Lithium what and how

[Sonar]

Considering a lithium battery system.
Been pricing the items required and it is about £700 and that’s NOT including any batteries.

I can list the items I require as the Moho is a 2003 so 20 odd years old now.
The reason I am thinking about this is they will be the last habitation batteries I will ever need …

Expensive again .

Anyone have any tips …

 

[trevskoda]

If you dont want to change any chargers or regulators i would go lead carbons at £200 each, 1300 cycles and can site in PSOC without damage, ok you wont be able to cycle below say half way but an easy swap, loach lead carbon for me next time round.

 

[Sonar]

If you dont want to change any chargers or regulators i would go lead carbons at £200 each, 1300 cycles and can site in PSOC without damage, ok you wont be able to cycle below say half way but an easy swap, loach lead carbon for me next time round.

Many thanks that’s another option I can consider ..

 

[QFour]

KS Energy Lithium are a straight swap for lead acid batteries. Fitted one to our Carthago 4 years ago.

 

[wildebus]

KS Energy Lithium are a straight swap for lead acid batteries.

A very sweeping statement there. And sorry to say an incorrect one.

(And yes, I know KS Energy make this claim on their website. Doesn't make it any truer).

Fitted one to our Carthago 4 years ago.

The Cathago electrics system as standard is fairly good and as such is more suitable to have Lithium dropped in without changes, but even then there are still potential 'gotchas'.
And if you have a typical British motorhome from the 2000's or so, you will never charge a Lithium battery to close to its capacity with what is installed.

 

[trevskoda]

KS Energy Lithium are a straight swap for lead acid batteries. Fitted one to our Carthago 4 years ago.

Nop.

 

[Sonar]

I have a list of items to change
The battery charger. And the battery to battery regulator the rest is fuses wire and ends.

There is nothing really hard about changing the system. Just a lot of wire moving and fit new wiring as I will remove both lead acid batteries from under the front cab seats and fit two lithium batteries in the tiny garage space.

Just started tidying up the wiring under one seat today. Will do the other tomorrow then really it’s just joining one wire from under each seat and another from the engine battery when the time comes .

Trying to make fitting the new stuff as easy as I can

 

[rugbyken]

when i was told lithium was a drop in on my hymer it was explained to me that yes i could drop in a lithium & it would work but not to its full ability ie charging speed, capacity ,or full power

 

[Sonar]

Mines an old Moho there’s no drop in spaces and no unplug and plug it things
So everything is going to be changed . 2003 there were at that time I guess not a lot of options for anything except what colour
Napkins would you like

 

[funkyronster]

A very sweeping statement there. And sorry to say an incorrect one.

I would like to hear the solid technical reasons why you say this is so. Lifepo4 can be charged with any voltage up to 14.6, and it matters not if any legacy charger can only supply 13.8 or anything less than that. If you look at the typical charge and discharge characteristics of 12v Lifepo4 any charge voltage over 13.5 will result in a near full charge - the last 2% is irrelevant in most applications. And in any event, the BMS in a lithium battery will protect it if the charge/discharge parameters are exceeded.

There is plenty of evidence out there to support this, and many battery manufacturers agree with KS - Fogstar is another, and the USA forums have detailed technical discussions on the subject.

So why are you swimming against this particular tide? What is your qualification and reasoning for doing so? I accept you are a grand daddy of this forum and give out great advice, and I don't want to knock that, I just want to know the technical reasons.

 

[wildebus]

I would like to hear the solid technical reasons why you say this is so. Lifepo4 can be charged with any voltage up to 14.6,

Lots of LFPs will disconnect and error if the charge voltage is too high. 14.6V is absolutely too high and will cause an error in the majority of cases.

and it matters not if any legacy charger can only supply 13.8 or anything less than that. If you look at the typical charge and discharge characteristics of 12v Lifepo4 any charge voltage over 13.5 will result in a near full charge - the last 2% is irrelevant in most applications. And in any event, the BMS in a lithium battery will protect it if the charge/discharge parameters are exceeded.

I don't agree with your statement about only needing 13.5v to virtually fully charge an LFP battery.
The chart you posted is a Discharge graph. Charging characteristics are not the same as discharging ones.

There is plenty of evidence out there to support this, and many battery manufacturers agree with KS - Fogstar is another, and the USA forums have detailed technical discussions on the subject.

So why are you swimming against this particular tide? What is your qualification and reasoning for doing so? I accept you are a grand daddy of this forum and give out great advice, and I don't want to knock that, I just want to know the technical reasons.

This 'tide' is promoted by companies with a vested interest in selling product.

Reasons why LFP is rarely drop-in ....

Chargers are not suitable - either too low a voltage or or high a voltage.
Chargers are not suitable - not designed to be running at full output for extended periods and will prematurely fail.
No protection in basic split-charge relay systems to limit current so Alternators could be overstressed.
User has no way to monitor charge level - Most motorhomes "monitors" are based on Voltage. barely adequate for Lead, totally unsuitable for LFP (LFP with built-in monitors are getting more common but not all have this).

Yes, LFP *can* be drop in in some situations where the right infrastructure is in place, but having a blanket statement say "this is a drop in" is both incorrect and unsafe.
It is up to you what you believe and it really doesn't matter to me if you believe me or not and I have no interest in attempting to convince you one way or the other.

 

[Sonar]

so far as the lithuim bettery system goes the only thing we have is the solar controller fitted already .