Lithium Phosphate batteries

Gents

Gents

Joined
Nov 7, 2018
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Bristol UK
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57,117
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Transit PVC
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Hi Funsters, I’m thinking of going mad & putting a whole new set up in my PVC.
I know it’s not going to be cheap but I like the idea of not being tied to hook up pitches.
Looking at Solar panels, inverter, B2B charger & 2 x 145W Lithium phosphate batteries. “Ouch, I hear you cry”. Me too,
would just like any feedback on what I am suggesting. I am looking for the extra easy life, the big 70 in Feb.
 
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It all depends on how much you use and where you go.

You may be surprised at how much or how little you use. I got a battery monitor and confirmed it wouldn’t be worth it for me investing in lithium.

The battery monitor can be used with a lithium setup as well should you decide to go for it so wouldn’t be wasted money either.

I did however get a decent solar setup and can last indefinitely 6 months of the year. Luckily I get 30 amps as standard on the Hymer I have so didn’t need a B2B either. I wouldn’t have known without the battery monitor.
 
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A battery monitor is essential to keep track of your energy use and energy needed to put back. We went with lithium from the start. Most of our energy demand is electric and supplemented with lpg as when needed. Our lpg under slung tank is 20l and this year we filled up two times only, not from empty. A good PV lithium B2B setup can give you almost 100% independence of grid. Depends on your needs, travel patterns and locations. Prices have come down now, you can get 100ah with bms inside for as little as 480 quid. A 3-400ah bank can give you a very reasonable reserve, and with the extra capacity you can back of the voltages to cycle 20-90% of the battery. That would quadruple the life of the battery. Lithium degrades if kept to long at high voltage. Keep away from extremities and can outlive your van.
 
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Gents said:
Hi Funsters, I’m thinking of going mad & putting a whole new set up in my PVC.
I know it’s not going to be cheap but I like the idea of not being tied to hook up pitches.
Looking at Solar panels, inverter, B2B charger & 2 x 145W Lithium phosphate batteries. “Ouch, I hear you cry”. Me too,
would just like any feedback on what I am suggesting. I am looking for the extra easy life, the big 70 in Feb.
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Hi, Kannon Fodda might be in a good position to advise you. A single lithium may well be enough

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Gents said:
2 x 145W Lithium phosphate batteries
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As Lenny HB says, you need to clarify this. Battery capacity is not measured in watts, but in watt-hours (Wh). Alternatively it can be measured in amp-hours (Ah). If you know the battery voltage you can convert between them easily:
Watt-hours = amp-hours x voltage.
So for example for a 12 volt battery 100Ah = 1200Wh
 
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I think he made a typo and should read 2x145ah, but as you guys pointed, he should confirm.
 
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I went down lithium route.. not particularily because i am a heavy 12v user but because I winter a lot in UK with no EHU so a large lithium bank (2x120ah) gives me piece of mind when we have heater on with associated fan.
I do, however, question why a lot of Funsters think they need an inverter... Yes I am sure a lot of you do and use them but how many fit them thinking they MIGHT find a use for them....how many are sitting in vans and never used????
 
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I designed my van from the start with a inverter. The list of use 230v is endless and safer on big power compared to 12v, once safely inverted. For me there is nothing close to being energy independent.
 
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Gents said:
Looking at Solar panels, inverter, B2B charger & 2 x 145W Lithium phosphate batteries.
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If (as Raul suggests) you have 2x145Ah LiFePO4 batteries, can I suggest a high-current B2B, at least 60A. Unlike Gels, Lithiums are quite happy with high current charging. I fact they would be happy with over 100A - but your alternator probably wouldn't be able to handle that. The same applies to the mains charger.

As an aside, you get a different perspective on driving when you have to drive 4 hours to charge the batteries, but it's only 100 miles to your next planned stop.

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Yes I did mean 145A/hrs not Watts.
You will have to forgive me, I am not very tech, so not sure if this will get posted.
Thanks to all for your responses, they will help. Thanks Guys.
 
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Do your maths. Fair enough if it's a challenge,but if you spend too much you might find ehu is cheaper.
 
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gpat said:
Do your maths. Fair enough if it's a challenge,but if you spend too much you might find ehu is cheaper.
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For most of us it is not the cost of an EHU that matters, it is simply that there no EHUs in the places we like to stay at.
 
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Yes it is more about convenience than cost, but I do take your point

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That is very expensive glorified old lead, almost half the cost of lithium. At that size, you will be lucky if you get 4-500 cycles out of it.
If I would be looking into lead, then flooded traction or tubular plates like OPZs batteries are best bung for the buck. Stick some recombination hydro caps on, and happy days for 8-10 years. For the lithium prices now, the lead is expensive if you calculate the total energy cycled through out the battery life.
 
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It is a new chemistry and not proven so there is a gamble to trying it.

IF (and that is an if) their claims are correct you can get 2000 cycles at 50% discharge and 1200 from 80% discharge. That's very good for the price. A decent quality brand lithium is a lot more than twice that cost. There are plenty of cheap lithiums of dubious quality.

I was all set to use one this year when Covid hit and my plans for the summer have been put on hold.
 
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It is impossible to fit in that small space enough active material necessary for the 2000 cycles @ 50% discharge. Maybe 15-20% max discharge, Batteries are constructed with a finite amount of material, that dictates cycle life. You will need about 6kg per cell for 2k cycles @80% and 5kg for 1k cycles. Anything below that, needs shallow cycle to get any meaningful service.

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I’m not sure how established and reputable Leoch is, but you’d have to wonder (if what you say is applicable) why they’d make claims so far from what is possible. Of course you expect any company to base their specs on best case lab tests, so real world would never reach them, but so far out? Why wouldn’t they make similar exaggerated claims for any other type of battery they make?

Even if it got half that number of cycles, that’s still far better than any lead acid or AGM battery and far cheaper than a decent lithium one (so likely still a better deal). Looks like a generic brand lithium is £500. A brand name £680. I wouldn’t chance £500 on a cheap lithium (being in IT I know how bad cheap lithium batteries are), but I consider £240 low enough to try it.

I’d be interested to see third party tests.
 
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To be fair, at over 31kg for a 100ah lead acid battery they show some promise in my view, keep the cycle down to no lower than 40-50% Discharge they might give good service life, they are around the price of Exide Gel so if they perform as well you should not be disappointed.
 
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What everyone has ignored is the charging.... you can have as many lithium's or whatever as you like but you still have to put the energy in to them in the first place.....its the solar which is the critical part if you want to stay off grid.. we have 400w of solar and manage to stay off grid as long as we like...and thats with good old LA batteries..
 
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If cost is not your main criterion you might consider buying an Efoy fuel cell instead of solar panels, B2B and lithium. I have LiFe PO4 and a B2B. However since investing in an Efoy I wonder whether I might have avoided a lot of wiring issues and clutter by simply buying the Efoy first. You don’t need an enormous bank of battery power if you have a device that can quietly keep your battery topped up.

With 70 creeping up is weight an issue? If you are running a 3500kg van you may not have the payload to add too many heavy items. I would start with assessing how much electricity you use. I run a CPAP all night, watch a bit of TV and use about 40Ah per day. A single 100Ah battery is fine for me because I can easily replace this amount every day.
 
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Gents said:
Hi Funsters, I’m thinking of going mad & putting a whole new set up in my PVC.
I know it’s not going to be cheap but I like the idea of not being tied to hook up pitches.
Looking at Solar panels, inverter, B2B charger & 2 x 145W Lithium phosphate batteries. “Ouch, I hear you cry”. Me too,
would just like any feedback on what I am suggesting. I am looking for the extra easy life, the big 70 in Feb.
Click to expand...
If your not bothered about weight then consider much cheaper lead carbon batteries. Same as AGM batteries but you can discharge them more with much less damage if you need to tap into reserves. They wont last as long as lithium but how long are you going to keep the vehicle as they will last a seriously long time if your van is only used for leisure. Lead carbon cant sulphate on the cathode (negative plates) as easy as its made of carbon. This means you can discharge to 90% if required and still get a healthy 500+ cycles. Thats ten years if you use the van every weekend or much longer if you dont need that reserve! It also discharges and recharges faster giving characteristics of lithium. Its like almost having lithium but half AGM for two thirds of the money if you shop around. Leoch look cheap enough.
 
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poppycamper said:
I went down lithium route.. not particularily because i am a heavy 12v user but because I winter a lot in UK with no EHU so a large lithium bank (2x120ah) gives me piece of mind when we have heater on with associated fan.
I do, however, question why a lot of Funsters think they need an inverter... Yes I am sure a lot of you do and use them but how many fit them thinking they MIGHT find a use for them....how many are sitting in vans and never used????
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The only time I use mine is when I need to charge my Macbook Air when on the move or wild camping - invaluable then!
 
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