LinkPro Battery Monitor issue

Lurking@

New member
I would appreciate feedback & thoughts regarding what I believe might be a drain or short...

Our 2016 Mercedes 2500 Sprinter has 300 W solar panels with 2 Lifeline AGM 100 amp batteries. We have not driven the vehicle for about 3 weeks. When parking we don't typically check the battery monitor, but this time it showed something like 98%. My understanding is that when driving the alternator should top-off the house batteries at closer to 100%, right?

Fast forward about 3 weeks and while doing some work on the van and I checked the LinkPro battery monitor which showed 76%. So I manually synced it by holding down the left & right arrow keys as instructed by the users guide after which it showed 100%. That was last week and since then nothing is or was turned on/utilized; no fridge, lights, electrical outlets, MaxxFan or water pump have been used.

The vehicle has been parked in our driveway in full sunlight which for the last several days means at least 6 hours. This morning the solar controller shows a charge being sent to the batteries. So why is the battery monitor now showing 95.5%?

Might this be due to some short or a drain on battery power that got it down to 76% last week? Or do I just not understand how this works?

Thank you,
Tom S
 

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borabora

Well-known member
It's hard to say what the problem is or if there is a problem without some other data. Battery monitors do basically two things to determine SOC. 1) They tally in and out current through the shunt. 2) Decide that the battery is fully charged or discharged based on voltage. The voltage at which the battery is considered 100% full varies with battery type and therefore is configurable in the meter. If that setting is for example 14.5V but your charge controller has a absorption voltage set to 14.4V then by solar alone the battery will never be 100% full as far as the meter is concerned and it can only estimate soc my means of the shunt measurement. Repeated shunt measurements without ever resetting to 0% or 100% will introduce small errors that can add up over time. That might be the case in your situation.

1) Measure the battery voltage when it shows 95.5%.
2) Check what the in/out current is when it shows 95.5% (in sun shine)
3) Find out your battery's absorption voltage.
4) Configure your charger for that absorption voltage.
5) Configure your battery monitor to consider the absorption voltage + 0.1V as 100% full
6) Don't reset your meter to 100% unless you are sure it is at 100% by measurement
 

OrioN

2008 2500 170" EXT
It's hard to say what the problem is or if there is a problem without some other data. Battery monitors do basically two things to determine SOC. 1) They tally in and out current through the shunt. 2) Decide that the battery is fully charged or discharged based on voltage. The voltage at which the battery is considered 100% full varies with battery type and therefore is configurable in the meter. If that setting is for example 14.5V but your charge controller has a absorption voltage set to 14.4V then by solar alone the battery will never be 100% full as far as the meter is concerned and it can only estimate soc my means of the shunt measurement. Repeated shunt measurements without ever resetting to 0% or 100% will introduce small errors that can add up over time. That might be the case in your situation.

1) Measure the battery voltage when it shows 95.5%.
2) Check what the in/out current is when it shows 95.5% (in sun shine)
3) Find out your battery's absorption voltage.
4) Configure your charger for that absorption voltage.
5) Configure your battery monitor to consider the absorption voltage + 0.1V as 100% full
6) Don't reset your meter to 100% unless you are sure it is at 100% by measurement
7) Make sure the correct battery/bank size/aH's is set in the monitor.
 

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