24v solar for Adventure Trailer

thardin68

Member
Hi all, been a while. I have procured a number of components for my system. I have:
  • Battery - Tesla S-series module
  • 057 Converter Board (for balance charger / BMS)
  • Samlex 2224 24V 2200W Inverter / Charger
  • Samlex Evo RC (Remote control & Screen)
  • (2) Renogy 300W panels
Planned but not purchased yet:
  • Victron Smartsolar MPPT 150/35 Charge Controller
  • Victron BMV-712 Smart Battery Monitor
  • Victron Smart Battery Protect 200A
I am starting to prepare a schematic to sort it all out and I am wondering if anybody has any input (other than ditch the Tesla because you will die)......

The Victron Charge Controller will be connected to the input of the Samlex, which allows for programming of the charge parameters. The 2224 includes a Temp probe to monitor battery temps and will adjust according to parameters set. The BMV-712 and BP200 I am planning to add a second layer of protection in case the Samlex unit fails to perform within the set parameters (Victron equipment will disconnect the battery if charging above set voltage or if battery is below a specific temperature). I assume I will need to set the Samlex piece with some more conservative settings and the Backup Victron components with a slightly more aggressive set-up, but still well within the limits of the Tesla Battery.

To keep things simple, I am going to skip the 24V/12V converter and just run everything off of the inverter. I have attached a schematic from the Samlex Manual for mobile installations. My system will be isolated, so no starting battery or isolator involved. I will also be managing AC input (shore power) or Generator connection manually, so the Samlex' ability to manage and auto start a generator are of no concern for me.

I will have (1) 300 Watt panel mounted to the top of my tow rig, with the 2nd panel available when set up for base camp. I will not be charging from vehicle (I have a separate dual battery system in the tow vehicle)

So thats the start of the plan. Any thoughts? ANy confirmation that the BMV / BP are necessary, or insufficient for my intent?
 

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luthj

Engineer In Residence
Lithium needs only minor charge voltage adjustment with temp (half or less than lead). So generally its easiest just to disable temperature voltage compensation. A temperature cut-out for high/low temp is important though.

Assuming you have a working balance board, monitoring pack voltage should be fine. Checking cell voltages manually should be done the first 5 cycles, then 10 cycles, then 50 cycles, and every 100 cycles thereafter. if everything is staying in balance, you can do it once a year after that.
 

thardin68

Member
luthj - thanks for the response. I understand what you are saying on temp compensation and will read up on it (for knowledge) and will likely disable any compensation as you indicate.

I have the 057 board and leads added to the battery which are supposed to allow you to monitor with a simple unit like the Tenergy 5in1 (or similar). I figured I would be checking it manually with this for the first few cycles for sure. I understand the limitations associated with this. I just started looking at a BMS board that Jehu Garcia is peddling now to see if it offers any protection for me. From what I have seen from those using the Tesla battery for such fractional use, nobody has been having any balance issues.

I am interested in your thoughts on using the Victron equipment to sense and disconnect the battery in the case where the Samlex does not do its job maintaining within the set parameters. I believe it was you who identified some much more low cost relays as options for providing overcharge protection? I dont mind spending as little $$$ to buy a manufactured product from a reputable company, especially if it allows Bluetooth connection to monitor.

Thanks again.
 
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