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FWC Electrical basics and upgrading to lithium!

lithium camper electrical batteries charging

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#61 Jon R

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Posted 24 February 2022 - 07:04 PM

I suspect it’s a non-issue.

I have a 2021 Grandby with a Maxxaire fan with remote. My camper has seen several days of operation with the solar system putting out 14.6 volts for several hours (due to battery already at or near full charge) with the fan on and off. I subsequently dialed the charging voltage down to 14.2. It’s also briefly seen 14.8 volts a couple of times from the Iota shore power charger before I realized how high that device would push the voltage trying to force 30 amps into an already charged lithium battery when it first comes on in bulk charge mode. The 14.8 exposures were with the fan off. (I now use the Iota only as a 13.4 volt shore power converter and not regularly as a charger. )

My fan and remote control have been unaffected by this so far.

Edited by Jon R, 24 February 2022 - 07:13 PM.

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#62 jdavis

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Posted 24 February 2022 - 10:05 PM

Seems to be a lot of people having issues for it to be a non-issue. Idk


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#63 craig333

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Posted 24 February 2022 - 10:20 PM

I've never had an issue at 14.6v nor have I heard of anyone who has.


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#64 jdavis

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Posted 24 February 2022 - 11:49 PM

I've never had an issue at 14.6v nor have I heard of anyone who has.

https://www.google.c...ltage regulator

 

I hope its not a problem, either way I'm installing a voltage regulator on the fan circuits. In that google search you can find threads from a lot of people who have had problems. I spoke with Maxxair and they seem very familiar with the problem and said 14v was the upper limit before the fan went into shutdown mode. Don't really understand why anyone would make a RV fan thats only rated for 14v??

 

On a side note, I contacted Dometic about my furnace, they said it was good up to 16v.


Edited by jdavis, 24 February 2022 - 11:50 PM.

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#65 Jon R

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Posted 25 February 2022 - 04:04 AM

Seems to be a lot of people having issues for it to be a non-issue. Idk


What I meant was that operating your camper’s 12 volt equipment at the charging voltage levels does not appear to be causing equipment failures.
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#66 Wallowa

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Posted 25 February 2022 - 04:22 AM



General question on lithium batteries, my camper lives on the truck full time, do i need to be concerned about cold snaps where temps are below freezing for a few days to a week straight? I know that charging is a definite NO, but short term storage OK?

 

 

I just returned from a ski trip with temps near zero or below....as a new and very happy convert to BB Li and all Victron devices [Bluetooth] here is my experience....with two Zamp solid panels and 340W of solar [170/160], I67 12-30, MPPT, DC/DC and 712 to maintain my heated 100Ah BB.  With use of frig and furnace, no DC/DC, only partial solar, my SOC min was 89% and when returning to Hawk around 1400 hrs with cloud cover, 100% SOC..If I moved, at 30 amps the DC/DC always topped off the charge at 100% in a few minutes of driving...sweet system...

 

Note;  Heated BB Li does not allow the battery temp to drop below 32 degrees F and in fact keeps it between 34-45 degrees to assure that solar charging happens while I was skiing...otherwise the BB BMS would stop charging below 32 degrees to protect the battery...you can get amps from battery below zero but can not charge it under 32...like previously stated you lessen the life of a Li battery by charging below 32...but can use all the amps from the battery even in extreme cold...


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#67 jdavis

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Posted 25 March 2022 - 01:51 PM

I have the PD 30amp Converter/Charger for my Lithium upgrade. When running on shore power and charging the converter would provide 14.6v to my DC panel. This would run my furnace, fans, lights etc. Should I be concerned about my furnace and fans getting voltage that high? Should I consider a voltage regulator - something like this: https://www.amazon.c..._qh_dp_hza?th=1

Thanks

Wanted to follow up on this. After a few weeks of use I have noticed the PD 30 amp only puts out > 14 volts at the very end of a charge. Then as soon as the battery is charged it drops back down to 13.8. So the window when the voltage is over 14 is pretty small. I have not had the main power switch on when my camper is charging so no idea how > 14 volts would affect the fans.


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#68 Jon R

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Posted 25 March 2022 - 11:11 PM

https://www.google.c...ltage regulator

I hope its not a problem, either way I'm installing a voltage regulator on the fan circuits. In that google search you can find threads from a lot of people who have had problems. I spoke with Maxxair and they seem very familiar with the problem and said 14v was the upper limit before the fan went into shutdown mode. Don't really understand why anyone would make a RV fan thats only rated for 14v??

On a side note, I contacted Dometic about my furnace, they said it was good up to 16v.


I have my Victron chargers limited to 14.2 Volts now. Today my solar was in float at 14.2 volts with the battery fully charged. the BMV712, my battery’s display, and my multimeter all indicated between 14.18 and 14.20 volts. I turned on the Maxxair fan to see if it would have any issues and it ran fine for several minutes before I turned it off.
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Jon R

2021 Grandby Slide-in Front Dinette

2021 GMC 3500HD CC LB SRW Gas

1993 Chevrolet K2500 Ext Cab LB






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