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Battery recharge on 110vac - temp above 95 deg F?

June 20, 2017, 11:42:40 pm

Sooooooooo..........

In Moab today the temp was 104 and has been almost as hot for the last few days  We have been here plugged in for 2 nights and my battery bank does not show 100% charged yet.  We were dry camping in Capitol Reef and was limited to 2 hours 2 times a day  -  total gen set running time, 4 hours per day.  (As noted in another thread -  we left early - due to heat.)  (Historical average here is 85deg  F.)  When we arrived here and plugged in,  we were about 85% SOC. 

For the last 2 days my Trimetric shows 93% State of Charge.

Question:  Would 98 to 104 ambient heat, around the batteries,  reduce the amp charging capacity of the battery bank? 

My next call will be to Prosine.

As always your indulgence is appreciated. 

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Re: Battery recharge on 110vac - temp above 95 deg F?

Reply #1 – June 20, 2017, 11:46:56 pm

The gauges accuracy can vary.  At least mine does.  The xantrex link pro has a set of up and down arrows that scroll through the function screens.  Went through the not 100% recently.

Finally pushed both arrows and reset the unit to 100%

At 13.6 float voltage for long term on our gels they were 100%.

Made the gauge match finally

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Re: Battery recharge on 110vac - temp above 95 deg F?

Reply #2 – June 20, 2017, 11:58:14 pm

Trimetric Voltage shows:  13.0

I do not have the Prosine ACS Control Panel on our 2.5 - No up/down arrows that I can see.

The question still stands -

Would 98 to 104 ambient heat, around the batteries,  reduce the amp charging capacity of the battery bank? 

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Re: Battery recharge on 110vac - temp above 95 deg F?

Reply #3 – June 21, 2017, 12:05:45 am

Good battery chargers change the charge and float voltage based on battery temperature almost a full volt lower for a hot battery than a cold battery.  Lower the charge voltage and the battery accepts fewer amps, so it always takes longer to put the same amps backing into a hot battery.  Battery manufacturers have optimum & maximum, float & charge voltages at different temperatures.  Follow their chart and battery life will be extended.

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Re: Battery recharge on 110vac - temp above 95 deg F?

Reply #4 – June 21, 2017, 12:52:33 am

Thanks Barry.

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Re: Battery recharge on 110vac - temp above 95 deg F?

Reply #5 – June 21, 2017, 01:13:18 am

To put some numbers next to that theory, here's what the magnum MS2812 does.  Maybe yours is similar.  See attached.

If your charger's float setting is set below 13.5, then  looks like you would only be putting in 13.0Volts-ish in that temperature, so it makes sense that your trimetric reads 13.0V and 93% full.
- If your float charge setting is higher than 13.5, something may be wrong.  Try resetting the Trimetric?
- If the float charge setting is around 13.5, and if you have AGMs, all is well, that sounds in the ballpark
- If the float charge setting is around 13.5 and you have wet cell, float charge should be higher.

Keep in mind that a half a volt isn't going to turn a 3-4 hours expected charge into two days... After that long of a time, either the float charge voltage is equivalent to your battery voltage, or you are getting a bad reading somewhere.

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Re: Battery recharge on 110vac - temp above 95 deg F?

Reply #6 – June 21, 2017, 01:17:40 am

Found this in my Prosine 2.5 manual:

"As with all inverters, the amount of continuous power that the Prosine inverter/chargers can deliver without overheating is limited by the ambient temperature. They will operate and deliver their continuous power ratings at higher temperatures, but the ambient temperature as well as the input voltage from the battery limits the extent to which they can do this. "

Sounds like the answer is yes.  The next question would be:  To what extent?

Will see what Prosine says.

Thanks Blinded04 -

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Re: Battery recharge on 110vac - temp above 95 deg F?

Reply #7 – June 21, 2017, 08:35:11 am

Do you have a battery temperature sensor accessory for your inverter?  They are usually connected at the inverter end by telephone-type connection and the other end attached to a battery terminal?  If so, it automatically adjusts charge voltage down as battery (and ambient) temperature rises.

And, do not rely totally on any gauge (even the really good ones) with "amps used", "amps from full" readings.  Suspect in their manual they will mention that their system is not 100% accurate and occasionally needs to be zeroed.

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Re: Battery recharge on 110vac - temp above 95 deg F?

Reply #8 – June 21, 2017, 10:54:18 am

We do have a battery temperature Sensor.

Talked to Prosine this AM and they confirmed that the battery sensor provides input to the charger limiting charge to the batteries so they do not over charge during higher ambient temperature. 

As usual I appreciate the support and input from my fellow FoFum members.

Guess I can put replacing the Prosine and having to decide whether to go with Magnum or Victron on the back burner. 

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Re: Battery recharge on 110vac - temp above 95 deg F?

Reply #9 – June 21, 2017, 11:06:45 am

I used to adjust the Trimetric 100 rating based on ambient temps.  Same hold two buttons in and it will adjust to 100.  If you decide to upgrade replace it with the Victron 702.  Much easier to use for the non engineer.  Best to Carol...we miss you two and Harley too.

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Re: Battery recharge on 110vac - temp above 95 deg F?

Reply #10 – June 21, 2017, 11:27:35 am

Our solar controller and old Freedom are temp compensated, at those temps 13v sounds about right

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