Traxide Dual Battery Voltages

Quote:

---

Originally Posted by LRD414

Another related point is that the 12.7V will drop to 12.4V with ignition on but engine off for a healthy cranking battery.

---

Just for clarification. When I get into the car and the voltmeter I have in the accessories port says 12.70 that's an accurate reading if I haven't yet turned the engine on or pressed the start button (ie switched on but engine not started). Just asking cause I know that opening the door wakes the beast up so to speak. :)

Martin

I'll throw this into the mix. A while back I got in touch with Optima USA regarding the SOC voltages for Optima batteries and this is there response.

State of charge for an Optima deep-cycle battery, while not under a load:
100% charged is 13.18 Volts
75% charged is 12.69V discharge up to 750 times
50% charged is 12.28V discharge up to 600 times
25% charged is 11.72V discharge up to 450 times
0% charged is 11.27V discharge up to 300 times

I assume the difference in SOC voltages is due to the different style of battery.

Quote:

---

Originally Posted by letherm

When I get into the car and the voltmeter I have in the accessories port says 12.70 that's an accurate reading if I haven't yet turned the engine on or pressed the start button (ie switched on but engine not started).

---

Martin, the 12.7 I stated earlier was a proxy for 100% SoC on a connected battery as per Tim's chart.

My actual figure is usually 12.5 from an accessory socket voltmeter, probably due to my lots-of-short-trips-in-city typical use.
When it "wakes up" voltage drops to 12.4

With your 12.7, is this in a socket connected to Traxide/aux or just factory/crank and does it stay at 12.7 without dropping?

Scott

Quote:

---

Originally Posted by LRD414

Martin, the 12.7 I stated earlier was a proxy for 100% SoC on a connected battery as per Tim's chart.

My actual figure is usually 12.5 from an accessory socket voltmeter, probably due to my lots-of-short-trips-in-city typical use.
When it "wakes up" voltage drops to 12.4

With your 12.7, is this in a socket connected to Traxide/aux or just factory/crank and does it stay at 12.7 without dropping?

Scott

---

Hi Scott.

I just had a look and it's 12.3 ATM (I quoted 12.7 to not confuse the issue). It's factory/crank. Dropped for a moment to 10.9 when I started the engine and then ran up to 13.3 and settled at 13.1 with engine running. I let it close down and it only went down to 11.7 compared to the first time. The voltmeter doesn't show anything when the car has closed down. I too do mainly very short trips so I put it on a charger occasionally, probably every 2 months. I mean to do it monthly but don't get to it. :p

I bought the voltmeter to keep a bit of an eye on it but I'm not very knowledgeable about these things. At least Tim's chart gives me an idea so I can take preventative action if needed.


Martin

We could be twins except mine is sitting a bit higher SoC initially and also sits higher when the car is running (at 14.1).

Try measuring the voltage using the pins on the white trailer plug (pins 3 -ve, 4 +ve) first thing in the morning or after it has been sitting for a couple of hours (locked). Measure before you unlock it and wake it up. This should give a more accurate reading and SOC of the cranking battery.

Quote:

---

Originally Posted by LRD414

We could be twins except mine is sitting a bit higher SoC initially and also sits higher when the car is running (at 14.1).

---

Mine does get into the 14 range sometimes but usually when I'm on the road instead of idling in the driveway. I haven't been constantly monitoring it, just looking now and then.

Quote:

---

Originally Posted by Mungus

Tim,
Please correct me if I am wrong, but;

1. When saying the Isolator/s has 'Shutdown', it is in the 'Isolated' state, as in the two batteries are disconnected?
2. When shutdown (batteries isolated), the cranking battery only, can be charged, be it from a generator/charger, solar via regulator etc., via the white 12S trailer plug?
3. When Shutdown (batteries isolated), the Aux. battery only, can be charged via your Anderson plug?
4. When batteries above 12.0V and Isolator is On (as in two batteries connected) charging via your Anderson plug will charge both batteries?
5. With batteries connected, charging to both batteries can still be done through the White 12S socket?

So if my assumptions above are correct, the newer SC-80 with reverse charge and future USI-160, whilst having advantages for certain scenarios, your current model USI-160 will be sufficient for my needs?

---

Hi Mungus and the USI-160 in it's present form still has features not available in the new SC80.

The main one being the ability to select either SHARED Mode, as the SC80 operates, or IGNITION Mode.

And your "assumptions" are correct.

Quote:

---

Originally Posted by rufusking

I'll throw this into the mix. A while back I got in touch with Optima USA regarding the SOC voltages for Optima batteries and this is there response.

State of charge for an Optima deep-cycle battery, while not under a load:
100% charged is 13.18 Volts
75% charged is 12.69V discharge up to 750 times
50% charged is 12.28V discharge up to 600 times
25% charged is 11.72V discharge up to 450 times
0% charged is 11.27V discharge up to 300 times

I assume the difference in SOC voltages is due to the different style of battery.

---

Yes and no, It has little to do with different battery types under normal use and is what is known as OPEN VOLTAGE readings.

My chart is pretty accurate for use with any type of lead acid battery, with a moderate load applied to it, like say a compressor fridge.

The voltage readings Optima supplied you are OPEN CIRCUIT voltage readings, and yes, this type of voltage reading will differ from one type of battery to another but is next to useless.

The reason a state that OPEN CIRCUIT voltage readings are next to useless is because they are only accurate once the battery has been sitting in a "No-Load/No-Charger" state for a least 24 hours.

this does not apply to an battery in a vehicle, because there is nearly always a load, even a very small load, applied to the batteries at all times, even when the motor is off.

Another problem with OPEN CIRCUIT voltage readings is that you must know that the battery is in good health when you take the readings otherwise, you may get a reading that shows the battery is fully charged, but the instant you apply a load, even something as small a load as a fridge, but the battery can go flat in a few minutes.