than $450. If you figure your usage and can get by with 2, then 220 amp hours is still pretty big, but figure on using onle 110 most of the time.

Start with figuring your usage. The big draws (continuous) I see are fans, heater, and fridge. Everything else is usually either a low draw or only used for short periods of time so it doesn't add up to much, because you don't run a blender for long. If you get a laptop charger that can run off 12 volts you can probable keep the inverter turned off until you need it. It can draw 20 amp hours just sitting by idling even with no load. I've gone to almost all 12 volt stuff and only turn on the inverter when needed (not very often really).

If you know what you will use you can design around it. Also do you plan to drive every day, if you do you can figure on getting some charging done from the alternator as you drive. If you are parked in one place for several days you need to be reliant more on the solar. Figure on getting no more than 70% of the rated capacity off the panels if they are mounted flat. Figure the average sun hours where you plan to operate, remembering you get more in summer and less in winter. Solar Insolation Map: How Many Sun Hours Do You Get? | Wholesale Solar

Using an average of 4 sun hours, you can expect about 300 w x 4 hr x 70% or 840 watt hours or (840 w / 12V) 70 amp hours of charging on sunny days. This varies a lot though. in the summer more, in some areas more, in the winter less. When it rains, much less.

Batteries can charge off the alternator when driving, so if you plan to drive every day you can get by with a smaller battery bank. Figure you only need one day to two days capacity if you plan to move around, I would plan on a little more if you don't and just know you can run the engine occasionally if you are without sun.

Normally camper van electrical usage is figured in amp hours because battery capacity is stated in amp-hours. For an example when I am not running my air conditioner but am in the van I use about 80 amp hours a day. This is split mostly between either the fan or heater( a gasoline webasto ) (30) and the refrigerator (40) with small amounts of other things.
 

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Your alternator is a 220 Amp. All diesels have that.
I’d welcome you to look at my thread “$500 solar and $700 complete electrical system” it may not work for you but the basics are there and it can be expanded. Estimate your use first and get back to us. I’d ask my friend to take the batteries back or resell them on craigs list if you decide to go a lead acid battery direction. You may be in over your head here.
 

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Your alternator is a 220 Amp. All diesels have that.
I’d welcome you to look at my thread “$500 solar and $700 complete electrical system” it may not work for you but the basics are there and it can be expanded. Estimate your use first and get back to us. I’d ask my friend to take the batteries back or resell them on craigs list if you decide to go a lead acid battery direction. You may be in over your head here.
Just gave it a read and some searching. Can't find any details on how you vented them. Mind sharing? Right now my battery bank is to be located on a box I built that covers the wheel well. The price and ease appeals to me and I don't mind maintaining them. Sounds like it would be a lot easier to connect me alternator to it too. What percent is it safe to draw them down to? I know the AGM is 50% suggested. Already in the works on ditching these complicated Lithiums.
 

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Just gave it a read and some searching. Can't find any details on how you vented them. Mind sharing? Right now my battery bank is to be located on a box I built that covers the wheel well. The price and ease appeals to me and I don't mind maintaining them. Sounds like it would be a lot easier to connect me alternator to it too. What percent is it safe to draw them down to? I know the AGM is 50% suggested. Already in the works on ditching these complicated Lithiums.
AGM and lead acid batteries are both the same basic chemistry, and 50% will give long life, but don't be afraid to draw down to 80% occasionally. Even if you treat them perfectly and only go to 50% they will wear out due to time. If you go much past 80% you are looking at a quite short life.

I can't speak to how others do ventilation as I am running a very complicated lithium setup. (I have air conditioning that runs off the batteries).

Generally you want to allow hydrogen gas to escape, it is lighter than air and will rise. If the box is fairly airtight a single small hose at the top leading outside will be good. Also a single small vent through the side wall will be ok as well.
 

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Those GBS cells are exactly what I have in my system - and they are NOT low cycle life batteries, they are rated for several thousands of cycles. For them, you need a BMS like the Elite Power Management system I have (https://www.elitepowersolutions.com/bms) - that has a circuit board for each cell of the battery that monitors cell voltage and temperature, and an over-all controller that talks to all the cell management boards, plus a high current contactor to do the disconnects (I use a TE Connectivity such as https://www.mouser.com/ProductDetail/TE-Connectivity-Raychem/LEV200A4NAF01?qs=R3KmN9Esfyu4S3%2BHsvZmmw==) .
As for the diesel heater - I have an Espar unit - be aware they take a LOT of amps at start up to fire the glow plug - about 20-30 amps in pulses. Once started they don't take much current, but you will have to size for the spikes.
There is a great deal of superstition on the board about Lithium batteries, and many of the people opining about them have no actual experience with them. I, on the other hand, have successfully built and used a 7200 Wh battery stack in my Promaster without problems for 4 years now. You are missing a couple of pieces, but you can pick them up without a lot of grief, and will have a great deal more usable power and a great deal less weight than you would with lead. Also, you will be able to charge much faster from the power sources you can get due to lithium's higher input current. As for the boogieman of low temperature charging - the Elite BMS will handle shutting down if it gets too cold, but I have found a simple length of electrical heat tape, such as used on pipes, is more than sufficient to keep my batteries at 40F even when it was 15F outside (and my batteries are underneath the rig in a box). Get the BMS, the 2 strings of cell management boards from Elite, a small NTSC display for the BMS to use, 2 TE contactors, and you will have what you need to make the batteries work. If you want a good inverter, get the Magnum Energy MHS3012 inverter, which will give you a sustained 3000W of sine-wave AC (bursts to 4000W for tens of seconds), as well as up to 3000W of charging current from AC, and will handle switching from shore power to inverter, AND will allow you to augment your shore power with solar when your batteries are fully charged.
 
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