High Volts? New Batteries and Morningstar TS-45-MPPT

Wanderman · June 2014

Hey all.

Recently my pair of batteries had 2 cells go bad on one battery. I replaced both Trojan 27TMX's with Trojan SCS225's. A bit more power (130aH vs. 105 aH)

With them in place, this morning. I am seeing odd reading on the Tristar RM-2 Monitor.

With fully charged batteries, I am seeing:

14.9V 64deg F 2.0A Absorb PWM

I checked at the batteries and they are at 14.96 V If I shut down the Tristar, and use the 4 stage converter charger it senses "float" and reverts to 13.6V (to be honest the tristar does charge higher)

I have the Tristar MPPT set to use Battery Type 6 (14.7 max, 13.6 Float Manual Equalize)

Is the high voltage an issue? I do not wish to destroy two new expensive batteries.

Thanks,

Rich

BB. · June 2014

Re: High Volts? New Batteries and Morningstar TS-45-MPPT

It does not sound correct... Have you validated the RM-2 meter reading with a hand held meter?

I would address it--That is too high of voltage for nominal charging.

-Bill

Cariboocoot · June 2014

Re: High Volts? New Batteries and Morningstar TS-45-MPPT

14.9 Volts is not too high an Absorb setting for Trojans.
As Bill suggested, check with a DMM to see if this the real Voltage.
Also be sure you are using a remote temperature sensor. The Battery Sense wire connections may help.
Then there is issue of how long they are being held at that Voltage: too long and the batteries will cook, rather than charge.

This is why I do not like the MS TriStar MPPT. Unlike Outback and MidNite, MS controllers are not fully programmable right out of the box. The 'preset' selections tend to be wrong for whatever batteries you've got. You probably will have to program a custom setting using a computer and their software.

Wanderman · June 2014

Re: High Volts? New Batteries and Morningstar TS-45-MPPT

I have checked the batteries with meter. 14.9 V

I do have a temp sensor it says the batteries were at 64 deg.

The Tristar MPPT 45 settings I am using (set with the dip switch) are:

Switches Battery Type Absorp.Stage Float Stage Equalize Stage Absorp. Time Equalize Time Equalize Timeout Equalize Interval

on-off-on 6 - Flooded 14.70V 13.50V 15.40V 180m 180m 240m 28Days

I have the cable and the software and can customize, no problem. The question is...how do I make sure I am not damaging the batteries and what should the settings be.

14.8V is what Trojan recommends for charging, but I am higher than that now with 14.7 as the Tristar MPPT set point.

What now?

Rich

Wanderman · June 2014

Re: High Volts? New Batteries and Morningstar TS-45-MPPT

Bit more info. It seems the RTS (Temp sensor compensation) value is .03 V per 1 degree below 25 deg C. At my temp 17.7 deg C (64 Deg F) I am around 7 degrees cooler. 7 x .03 = .21 V compensation. Set point is currently (no pun intended!) 14.7 V. So:

14.7 + .21 = 14.91 V I am seeing 14.9 V on the Tristar RM-2 Remote display and 14.96 at the battery.

Sounds reasonable, no?

Rich

inetdog · June 2014

Re: High Volts? New Batteries and Morningstar TS-45-MPPT

Yes.

.................

zoneblue · June 2014

Re: High Volts? New Batteries and Morningstar TS-45-MPPT

Yeah just sounds like your temp comp kicking in like it should.

Wanderman · June 2014

Re: High Volts? New Batteries and Morningstar TS-45-MPPT

OK that's great news!.

What about damage to 12V powered items at ~15V?

Rich

inetdog · June 2014

Re: High Volts? New Batteries and Morningstar TS-45-MPPT

Wanderman wrote: »

OK that's great news!.

What about damage to 12V powered items at ~15V?

Rich

Some electronics will not be happy. Anything designed for use in a motor vehicle should be able to stand up to ~15 volts because the alternator may be putting that out to the battery some of the time. Something designed for use with an actual 12 power supply may not fare as well.

An incandescent light bulb, on the other hand, may burn out more quickly.

High Volts? New Batteries and Morningstar TS-45-MPPT

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