Another lithium battery question to replace two 110ah AGM’s

Aug 11, 2019
65
49
Funster No
63,159
MH
Swift Kon Tiki 679
Exp
2018
Hi everyone I have a swift KonTiki 669 with 500w of solar, 4kw inverter and Victron solar controller , B2B and mains charger.

I have two 110 AGM cheap Halfords batteries about 2 years old. I also have a vanbitz device to keep the engine battery topped up. Vehicle split charge relay disconnected and factory mains charger are turned off. Have not worked out how to wire the step to autoclose and put 12v on fridge after split charge disconnected - actually it stopped working just as was fitting b2b that’s another story!

The motor home has a lot of electrics TV, and we use the car audio for surround sound. On a really dull day when solar is down to less than 50w we can discharge in a day with heater blower on, tv, audio etc. Interestingly the engine battery also discharges to around 11v so suspect it needs replacement (it’s original and 12 years old). Most days we get 150w easily and in full sun we get 350-400w from the solar setup.

ive checked for current leakage ans can get it to 0 if I turn everything off. It’s amazing how many device pulling around 200mA we have 😃

Most days in Uk have more than enough solar for us it is really just the odd overcast day. It was much worse when we just had 300w of panels - roof cannot take any more.

My question is if I wanted to replace the two 110A agm batteries with Lithium etc what could be fitted in same space to maximise storage?

current batteries are under floor in dedicated box and am aware of cold charging issues. I think I could live with this.

Am interested to know what people physically swap two 110A leisure batteries when they go to lithium. Lifepo4’s get good reviews but how many of say the 100amp ones can you fit in the space? Weight saving will be welcome but would like to know how many I can fit (budget permitting)
 
Mar 21, 2010
2,103
2,326
Funster No
10,727
I swapped two lithium 110 amp batteries , as advertised just “drop in”. Which I did and they are working brilliantly. Bought from Eco Tree very good firm to deal with and very good prices.

colyboy
 
Dec 23, 2014
1,702
1,912
South Somerset
Funster No
34,546
MH
Carthago C-Line I 50
Exp
Since 2009
I swapped two lithium 110 amp batteries , as advertised just “drop in”. Which I did and they are working brilliantly. Bought from Eco Tree very good firm to deal with and very good prices.

colyboy
I would like to do that but I'm nervous of doing damage to my alternator and other system bits. Have you used yours much and is everything still running well?
 
Mar 11, 2013
1,255
1,560
Arundel
Funster No
25,066
MH
A Class
Exp
since 2009
It does not end just with the batteries. You will need to look at your charger unit fitted. I have just gone through the assessment in my part to invest in lithium to replace 2 80A gels. You have all the add ons that will support your topping up. Its all down to the amount of draw you are into. Do you sit for days at a time using your power up and this draw larger than what you are putting in, if so it maybe you may benefit with lithium giving more capacity for two 12amp at around £2000. Or is a case that you move on every few days thus the B2B kicks in with the solar and you are back up to full batteries, then having lithium will not benefit.
We had the Kontiki 669 and the battery compartment is large and most 110 Lithiums are the same size of 110 wets.
 
OP
Largejj
Aug 11, 2019
65
49
Funster No
63,159
MH
Swift Kon Tiki 679
Exp
2018
Thanks. I’ve got Victron solar mppt, Victron B2B and Victron mains charger and all have lithium settings so don’t think I need to change anything. Would like to be able to ride out 1-2 dull days when solar is not sufficient. We move around for longer trips but do weekend in sme place a lot which is off grid.

I’ll heve a measure of the 110a eco tree drop in. You are right battery compartment on KonTiki is large, may see if I can fit one of these In

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Nov 25, 2013
893
1,213
kent
Funster No
29,170
MH
Swift Kontiki 669
Exp
Since April 2013
I am looking at the same conundrum, also have a 669, I have been told that I will have to change the solar regulator as it needs to have a lithium capacity, also I would have to change the charge regulators. I was looking at the project so I could plumb in my invertor to the ring main system , instead of just having as an add on as at present. I was recommended to use Victron kit to do this. I have so many leccies giving me different versions of what is needed I am not sure whether or not to continue with the project. It was only to have the convenience of the Coffee Maker and microwave when off grid. I have Alde Heating and all led so not too much current draw. I also have Solar which keeps the system topped up adequately.

2k seems a very expensive cup of coffee.

I will be interested to see what conclusion you come to.
 
Mar 11, 2013
1,255
1,560
Arundel
Funster No
25,066
MH
A Class
Exp
since 2009
Thanks. I’ve got Victron solar mppt, Victron B2B and Victron mains charger and all have lithium settings so don’t think I need to change anything. Would like to be able to ride out 1-2 dull days when solar is not sufficient. We move around for longer trips but do weekend in sme place a lot which is off grid.

I’ll heve a measure of the 110a eco tree drop in. You are right battery compartment on KonTiki is large, may see if I can fit one of these In

Yes but the natural world can still only put the same amount in as you have now. Its a case of the extra capacity that two lithium 110s would give you when the natural world tops them up. You then use as much as you have available. We have found that wilding in Spain and France in the Winter gives us a lot more natural light for the Victron ~MPPT and we manage well. Its the Winter this last year in the UK that we have struggled to top up from sitting still.
Re the onboard charger on the Kontiki when on EHU, I think you will find, unless its been changed, it may not be sufficient to change two 110 lithiums. Opps missed that you have victron mains charger. So will be OK

Sterling are doing 110 Lithiums direct from them for £600 each
lithium-batteries
 
Last edited:

Tombola

LIFE MEMBER
Nov 21, 2020
1,402
4,354
Merseyside
Funster No
78,053
MH
Rapido 8094DF
Exp
Since 2004
I took out my 3 120ah leads and dropped in 1 x 200ah lithium from quality source.

With you having 500w solar (I have 360) id imagine your mppt is the 100/50 and not 100/30

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cmcardle75

LIFE MEMBER
Jun 8, 2012
2,317
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Riot Van Conversion
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Since 2012
My question is if I wanted to replace the two 110A agm batteries with Lithium etc what could be fitted in same space to maximise storage?

current batteries are under floor in dedicated box and am aware of cold charging issues. I think I could live with this.

Depends on exact sizes. You have to work out what the space actually is and work from there. Remember, Lithium can be turned on its side. It isn't like lead acid. It doesn't care which way is up.

I'd think you'd get a 200A Lithium into the space of a 110A AGM. Thus, the same space will likely give you up to 400Ah. Your AGMs probably provide about 165Ah of discharge capacity at 75%, so you'd have about 2.5 times the usable storage capacity.

I note that you have a 4kW inverter. The Lithiums will drive this far more efficiently than any lead acid, so if you use that a lot, your uplift in usable capacity will be far greater, coupled with far more effective solar charging.
 
OP
Largejj
Aug 11, 2019
65
49
Funster No
63,159
MH
Swift Kon Tiki 679
Exp
2018
I am looking at the same conundrum, also have a 669, I have been told that I will have to change the solar regulator as it needs to have a lithium capacity, also I would have to change the charge regulators. I was looking at the project so I could plumb in my invertor to the ring main system , instead of just having as an add on as at present. I was recommended to use Victron kit to do this. I have so many leccies giving me different versions of what is needed I am not sure whether or not to continue with the project. It was only to have the convenience of the Coffee Maker and microwave when off grid. I have Alde Heating and all led so not too much current draw. I also have Solar which keeps the system topped up adequately.

2k seems a very expensive cup of coffee.

I will be interested to see what conclusion you come to.


i hard wired my inverter into the kontiki. I had to modify the wiring as there are two circuits for sockets and installed changeover relays and a separate rcd for the inverter. Took a while but well worth doing. I just got a relatively cheap 4kw pure sin wave inverter from amazon with remote on/off switch. Used for wife’s hairdryer and straighters only and a charger for my drill and Hoover,

ive Probably spent 2k on victron kit, solar and inverter. Batteries were always going to be the last investment.
 
OP
Largejj
Aug 11, 2019
65
49
Funster No
63,159
MH
Swift Kon Tiki 679
Exp
2018
Depends on exact sizes. You have to work out what the space actually is and work from there. Remember, Lithium can be turned on its side. It isn't like lead acid. It doesn't care which way is up.

I'd think you'd get a 200A Lithium into the space of a 110A AGM. Thus, the same space will likely give you up to 400Ah. Your AGMs probably provide about 165Ah of discharge capacity at 75%, so you'd have about 2.5 times the usable storage capacity.

I note that you have a 4kW inverter. The Lithiums will drive this far more efficiently than any lead acid, so if you use that a lot, your uplift in usable capacity will be far greater, coupled with far more effective solar charging.
Yes I agree. Will investigate the space. 400ah would allow me to run mains 240v air con on low settings in full sun😁

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Mar 11, 2013
1,255
1,560
Arundel
Funster No
25,066
MH
A Class
Exp
since 2009
i hard wired my inverter into the kontiki. I had to modify the wiring as there are two circuits for sockets and installed changeover relays and a separate rcd for the inverter. Took a while but well worth doing. I just got a relatively cheap 4kw pure sin wave inverter from amazon with remote on/off switch. Used for wife’s hairdryer and straighters only and a charger for my drill and Hoover,

ive Probably spent 2k on victron kit, solar and inverter. Batteries were always going to be the last investment.
We miss our old 669 at times the space is just out of this world
 
OP
Largejj
Aug 11, 2019
65
49
Funster No
63,159
MH
Swift Kon Tiki 679
Exp
2018
I took out my 3 120ah leads and dropped in 1 x 200ah lithium from quality source.

With you having 500w solar (I have 360) id imagine your mppt is the 100/50 and not 100/30
i have the 100/30 but with really heavy duty wiring. In UK I’ve never had more than 25 amps at peak. will upgrade to 100/50 at some point, particularly if we head south.

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Jan 13, 2014
1,904
5,298
Leeds - Yorkshire
Funster No
29,678
MH
A Class
Exp
30
i hard wired my inverter into the kontiki. I had to modify the wiring as there are two circuits for sockets and installed changeover relays and a separate rcd for the inverter. Took a while but well worth doing. I just got a relatively cheap 4kw pure sin wave inverter from amazon with remote on/off switch. Used for wife’s hairdryer and straighters only and a charger for my drill and Hoover,

ive Probably spent 2k on victron kit, solar and inverter. Batteries were always going to be the last investment.
You are almost there, it’s not always about the cost or the fact that your current system copes with your power demands in my case it’s the knowledge that l do not have to think about my requirements as l no longer have to,whatever we want to switch on as it were we can for as often and as long as we wish.
 
OP
Largejj
Aug 11, 2019
65
49
Funster No
63,159
MH
Swift Kon Tiki 679
Exp
2018
I’ve installed 4 x 100amp lithium batteries. Really pleased with performance so far. I can really use the inverter much more for kettle and air con - before only used it for hair dryer and straighteners (not for me)

Boiling the kettle takes about 1-2 % off battery state of charge and I can run the air con (1kw) when the solar is at about 300w + for a few hours when it’s really hot and only use 10-15 %.

Next project is perhaps to see if I can get the 3 way fridge to auto switch to 12v when the solar is good and battery near full. I know it lasts for ages off gas but when the batteries are full and it’s sunny would be good to be able to use the free power for some use.

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May 16, 2021
200
218
Funster No
81,251
MH
Autotrail
.... Next project is perhaps to see if I can get the 3 way fridge to auto switch to 12v when the solar is good and battery near full. I know it lasts for ages off gas but when the batteries are full and it’s sunny would be good to be able to use the free power for some use.
I have that setup on my Motorhome. The Fridge is able to switch to AC when the Leisure Battery is above a certain SOC (State of Charge) and then switches back to Gas once the Battery drops to another SOC.
You can see a bit of a write-up here - https://wildebus.com/how-to-automate-power-to-fridge-water-heater/

I did this on the AC side for a few reasons.
1) the Fridge on AC is much more effective than the DC side, so if you are going to use battery power, may as well use it as efficiently as possible
2) I am doing the same with the Water Boiler, and that is AC or Gas only, no DC
3) the 12V DC for a Fridge comes from the Starter Battery so you would need to break into the 12V supply to switch it from Starter to Leisure when you want to use it that way. Not that hard using a NO/NC relay but I preferred controlling the AC side.

I initially did this in my Campervan to automate the feed to the 240V Water Heater at high battery SOC to avoid wasting solar harvesting potential and it worked very well so decided to expand the design in the Motorhome :)
 
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