Swapping my leisure battery to LiFePO4

[roadtripper]

There are a lot of similar threads if you search for the common all in one brand names like "Sargent"

Search results for query: Sargent lithium

www.t6forum.com

It's in reach of DIY certainly, but you'll be handling potentially much higher currents than normal that will need some experience and tools, last thing you want is a fire in the vehicle you are travelling or sleeping in. As a rule of thumb anything under 30A circuits is "general wiring" but the charging circuits for DC-DC are often higher than that. If you lack confidence/experience no shame in getting an auto electrician to do the core high current bit on the DC-DC and you do the rest.

To give some idea of the scope your current system is likely using a split charge approach, probably one built into the all in one power unit. Understanding how your battery is being charged when driving is key to the next step so carry on working that out.

Then what you will need to plan is:

• Add a lithium capable DC-DC charger (Disabling the current split charge relay in the all in one power unit, or using it only as a charge trigger) to charge the leisure system from the vehicle electrics.
• Potentially you may need to run a new higher capacity cable to the vehicle electrics as it may only be sized for lower current charging.
• Disable the built in mains charger and add a lithium capable mains charger to charge the leisure system from EHU
• Replace the solar charge controller with one that has a lithium profile to charge the leisure system from sun.

Keep in mind that a lithium battery is often smaller for the same capacity so you can often fit them and the smaller DC-DC chargers in the same physical space of the old leisure battery.

Also for safety the battery you choose should have its own local low temperature charge cutoff, or every charger must have it. You mustn't charge a lithium battery when it's below freezing.

 

[mutantspy]

thanx for all the info you've been great help
i will update the way im gonna go depending on cost and confidence. cheers

 

[Stay Frosty]

I've got a 67 plate Redline camper and happy enough with the majority of the conversion which dates from late 2018 but they hadn't really got a clue with the leisure electrics on a Euro 6 van.
Mine had a split charge relay and that Sargent EC160 unit which is underwhelming, the trouble is if you mainly use hookups on campsites you don't notice that the leisure setup isn't fit for purpose until you try to camp off grid and find that the Waeco fridge is pretty power hungry in summer and that the split charge relay and the vans smart alternator have killed the leisure battery already anyway.
I'm not that sharp and killed two successive 110Ah batteries before butchering the Redline install and going Lifepo4 and B2B charger plus solar and 230volt inverter.
There's a Roamer 100Ah battery in the for sale section at the moment that would get you started but realistically while you could carry on just replacing the existing cheap lead acid leisure battery on a regular basis you won't be able to survive more than a weekend off grid with that and will lose the fridge at some point during the weekend.
There's loads of info on the forum and Lee @Dellmassive has posted a load of "how I done it" threads but while my ghetto system works splendidly there is no right or wrong system but basing the leisure setup on lithium and a B2B chargermeans you'll squeeze everything out of the battery when needed rather than half of the lead acid stated capacity and game over.

 

[mutantspy]

Hi thanx again for all the info it's been a great help
I've put the feelers out for some quotes to do all the work as not very confident in electrics will let you know if I get any decent quotes.

 

[mutantspy]

So after talking to redline and asking for a quote for an upgrade I'm still waiting
Other quotes have come in at around £1700 that's just over a grand for the components and 4 to 6 hundred for fitting.
So after much deliberation I have gone with an aferiy p210 power generator and the 400w solar panel charger you can charge ur van up like an electric hookup would if needed plus all the other charging capabilities it has. I have also renewed the leisure battery for a 95wh yausha
The reason why I went down this route is mainly for the diversity of the unit and also if we sell the camper we can take the power generator with us to the next vehicle also use in the garden at bbq time and any power outage we have which are common for where we live to run the tv and internet.
Thanks for all the advice given I'm sure I will de asking more questions concerning the camper

 

[DXX]

Not sure how far off grid you are planning on camping but if you are anywhere near residential areas or other people in vans a generator is going to attract unwanted attention.

 

[mutantspy]

It's an electric generator less than 65db have a look it's the aferiy p210 2400 wh battery generator with the 400watt solar charger

 

[drinfinity]

The unit linked is a big battery and inverter, not an engine attached to a generator.

 

[mutantspy]

that's the one

 

[DXX]

It's an electric generator less than 65db have a look it's the aferiy p210 2400 wh battery generator with the 400watt solar charger

It’s battery storage not a generator, understood.

 

[mutantspy]

yes sorry for the misunderstanding

 

[wallport]

After a lengthy battery diagnosis thread Newbie battery charger questions, this is a new thread to discuss the swap I decided to do - not without some big doubts about my skills.

So I am looking to replace my Yuasa L36-100 lead acid with a Fogstar Drift Lifepo4 105ah. You can see the recommendations for this choice in the previous thread - lots of good stuff from the experts in there. The whole lot is worth a read but it was getting a bit lengthy. I'm hoping the guys who know what they are talking about will follow me over here and provide more brilliant advice as the challenge is still concerning me.

The issues I have with this swap are basically down to the differing physical dimensions of the new battery. My chargers are all compatible it seems but my wooden battery compartment will need extending. The Yuasa is 360l x 180w x 197h. The Fogstar is 260l x 168w x 209h.

So, I need to fit the new battery onto the existing cabling as there is no way I'm ripping out the panelling and I have near zero woodworking skills to sort out extending the battery compartment.

Some photos
This shows the box - just two pieces of wood.


This shows the battery screwed to the floor on just this one side. Not sure new battery has this option.


The box removed.


The holes in the panel.

Where I am with this:
The extra height of the new battery may not be too high but it's getting close given where the fuse banks are. It all depends on whether connecting to the terminals adds more height. I also wonder whether there are connectors which could take the connections at right angles and downwards.
The battery could also go on it's side but this reduces the space under the seat where we store the awning.
I also don't yet know how much extra wire is available on each of the terminals. I did previously have the negative one off and think there was some slack. Given the shorter length of the new battery as well as the different height, this could be an issue.

As for the woodwork, my thoughts are to screw a thicker extra piece to the floor and screw the existing piece to this. Thus mostly keeping the matching wood. This obviously doesn't work with the battery on its side.

I have no idea how to secure the battery at this point but whatever the solution, I don't want to make the battery higher.

Appreciate any thoughts and any info on the terminals on the fogstar and connector options.

 

[TallPaul_S]

Can you add a picture of your terminals and connections on them? The fogstar batteries have M8 terminals so you'll need to take that into account - you'll need to check the ring terminals to make sure they're big enough to fit the fogstar terminals.

 

[wallport]

Could do more if necessary.

 

[TallPaul_S]

Cheers - tbh they might already be 8mm studs so I think all your connections will just transfer straight across.

 

[Stay Frosty]

You could butcher a ratchet strap screwed to the floor as that wouldn't be any worse than the fixings on the original lead acid battery.
Obviously threaded rod through the floor and a metal strap over the battery would be a lot more solid but I would rather eat my own shreddies than drill blind through the floor.
A woven strap wouldn't add to the new battery height which is only 12mm taller than the old by the measurements indicated, more of a possible problem is where the new posts are compared to the old but to be honest swapping these batteries around shouldn't be horrendous.
Looking at all those crimp lugs on each battery post in your pics you could fit a shunt to take care of the neutrals and give an indication of battery state, taking that down to one thicker black wire from the shunt busbar onwards to the battery, similarly all those reds could go to a busbar or multi maxi fuse holder and one much thicker red to the new battery live post.

 

[TallPaul_S]

You could butcher a ratchet strap screwed to the floor as that wouldn't be any worse than the fixings on the original lead acid battery.
Obviously threaded rod through the floor and a metal strap over the battery would be a lot more solid but I would rather eat my own shreddies than drill blind through the floor.
A woven strap wouldn't add to the new battery height which is only 12mm taller than the old by the measurements indicated, more of a possible problem is where the new posts are compared to the old but to be honest swapping these batteries around shouldn't be horrendous.
Looking at all those crimp lugs on each battery post in your pics you could fit a shunt to take care of the neutrals and give an indication of battery state, taking that down to one thicker black wire from the shunt busbar onwards to the battery, similarly all those reds could go to a busbar or multi maxi fuse holder and one much thicker red to the new battery live post.

That's good point about the shunt - your current cbe led guage will be useless as LiFePO4 voltages are very different to AGM.

You'll be able to monitor the battery status via the Fogstar app, but if you wanted further monitoring you could fit a shunt - you would need to find a nearby chassis ground for that.

 

[wallport]

Ratchet strap - that sounds within my talents! Something like this?

On the battery monitoring - good point about the lights but to be honest they were useless anyway. I was kind of looking forward to the data the battery gives you via the app which sounds like it really tells you what you want to know.

If I do need to extend the connections from the battery terminals, aren't there solutions providing extensions which just screw on to the terminals and which you then screw onto the other end. Feel free to educate me if this isn't the done thing.

 

[roadtripper]

Shouldn't need another chassis ground for a shunt, the only requirement is that all the current must flow through it for it to do it's job. Technically you could put it on the positive side too but it's generally accepted that the positive terminal already has enough connections on the fusing so negative is easier.

If you put all the existing wiring on to one side of a shunt and then a new negative from the other side to the negative battery terminal then that would be fine.

If I do need to extend the connections from the battery terminals, aren't there solutions providing extensions which just screw on to the terminals and which you then screw onto the other end. Feel free to educate me if this isn't the done thing.

That's basically what's being suggested. You can just get a single post to bolt everything together, but they often get quite crowded especially as most connections need to splay out to fit comfortably. So instead fit a short bus bar or a device that acts like one and does a useful additional duty like a shunt or a master fuse.

Power posts:

Power Posts & Bulkhead Feed-Through Connectors | 12 Volt Planet

Power posts & bulkhead feed-through connectors for power distrbution in vehicles and boats. Marine grade fixing for corrosion resistance.

www.12voltplanet.co.uk

Bus bars:

Busbars | 12 Volt Planet

Busbars for distributing power around a vehicle or boat in various configurations and with marine grade fixings to resist corrosion.

www.12voltplanet.co.uk

Large fuse holders:

High Power Fuse Holders

Suppliers of high quality electrical parts, components & accessories for campervans, motorhomes, boats & off-grid applications.

www.12voltplanet.co.uk

 

[TallPaul_S]

Yes, of course you don't need to run a shunt to chassis ground do you. Tbh you probably won't need one as the BMS via the app will give you loads of info.

The easiest way to extend the positive and negative connections would be with a couple of busbars:

https://amzn.eu/d/hNS6Tjj

You could mount these inside the cupboard where the cables exit. Then you'd run a short section of beefy cable from the busbar to the battery terminal.

You can buy pre made battery cables here

25mm² Lead up to 1mtr long with 1 OR 2 Ring terminals | Electrical Car Services

Buy 25mm² Lead up to 1mtr long with 1 OR 2 Ring terminals - ECS BLRT25/1The Tech Spec:Battery Lead Amperage: 170 ampsCable Cross Section: 25.0 mm²AWG number: 3Conductor Construction: 322/0.30 ØmmResistance per metre at 20°c: 0.00077 Ω/kmDiameter including insulation: 10.1 ØmmSuitable for 200amp...

www.electricalcarservices.com

If you're doing this, you may as well add a mega fuse holder and a main isolator switch between the busbar and battery.