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How to Set Up a TriStar PWM Charge Controller with LiFePO4 Batteries

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Setting up your Tristar PWM charge controller to work with Battle Born LiFEPO4 batteries is a cinch!

Step 1:

Remove the access cover. This is the front cover on the unit that is held in with four screws.

Step 2:

Adjust the first three DIP switches.

The first three DIP switches are related to the system voltage. Use Table 1 below to configure the first three DIP switches. We do not recommend that you use the “Auto” setting because variations in battery charge levels and connected loads can cause unwanted errors.

 How to Set Up a TriStar PWM Charge Controller with LiFePO4 Batteries

Table 1: System Voltage

Step 3: 

Set the remaining DIP switches to the following:

4: OFF
5: ON
6: OFF

7: OFF

8: ON

Note: Do not connect the RTS cable and never set the unit into equalization mode.

If you have any questions or comments on how to set up a TriStar PWM charge controller with LiFePO4 batteries, please send us an email at [email protected] or give us a call at (855) 292-2831.

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11 thoughts on “How to Set Up a TriStar PWM Charge Controller with LiFePO4 Batteries

  1. These Dip switch settings will cause the TriStar to hold the absorption voltage (14.3V) for 150 minutes.
    The manual states absortion time should be 20min. For each battery in parrallel, so this is way too long according to the manual unless you have 7 batteries in parrallel.

    Are the Custom settings really lost on the TriStar when the power is removed ?

    1. Hi John,

      The absorption time being held for a longer period than recommended is not critical for properly charging the batteries. As long as each battery in your bank is held for 20-30 minutes at least a couple times a month, you will have batteries that are internally balanced and fully charged.

      We would have to check with TriStar in order to verify that the settings are lost each time the power is removed.

      Thank you,

  2. I have a large solar array.
    Every sunny day my batteries will be at the absorption voltage for 150 minutes with the settings you reccomend, not just a couple of times a month, it could be every day of the month.

    Is that OK ?

    I am able to program a custom setting if that would be better.

  3. Your manual says that the absorption stage should be 20 minutes for each battery in parrallel.

    That seems to say 20 minutes times the number of batteries in parrallel.
    That makes no sense to me ? Why would the number of batteries in parrallel make any difference ?
    Was that intended to be batteries in SERIAL ?

  4. This makes no sense. Stays in Absorb way too long and like someone else mentioned; the batteries are in parallel not series so the time for absorb would be 20min not 20 X the number of batteries.

    Also this occurs every day and depending on conditions and load, it may occur several times a day. So we’d be holding 14.4v for 1.5 hours every time it cycles during the day.

    Author mentioned to do this a couple times a month? That makes no sense either because these dip switch settings are constant (all the time) not day specific (couple times per month).

    I wish SOMEONE would come up with a the proper charge profile for LiFePo4 batteries. The chemistry is the same for all of these batteries. The only difference is the BMS and how it balances the cells. Correct?

  5. The Morningstar web site says:

    We never want our batteries to enter the absorb or float states.
    Set dip switches to “Custom”.
    Set the absorb voltage to 14.00v (it will never get this high)
    Set the High Voltage Disconnect (HVD) parameter is set to 13.88 volts
    Set the High Voltage Reconnect (HVDR) parameter is set to 13.29 volts (3.323vpc).
    Battery will charge in BULK mode until it reaches 13.88 volts. At 13.88 volts HVD creates a “FAULT” condition, the solar panels are disconnected from the system, and charging halts. When the battery voltage drops to 13.29v or below, charging resumes in BULK mode (the ABSORB voltage of 14.00 was never reached so the controller
    remains in BULK charge mode) and the charge cycle starts over again.

    Now the only thing that remains is balancing which requires 14.4v a couple times per month at most. This can be set in the “Enable Equalize” tab of MSView. Set Equalize voltage to 14.4 and the time for 20-30 minutes. You can set the Auto Equalize interval to 7, 14, 28 or how ever many days you want it to cycle. Every 7 days should be more than enough and prevent the batteries from being held at a very high voltage for prolonged periods of time. You could also set the Equalize Timeout to 1h0m0s so that if you ever use the low noise setting (to minimize RFI for ham radio reception) it will force the equalize to make sure to shot off after 1 hour.

    This should work perfectly. Anyone see any problems with it?

  6. I’m not sure but the HVD of 13.88 might prevent the TriStar from ever being able to go into Equalize mode.

    I’m sure there is a way to set this up properly without having to go to 14.4 every day or worse several times a day.

    Every web site I look at has different recommendations and none of them seem to be correct.

    1. Hi Norm,
      Thank you very much for the feedback. Our team can certainly look into restructuring and updating this blog to make it appear clearer when using this particular charge controller. The technical team suggests to take Morningstar’s suggestions or give their company a call. If you have any questions about your Battle Born Batteries please give our sales and tech team a call at 855-292-2831 or send an email to [email protected]. Thank you again and have a great rest of your evening.

    1. Hi Bruce, thanks for reaching out. You would need to contact the manufacturer. We only deal with 12, 24, 36, and 48V settings. Please let me know if you have any additional questions and have a great rest of your afternoon.

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