Lithium upgrade questions (1 Viewer)

[nigelivy]

Ivys & nigelivy wow where do I start to say thanks for the massive very helpful replies,
Taking on board what you'd have said I think I am going to get 4 x 280 ah CATL cells along with the Daly 18650 Smart LiFePO4 4S Battery Management System (BMS) 12V 200A with Bluetooth from chrisandbev as long as all is compatible and I source the cells OK, my max draw is the microwave at around 125 amps which works flawlessly in my current lead acid setup

That'll be a great setup! Glad to have been of some help!

 

[Clive Mott]

Stick to sites with a mains Hookup if you need that amount of mains kit!!

 

[RogerIvy]

I think I am going to get 4 x 280 ah CATL cells

If possible to get cells that have welded studs instead of the traditional threaded holes. Our tests have shown that welded stud terminals heat up a lot less under heavy load. Also, traditional threaded holes strip very easily as they are soft aluminium and usually only 6mm deep.

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[Two on Tour]

I have just bought 4 x CATL 271Ah cells and the threaded terminal is only 5mm deep, so to make use of all the thread depth I have fitted them with M6 studs and M6 nuts, and this reduces the chance of ripping out the thread with a bolt that is too short or not clamping hard enough if the bolt is too long.

 

[RogerIvy]

I have just bought 4 x CATL 271Ah cells and the threaded terminal is only 5mm deep, so to make use of all the thread depth I have fitted them with M6 studs and M6 nuts, and this reduces the chance of ripping out the thread with a bolt that is too short or not clamping hard enough if the bolt is too long.

Given that you can tighten to a very low torque (probably no more than 5Nm) you will need to prep your surfaces very well. For these sort of terminals we use a diamond pad to both flatten and remove oxidation from the terminal surface. Then we do same for the bus bars and the lugs. Your Daly will come with an 8mm lug so you would need to replace that with a 6mm and make sure it's flat and free of oxidation.
Finally, it's a good idea to use a tiny bit of dielectric paste to prevent future oxidation (especially if you're close to the coast).

 

[Bart]

If possible to get cells that have welded studs instead of the traditional threaded holes. Our tests have shown that welded stud terminals heat up a lot less under heavy load. Also, traditional threaded holes strip very easily as they are soft aluminium and usually only 6mm deep.

I've just been on the phone with the seller, the cells are not actually CATL as they've sold out, the ones for sale are Basen, are these good cells as well?

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[RogerIvy]

I've just been on the phone with the seller, the cells are not actually CATL as they've sold out, the ones for sale are Basen, are these good cells as well?

Yes, on the whole Basen are viewed positively on various forums. We've not had personal experience with them but they should be good.

Try to make sure you're supplied with Grade A cells. Grade B will most likely have big differences between the cells resulting in an imbalance. When we top-balance our stock cells (280ah) they start off being very close anyway so we choose the "faster" balancing method. When we've top-balanced others (such as some "420ah" cells we tested recently) they were so different that we had to do a traditional slow top-balance.

 

[Snapper]

Roadpro fitted ours. Damian their electronics wizkid is right on the ball. Works wonderfully well, one of the best additions we have purchased for our van.

 

[Bart]

Yes, on the whole Basen are viewed positively on various forums. We've not had personal experience with them but they should be good.

Try to make sure you're supplied with Grade A cells. Grade B will most likely have big differences between the cells resulting in an imbalance. When we top-balance our stock cells (280ah) they start off being very close anyway so we choose the "faster" balancing method. When we've top-balanced others (such as some "420ah" cells we tested recently) they were so different that we had to do a traditional slow top-balance.

Checked with seller and yip Grade A

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[Bart]

chrisandbev I'll have to withdraw interest in your Daly BMS , as I ended up buying a 280a cell & BMS package, thanks for the offer and advice

 

[RogerIvy]

Roadpro fitted ours. Damian their electronics wizkid is right on the ball. Works wonderfully well, one of the best additions we have purchased for our van.

Roadpro are great. They've done a bunch for us through the years.

 

[two]

These are my views, regarding the leisure battery:

You only need enough capacity to get you through ‘charging famines’. If you are someone who always runs around with a full tank of fuel, rather than enough for the journey, you may believe that “you can never have too much battery capacity”. That’s fine, so long as payload is not an issue, in which case, maybe the need for Lithium is not so necessary either?

280Ah of Lithium stores a lot of useful electricity (3kWh, say). Good, perhaps, for when going beyond the polar circle (which you are unlikely to do more than once) and remaining frozen to the spot for several days without EHU. You could save a lot of investment and anxiety by being more conservative with your consumption instead. The minimum capacity needs to be enough to get you through a cold Winter’s night, something which many achieve with a conventional 85Ah battery (and only ½kWh of power, at best).

Battery capacity reduces with time, so there could be some wisdom in installing extra to compensate for that but still be prepared to swap them out when they start to hold insufficient for your needs.

You could plan to keep your investment when you change vehicles but you would need to replace them with something else (additional cost and hassle to consider) and, as technology is moving apace, there could be a more attractive solution by then.

As for Lithium batteries, there are different qualities of battery and BMS. Read the detailed specs, if you can get them, and you'll see that none are the same. You will tend to get what you pay for and I’d be wary of guarantees. My own preference would be for a ready-made (12V) cell from someone with a reputation to keep. You need to put your faith in their belief that they got it all right – you may not find out for several years down the line, by when the cheapskates will have moved-on. I’d be wary of building a solution from individual components, unless you enjoy that kind of thing and are prepared to start again: you can be sure that everyone will point their fingers at someone else in the equation if anything goes wrong.

If cost is an issue, it may be better to stick with convention, where there’s far more experience and much less opinion. Finally, don’t overlook the cost of improvement over that of paying for EHU…

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[Raul]

chrisandbev I'll have to withdraw interest in your Daly BMS , as I ended up buying a 280a cell & BMS package, thanks for the offer and advice

Look forward to the install and usage feedback.
I can’t believe you haven’t gone for the winston with the yttrium doping LiFeYPo. Those cells are rock solid, and highly praised by off grid community.
Never the less I hope some good reviews from your new acquisition.

 

[jongood]

Stick to sites with a mains Hookup if you need that amount of mains kit!!

Why?

 

[Bart]

unless you enjoy that kind of thing and are prepared to start again: you can be sure that everyone will point their fingers at someone else in the equation if anything goes wrong.

That sounds like me

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[Bart]

Look forward to the install and usage feedback.
I can’t believe you haven’t gone for the winston with the yttrium doping LiFeYPo. Those cells are rock solid, and highly praised by off grid community.
Never the less I hope some good reviews from your new acquisition.

For me that's one of the negative of not living in mainland UK , so many distributors do not post certain items to n.Ireland , that along with not wanting to be landed with unexpected/unknown import fees if buying from outside the UK... thanks to all those who voted to leave the EU,

 

[jongood]

These are my views, regarding the leisure battery:

You only need enough capacity to get you through ‘charging famines’. If you are someone who always runs around with a full tank of fuel, rather than enough for the journey, you may believe that “you can never have too much battery capacity”. That’s fine, so long as payload is not an issue, in which case, maybe the need for Lithium is not so necessary either?

280Ah of Lithium stores a lot of useful electricity (3kWh, say). Good, perhaps, for when going beyond the polar circle (which you are unlikely to do more than once) and remaining frozen to the spot for several days without EHU. You could save a lot of investment and anxiety by being more conservative with your consumption instead. The minimum capacity needs to be enough to get you through a cold Winter’s night, something which many achieve with a conventional 85Ah battery (and only ½kWh of power, at best).

Battery capacity reduces with time, so there could be some wisdom in installing extra to compensate for that but still be prepared to swap them out when they start to hold insufficient for your needs.

You could plan to keep your investment when you change vehicles but you would need to replace them with something else (additional cost and hassle to consider) and, as technology is moving apace, there could be a more attractive solution by then.

As for Lithium batteries, there are different qualities of battery and BMS. Read the detailed specs, if you can get them, and you'll see that none are the same. You will tend to get what you pay for and I’d be wary of guarantees. My own preference would be for a ready-made (12V) cell from someone with a reputation to keep. You need to put your faith in their belief that they got it all right – you may not find out for several years down the line, by when the cheapskates will have moved-on. I’d be wary of building a solution from individual components, unless you enjoy that kind of thing and are prepared to start again: you can be sure that everyone will point their fingers at someone else in the equation if anything goes wrong.

If cost is an issue, it may be better to stick with convention, where there’s far more experience and much less opinion. Finally, don’t overlook the cost of improvement over that of paying for EHU…

That argument suggests that ehu will always be available. I want the freedom to be able to "camp" in places that may not have ehu with ability to do it in whichever season without worrying about conserving power. As long as I'm A, not causing a nuisance an B, happy to put the effort and investment in- then I can't really see a problem.

 

[two]

That reinforces the need to know the potential duration of your ‘charging famine’ = the period of time before you are able to replenish what you use. Clearly, if you are on EHU, you need no capacity to store anything at all. Off grid, you need to be able to survive until you recharge by travelling or through solar. When solar is ‘aplenty’ you should be recouping everything you need each day, so only need to store enough to get you through the night (assume a winter one when, you would need the most power) plus some compensation for really dull days or when travelling further from the sun. If your habit is to move on regularly, you may not need solar at all; just travel for long enough to capture enough to cover your next stop (for me, that’s up to three days stationary). Solar power is at no additional cost, however, whilst that from the engine will be considerably more expensive.

A B2B is very good at recharging things quickly, but 60A seems over the top unless you never travel very far each day. My journeys tend to be between one and two hours, which is more than enough time to recover what I’ve used, without a B2B.

You cannot go wrong by having plenty of everything but that approach is likely to lead to overkill. You need to measure your consumption carefully (use a battery monitor) to understand (and control) your usage. Until you know how much you use, you can only guess at what you might need to recover it.

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[jongood]

That reinforces the need to know the potential duration of your ‘charging famine’ = the period of time before you are able to replenish what you use. Clearly, if you are on EHU, you need no capacity to store anything at all. Off grid, you need to be able to survive until you recharge by travelling or through solar. When solar is ‘aplenty’ you should be recouping everything you need each day, so only need to store enough to get you through the night (assume a winter one when, you would need the most power) plus some compensation for really dull days or when travelling further from the sun. If your habit is to move on regularly, you may not need solar at all; just travel for long enough to capture enough to cover your next stop (for me, that’s up to three days stationary). Solar power is at no additional cost, however, whilst that from the engine will be considerably more expensive.

A B2B is very good at recharging things quickly, but 60A seems over the top unless you never travel very far each day. My journeys tend to be between one and two hours, which is more than enough time to recover what I’ve used, without a B2B.

You cannot go wrong by having plenty of everything but that approach is likely to lead to overkill. You need to measure your consumption carefully (use a battery monitor) to understand (and control) your usage. Until you know how much you use, you can only guess at what you might need to recover it.

I like options so would rather carry a bit of surplus capacity and that would be one of the factors determining how long I can stay in places or what appliances I can use. Even when we go to campsites there's frequently different sections for EHU. We stayed in one last month where the non EHU space was just a big open field with fabulous views whereas the EHU area was pretty grim.