Hello Forum, I'm a brand new newby

zman7458

Hi my name is phil. You can call me Phil or zman or Hey newby whatever you like. I looked for an introduction thread briefly and didn't find one. If a mod spots this and knows where one is please feel free to verbally abuse me and move this thread to the appropriate place for it. A little about myself just so you can start to form a picture of what your dealing with here. I'm 58 years old last 4th of July, I was born in '58 so this is a numerically auspicious year for me, and to shake things up I've quit my job as an electrician of 34 years and have bought a 38' toy hauler. In December I'm loading my wife of 34 years (yes we was married the same year I started school), My TBI 25 year old son and my 3 huskies up and we are going to hit the road for a year to see if we like it. After which I will come back and either sell my house or make a permanent pad in the backyard and park the RV back there and plant roses in it. I've plans to try my hand at prospecting knowing full well I will not get rich doing it, but I need to get my family (myself included of course)out into the world and move our collective asses before the PTB's sweep us off into our graves for sitting around the house and wasting the time we've been given for too long.

Alright, now with that all being said I can get down to the brass tacks of why I'm here boring you good people with my little story. I've decided that if we're going to be sitting out on BLM land in the desert somewhere (most likely Arizona for awhile at any rate) I'm gonna need something other than fossil fuel to be able to stay out there for as long as we can keep ourselves fed and entertained without being strapped to a gas tank running a generator. That primarily ( not necessarily exclusively) involves a solar system sitting up on top of my rig. Now while I have never actually worked on a PV system since I'm a commercial inside wireman, I have read a little bit about them just because it's fringe technology to my profession, I also play with computers, drones cameras...you get the point. So while I understand the math and principles involved my practical application is nill. In  my hubris I have sat down with the help of the internet and put a system together to capitalize on the space, payload capacity and of course budget of my circumstance. Now I know this is going to come off like I'm some kind of an "a"hole, and I don't mean to sound like one, but the truth is I've already bought all of the components and have made a good start at installing them, but I've reached the point where I don't know how to proceed and I really don't want to burn my $100k toy to the ground before I get to go play in it. I'll put up some pics and diagrams for you to look over if you would care to, and please feel free to tell me how stupid I was to do this this way or that that way and I will surely be grateful for the advise but please understand I already have the stuff sitting in my garage I can't make any major changes (exclusions sure but exchanges not so much).

The coach is a 2014 Thor Outlaw 37MD (the 37 is not as I originally thought the length, which is actually 38' 6"),. It comes with a minimal electrical storage system consisting of 2 6volt Duracell batteries in parallel with a 1000 watt inverter and a 30 amp battery charger which is tied into the coach alternator and a Onan 5500 watt generator with a transfer switch to  tie into hook up to 20, 30 or 50 amp shore power. someone also came along and added a cheater box the as far as I can tell allows for hooking up a second 20 amp feed that splits part of the load (I think an air conditioner and a few lights) so you can cheat parks that only give a 30 and 20 amp feed into giving you 50 amps. Thats the extent of my understanding of the existing coach electrical.

My proposed system is to be 8-100watt PV panels on tilt bases with 20 amp breakers on each one, in series parallel no combiner boxes just "y's" with #10 AWG feeding a 60 amp solar charger which in turn will have a #2 AWG feed to 8-6volt 225 AH batteries tied series parallel making a 12 volt 900 AH bank feeding a 3000 watt inverter which has a 100 amp charger built in. I have combo circuit breaker/switches in every line to every component (I know someone out there is screaming overkill, I appologize for doing that to you) and shunts with multi-meters in every separate line going to the separate components. So basically I can isolate any part of the system and tell at a glance what the voltage and amperage is in each section and the breakers are rated to the wire used. I also have lightning arrestors on the solar charger and the house 110vac panel (once again apologies to my minimalist friends). The solar charger and inverter have remotes coming into the wall in the coach where all the coach components are controlled and or monitored.

I've got the battery bank assembled and wired with 4/0 ultra flex welding/battery cable and a 400 amp breaker on each leg except ground and is ready except for final connection to the charger and inverter. The PV wires are run from the roof to the charger but not hooked in yet. the pads for the PV panels are laid and I'm installing the breakers in them right now they also have the modified tilt bases installed and I will be placing them this week. I'm staying in the coach at night with my youngest fur baby to get her used to going potty on her porta potty and not on my floor, so I won't be tearing out the old electrical storage system until I'm completely ready to switch over.

And so now we come to the point where I have no idea how to proceed. My instincts tell me I should just simply remove the old system in its entirety and drop my new system directly where I took the old one out, but I've lived long enough to know that things are rarely so easy and I'm almost certain there are some things involved that I don't know enough about to just blindly go forward and end up burning something up rather than seeking help from someone who has done this before. So this is me asking anyone who has the time or inclination to lend a brother a hand and maybe clue me in to what comes next?

These are the pics and drawings I have so far. Please feel free to comment and or critique as you please. I'm not the sensitive type and promise not to cry or get upset, and thank you so much for taking the time to look this over. Phil

zman7458

A couple pics of the start.

mike95490

Being an electrician, you know about current density in wires, and the importance of a good crimp and bolt on connection,
Trying to run a 3KW load can melt the terminals off the batteries @ 12V
So if you are going to consider heavy loads like air conditioning, you HAVE to up the system voltage to at least 24V.   And then that puts all the 12V appliances out of business.
 The rule of thumb is for every 1,000 w of load, you need another 12V increment in battery voltage,
1Kw = 12V
2Kw = 24V
3Kw or more = 48V (since 36v gear is rare)
  So your load calculations are going to have to happen before anything else, (Both peak load, and 24hr consumption total KWh)

As daily Kwh goes up, your battery voltage also goes up, it's better to place cells in series than parallel (current hogging in parallel circuits)

But if you have already bought all this stuff, the fun begins on how to make it work, so first the loads, Peak and Daily

westbranch

As Mike said , at least a 24 Volt system.

Do I see correctly, an AIMS inverter and a TriStar Charge Controller? 
Which Tristar is it ? PWM or MPPT?
You might want to see if an exchange for the Aims is possible....

I forget the trade name for the factory installed 'charger' (maintainer?) but most do a lousy job at charging, as the settings are generic, You need to check out the charge parameters if you are going to use it, and look at what the battery manufacturer wants...

Flesh out the equipment you have and adding it to your sig line will help a lot.

enjoy!

zman7458

mike95490 said:

Being an electrician, you know about current density in wires, and the importance of a good crimp and bolt on connection,
Trying to run a 3KW load can melt the terminals off the batteries @ 12V
So if you are going to consider heavy loads like air conditioning, you HAVE to up the system voltage to at least 24V.   And then that puts all the 12V appliances out of business.
 The rule of thumb is for every 1,000 w of load, you need another 12V increment in battery voltage,
1Kw = 12V
2Kw = 24V
3Kw or more = 48V (since 36v gear is rare)
  So your load calculations are going to have to happen before anything else, (Both peak load, and 24hr consumption total KWh)

As daily Kwh goes up, your battery voltage also goes up, it's better to place cells in series than parallel (current hogging in parallel circuits)

But if you have already bought all this stuff, the fun begins on how to make it work, so first the loads, Peak and Daily

Crimp, lugs and bolt are all spec'd out, I had considered going 24 and even 48 volts for a time but the losses in converting back down to 12 volts talked me out of it. I've gone all led in the couch and induction on my range for cooking so thats 10 amps there. the A/C is the main load for the main cabin it's 13 amps, and for while we're away the dogs room A/C is 4.8 amps. The fridge is a small unit at 2.5 amps and I can run that on LP if need be. I think my load calcs will work just fine for my application. My main concern is this switch over from old to new and making sure I'm not forgetting to take something into account that I'm not aware of. like loading on my alternator and things like that which I don't encounter in my everyday commercial electrical work. Thanks Mike

As an after thought tho. my calcs say that 3kw@12vdc=250 amps which my 2' long 4/0 copper wire and lugs are rated at 300 amps, not to mention the manufacturer suggests 4/0 wire and a 400 amp fuse for their 3kw inverter, add to that, that I am installing a cooling system/monitor for the inverter and batteries I think I'll be alright. I don't mind erring on the safe side but allowing 200% seems extreme out of the norm. JMHO tho

westbranch

If that is a 3 way fridge, is that 2.5A 12V or 120V, I'm thinking it's 120 therefore =  300Whrs per day...

ADD:  what is the recommended CB size from the panel maker, see plate on back of panel?

Estragon

What is the venting like for the battery compartment? Presumably it will be a small confined space and buildup of potentially explosive gas during charging could an issue.

zman7458

westbranch said:

As Mike said , at least a 24 Volt system.

Do I see correctly, an AIMS inverter and a TriStar Charge Controller? 
Which Tristar is it ? PWM or MPPT?
You might want to see if an exchange for the Aims is possible....

I forget the trade name for the factory installed 'charger' (maintainer?) but most do a lousy job at charging, as the settings are generic, You need to check out the charge parameters if you are going to use it, and look at what the battery manufacturer wants...

Flesh out the equipment you have and adding it to your sig line will help a lot.

enjoy!

mppt-60. I like the equipment as is. what I need help with is the final step of tying the new  system into the old. I would think with all these experts here I could get my actual question answered. I already know what you're trying to say, but that is not what I'm asking for help with. theres a thousand or more different ways to do what I am doing as far as equipment is concerned, but I'm not asking for advice on that, I've already been down that road on a couple other sites and this is what we've come up with. But it's kind of like it is here, everyone wants to say what buy and why (which I've done within reason ) but now that it's time to put it into practice everyone clams up. okay heres the question, "is there anyone here that has actually installed a system similar to this in an RV similar to mine"? if yes was there anything you had to do in addition to removing the old AC feed and the old DC feed and plugging the new ones in where the old ones came out? It's really a very simple question really, If there isn't anyone who has done this then I will thank you for your time and bid you a good day and happy journeys. If there is then lets talk about it because that's where I'm unsure of how to proceed.

westbranch

Most of the land cruisers are over here: http://forum.solar-electric.com/categories/caravan-recreational-vehicle-and-marine-power-systems.  The section is not very active till just before someone is heading out on the road..

All we are trying to do is make you aware of the issues with a 12V choice and considerations/consequences of really heavy loads at that voltage, wiring issues. etc.

mike95490

At least plan for your battery replacement.   When that is due, look into getting 2V or 4V batteries and wire them in series and skip the parallel business.

at 250 amps, it's not the 300A wires that are the problem, it's the stud on the inverter, the internal inverter wires, the crimp terminal that looks good but has a flaw.  At 200A, something lets loose.   But let's hope you have good crimpers and it all holds together,

I did not see a Solar PV combiner box with breakers,  When you parallel more than 2 panels/strings, you need circuit protection to prevent good strings from BBQ a faulty panel.

BB.

OK--I will make a few comments for safety...

I notice you have two breakers--+ and - leads in the DC bus system. In general, if you are grounding the negative bus to RV chassis--You would not need any breaker in the - leads since they will (under normal conditions) go above chassis ground.

However, if you are going to float the negative bus--It is a good idea to use double pole breakers--However, to do it "safely", you should have the breakers ganged so that if one pole is tripped, it turns off the second breaker too. If you do not, it is possible to energize the negative power bus (i.e., a short to a positive bus/lead somewhere not makes a "positive ground system"). For many 12 volt automotive devices (such as a car radio), they use the chassis ground as negative return--And it is possible with the now "positive ground" system to cause problems with excessive current flow in various return leads (you need double pole breakers in all bus to distribution connections for a truly "safe" floating output DC power system.

If you go with a standard Negative Ground bonded system--You can just put breakers in the "hot leads" (+) only. It will save you 1/2 your breakers and fuses and help prevent non-obvious problems (one for example are your shunts which are normally in the negative / return wiring. That way, when you measure voltage drop, the wires are very near zero volts with respect to ground. If you have a floating system that gets a positive to ground short, the negative bus goes to -12 volts--Now your sense leads are at -12 volts and XXX amps or more of available current--So each sense lead should have a resistor or small 1/2 amp type fuse before going into the wiring harness/remote meter head).

You might want to put fusing (or breakers) in each battery parallel connection. If you have a short circuit, the other three strings of batteries can feed significant short circuit current into the short. 4/0 cable probably will not fuse--But you might want to think about using these Blue See bolt on fuse holders (plus high current fuses). Very small size (relative to other fuse holders/breakers) and uses explosion proof fuses:

https://www.bluesea.com/products/category/16/72/Fuse_Blocks/Terminal_Fuse_Blocks

MRBF Terminal Fuse Block - 30 to 300A

Back to the breakers for the main DC Bus--Are these DC rated breakers with over X,000 amps interrupt capability? 12 volts is close to not arcing--But AC only rated breakers/fuses tend not to be a good solution (DC rated current protection devices tend to be a lot heavier duty).

Are this AGM or Flooded Cell Batteries? AGMs will support much higher surge current (need per string fusing for battery bank). If flooded cell (and as AGMs age/get over charged), they will vent Hydrogen (and Oxygen) as well as electrolyte (diluted sulfuric acid). Need good ventilation and/or suggest to not put your electronics (charge controller/inverter/etc.) right next to the battery bank--You can get corrosive fumes on your expensive shiny stuff.

If you are going to be working over the top of the battery bank--I would suggest something to stop tools/hardware from dropping on the battery bank and causing short circuits.

I am not sure you really need a shunt (or even volt meter) on the solar array wiring--In general, the MPPT controller should give you that information with the display / computer interface. Many people still put a breaker (or DC switch) in the solar array wiring so they can turn off the MPPT controller easily.

On you solar array, make sure you have an easy place you can place a DC current clamp meter on one leg from each of your parallel array. It makes it easier to debug array wiring problems and possible panel failures (see which string has reduced current output). Some folks put the on/off array switches on each + array string--This allows you to turn off one array or the other to debug low array output current (without needing a DC current clamp meter).

Just out of curiosity--How many Amp*Hours (at 12 volts) and or Watt*Hours (120 VAC) do you expect from your system per day?

How deeply do you wish to cycle the battery bank? For off grid homes, we usually suggest 25% discharge per day for 2 days, and 50% maximum discharge for longer battery life. For RV's with weekend/couple week trips a year, many times they use 50% discharge per day (one day of storage)--But you need sun/genset the next day to recharge (for many reasons, limiting discharge to 25% per day with flooded cell lead acid batteries is better for full time off grid living).

With 12 volt systems, you are best if you have 0.5 volt maximum drop at full current for DC wiring from battery bank to loads/inverter. For your charging system, try to have a maximum of 0.05 to 0.10 maximum voltage drop from charge controller to battery bank.

Also, is really nice to have a Remote Battery Temperature Sensor for the Solar Charge Controller (hot batteries need lower charging voltages)--Unfortunately, not many AC battery chargers have RBTS options.

It looks like you may have switches for your major loads in the return lines? Suggest using switchable circuit breakers in the + leads only (especially if you are negative grounding). Will also save hardware costs and room for "double switching". And turning off return circuits instead of hot circuits is considered bad form--Leads somebody (other than you) to think a branch circuit has been de-energized--Whereas it is still hot (with respect to ground).

Is this the feedback you are looking for?

-Bill

zman7458

quote "Is this the feedback you are looking for?

-Bill"

quote: " okay heres the question, "is there anyone here that has actually installed a system similar to this in an RV similar to mine"? if yes was there anything you had to do in addition to removing the old AC feed and the old DC feed and plugging the new ones in where the old ones came out? It's really a very simple question really, If there isn't anyone who has done this then I will thank you for your time and bid you a good day and happy journeys. If there is then lets talk about it because that's where I'm unsure of how to proceed."

Everyone still wants to showoff how much they know, by showing how much I don't know. So lets try this this way, assuming the perfect system (I'll bet you a dollar to a donut there's not any two of you can agree what that would be, so anyone who's head didn't just explode at trying to imagine that) when you have your system built exactly how you want it. now what do you do to install it in the RV I described above? I.E, do you simply unplug the old DC system and plug in your new DC system then unplug your old AC feed from the old AC feed (the part coming from the converted DC side of course not the whole AC system, just the part relating to the new DC system you just built) now heres the important bit that I'm lacking in is there anything else I need to do since this is a solar system being added to where an old DC system used to be, 

IMPORTANT PART TO FOLLOW

 is there anything that I need to do other than just swap them out?

IMPORTANT PART ABOVE

zman7458

westbranch said:

Most of the land cruisers are over here: http://forum.solar-electric.com/categories/caravan-recreational-vehicle-and-marine-power-systems.  The section is not very active till just before someone is heading out on the road..

All we are trying to do is make you aware of the issues with a 12V choice and considerations/consequences of really heavy loads at that voltage, wiring issues. etc

Okay that link is broken. and yes I know everyone has an opinion and just can't wait to have someone ask for it, but all I really want to know is how to proceed from after building the solar system? What are the steps to safely incorporate it into my RV without burning anything up? or freaking anything out? for example in my line of work the rule is your ground is "first to make, last to break", does that still apply here with DC solar? what is my alternator going to think about this load? is there anything I need to do to keep it happy? you know things like that that just a normal electrician might not know about when doing the final hookup? could you please post a good link to the RV area please? perhaps someone over there will know what I'm talking about? Thank you so very much

westbranch

don't know why it didn't as it is on this forum under categories..  here it is again...

http://forum.solar-electric.com/categories/caravan-recreational-vehicle-and-marine-power-systems

tested and it is working...

BB.

zman7458 said:
Okay that link is broken. and yes I know everyone has an opinion and just can't wait to have someone ask for it, but all I really want to know is how to proceed from after building the solar system? What are the steps to safely incorporate it into my RV without burning anything up? or freaking anything out? for example in my line of work the rule is your ground is "first to make, last to break", does that still apply here with DC solar? what is my alternator going to think about this load? is there anything I need to do to keep it happy? you know things like that that just a normal electrician might not know about when doing the final hookup? could you please post a good link to the RV area please? perhaps someone over there will know what I'm talking about? Thank you so very much

OK--I will try again... You are talking about NEC (and other codes)... That is why I asked why you are placing circuit breakers/fuses in the return lines. This is the same as placing circuit breakers in the neutral of a  North American 120/240 VAC home with a safety ground/neutral bonded system.

Note--The whole issue of AC neutral bonding can be an issue with RVs... Depending on how you wire the AC transfer switch/Inverter in your RV, this can be an issue. When you have shore power, it will have the Neutral+Earth (green wire) safety ground somewhere at the AC source. When you are on inverter or genset AC power, you have a choice of leaving the "neutral" (for most pure sine wave AC inverters and smaller AC gensets) to either ground bond the neutral locally (in the RV) or leaving the AC power floating. One solution to this is the AC transfer switch that switches L1 and L2 AND the local greenwire to RV frame ground bond. Or not... Your choice.(most larger portable gensets... Say over ~3kWatt) will come with the AC ground bonded to the AC neutral line. You can have problems with GFI outlets (especially if the shore power is GFI protected) if you have the neutral bonded in two locations (say shore power and genset).

If you are tying your system to the vehicle's alternator--Then your house battery system will be grounded to the vehicle frame. Most vehicle type alternators do not have a separate (isolated) return line--Placing a fuse/breaker in return lines is, at best, not needed. At worst, can create alternate return paths where excessive current (short circuits, an open return line, high AC inverter DC current) can cause high current flow through small return leads and cause a fire.

There is a typical "rule reversal" for working on negative grounded battery banks in a vehicle--For batteries, lifting (unbolting) the ground/negative lead first--Then the positive leads second. The idea is that swing a metal wrench on the negative (grounded to metal) connection will not create a short circuit if the wrench hits the metal framework of the RV/vehicle. Once the negative lead is lifted, then you can unbolt the positive cable connections without fear of a short circuit if the wrench touches metal (of course, using electrical tape on wrenches and tools to insulate the non-working surfaces when working on battery banks is always a good idea).

Regarding the alternator question... Your battery bank can take hours of of high current (if low state of charge)--Most non-commercial alternators tend to run hot and greatly reduce their output current after a few minutes at high current. If you plan on using the vehicle alternator for substantial charging current/time--You might look at a marine alternator.

Balmar also has adjustable voltage set points--Car alternators (at least older ones) tend to charge around 14.0 volts +/- 0.2 volts or so... A deeply cycled flooded cell battery can take 14.75 volts, and an AGM upwards of 14.4 volts:

http://www.balmar.net/

Assuming you will be equalizing the battery bank once a month or so (AGM/GEL do not support equalization)... You will generally need ~15.0 to 15.5 volts (depending on battery brand/type). And if you are in a cold climate (below freezing), you could need/see >16.5 volts (many AC inverters and 12 volt DC converters/loads can have have problems with >15.0 volts)

Also, I forgot to add another reason for venting your present battery box design... The MPPT controller will add about 5% of its array power as heat into the the battery box... And the inverter will add another ~5-15% of its output power to the battery box too. Running electronics (and batteries) hot will reduce their life (an engineering rule of thumb, for every 10C increase in temperature results in a 1/2 reduction of life). Also--Thermal cycling is another major cause of faults in electronic systems (hot during day/charging, cold at night).

Lastly, the link Westbranch provided was just to the RV section of this forum--Not a separate forum. Many threads can be fine in any of several forums (this can be in beginners, RV, etc.). Not a big concern and will not really change the number of people in this forum responding to your question(s) (the answers may be more or less technical depending on the forum that this is posted in--But your experience would tend to get more technical answers).

If anyone has a link or two for good RV forums--Please feel free to post them.

-Bill

Estragon

Re: marine alternator note that swapping in a high output unit can be problematic. Aside from modifying belts/pulleys/mounts there may also be issues with excessive side loading on bearings.

I looked at swapping a 35A alternator in a sailboat to a high output model for charging a larger house bank, but the mods and side loading issues made impractical. I repowered the boat because of an unrelated failure, and the new (smaller) diesel came with a high output alternator.

The OP might also want to install a 1/2/both/off switch for batteries if not already so equipped. The ability to start from the house bank if need be is useful.

zman7458

BB. said:

zman7458 said:
Okay that link is broken. and yes I know everyone has an opinion and just can't wait to have someone ask for it, but all I really want to know is how to proceed from after building the solar system? What are the steps to safely incorporate it into my RV without burning anything up? or freaking anything out? for example in my line of work the rule is your ground is "first to make, last to break", does that still apply here with DC solar? what is my alternator going to think about this load? is there anything I need to do to keep it happy? you know things like that that just a normal electrician might not know about when doing the final hookup? could you please post a good link to the RV area please? perhaps someone over there will know what I'm talking about? Thank you so very much

OK--I will try again... You are talking about NEC (and other codes)... That is why I asked why you are placing circuit breakers/fuses in the return lines. This is the same as placing circuit breakers in the neutral of a  North American 120/240 VAC home with a safety ground/neutral bonded system.

Note--The whole issue of AC neutral bonding can be an issue with RVs... Depending on how you wire the AC transfer switch/Inverter in your RV, this can be an issue. When you have shore power, it will have the Neutral+Earth (green wire) safety ground somewhere at the AC source. When you are on inverter or genset AC power, you have a choice of leaving the "neutral" (for most pure sine wave AC inverters and smaller AC gensets) to either ground bond the neutral locally (in the RV) or leaving the AC power floating. One solution to this is the AC transfer switch that switches L1 and L2 AND the local greenwire to RV frame ground bond. Or not... Your choice.(most larger portable gensets... Say over ~3kWatt) will come with the AC ground bonded to the AC neutral line. You can have problems with GFI outlets (especially if the shore power is GFI protected) if you have the neutral bonded in two locations (say shore power and genset).

If you are tying your system to the vehicle's alternator--Then your house battery system will be grounded to the vehicle frame. Most vehicle type alternators do not have a separate (isolated) return line--Placing a fuse/breaker in return lines is, at best, not needed. At worst, can create alternate return paths where excessive current (short circuits, an open return line, high AC inverter DC current) can cause high current flow through small return leads and cause a fire.

There is a typical "rule reversal" for working on negative grounded battery banks in a vehicle--For batteries, lifting (unbolting) the ground/negative lead first--Then the positive leads second. The idea is that swing a metal wrench on the negative (grounded to metal) connection will not create a short circuit if the wrench hits the metal framework of the RV/vehicle. Once the negative lead is lifted, then you can unbolt the positive cable connections without fear of a short circuit if the wrench touches metal (of course, using electrical tape on wrenches and tools to insulate the non-working surfaces when working on battery banks is always a good idea).

Regarding the alternator question... Your battery bank can take hours of of high current (if low state of charge)--Most non-commercial alternators tend to run hot and greatly reduce their output current after a few minutes at high current. If you plan on using the vehicle alternator for substantial charging current/time--You might look at a marine alternator.

Balmar also has adjustable voltage set points--Car alternators (at least older ones) tend to charge around 14.0 volts +/- 0.2 volts or so... A deeply cycled flooded cell battery can take 14.75 volts, and an AGM upwards of 14.4 volts:

http://www.balmar.net/

Assuming you will be equalizing the battery bank once a month or so (AGM/GEL do not support equalization)... You will generally need ~15.0 to 15.5 volts (depending on battery brand/type). And if you are in a cold climate (below freezing), you could need/see >16.5 volts (many AC inverters and 12 volt DC converters/loads can have have problems with >15.0 volts)

Also, I forgot to add another reason for venting your present battery box design... The MPPT controller will add about 5% of its array power as heat into the the battery box... And the inverter will add another ~5-15% of its output power to the battery box too. Running electronics (and batteries) hot will reduce their life (an engineering rule of thumb, for every 10C increase in temperature results in a 1/2 reduction of life). Also--Thermal cycling is another major cause of faults in electronic systems (hot during day/charging, cold at night).

Lastly, the link Westbranch provided was just to the RV section of this forum--Not a separate forum. Many threads can be fine in any of several forums (this can be in beginners, RV, etc.). Not a big concern and will not really change the number of people in this forum responding to your question(s) (the answers may be more or less technical depending on the forum that this is posted in--But your experience would tend to get more technical answers).

If anyone has a link or two for good RV forums--Please feel free to post them.

-Bill

ahha, the breaker/disconnects are there as a means of isolation in case I need to totally remove a component from the system. it's kinda like the reason behind all the redundant multimeters I put them in because if I'm out there troubleshooting where the problem that a squirrel ate into my system somewhere is I can turn everything off and then watch as I bring one thing at a time online. It's more for convenience than need. I have AGM's so the fresh air isn't a concern for them, but it is a concern for heat dissipation which is why I'm installing two ducted bilge fans with separate thermostats one for the inverter/solar charger and one for my battery bank. if you look closely at the picture you'll see that I left a couple inches if space all the way around the mounting board and cut the corners out to run my flex duct to the blowers for fresh air. It's an open pass through bay on the backside of the board which I will be opening a 12"x24" rectangular opening with a furnace filter in a track to supply the fresh air, and if thats proves to still be inadequate then I'll open a space in the floor and pull air conditioned air into that bay, so keeping my electronics cool shouldn't prove to be a problem I hope (knock on wood). I think the existing house batteries are tied to the RV's alternator but sources on another site have informed me that that shouldn't be an issue if it is indeed the case. lol now as to the only question I've actually asked (which in the mean time has been answered on another forum, so it really is a moot point now) is as follows "can I simply remove the old ac/dc system I.E battery charger, inverter, batteries, and do a direct replacement with my new system? Thats really all I wanted to know, I simply supplied all the information about the existing and my new system as to get an accurate answer to that one question, which although you have provided me some great information, you have yet to tell me if I can or can't so that brings me to believe that you nor anyone who has read this post doesn't actually know the answer and I've wasted your time in keeping this thread going. So I very sincerely thank you for all the great info and I am very impressed with the depth of the knowledge pool here. Thanks. Phil

BB.

I guess that Phil got his answers here:

http://www.irv2.com/forums/f56/12-volt-900-ah-solar-system-so-far-308785.html

Looks to be a very active forum.

-Bill

petertearai

I for one have always been very appreciative of  the extra answers to my Questions. I am continually amaised by the generous time and thought that gets put into this forum by regular contributors and moderators .

BB.

Thank you Peter... We all try, but sometimes it can be difficult for folks to connect in a forum--And we somehow miss each other.

-Bill

South Africa

Respect Bill.

Dave Angelini

Always! Like an atomic clock!