15 replies to this topic

[radarcontact]

Looked thru previous posts but couldn't find a clear answer on this...

 

When storing your lithium battery FWC in the garage between camping adventures, SHOULD you ever  plug it into shore power and walk away?  Since the camper AC to DC converter will float charge, I'm thinking it's not a good idea, nor necessary because of the slow discharge rates of Li batteries, but there's lots of conflicting info out there on this topic.

 

I'm basically talking about spring/summer/fall usage and storage.  In winter I would take measures to ensure the battery didn't get too cold (I live in Wyoming), and check charge every two months/charge with battery charger if needed.

[TacomaAustin]

My preference would be to replace the stock Iota AC to DC converter which is for a lead acid with an updated converter/charger that has the correct profile for lithium.  Also, there are other considerations such as the 10 AWG wiring FWC uses from the truck battery to the house battery and whether to install a DC to DC charger for charging while driving.

 

From the one of many threads on the Electrical, Charging, Solar, Charging and Generator forum - https://www.wanderth...-help/?p=258037

Edited by TacomaAustin, 06 July 2022 - 02:18 AM.

[radarcontact]

Tacoma, thanks for the link, missed it somehow.  Rando has been very helpful in the past when I've had questions regarding electrical stuff.  I'm onboard with the wiring revisions and DC-DC charger.  

 

I'll probably limit my shore power charging.  

[Charlie]

I think one of the confusing aspects of this topic is the self-discharge rate of a lithium battery vs. base load. For sure, a completely unconnected lithium battery has a very low self-discharge rate, and can sit on a shelf for a very very long time before it gets to a significantly low state-of-charge.

 

However, it’s typical for a camper to have some very low draw devices, which will still add up to a significant load. For instance, my camper has a base load of about 300 mA. Half of this is from the CO/propane detector, and the rest is from lighted USB outlets and the circuit breakers LED indicator lights. That amounts to ~6 Ah/day, which will clearly draw down a 100 Ah battery in a few weeks. Similar to the dome light in your car when you you leave the door open for a few weeks.

 

FWC has the “silver switch” which lets you disconnect the battery from all loads, if you remember to use it. I replaced the Iota IQ4 charger (AGM) with a Victron IP22 (lithium) charger, just so that I could plug it in for the winter and just forget about it.

Edited by Charlie, 06 July 2022 - 02:55 AM.

[rubberlegs]

I've read that lithium batteries like to be at about 50% while in storage. So one idea is to attempt to use it to about that level, plus or minus quite a bit (35%-65%?), then disconnect the battery and forget about it all winter. I'm not sure if that's ok in very cold temperatures though.

[PaulT]

I've read that lithium batteries like to be at about 50% while in storage. So one idea is to attempt to use it to about that level, plus or minus quite a bit (35%-65%?), then disconnect the battery and forget about it all winter. I'm not sure if that's ok in very cold temperatures though.

Contact the engineering/technical department of the company that made your battery and ask them. They have a vested interest in you having good information as to the care & feeding of their batteries and are certainly the best source of info.  Send an email with the list of questions you need answered.  

 

Paul

[m5040]

Contact the engineering/technical department of the company that made your battery and ask them. They have a vested interest in you having good information as to the care & feeding of their batteries and are certainly the best source of info.  Send an email with the list of questions you need answered.  

 

Paul

It would be nice to let us know what they advised.

[BlueSky]

Every LifePo4 battery I looked at was required to be stored at less than 100% charge. The instructions that came with mine (off-brand Amazon) said store at 80% and do not charge when temps are below freezing (so I don't leave it on trickle charge of any kind). I have always disconnected batteries from the fuse panel to eliminate phantom draw down during long term storage.

[radarcontact]

I think one of the confusing aspects of this topic is the self-discharge rate of a lithium battery vs. base load. For sure, a completely unconnected lithium battery has a very low self-discharge rate, and can sit on a shelf for a very very long time before it gets to a significantly low state-of-charge.

 

However, it’s typical for a camper to have some very low draw devices, which will still add up to a significant load. For instance, my camper has a base load of about 300 mA. Half of this is from the CO/propane detector, and the rest is from lighted USB outlets and the circuit breakers LED indicator lights. That amounts to ~6 Ah/day, which will clearly draw down a 100 Ah battery in a few weeks. Similar to the dome light in your car when you you leave the door open for a few weeks.

 

FWC has the “silver switch” which lets you disconnect the battery from all loads, if you remember to use it. I replaced the Iota IQ4 charger (AGM) with a Victron IP22 (lithium) charger, just so that I could plug it in for the winter and just forget about it.

I would use the silver switch and do what you do if I had the IP22....but living in Wyoming, where my garage gets down below zero regularly, negates winter garage charging.   I'll probably move the battery into the house during winter months.

 

Because I don't have a lithium friendly AC to DC converter, I'll most likely just plug it in to AC for a day or so if needed during the warmer months, as Rando suggested, then unplug it and use the camper cutoff switch (silver knob) to disconnect camper loads from the battery when it's sitting idle.  

Edited by radarcontact, 06 July 2022 - 02:22 PM.

[radarcontact]

I've read that lithium batteries like to be at about 50% while in storage. So one idea is to attempt to use it to about that level, plus or minus quite a bit (35%-65%?), then disconnect the battery and forget about it all winter. I'm not sure if that's ok in very cold temperatures though.

My take on this is similar to yours, except I've read that the batteries like to be anywhere between 50%-100%....the percentages seem to be all over the map, and there's no clear-cut rule to follow on set level before you disconnect and leave it idle.  I'm not sure if it makes much of a difference...main thing is to not allow the battery to drain to 0%, then you can't recharge it.  Leaving Li batteries idle without charging, in cold weather, from my understanding, is OK, but there's evidence that it shortens the overall life span of the battery...so putting it in an environment that's above freezing is supposedly helpful during winter storage.

Edited by radarcontact, 06 July 2022 - 02:29 PM.