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locked 2008 View - Wiring a DC to DC Charger


David Harper
 

Hi all,

I am hoping someone can help!  I am trying to install a Victron Orion 30 amp charger in my View.  I have 2 100AH lithium batteries, and they charge inconsistently from the alternator.  I am afraid of burning out the alternator, or not getting any charge while driving.  Seems it's one or the other.  Charging is not too much of a problem normally, as I have 300watts of solar, and i changed my charge converter to a Progressive Dynamics model that is designed for lithium.  I want to better control the alternator charging, and to make sure the voltage coming to the batteries is appropriate for lithium charging.  I can do all that adjustment with the Victron charger.

My problem is that I am totally stumped by installation.  If no preexisting connection between chassis and coach batteries, it would be easy.  BUT - I have the solenoid/battery boost, and I think the battery isolator next to it, all under the passenger seat, and I am terrified!  I looked at the Winnebago wiring diagram, and i see generally where things go, but I do not know what to disconnect and what to connect to the charger so that the new DC2DC charger does not compete with the existing connection betweed house and chassis batteries.  

Should I disconnect the Boost circuit?  

I would really appreciate any help with this. 

Thanks in advance for any help.

david Harper
2008 VJ Central Florida


old_b4_my_time
 

I'm not quite there yet but I sympathize with you.   I think what most are doing is actually disabling the boost solenoid and using the "engine side" heavy wire to feed in the input of the DC2DC and the "house side" of that solenoid to route to the output of the DC2DC.   (Battle Born says the boost action should not be used with their lithium batteries so you have to give up "boost" action when you choose lithium according to their support staff)

I haven't bought into lithium yet but what I am going to try first (when I do) is to salvage a speed control from a very old golf cart or actually winding my own coil of 12/14 gauge wire on some insulated high temperature spool material and then mount that in a place first where it won't catch anything on fire of course, then place that coil in series with the boost solenoid to reduce the current.   Then I'll add a couple of items, an additional boost style solenoid to short that coil and add a digital read out current meter to let me know when it's safe to short out the resistance coil which will pass the full charge current from the alternator to the batteries when the initial peak charging current spike has passed.

Now this design is based on what I have come up with in my imagination after reading on SprinterSource which says the initial amperage drawn is only at the extreme high peak during an initial period of 10-20 minutes and thus the point of most concern with over-burdening the alternator.   The contributor there said he addressed the issue by having a similar setup but his initial charge (he claims for the first 10-20 minutes) was all he needed for the DC2DC and he had circuitry then to connect directly to the alternator for full amp charge once that peak had settled down to a lower steady amperage (in the 50-80A range which should be OK for a 150A alternator).   My idea that came to me is why not just use a cheap hand-wound resistor made of the 12/14 gauge copper spool and save the $300 on the DC2DC converter.

Still if you've already invested in the DC2DC, and you are sold on it, I'd wire it up while taking the boost relay out of the circuit and wire as I explained.    Whether you want to go to the extent that this fellow in SprinterSource went to and that is to electronically take the DC2DC out of the circuit after the initial peak charge was settled to an acceptable level will then this decision would be up to you and it would be something that you might look into if the slow 30A was not cutting it in the "time required to charge" department.

Most "engineers" argue that you need the 14.6VDC to truly charge the lithium bank but if you look at the specs for LiFePo4s, the cells claim to have reached a 90% charge at 14.2VDC - so if your Sprinter regulator is putting that out, you could use the 14.2VDC in a two step charge to get to 90% and hope the solar would get you the rest of the way.

I am going to have to do some experimenting, though if and when I go lithium.   I am personally (at the moment) not excited about a 20-30A charge through a $300 DC2DC and I don't want to lay down $1200 for the Victron all in one (forgot the model number) to get the 80A alternator charge because I already have a 2000PSW inverter.    So since I like projects I'll likely start with the homemade wire-wound resistor and relay to short it after 10-20 minutes to provide direct connect to the alternator while assuming the SprintSource contributor gave accurate info where he stated the the charge current was on a down-sloped curve at least similar to lead/acid where like I have seen on my two GC2's that the alternator on a 40% depleted bank shows 55A on my victron meter and drops to about 40A to steadily decline after 15 minutes.   If that same curve happens on the lithium set, my initial thoughts that switching a homemade wire-wound resistor in series with the existing "boost solenoid battery bridge" setup would give me the ability to start off driving with the resistor switched in and as soon as the load dropped below around 70-80A, I could throw a switch which had an additional solenoid that would short together the ends of that resistor that was inline and in series and thus the lithium bank would be direct connected to the alternator after that initial peak charging spike had settled down.

And unless Mercedes was using a true 14.2VDC regulator, this wouldn't work as wellk.   I think the stock regulator only produces about 13.8VDC but when my regulator burned up (no lithium, just from old age) I replaced it with a cheap Chinese replacement which now produces the common US automotive value of 14.2VDC which is better for charging batteries.
--
Don - 2006 Navion J


old_b4_my_time
 

David, sorry forgot a traditional greeting but I am social;u inept LOL ....

What is your amp reading when you start the engine after the bank is sufficiently depleted?   If you are not going over 80-90A on your battery monitor, I don't think I would add a DC2DC.   If you have a Victron Battery Monitor, what percentage of charge to you show after a significant drive?   If you are over 90% and assuming your solar charge controller is going to top that up, you might just stick with what you have and not worry with the DC2DC.    I know several have commented here they they don't see any problems with two 100aH lithiums, so you might be in the same boat.   In this case the thing though to watch for might be if you ever spent a long boondock in heavy cloud cover or rain, at that point the high amp draw might over-tax the alternator.

Still with all this aside and if you find over time you are working within specs of your alternator's amperage output ability, I'd be reluctant to use the boost solenoid switch to start the engine unless the engine battery still has some power but simply wasn't turning the starter fast enough due to a partial discharge.   On a full discharge or dead cell situation of the chassis battery, due to the starting amperage required and if a spike occurs from the counter EMF of that starter winding and that spike was placed across your lithium internal BMS units, it could very well smoke the BMS inside the lithiums.   To repeat myself, Battle Born says not to use the boost solenoid to start the engine, and again you might get away with a boost on a low chassis battery because the lead/acid would sink a lot of the voltage spikes coming from the starter motor but if the engine battery was completely shot, one of those spikes from the starter motor could damage the BMS irreparably.
--
Don - 2006 Navion J


David Harper
 

Wow! Thanks so much for the extensive explanation.  I understand the substitution of the DC To DC charger for the boost solenoid, but in the view, (the 2008 anyway), the boost solenoid is connected to an isolator of some sort that seems to be connected to the house batteries.   The schematics from Winnebago show one side of this isolator device has a line labeled “generator “.  If I eliminate the boost solenoid, I presume the battery boost cable that feeds the isolator would connect directly to the charger output to house batteries.  

That make sense?

David
2008 VJ Central Florida 


On Sep 25, 2020, at 1:19 PM, old_b4_my_time <donphillipe@...> wrote:

I'm not quite there yet but I sympathize with you.   I think what most are doing is actually disabling the boost solenoid and using the "engine side" heavy wire to feed in the input of the DC2DC and the "house side" of that solenoid to route to the output of the DC2DC.   (Battle Born says the boost action should not be used with their lithium batteries so you have to give up "boost" action when you choose lithium according to their support staff)

I haven't bought into lithium yet but what I am going to try first (when I do) is to salvage a speed control from a very old golf cart or actually winding my own coil of 12/14 gauge wire on some insulated high temperature spool material and then mount that in a place first where it won't catch anything on fire of course, then place that coil in series with the boost solenoid to reduce the current.   Then I'll add a couple of items, an additional boost style solenoid to short that coil and add a digital read out current meter to let me know when it's safe to short out the resistance coil which will pass the full charge current from the alternator to the batteries when the initial peak charging current spike has passed.

Now this design is based on what I have come up with in my imagination after reading on SprinterSource which says the initial amperage drawn is only at the extreme high peak during an initial period of 10-20 minutes and thus the point of most concern with over-burdening the alternator.   The contributor there said he addressed the issue by having a similar setup but his initial charge (he claims for the first 10-20 minutes) was all he needed for the DC2DC and he had circuitry then to connect directly to the alternator for full amp charge once that peak had settled down to a lower steady amperage (in the 50-80A range which should be OK for a 150A alternator).   My idea that came to me is why not just use a cheap hand-wound resistor made of the 12/14 gauge copper spool and save the $300 on the DC2DC converter.

Still if you've already invested in the DC2DC, and you are sold on it, I'd wire it up while taking the boost relay out of the circuit and wire as I explained.    Whether you want to go to the extent that this fellow in SprinterSource went to and that is to electronically take the DC2DC out of the circuit after the initial peak charge was settled to an acceptable level will then this decision would be up to you and it would be something that you might look into if the slow 30A was not cutting it in the "time required to charge" department.

Most "engineers" argue that you need the 14.6VDC to truly charge the lithium bank but if you look at the specs for LiFePo4s, the cells claim to have reached a 90% charge at 14.2VDC - so if your Sprinter regulator is putting that out, you could use the 14.2VDC in a two step charge to get to 90% and hope the solar would get you the rest of the way.

I am going to have to do some experimenting, though if and when I go lithium.   I am personally (at the moment) not excited about a 20-30A charge through a $300 DC2DC and I don't want to lay down $1200 for the Victron all in one (forgot the model number) to get the 80A alternator charge because I already have a 2000PSW inverter.    So since I like projects I'll likely start with the homemade wire-wound resistor and relay to short it after 10-20 minutes to provide direct connect to the alternator while assuming the SprintSource contributor gave accurate info where he stated the the charge current was on a down-sloped curve at least similar to lead/acid where like I have seen on my two GC2's that the alternator on a 40% depleted bank shows 55A on my victron meter and drops to about 40A to steadily decline after 15 minutes.   If that same curve happens on the lithium set, my initial thoughts that switching a homemade wire-wound resistor in series with the existing "boost solenoid battery bridge" setup would give me the ability to start off driving with the resistor switched in and as soon as the load dropped below around 70-80A, I could throw a switch which had an additional solenoid that would short together the ends of that resistor that was inline and in series and thus the lithium bank would be direct connected to the alternator after that initial peak charging spike had settled down.

And unless Mercedes was using a true 14.2VDC regulator, this wouldn't work as wellk.   I think the stock regulator only produces about 13.8VDC but when my regulator burned up (no lithium, just from old age) I replaced it with a cheap Chinese replacement which now produces the common US automotive value of 14.2VDC which is better for charging batteries.
--
Don - 2006 Navion J


Dunc 18ND W.CO
 

David, 

Please do not follow Don's non-engineered suggestions. There are so many "wrongs" there, voltages, current, etc. I don't know where to start.

I have the Victron Orion 15A TR Smart charger installed, and it works very well. I hope you purchased their "charger" not a "DC to DC converter" per the subject line. I like the ability to monitor the Smart from my phone. I only use mine when I need an extra boost to Lithium house batteries while driving, and rely upon solar for most charging needs.

I have not verified your specific wiring, but generally there are two wires that enable the "boost" solenoid - the small post. One comes from the "boost" switch on the dash, the other from the ignition switch. The latter wire simply needs to be disconnected so that the boost solenoid is not enabled when driving - you will be charging through the Victron charger.

I had originally toyed with the idea of mounting my Victron under the seat, but opted to mount with my other Victron equipment in the right front exterior cargo bay. One of the considerations was charger control. I don't know if your BMS has a charge control line, but this can be connected to your Victron Orion or a manual switch can be used. The latter is simplest solution. This is in addition to the internal control provided by Victron where you can program the required alternator input voltage, bulk, and float voltages per your battery needs. Do not use Don's suggested voltages as Lithium battery voltage vary significantly, most due to chemistry and internal configuration.

Let me know if you need further help. 
--
Dunc, W.CO, 2018 N24D
800W Solar, 10kWh Tesla Coach
Gyrocopter Toad


David Harper
 

Disconnecting the solenoid and connecting to the DC to DC Charger (It is the Charger - the Orion 12v - 30Amp) seems simple enought, but the solenoid is directly connected to the round black thing that I think is an isolator. If I disonnect that, it loses power.  From the schematic, I think this is connected to the generator, and probably the house batteries. I do not know what to do with this connection.  Should the Charger go in between the solenoid and the black isolator, simply replacing the solenoid?

i apologize to all for including these photos, but I hope they illustrate my point/question.


I'm feeling pretty stupid about this.  Clearly I am no electrician.  Thanks for your help

david

2008VJ Central Florida



On Sep 25, 2020, at 2:06 PM, Dunc 18ND W.CO <n185ra@...> wrote:

David, 

Please do not follow Don's non-engineered suggestions. There are so many "wrongs" there, voltages, current, etc. I don't know where to start.

I have the Victron Orion 15A TR Smart charger installed, and it works very well. I hope you purchased their "charger" not a "DC to DC converter" per the subject line. I like the ability to monitor the Smart from my phone. I only use mine when I need an extra boost to Lithium house batteries while driving, and rely upon solar for most charging needs.

I have not verified your specific wiring, but generally there are two wires that enable the "boost" solenoid - the small post. One comes from the "boost" switch on the dash, the other from the ignition switch. The latter wire simply needs to be disconnected so that the boost solenoid is not enabled when driving - you will be charging through the Victron charger.

I had originally toyed with the idea of mounting my Victron under the seat, but opted to mount with my other Victron equipment in the right front exterior cargo bay. One of the considerations was charger control. I don't know if your BMS has a charge control line, but this can be connected to your Victron Orion or a manual switch can be used. The latter is simplest solution. This is in addition to the internal control provided by Victron where you can program the required alternator input voltage, bulk, and float voltages per your battery needs. Do not use Don's suggested voltages as Lithium battery voltage vary significantly, most due to chemistry and internal configuration.

Let me know if you need further help. 
--
Dunc, W.CO, 2018 N24D
800W Solar, 10kWh Tesla Coach
Gyrocopter Toad


Dunc 18ND W.CO
 

That is the coach battery disconnect. You should not need to worry about that.

In my case, this needed modification because my coach batteries are 24V and I chose to supply 12V from the chassis battery for those circuits.
--
Dunc, W.CO, 2018 N24D
800W Solar, 10kWh Tesla Coach
Gyrocopter Toad


old_b4_my_time
 

David, since Dunc believes he need to pass out character critiques, realize you are talking to a guy who just installed a Tesla water cooled battery system and paid over 5 figures for it all. He was willing to trade that much money for 3-4 hours AC use in his coach, something he'll never recover through a solar charge sequence and will be actually just pushing around the energy he gains from a tank of petroleum in order to pretend to everyone that he has a solar powered AC setup, something that looks good on a drawing board but exists as only a novelty in the field.  Money is no object for him so if you have that kind of cash, go ahead and follow his direction LOL.

Otherwise the information I gave of disconnecting the boost solenoid and attached at those two connection points will work fine, but again why install a DC2DC if you don't really need it?.   I work from experience and don't follow a sales guideline or what is "supposed to work" and I don't buy unneeded and overpriced equipment because it boosts my ego.     .Anyway I have more to say about people who post their credentials at the bottom of their posts but I digress and I also realize no one is really interested..   Besides, engineer or not, if you have to go around telling someone how important or smart you are, that says more about you than what you claim you know.    Anyway I would think a true engineer might ask for some current readings and SOC readings from a battery monitor to see what your situation was.   I would also think that an engineer would factor in the previous posts here that some seem to be making it fine with no DC2DC converter.   I would also think that an engineer might take into account the Lion lithium batteries, which Costco sells has on the company website to just run a 12 to 14 gauge wire to charge the batteries (their "engineers" said that - not me).  

Cheers ..... and best of luck to you.    If you have a curiosity here, do go back and see those who have done lithium upgrades without altering the alternator or installing a DC2DC converter.   I trust their experience and that's what I was referring to.    A search will provide that same information for you that it did for me.   
-
Don - 2006 Navion J
More degrees than a thermometer
Extremely knowledgeable and competent, yet quite irreverent
Pioleted a Piper Cub illegally at the age of 12
Stromberg Carlson telephone central office switch installation engineer at the age of 17
Disco DJ at the age of 19
Bachelor of Science with major in Physics
Radio Television Production engineer
1st Class FCC license ("First Phone" broadcast engineer license)
Main frame computer engineer for America's largest computer company
Main frame computer programmer
Computer programmer, IBM Mainframe
Computer programming teacher
MCSE Certification (Microsoft Systems' Engineer)
Microsoft VB Programmer
Hobbies include building 3 homes from the ground up
Rebuilding engines
All aspect of electronics hobbies
Larger in the anatomy department, demanding much less in the ego department
Latest endeavor - Exposing arse-howels
Bored Yet?
--
Don - 2006 Navion J


old_b4_my_time
 

Anyway, I apologize for taking myself down to someone else's level.   I don't do that too often but sometimes the unneeded character or qualification "critiques" are too much for anyone to handle.    Regardless, your situation with what I am assuming is a "drop in replacement" for a lead/acid, if you believe this site here:
https://www.powerstream.com/lithium-phosphate-charge-voltage.htm

They state that in nearly all cases of LiFePo4 batteries a cell will attain a SOC of 99% at a voltage of 3.5VDC.   If you multiply that by four cells in your battery that is 4 x 3.5VDC which comes up to 14VDC in my engineering guide (wink) so this means in simplified layman's terms (wink) that if you alternator is outputting 14.2VDC, then you should be sufficiently charged or at least 99%-so by using a conventional engine alternator.   Then all you have to worry about is that the initial high current curve in amperage drawn will not overload your alternator.   And I don't know what that is because I don't have a lithium setup yet to test it.   That's why I asked you for figures on what you were seeing and why you are describing your existing setup as failing.   

My guess at this point (which might come close to someone who had a 24V system using a different chemistry and was also guessing, proven from all the assumptions and no requests for further information) would be that the initial charging "current hump" might be proportional to what level the batteries had discharged to.   Now I base my own guesses from comments I read from the van builders on Sprinter Source and what a few here have said, that they operated seemingly well with no "charger" or DC2DC or whatever you want to call the expensive device that limits current and augments voltage.   I call it a boost converter with current limiter but it doesn't matter what you call it, the question seems if there is a way to avoid paying a great deal of money for something that may not be entirely necessary.    And I personally believe people are being "penny wise and pound poor" if they go to lithium while touting the higher charge capability of these batteries because they later (seemingly happily) settle for a 20-30A charge rate because they wanted to spend only $300 for the 20-30A instead of $700 for the 50A or higher lithium charger.   

Still I don't want to lead you astray.   Even considering that many are operating fine without a "charger" or DC2DC or whatever you want to call it, I would imagine they may be on a cusp and there could be a situation in the future where they will deplete their bank enough and to a point that the initial large current draw for the front-end of the charge cycle could very well destroy their alternator at some point in the future.   So I would feel terribly bad if I convinced you to wire direct, which I would not really do without knowing what your current draw is during the charge cycle of the lithiums (that I assume) you now have direct connected.   Even in my own experimental suggestion, as I have stated would not hook up a new bank of lithium direct to the alternator without knowing the my current draw levels at various states of charge of the lithium bank.  I'd keep a close eye on the battery monitor and see how they performed over time before like you, going to a low-current battery charger as an alternative for direct charging.

So to be 100% honest, for the sake of not wanting to be liable or to feel very, very bad if I lead you astray I'd say to go ahead and use that Dc2Dc that you must have already purchased.   But to be 100% honest, I also would say to myself when I walk away "wonder why everyone is automatically willing to accept such a low charge rate of 20-30A out of these things when a 150A-210A alternator is just sitting there waiting for a nice task to do".

Still if you want to do a character and skill evaluation, then maybe ask why I'm not willing to accept a 20A-30A charge rate from my alternator into my possibly "extremely hungry" lithium bank and other's who are blessed with the knowledge that I have been accused of lacking are willing to accept it without question.

And speaking of questions, I see that my good friend Dunc did let you know that the "black thingy" is the house battery disconnect can be ignored if you are wiring in while removing the boost solenoid.

On another plane however, if you do have a battery monitor before you start on this DC2DC charger installation, I'd be interested in how much current (amps) are flowing into your new lithium battery bank from the alternator when the engine is cold and you initial start the engine.  The failure you explain could be a matter as simple as your boost solenoid when presented with this current load (the stock ones I believe are at 80A where the Cole-Hersey that people recommend is rated at 200A) may have simply "pitted out" and given up trying to pass the high current those new lithium's are calling for.    Still we teeter on what you actually want to be a solution and what you feel comfortable with.   Passing me these amp-levels would only be to clear up my own curiosity before you go and remove that boost solenoid to install the new charger.  I'd really like to know what's happening in your system with it direct connected to the alternator.

Cheers ...

--
Don - 2006 Navion J


Ken Marr
 

Peace, love and happiness brothers! It's time to take a deep breath and enjoy life as it's too short to be squabbling!

Ken
11J Happy with 300W solar, 2000W inverter powered by two old fashion 6V Trojan T105 batteries... But.... LiFePO4 do sound intriguing.... :-)
WA



mrc3
 

I helped a friend with a DC to DC charger/converter install.  He had purchased LiFe batteries for his coach.   He said the manufacturer recommended the installation of a DC/DC charger and I also wondered why.  The answer upon some research had little to do with achieving full charge, but rather how much load would be placed on the Sprinter alternator from a nearly fully discharged pack.  The Internal resistance of the LiFe batteries is significantly lower than lead acid... which is great, they can deliver more power without significant voltage drop than lead acids.  Want to use your microwave to warm up a cup of coffee off of a suitable inverter... no problem.  But it also means they do not limit the current charging the batteries unless the internal BMS does so... But usually the internal BMS is simply to balance the cells and keep from overcharging individual cells.

 The internal resistance of a lead acid battery will prevent exceeding the capabilities of the alternator no matter what the state of discharge.  Not true for the LiFe batteries.

We did a pretty simple under seat installation of a Renogy Dc/Dc converter.  Disconnected wire from Boost Solenoid and connected to output from DC/DC.   Connected Boost Solenoid to input of DC/DC.  And with this simplified approach, he will not have a functional Boost Switch.  Also he will not have a parasitic drain from the DC/DC on his chassis battery when the engine is not running.

Regards,
Mike Carney - 09NH


Rick 17VV
 

I've read this in several similar threads. Some people just disconnect the wire coming from the ignition going to the solenoid to keep the boast capability. Guess it depends on what you want. Others disconnect the ignition wire and don't worry about the alternator charging the coach batteries. Lots of choices and pros/cons on all of them. Not sure which way we will go yet.
--
Rick
17VV


old_b4_my_time
 

Don't think anyone is squabbling - I kid the Dunc.   He needs a bit of ribbing now and then to keep on the light side LOL.

Lithium is indeed intriguing .... I am getting more piggish on my power consumption, that's why I have been doing a lot of research on lithium. I don't know why it bothers me so that they are flashlight batteries in a case and if I hadn't seen that old codger in the youtube video who reminded me some of the same cells were used in my cordless drill that I absolutely hate, well I can't say hate because I have one battery now that has lasted 5 years but it ends up being nickle metal hydride (sorry I obviously can't spell and too lazy to look it up most times)  but I continuously worry that one or two of these apples will go bad and spoil the whole bunch. (Maybe these guys building the power walls out of slip-in 18650's are not so dumb after all.  At least you can swap one out if it goes bad. LOL)  Still we are stuck between a rock and a hard place with the weight issue when looking for viable power sources.   So I'm still searching.   I want to do a build it yourself project if possible and I may be simply living under an illusion that I can get a 100aH single cell for $100 that is anything but a second or reject but the aliexpress ads always create the most foolish behavior in me.   I first was considering a Winston with the large yellow 400aH single cells but then I saw that a reasonable BMS in that high current model will need to be the type that disconnects through relays and that means a large phantom current flowing whenever the coach would be parked for long periods and still need power "on call" so to speak.   So that means several solid state BMS in parallel (like the drop-in replacements most people are opting for) will have the MOSFET type BMS which is minimal phantom load (and will not require the relays needed for 400 aH Winston e.g. the high amperage marine grade 123BMS.    Still I have some kind of phobia toward bending over and swallowing the Battle Born marketing ploy, as $500 per battery for an insurance policy seems pretty high if I can indeed find some acceptable aliexpress cells and a relatively cheap yet dependable BMS.  However, maybe the insurance policy route (Battle Born) is the only way to go when running the house lights off flashlight batteries (joke).
--
Don - 2006 Navion J


John Purwin
 

David; I wired in a B to B charger when I installed my Lithium Batteries.
I left the battery boost solenoid in place to ensure the b to b shut off when the engine was not running.
I have a 2019 J and I installed the lithionics batteries. I used a Kasie b to b,
To wire the b -b move the house battery cable from the boost solenoid to the shut off solenoid ( on mine it is a red cable with yellow tape on the end)
Disconnect the jumper between the boost and shut off solenoids.
Wire the b to b charger between the boost and shut off solenoids.
I wired the negative connection to the ground under the drivers seat and not directly to the engine battery, so that the engine disconnect still worked.
The new b-b charger will prevent the house batteries from starting the engine and by leaving the boost solenoid in place, it is able to disconnect the b-b from the engine system when the engine is not running.
What I found is that with my 300 watts of solar, i needed a way to shut off the b-b charger when returning home to not have a fully charged battery when we stored the RV.
I did this by adding a switch to the LR wire that runs between the boost switch and the solenoid.
Check your wire diagrams for your year to confirm which wire it is if you decide to add this.
I have found with my setup, that the solar handle most of the charging and when we do go to a site with Electric, that the get to a full charge with an hour or two.
I tried to upload your PDF marked up but i was not succesfull.
John P.
2019 N25J


David Harper
 

Thanks Mike!


On Sep 26, 2020, at 10:14 AM, Rick 17VV <rreynolds51@...> wrote:

I've read this in several similar threads. Some people just disconnect the wire coming from the ignition going to the solenoid to keep the boast capability. Guess it depends on what you want. Others disconnect the ignition wire and don't worry about the alternator charging the coach batteries. Lots of choices and pros/cons on all of them. Not sure which way we will go yet.
--
Rick
17VV


Dunc 18ND W.CO
 

David,

Follow John's excellent wiring advice. My manual override switch was added for a different reason, but great idea also for those that want to store slightly discharged. I store my rig at home, with shore power and the refrigerator stocked and running. We have been camping a few days every week for the last three months. Be sure to use your (still unspecified) battery manufacturer's suggested values for bulk, absorption and float when programming the Victron Orion. I assume you have already calculated your current or projected power storage needs are not met by FLA battery chemistry, and made the jump.  Good on ya!

Mike,

Lithium charging is best handled with a purpose-built charger. Since lithium batteries are expensive, this is the best insurance you can buy. 

Don,

Cut the meandering BS from this thread. Most of what you present is simply a "guess" or your personal opinion. PM me if you want to exchange CV material. We will likely find lots of common ground and personal history to actually become friends. This discussion list is not the venue.

Your personal aspersions to me and facts are grossly incorrect and I will redress herein.

If you had researched/read my Tesla installation post you will see that I spent $5K, not your stated "five figures". For this amount, I have a 10kWH system plus a full featured 3kW inverter, where just the Battle Born or equivalent battery cost would be ~$8K. A good DC-DC charger is the sole "additional expense" of any proper simple lithium installation, just as David is doing. My programmable/BlueTooth Victron Orion DC-DC was $260) The only additional expense for a 24V system is a single 24-12V converter. My Victron 24-12/70A was $265. My fully optional upgrade to a 3kW Victron inverter/charger cost $1200 but is included in that total system upgrade cost. Each of these Victron units have many useful features as outlined within my installation post, and I felt well worth the additional expense, plus their US-based customer support. Both Tesla batteries perfectly fit within the OEM under-step battery compartment - no storage space loss.

"To each according to their needs" is a good lead-in statement for the following. My wife and I both use CPAP at night, plus a constant flow oxygen concentrator. Our typical nighttime power use with refrigerator, etc. is about 300W, so for 8 hrs = 2.4kWh required. This would completely drain two (1.2kWh) Battle Born batteries. The two Tesla batteries provide three days of power with reserve even with no solar, generator, nor shore power. Yes, I can run the air conditioner for several hours. If 2.4 kWh of power storage is used, the solar system must be sized appropriately. You need to charge at least 2.4kWh each day. PV capacity x 50% is a good rule of thumb, so at least 600W PV. My 800W PV is usually enough, but still not always - especially with the current West Coast wildfire smoke here in Colorado. I hope those captured arsonists could be burned on a stake! 

--
Dunc, W.CO, 2018 N24D
800W Solar, 10kWh Tesla Coach
Gyrocopter Toad


old_b4_my_time
 

On Sat, Sep 26, 2020 at 07:41 AM, John Purwin wrote:
I wired in a B to B charger
David, that is an excellent idea.  I've read where some of these units have an "enable line" and that would ensure they didn't draw down the chassis battery when the engine is not running, but having the boost solenoid cut off the power source would be double insurance..
 
--
Don - 2006 Navion J


Dick Stevenson
 

Hi David, Your pics make me think of those movies where picking the correct wire disables a bomb in conjunction with anxious music and sweaty brows "Cut the yellow wire..." Dick