Jump to content


Photo

I need more power Scotty!


  • Please log in to reply
308 replies to this topic

#281 Vic Harder

Vic Harder

    Doctor Electric

  • Site Team
  • 4,898 posts
  • LocationCalgary, Alberta

Posted 08 January 2021 - 07:38 PM

Good article on how to wire up your batteries.  Among other things, it has a great guide on wire sizing

 

https://enerdrive.co...s-correctly.pdf


  • 1

#282 Vic Harder

Vic Harder

    Doctor Electric

  • Site Team
  • 4,898 posts
  • LocationCalgary, Alberta

Posted 25 March 2023 - 11:42 PM

After having my brand new Optima Yellow Top truck batteries die twice over the winter, I made a few changes to my charging system. Turns out that I have a small parasitic draw (will track that down once the weather warms up) in the truck that will kill the truck batteries in a week or so.  So, I need to be able to charge the truck batteries from the solar system on the camper to prevent this. 

 

What I did was add heaters for the batteries so they can be charged when it is -30*C out, and I am using both the ACR and DCDC charger.  The point being to be able to charge the 200AH BattleBorn battery bank, and keep my truck batteries charged too.

 

Let’s talk about using BOTH the Victron Orion 30A DCDC charger and a BlueSea ACR at the same time.  I used to think this wouldn’t work, and it doesn’t, and it does.  The input from the truck is fed via 2AWG welding cables protected by 100A breakers, so LOTS of juice can flow over those wires if needed.  The DCDC limits charging current to 30A, which is generally a good thing; however, the current only flows one way, from the truck into the camper.  The advantage of the ACR or battery isolator device is that it keeps both systems connected when charge is available and disconnects them when either is severely draining the other. 

 

To use both, I simply manually connected them in parallel.  The ACR I have is the BlueSea ML-7622 with remote switch.  This device can be manually locked ON or OFF, or left to run automatically.  I am testing it out in manual mode.  So it is essentially a fancy 500A rated battery switch.  With the ACR switched OFF, it is no longer in the current path, so the DCDC works as usual.  With is switched ON, the ACR allows current to flow both ways. 

 

We haven’t finished with the details/and gotcha’s of doing this, but let’s look at the battery heaters for a moment.  I used two heating pads (10A draw/ea) designed for 3D printers and glued those to a sheet of ¼” aluminum that fits under both 100AH BB batteries.  Those can get the aluminum VERY hot, so I use a 40*C thermistor to turn off the current flow to the heaters when it gets too hot.  I can touch the surface without hurting myself, so I figure the battery cases are fine too.  The current to the heaters is controlled by the Victron BMV 712’s “Relay” function, which in turn fires up a 40A relay for the heaters.  This Relay function is very powerful.  I set mine to turn the heaters on when the temperature falls to +5*C, and off at +10*C.  The batteries are in an unsealed enclosure, so the air can warm up in there nicely.  But not when it is -30*C out.  Add in night time, and the batteries can drain pretty quickly.  12 hours of darkness at 20A and I am potentially pulling 240AH… out of a 200AH battery?  Nope.  Luckily they don’t have to run for 12 hours, but close enough that over 2-3 days the batteries would be totally discharged.  Not good. 

 

To compensate on super cold days, I plug the camper in to shore power, and that keeps the camper batteries topped up… But on “Spring” days like today, where the temperature is fluctuating around 0*C a dozen degrees or so, the batteries stay warm and the 330W solar panel can do its thing.

 

How does that work?  Well, the solar panels charge the camper batteries to 100% by mid afternoon, and then all night long the camper batteries keep themselves warm and because LiFePo4 batteries rest at around 13.4V, they are trickle charging the truck’s AGM batteries (which rest at 12.7V) all night/day long.

 

Truck starts every time now, no more dead starting batteries! 

 

 

Downsides/gotchas?  I have to remember to switch OFF the ACR when driving, because I have yet to measure how much current the BB batteries will take from the alternator.  It could be too much for both the batteries and for the alternator.  I have a BlueSea Ammeter that I will be installing to check that. 

 

The DCDC seems to get confused by the voltages it is seeing on the input/output and is actually running while the ACR is on.  Having a double pole switch and actually removing the DCDC from the circuit instead of having it in parallel with the ACR would be better, but it doesn’t seem to be hurting anything.

 

When I have the ammeter and the ACR remote switch mounted in the cab of the truck, I’ll be able to control things more closely.  In the meantime, I am happy with the results.


  • 2

#283 Wallowa

Wallowa

    Double Ought

  • Members
  • 2,173 posts
  • LocationNE Oregon

Posted 26 March 2023 - 04:54 AM

Long thread with much valuable information...definitely helped me in our conversion to Li battery..might add that we have found the BB internal heater valuable as it has kept the BMS from stopping any input charge at very low battery temps [25F?]; so in Winter our panels keep the battery up even in minus temp conditions while we are out skiing...just a thought...as I remember the BB internal heater keeps battery at between 35 and 45 F...


Edited by Wallowa, 26 March 2023 - 04:55 AM.

  • 0

#284 Vic Harder

Vic Harder

    Doctor Electric

  • Site Team
  • 4,898 posts
  • LocationCalgary, Alberta

Posted 26 March 2023 - 06:11 PM

Internally heated is definitely the way to go.  Those were not available/out yet when I bought mine.


  • 0

#285 Wallowa

Wallowa

    Double Ought

  • Members
  • 2,173 posts
  • LocationNE Oregon

Posted 26 March 2023 - 06:14 PM

Internally heated is definitely the way to go.  Those were not available/out yet when I bought mine.

 

 

As usual Vic you engineered an innovative and effective work around!


Edited by Wallowa, 26 March 2023 - 06:14 PM.

  • 0

#286 Bigfoot Dave

Bigfoot Dave

    Senior Member

  • Members
  • 128 posts

Posted 27 March 2023 - 12:17 AM

Thanks Vic, What voltage are your solar panels running at? 12V or 24V?

My camper has 2 renogy 100W panels and I currently have them in parallel vs series.

Getting ready to go 200 or 300A lithium with Victron gear and trying to figure out what equipment I need,

Thanks, Bigfoot Dave


  • 0

#287 Vic Harder

Vic Harder

    Doctor Electric

  • Site Team
  • 4,898 posts
  • LocationCalgary, Alberta

Posted 27 March 2023 - 02:22 AM

Thanks Vic, What voltage are your solar panels running at? 12V or 24V?

My camper has 2 renogy 100W panels and I currently have them in parallel vs series.

Getting ready to go 200 or 300A lithium with Victron gear and trying to figure out what equipment I need,

Thanks, Bigfoot Dave

Hey Bigfoot Dave:

I have just a single 330W panel up on the roof.  I'd wire yours in series unless you are really worried about partially shading your panels.  200AH of usable battery is a lot.  I have that much for use with an Induction cooktop.  But, if you have the room and the need, go for it.

 

As for what gear you need, a lot depends on what you already have, and how much you want to spend!  In order of priority:

 

1) Battery Monitor.  Victron BMV-712 or Smart Shunt.  Offshore knockoffs are likely ok too

2) Good MPPT solar controller.  Victron 100/30 or similar, depending on how much solar you anticipate having

3) Upgraded wiring from truck to camper 6AWG minimum, and a Victron Orion non-isolated DCDC 12/30

4) Shore power charger.  If you have the factory Iota, check to see if has the swappable dongle.  If so, order an IIQ4 for Lithium.  If not, that should be swapped out for a Victron ACDC charger too eventually.

 

If you want more solar, I and others here recommend large residential/commercial panels.  A single panel can put out 360+ watts and weigh less than individual panels.  

 

FYI, I have no affiliation with Victron, I just like their gear.  I hope that helps.  


  • 0

#288 ntsqd

ntsqd

    Custom User Title

  • Members
  • 2,879 posts
  • LocationNorth So.CA

Posted 04 April 2023 - 02:44 AM

Some wiring trickery would nearly fail-safe turn off the ACR when the engine is turned on. Use typical "sugar cube" NO/NC relay with wire for the remote switch running thru the NC power contacts. Tap into an IGN source for the relay's coil power. IGN on = remote off.

:)

 

OR write a bunch of code, do some additional wiring, and turn all of the control of the system over to an Arduino.

 

:) :)


  • 0
Thom

Where does that road go?

#289 Vic Harder

Vic Harder

    Doctor Electric

  • Site Team
  • 4,898 posts
  • LocationCalgary, Alberta

Posted 04 April 2023 - 06:23 PM

Some wiring trickery would nearly fail-safe turn off the ACR when the engine is turned on. Use typical "sugar cube" NO/NC relay with wire for the remote switch running thru the NC power contacts. Tap into an IGN source for the relay's coil power. IGN on = remote off.

:)

 

OR write a bunch of code, do some additional wiring, and turn all of the control of the system over to an Arduino.

 

:) :)

Thanks. for that tip.... I got the DCDC to turn off when the ACR is closed by tweeking the engine running voltages.  I was already thinking of using an "ignition detection" wire to simultaneously turn on the DCDC and turn off the ACR, using a DPDT relay.  As it is, there are times when I may want to use the ACR connection when the engine is running, like letting the batteries charge as fast as possible by taking whatever current the alternator puts out.  Not doing that until I have my BlueSea shunt based current meter in the circuit again.  


  • 0

#290 Jollyrogers

Jollyrogers

    Senior Member

  • Members
  • 147 posts

Posted 24 July 2023 - 12:08 AM

I just finished converting over to LifePo4, replacing my IOTA, new truck wire and DC converter. I tested charging from the Victron 12|12-30 DC2DC charger. It all worked, but my gawd that thing gets hot! I have everything separated by breakers, so was thinking of adding a 12vdc fan to blow right on it. It would just come on with a manual switch I think. I’m honestly a little scared about how hot it gets, and that was with the door open.

Also, is it worth adding standoffs to get it up off the compartment wall?
  • 0




0 user(s) are reading this topic

0 members, 0 guests, 0 anonymous users