• Well done, you found us. THIS IS THE NEW SERVER

Lithium = About Turn? (1 Viewer)

Nov 18, 2022
149
138
Holmfirth, UK
Funster No
92,520
MH
Elddis Majestic 135
Have I got this right? Having switched to Lithium I need to ensure that the battery isn’t being charged. It should rest between trips at roughly 50%. So:
1. I should turn off the 240v charger (The van is on permanent hookup on a “Well, why not?” basis)
2. I should fit a switch in the solar panel positive lead so that it is not trickle charging the battery.
3. I should fit a switch in the B2B booster's “D+” lead to the smart alternator so I can turn off charging when travelling.
4. I just switch on the mains charger the night before a trip.
It’s a 120Ah battery with a single (at present) 100W solar panel and a Renogy MPPT Bluetooth controller.
The only drain I can think of is the Battery Master to the starter battery. I don’t think that the fridge can draw from the leisure battery. Can it?
I should discharge the battery down to 50% after a trip if necessary. (I need to disconnect it and use a multimeter to establish that?)
I think that I can turn off solar charging by just selecting low voltages in the controller?
I’m a complete novice at MH-ing.
 

pappajohn

LIFE MEMBER
Aug 26, 2007
43,433
50,269
Dark side of the moon
Funster No
172
Exp
Since 2005
I believe lithium's like to stand at 80% charge.
Solar panel.....
Modern solar controllers need the battery connected BEFORE the panel is connected for it to acertain the battery voltage.
 

Tombola

LIFE MEMBER
Nov 21, 2020
4,942
16,049
Merseyside
Funster No
78,053
MH
Rapido 8094DF
Exp
Since 2004
1. I should turn off the 240v charger (The van is on permanent hookup on a “Well, why not?” basis)
yes, dont leave it keeping Full all the time, not ideal for Lifpo

2. I should fit a switch in the solar panel positive lead so that it is not trickle charging the battery.
You can do this, (I have) as it is handy for isolating the panel in future for any works etc, but your renogy app may possibly have a "off" function on it

3. I should fit a switch in the B2B booster's “D+” lead to the smart alternator so I can turn off charging when travelling.
I also have this is handy when b2b charge not needed but a decent b2b will tail off the charge anyway...dont forget to turn it back on like i do sometimes :wasntme:

4. I just switch on the mains charger the night before a trip.
Yes

It’s a 120Ah battery with a single (at present) 100W solar panel and a Renogy MPPT Bluetooth controller.
The only drain I can think of is the Battery Master to the starter battery. I don’t think that the fridge can draw from the leisure battery. Can it?
I should discharge the battery down to 50% after a trip if necessary. (I need to disconnect it and use a multimeter to establish that?)
anything less than 80% will suffice, and you will probably find natural "drain" will take it down soon enough especially if you have an inverter etc. I sometimes flick my inverter on to draw some power out if Im going to leave it a good while and switch off the 12v hab control.

I think that I can turn off solar charging by just selecting low voltages in the controller?
yes probably, though Im victron and not renogy, mine has an option to switch off charger function via the app

I’m a complete novice at MH-ing.
We all were at one time ! good luck
 
OP
OP
P
Nov 18, 2022
149
138
Holmfirth, UK
Funster No
92,520
MH
Elddis Majestic 135
I believe lithium's like to stand at 80% charge.
Solar panel.....
Modern solar controllers need the battery connected BEFORE the panel is connected for it to acertain the battery voltage.
Thanks for reminding me! I’d forgotten about that sequence. Makes disconnecting and reconnecting the leisure battery more complicated!
 
Sep 3, 2012
7,615
26,209
Cheshire
Funster No
22,759
MH
C Class Elddis 175
Exp
8+ years
I think you will find that whilst you are using the battery its not so much of an issue.
When your motorhome is in storage or not being used for a while that's the time to reduce the charge. There is no need to turn off your b2b ,or solar charger whilst your using your van and if your on ehu most of the time. Why do you need a lithium battery?
 
Feb 27, 2011
14,882
77,229
UK
Funster No
15,452
MH
Self Build
Exp
Since 2005
If you have access to the BMS settings You could always create a profile and have it set at 80% full voltage max. The BMS would disconnect above this? I don't know what battery/BMS you are using so can't advise.
Wissel is the guy I turn to for all Battery/BMS stuff these days.
 
May 7, 2016
7,366
11,945
West Sussex
Funster No
42,951
MH
Malibu Van 640 LE K
Exp
Since 2003
I think people get overly concerned about storing LiFePO4 fully charged. My battery instructions say charge at 14.4V for normal storage. The 50% charge level is suggested for longer term storage of over 3 months.

Subscribers  do not see these advertisements

 
Feb 22, 2016
3,641
11,059
York
Funster No
41,744
MH
Bailey 620 Approach
Exp
Since 2015
I think people get overly concerned about storing LiFePO4 fully charged. My battery instructions say charge at 14.4V for normal storage. The 50% charge level is suggested for longer term storage of over 3 months.
This is the advice I received from the fitter of our two lithium batteries. I was worried about leaving it on hookup whilst we are away for 4 weeks. The van is stored indoors so no solar and have a battery master fitted. I was concerned that the alarm, tracker etc would reduce the van battery to a level too low to start the van when we returned. So was advised to leave it on hook up for the 4 weeks and the batteries will be ok.
 
Apr 14, 2022
292
530
Carvoeiro, Portugal
Funster No
88,080
MH
Bavaria T71LP
Exp
50 years of boating, just one on motorhomes.
We really over think this. An old lead battery gets abused and no one worries about it. A lithium is much more resistant to abuse and has a BMS installed to protect it. Worse case is that you can reduce the number of full cycles it will achieve and, given the fact that most are 3000 even if you full cycled them every day that takes nearly ten years. I doubt I will fully cycle mine more than four or five times a year so call that 600 years! I suspect that in 30 years time, if my MH is still going the only bit working well will be the lithium battery!
 

Join us or log in to post a reply.

To join in you must be a member of MotorhomeFun

Join MotorhomeFun

Join us, it quick and easy!

Log in

Already a member? Log in here.

Latest journal entries

Funsters who are viewing this thread

Back
Top