Lithium battery conversion

[Sea Change]

Indeed - in fact most people now are just using fibre tape for the compression which works perfectly for a few quid a roll. But its worth noting that additional costs are incurred - not everyone will already own crimping tools etc as well as the power supply. When making a comparison it is best to give all the facts.

I am all for building packs - I do at least one every week and sometimes as many as 4 . The biggest issue people will face is the time to top balance their battery pack. A stable supply for £50 as you note , will only be 10amp and so running 4 cells from perhaps 40% full to 100% full can take days. I tend to use a 30 amp supply with the cells in series at 14v to go up to about 90% and then swap to the bench supply and reconfigure to parallel to top balance at 3.6v - even so in a week when I have lots to make the charging is happening continuously from dawn til dusk.

It is all straightforward to do but not everyone wants to spend the time or trust their own electrical skills so the "drop in" option is still popular and better for some.

Yes time is an issue if you're doing a lot of packs. For someone building a single pack over winter whist the boat isn't in use, less of a problem.
On my last build I sped things up by charging in series using a 30A 12v, using the BMS set to very conservative limits, and then switched to parallel charging at 10A when the cells were above 3.4v.

The big hydraulic crimper (£30) was essential, but only because I was doing a huge upgrade with new components. The battery type wouldn't have changed that.

 

[GHA]

Yes time is an issue if you're doing a lot of packs. For someone building a single pack over winter whist the boat isn't in use, less of a problem.

Up to 14v will be up near 97/98% or more SOC so a day paralleled on a cc/cv power supply (cheap off ebay for dc/dc buck boost) gets a 300Ah 4s bank balanced.

 

[gregcope]

Agree with @Trident. I would challenge that assembling packs is “not that much”. Consumables add up and you need tools which many people will not have.

You need decent sized cables (25-35mm2 or even bigger). Decent lungs to go with them and often two sizes like 8mm or 6mm. Chaff/wire loom tape. T class fuses and holders. Possibly decent Isolators. Probably a few large capacity busbars.

You may also need a decent crimper, for large and small crimps. A charger or desktop power supply. A capacity tester. Possibly an IR/Thermal camera or gun to measure temps.

You might have a workshop and all these bits lying around. You may not.

 

[Sea Change]

Agree with @Trident. I would challenge that assembling packs is “not that much”. Consumables add up and you need tools which many people will not have.

You need decent sized cables (25-35mm2 or even bigger). Decent lungs to go with them and often two sizes like 8mm or 6mm. Chaff/wire loom tape. T class fuses and holders. Possibly decent Isolators. Probably a few large capacity busbars.

You may also need a decent crimper, for large and small crimps. A charger or desktop power supply. A capacity tester. Possibly an IR/Thermal camera or gun to measure temps.

You might have a workshop and all these bits lying around. You may not.

If you're going to install 'drop in' batteries, you'll need to upgrade to a class T fuse. And that means you'll need to make up suitable leads, which requires the crimper.

There's nothing wrong with drop-ins, they just don't simplify things as much as you might think. All the hard bits of a lithium installation are still there.

 

[geem]

The Renogy is one of the best (I have been installing them for years and still do for many cases) and if you're happy with it then its not expensive other than when compared to building your own pack - but even then when you consider that you need to get a stable voltage supply unit to top balance the pack, a way to give compression to the pack etc, its not really all that much cheaper but you'd get 280ah not 200. [Inappropriate quoted content removed]

The BMS on the Renogy is great, not as informative as the JK , but it's high quality and they use the right size leads internally to allow that full 200a discharge which is where many cheaper brands fail - 200a BMS but 10mm2 wires to try and handle it

EVE cells will work out cheaper but you do need to balance them with a fixed supply, you need to do a bit of wiring (making battery leads and attaching terminals to the balance wire - all straightforward) and if you don't already have the equipment then the cost is probably the same

I haven't needed to balance the Grade B Envision cells, even though I have a bench top supply. I let the JK do the balancing and it achieved it pretty easily. If I had solar available at home, I could just have let the mppt do the power supply, instead, I used the bench top supply to do the last bit of charging as my battery charger wasn't lithium compatible

 

[geem]

Agree with @Trident. I would challenge that assembling packs is “not that much”. Consumables add up and you need tools which many people will not have.

You need decent sized cables (25-35mm2 or even bigger). Decent lungs to go with them and often two sizes like 8mm or 6mm. Chaff/wire loom tape. T class fuses and holders. Possibly decent Isolators. Probably a few large capacity busbars.

You may also need a decent crimper, for large and small crimps. A charger or desktop power supply. A capacity tester. Possibly an IR/Thermal camera or gun to measure temps.

You might have a workshop and all these bits lying around. You may not.

I made my own busbars. You don't need class T fuses. Use NH series. Far more cost effective and probably better than class T.
I bought a hydraulic crimper for £35. You don't need a capacity tester. Yes you will need a charger, but won't you anyway? Fingers work pretty good as temperature sensors

 

[Trident]

I haven't needed to balance the Grade B Envision cells, even though I have a bench top supply. I let the JK do the balancing and it achieved it pretty easily. If I had solar available at home, I could just have let the mppt do the power supply, instead, I used the bench top supply to do the last bit of charging as my battery charger wasn't lithium compatible

It is not recommended by EVE to let the BMS balance - I did try it on one pack for my workshop use and it did so very quickly with 2kw of solar plugged in but I assume the manufacturers advice is there for a reason

 

[geem]

It is not recommended by EVE to let the BMS balance - I did try it on one pack for my workshop use and it did so very quickly with 2kw of solar plugged in but I assume the manufacturers advice is there for a reason

From a technical perspective, I wonder what that might be? The JK bms had the cells balanced to 2 mV deviation. The cells don't know that they are hooked to a bms. I balanced my CATL cells the conventional way but did all batteries I have built since using the JK bms. I haven't noticed any difference in performance. I can imagine if you were balancing with a passive balancer, it would be a very, very slow process and may not even balance at all.

 

[Sea Change]

One other factor that I haven't seen mentioned is that a DIY battery can be much more compact than a drop-in. Maybe it varies between different designs, but the drop-ins I've seen have all been considerably bulkier than the comparable DIY pack. E.g. my 60Ah drop-in is only slight smaller than my 280Ah pack.

 

[geem]

One other factor that I haven't seen mentioned is that a DIY battery can be much more compact than a drop-in. Maybe it varies between different designs, but the drop-ins I've seen have all been considerably bulkier than the comparable DIY pack. E.g. my 60Ah drop-in is only slight smaller than my 280Ah pack.

I just built a 280A at 24v battery (equivalent to a 560Ah at 12v) overall size is 400mmx 350mm x300mm high. Weight is 45kg. It's a big battery but with a useful capacity when compared to lead of approximately 1000Ah. Total cost £650 including a Jk BMS

 

[Trident]

One other factor that I haven't seen mentioned is that a DIY battery can be much more compact than a drop-in. Maybe it varies between different designs, but the drop-ins I've seen have all been considerably bulkier than the comparable DIY pack. E.g. my 60Ah drop-in is only slight smaller than my 280Ah pack.

I swapped 700ah for over 900 ah and saved 50% space and 10 kg even though my previous batteries were lightweight anyway. I think they make the cases for drop ins to standard LA sizes which of course are as you say pretty big

 

[Trident]

From a technical perspective, I wonder what that might be? The JK bms had the cells balanced to 2 mV deviation. The cells don't know that they are hooked to a bms. I balanced my CATL cells the conventional way but did all batteries I have built since using the JK bms. I haven't noticed any difference in performance. I can imagine if you were balancing with a passive balancer, it would be a very, very slow process and may not even balance at all.

I assume that as the BMS asks for a reference voltage etc that should be set with the entire pack the same though as you say the JK BMS detects to 3 decimal places and actively balances quickly and accurately, even allowing for the varying resistance in the balance wires if not all the same. Perhaps the advice is a throw back to earlier technology on the BMS front but I do what the manufacturer recommends without having further information either way. I'd like packs I build to last at least 15 years and not lose capacity to any great degree. Shorter term tests don't tell us much but its possible with the latest BMS systems that advice may change .

 

[geem]

I assume that as the BMS asks for a reference voltage etc that should be set with the entire pack the same though as you say the JK BMS detects to 3 decimal places and actively balances quickly and accurately, even allowing for the varying resistance in the balance wires if not all the same. Perhaps the advice is a throw back to earlier technology on the BMS front but I do what the manufacturer recommends without having further information either way. I'd like packs I build to last at least 15 years and not lose capacity to any great degree. Shorter term tests don't tell us much but its possible with the latest BMS systems that advice may change .

I was surprised that the grade B Envision 280A cells balanced up so easily. I was expected to have to rig up my balance leads to put them all in parallel but that wasn't necessary. I will install the grade B cell battery next weekend and run it parallel to my CATL grade A cells. It will be fun to see how they get on. With so much info available from a Bluetooth bms, it should be easy to spot any differences in how they perform.

 

[Neeves]

Are they good enough, they can certainly be cheap.

Battery Lug Copper Lugs Awg10 - Temu Australia

Again prices in A$, work with a 2:1 exchange rate

Jonathan

 

[noelex]

Are they good enough, they can certainly be cheap.

Battery Lug Copper Lugs Awg10 - Temu Australia

Again prices in A$, work with a 2:1 exchange rate

Jonathan

They look like cheap, thin walled, non tin plated terminals. They will only accept small wire gauges despite the pictures.

The low voltage on boat systems means the current is high for even moderate loads. This requires good quality components.

There are better choices.

 

[Neeves]

Deleted

 

[geem]

Before Lithium I had minimal need for such kit and begged and borrowed the crimp connector and bought the untied lugs - because tinned are not off the shelf where I live. All our custom wiring was tinned but bought in components that did not have tinned wiring did not suffer - modern yachts are less humid and dry. I suspect many owners have similar needs and for Stg7 - are your comments realistic and balanced.

The terminals look to be the same as ones I bought, from Timu - and they seem pretty heavy duty to me. But you know best, your powers of observation are well known and recorded.

So...opportunity for you

Cut terminal and measure its thickness, define terminal thickness size. I'll do the same, I have a cross section of terminals. Mine are not tinned. Lets compare. .

I know hydraulic kit is better - but not everyone can justify the expense (and I suspect not always necessary) - you obviously don't need 'Scots pockets'.

Scots are not mean, in fact all those I know are generous (but then I'm biased). Scots simply don't spend hard earned money unnecessarily.

Jonathan

You need hydraulic crimping, especially with lithium. The high current potential of lithium will not tolerate high resistance connections. A set of cheap hydraulic jaws is about £35.

 

[gaylord694]

Before Lithium I had minimal need for such kit and begged and borrowed the crimp connector and bought the untied lugs - because tinned are not off the shelf where I live. All our custom wiring was tinned but bought in components that did not have tinned wiring did not suffer - modern yachts are less humid and dry. I suspect many owners have similar needs and for Stg7 - are your comments realistic and balanced.

The terminals look to be the same as ones I bought, from Timu - and they seem pretty heavy duty to me. But you know best, your powers of observation are well known and recorded.

So...opportunity for you

Cut terminal and measure its thickness, define terminal thickness size. I'll do the same, I have a cross section of terminals. Mine are not tinned. Lets compare. .

I know hydraulic kit is better - but not everyone can justify the expense (and I suspect not always necessary) - you obviously don't need 'Scots pockets'.

Scots are not mean, in fact all those I know are generous (but then I'm biased). Scots simply don't spend hard earned money unnecessarily.

Jonathan

If you only need a few cables made up then use

Before Lithium I had minimal need for such kit and begged and borrowed the crimp connector and bought the untinned lugs - because tinned are not off the shelf where I live. All our custom wiring was tinned but bought in components that did not have tinned wiring did not suffer - modern yachts are less humid and dry. I suspect many owners have similar needs and for package of Stg7 - are your comments realistic and balanced.

You seem to be nit picking - the offer is for a package.

The terminals look to be the same as ones I bought, from Timu - and the ones I bought seem pretty heavy duty to me. But you know best, your powers of observation are well known and recorded.

So...opportunity for you

Cut terminal and measure its thickness, define terminal cable size. I'll do the same, I have a cross section of terminals. Mine are not tinned. Lets compare. .

But the offer is not for terminals but the whole kit. If you feel the need for thick-walled lugs (wait till the kit arrives and make you own decision - go buy). The offer is not for terminals alone but the crimper etc.

I know hydraulic kit is better - but not everyone can justify the expense (and I suspect not always necessary) - you obviously don't need 'Scots pockets'.

Scots are not mean, in fact all those I know are generous (but then I'm biased). Scots simply don't spend hard earned money unnecessarily.

Here is a package, cheap as chips - and you complain, based on a quick glance - and even your detailed glances are questioned, about the smallest part of the offer - the lugs.

Beggars belief.

Jonathan

If your only going be doing a system for yourself then ECS is your best bet. Far better than paying out for crimpers etc your probably never going use again if your not in that industry

 

[geem]

Are they good enough, they can certainly be cheap.

Battery Lug Copper Lugs Awg10 - Temu Australia

Again prices in A$, work with a 2:1 exchange rate

Jonathan

You can buy tinned lugs from a good electrical factors supplying commercial kit to the electrical industry. Every power distribution board uses tinned terminals. I have never seen a commercial power distribution board that doesn't

 

[gaylord694]

You can buy tinned lugs from a good electrical factors supplying commercial kit to the electrical industry. Every power distribution board uses tinned terminals. I have never seen a commercial power distribution board that doesn't

Think your missing the point ,yes you can by tinned lugs but you still need the tools to secure them properly because as you know the cause of fires/burnt cables,melted etc are loose connections especially with some of the amperages on 12v systems