FireFly Battery Operational User Notes

[kmacdonald]

Originally Posted by docrn

Thanks Miltiempo

I almost had myself convinced I wired it wrong.

If your batteries are reading 20 plus volts you have it wired wrong.

[docrn]

Originally Posted by kmacdonald

If your batteries are reading 20 plus volts you have it wired wrong.

My battery voltage is not 20 plus. I just noticed the history on my battery monitor says max battery voltage at some point was 20.34 for the house bank and 21.02 for the max starter voltage. Obviously it’s concerning and led me to double check my wiring setup and I can find no issues.

I don’t know if it could have been a surge or what. I did have the input from the charge controllers on the wrong side of the shunt for a minute (almost immediately caught it during the install) but I have never seen my batteries read that high and I’ve spent quite a bit of time with my Victron app checking things out.

Wondering if the Balmar alternator tried to over charge when we were runnning? Hell if I know at this point. You had mentioned a few posts back that my temp compensation was wrong. Do you know how to get to that number? It seems to be a closely guarded secret or no one else knows what it should be because I don’t see mention of it anywhere in this thread or elsewhere.

[sailorboy1]

Originally Posted by docrn

You had mentioned a few posts back that my temp compensation was wrong. Do you know how to get to that number? It seems to be a closely guarded secret or no one else knows what it should be because I don’t see mention of it anywhere in this thread or elsewhere.

For which piece of equipment? For the batteries is is 24mV/1C with 0 at 25C/77F and the measurement is suppose to be the air around the battery, not on it. It is right in the FF manual, do you have a copy?

[docrn]

Originally Posted by sailorboy1

For which piece of equipment? For the batteries is is 24mV/1C with 0 at 25C/77F and the measurement is suppose to be the air around the battery, not on it. It is right in the FF manual, do you have a copy?

Thanks

That’s what it’s currently set at (I looked it up and changed it). Someone had mentioned it needed to be a negative number and had me thinking I missed something.

I should have been more specific. The temperature coefficient setting (on the 712) has been the elusive number for me. It’s value is measured in %cap/C.

[kmacdonald]

Originally Posted by docrn

Thanks

That’s what it’s currently set at (I looked it up and changed it). Someone had mentioned it needed to be a negative number and had me thinking I missed something.

I should have been more specific. The temperature coefficient setting (on the 712) has been the elusive number for me. It’s value is measured in %cap/C.

It needs to be -24mV/C. Yes, that's negative. Note location of temp sensor.

Manual says: Temperature Compensation: If you have hardware that allows the user to enter a
temperature coefficient, use 24mV/C° for temperature compensation for a 12V battery &
48mV for a 24V battery. Contact us for higher voltages. The temperature compensation
should be zero at an ambient temperature of 25°C/77°F. This means that for every
degree the battery is ABOVE 25°C, the charge V should be reduced by 24mV/48mV. For
every degree that the battery is BELOW 25°C, the charge voltage should be increased by
24mV/48mV. Note that with Firefly batteries, the battery temperature sensor only
needs to be near the batteries to measure ambient temperature. It isn’t necessary to put
the sensor directly on the battery. This is different than other Pb batteries.

[kmacdonald]

Originally Posted by docrn

My battery voltage is not 20 plus. I just noticed the history on my battery monitor says max battery voltage at some point was 20.34 for the house bank and 21.02 for the max starter voltage. Obviously it’s concerning and led me to double check my wiring setup and I can find no issues.

I don’t know if it could have been a surge or what. I did have the input from the charge controllers on the wrong side of the shunt for a minute (almost immediately caught it during the install) but I have never seen my batteries read that high and I’ve spent quite a bit of time with my Victron app checking things out.

Wondering if the Balmar alternator tried to over charge when we were runnning? Hell if I know at this point. You had mentioned a few posts back that my temp compensation was wrong. Do you know how to get to that number? It seems to be a closely guarded secret or no one else knows what it should be because I don’t see mention of it anywhere in this thread or elsewhere.

The shunt measures current, not voltage. You need to be absolutely sure the batteries aren't 20 plus volts at any time. It will ruin they very quickly. I'm still guessing you saw 20 plus volt reading from the charge controller and that was the solar panel voltage. Set the battery monitor to volts and read it with the solar on and engine off. Then with the solar on and engine on.

[kmacdonald]

The temp compensation is configured on the solar charge controllers not the battery monitor.

[kmacdonald]

Firefly Manual: https://www.emarineinc.com/Shared/pd...ers-Manual.pdf

[kmacdonald]

If you don't have the optional Victron Smart Battery Sense that measures temperature and battery voltage at the battery then I doubt the temp compensation is adjustable. It would be -16mV/C with the internal temp sensor on the solar charge controller. Play with it to make sure.

[docrn]

Thank you kmacdonald.

I changed the controller to a negative value (-24.00mV/C). When I read the manual the word “reduced” clearly didn’t click for me. Lol.

I agree, changing the coefficient on the monitor is likely a wasted effort if the temp sense is not installed. I have it but am wrestling with which is more important, temps or voltage. Since for the moment I have to pick one or the other what would you recommend?

[docrn]

Also the history on the monitor (see link) is where I saw the high voltages. Never saw them get that high with with my own eyes in real time though. No idea when it happened.

https://drive.google.com/file/d/1Hsn...w?usp=drivesdk

[kmacdonald]

On the solar charge controllers set absorption voltage to 14.4 volts and float to 13.45 volts. If you have multiple charge controllers set them all the same. If you have the smart battery sense the solar controllers will sync what stage they are in, ie both will be in bulk, absorption, or float at the same time. That is good and worth the $40 for the smart battery sense. If your batteries are in an engine compartment that gets hot the SBS temp compensation REALLY helps.

Reset the min-max readings on your battery monitor and make sure you don't get those high readings again. I bet the solar panels were hooked up to the batteries directly for a brief period of time and those high readings were recorded then.

[sailorboy1]

Well it looks that my charge efficiency for the battery monitor of 88% is too low. My system is currently at absorption 14.4V and has been a while and the BM says 98% but the batteries are accepting less than 1 amp each. I bet the real problem is that I just need to stop thinking like a FLA user as this really isn't an issue for the FF!

And I just learned something new about my BM. two minutes ago is was showing 14.4V, -12CE and about +4 amps. In those conditions it is programed to reset after 2 minutes. It did and now shows 100% SOC and 0 CE. So the reset/sync conditions zero out the CE (amp-hours)

[RickG]

Originally Posted by sailorboy1

Well it looks that my charge efficiency for the battery monitor of 88% is too low. My system is currently at absorption 14.4V and has been a while and the BM says 98% but the batteries are accepting less than 1 amp each. I bet the real problem is that I just need to stop thinking like a FLA user as this really isn't an issue for the FF!

And I just learned something new about my BM. two minutes ago is was showing 14.4V, -12CE and about +4 amps. In those conditions it is programed to reset after 2 minutes. It did and now shows 100% SOC and 0 CE. So the reset/sync conditions zero out the CE (amp-hours)

Yep, same here on both accounts. I moved charge efficiency up from 90% to 92%. We had steady sun all week. The batteries were at 50% DOD at the beginning of the week and have been reaching a higher state of charge every day. The charge acceptance went very low yesterday and the coulomb counter, with the charge efficiency discount, still showed a significant discount.

Today charge acceptance is down to 2-3 amps and the coulomb counter shows a -13.1Ah deficit; I haven't hit the SOC 100% synchronization criteria yet. That's a 1.6% deviation from theoretical capacity of 812Ah, or 1.7% if you believe each battery capacity is 110Ah. I'll get a bigger baseline before I go crazy and set charge efficiency to 93%.

Sure, we're splitting hares here, but that rabbit is already committed. We're on page 11 of the thread, so only the OCD are still tuned in.

Time to go clean the bottom.

Cheers, RickG

[sailorboy1]

Originally Posted by RickG

Yep, same here on both accounts. I moved charge efficiency up from 90% to 92%. We had steady sun all week. The batteries were at 50% DOD at the beginning of the week and have been reaching a higher state of charge every day. The charge acceptance went very low yesterday and the coulomb counter, with the charge efficiency discount, still showed a significant discount.

Today charge acceptance is down to 2-3 amps and the coulomb counter shows a -13.1Ah deficit; I haven't hit the SOC 100% synchronization criteria yet. That's a 1.6% deviation from theoretical capacity of 812Ah, or 1.7% if you believe each battery capacity is 110Ah. I'll get a bigger baseline before I go crazy and set charge efficiency to 93%.

Sure, we're splitting hares here, but that rabbit is already committed. We're on page 11 of the thread, so only the OCD are still tuned in.

Time to go clean the bottom.

Cheers, RickG

You sound big time charged! Should maybe consider changing your reset/sync setting.

I have my solar controller set for 5 hours of absorption. I think that would be bad as it looks that the FF only spend a couple hours to get to 100% by the time my 640W can get them to 14.4V. But my controller also has a current limit and I have that set to 9 amps currently (would be a little less than 1% plus daytime house load), so the solar dropped to float when it saw that.

I am going to change my alternator regulator to only an hour at absorption. That really means 2 hours as I have the bulk voltage set the same. I think better to end up at 98% SOC than boil out the batteries!