NZ - LiFePO4 Cell Sources? It's the shipping...

[KJU]

Has anyone in New Zealand found an economical source for LiFePO4 cells?
In my searches, shipping cost runs roughly equal to purchase price.

My interest: 24 or more Prismatic LiFePO4 cells of about 150AHr (+/- )

I'm using 'drop-in' batteries now. And not liking them in series.
Considering disassembling for the cells inside / transplanting BMSs & etc.
But cell quality & matching seem... variable.
KJU

 

[AussieSim]

Shipping is very expensive at the moment

A surge of imports is causing havoc in the world’s ports

And the hold-ups are worsening jitters about Brexit

www.economist.com

 

[HateGrid]

KJU - are you using a freight forwarder for the shipping charges or are you relying upon the seller's shipping?

 

[KJU]

Hi HG,
The only shipping cost estimates I looked at for cells were from AliExpress - their 'standard shipping.'
For the BMSs I bought there (ICGOGOGO store) AliExpress shipping was free.
It took about twice their estimated time to arrive.
Cheers,
KJU

 

[HateGrid]

I haven't had much luck with AliExpress shipping and batteries. I have had some 20Ah pouch batteries arrive safely after about 12 weeks, but this was three years ago. They were sent by train to the Netherlands and then sent by NL Post to New Zealand. The rules have tightened down since then and most suppliers will not ship to New Zealand.

For 24 batteries, you will probably want to buy from Alibaba and use a freight forwarder or try and get the seller to do it DDP. I did FOB for a CNC router 5 years ago and that worked out fine. I'm hoping to get indicative pricing next week from freight forwarders for some PV panels and 48V 10 KW "powerwall" battery packs or some rack-based batteries.

By drop-in batteries, are you talking about 12V "car battery" LiFePO4 packages? If you want something with a BMS, these units from Micromall (a New Zealand Chinese importer) look pretty good: https://www.micromall.co.nz/index.php?route=product/product&product_id=505

 

[KJU]

I haven't had much luck with AliExpress shipping and batteries. I have had some 20Ah pouch batteries arrive safely after about 12 weeks, but this was three years ago. They were sent by train to the Netherlands and then sent by NL Post to New Zealand. The rules have tightened down since then and most suppliers will not ship to New Zealand.

For 24 batteries, you will probably want to buy from Alibaba and use a freight forwarder or try and get the seller to do it DDP. I did FOB for a CNC router 5 years ago and that worked out fine. I'm hoping to get indicative pricing next week from freight forwarders for some PV panels and 48V 10 KW "powerwall" battery packs or some rack-based batteries.

By drop-in batteries, are you talking about 12V "car battery" LiFePO4 packages? If you want something with a BMS, these units from Micromall (a New Zealand Chinese importer) look pretty good: https://www.micromall.co.nz/index.php?route=product/product&product_id=505

Hi HG,

Starting with MicroMall...
I have two of their 24V 130AH batteries. Paul opened one up for me - they have JBD 8s BMSs, and the advert says 'Install 3A Active Balancing' - I don't know if it's in there or not. Wired in series for our 48V yacht propulsion, they discharge quite unevenly. One of the units hits a cell LVD early enough to yield <110AH in real-propeller tests. The boxes are pretty, but I can't entirely vouch for the quality or capacity of the cells, or their balancing.

I have a new ANT 16s BMS that I may use to siamese-twin the two 8s units. I'll probably concentrate on those for practical purposes, and on the 24 used cells for entertainment, so I'll be ordering nothing for now.

Thanks for your shipping stories.

KJU

 

[HateGrid]

Hi KJU,

Thanks for the reply. Sorry to hear about your experience. Will be interested to hear how your tests go once you convert your 2x 8S system into a 16S system.

What sort of discharge rate are doing?

FYI - for others, here is a link to the battery: https://www.micromall.co.nz/index.php?route=product/product&product_id=507

 

[KJU]

Hi HG,

The experience isn't so sorry as, well, predictable. I never asked each of the old AGM PbAcid batteries in series how they felt about their share of the load. But with these newfangled ones, they let us know. My hope now is that the cells are okay, can be balanced better in series string than in series packs, and give us a good 120+AH.

We motor slowly and as little as we can. We sail instead, and accept limited motoring range. Fortunately, wind is common in NZ. We use between 18 and 30 Amps to go 2 or 3 knots. A short spurt of 40+ Amps very occasionally. Almost never higher. (48V nominal system)

Cheers,
KJU

 

[HateGrid]

OK, the 18 to 30 Amps with a burst to 40 occasionally shouldn't affect the capacity much. I was just curious if you were running it at 100A or more at which point power losses in the batteries and cables could make it look like lower capacity.

If you have two BMSs in series, then during charging, one battery would start balancing before the other one finished charging. The charge current would then be the balancing current of 3A and it could actually go open circuit if the voltage goes high enough on one of the cells. This would leave the other battery unbalanced.

If the BMS was configured correctly, then there shouldn't be any damage to the cells as the under-voltage cut-out will disconnect the cell to avoid further discharge. Just make sure you charge it so that it doesn't eventually self-discharge below its minimum voltage.

Once you connect the 16S BMS, you should be fine. You could also charge the two 24V batteries separately with a 24V charger.

Lead-acid batteries are self-balancing when in series, so you never have to deal with this complexity.

Hope that helps.

 

[Steve_S]

I believe that Luyuan Tech on Alibaba has sent cells to members in NZ. The Shipping Guestimator on Baba "sux" you need to talk with Amy Wan in their chat / messenger app. Shenzhen Luyuan Technology Co., Ltd. - Lifepo4 battery, LTO battery (alibaba.com) Just because a vendor site does not indicate NZ, check with the reps to make sure. We KNOW Good Vendors as well as BAD Vendors here, tons of experience, so search the forum if in doubt on any vendor.

Your descriptions in the thread are indicative of Unmatched / Unbalanced cells misbehaving in your existing battery packs. This is not unusual for that type of "Bulk Commodity cells". Active Balancers can mitigate some minor deviations but no balancer or BMS can "fix" bad or weak cells. I am also unaware of any JBD BMS with built-in Active Balancing, a few have Passive Balancing. Li-Ion BMS - White Paper - Dissipative vs. nondissipative balancing (a.k.a.: Passive vs. Active balancing) It may be possible to extract the cells & BMS (disconnect BMS Harness from BMS prior to disconnecting any other wires) and perform a Top Balance on the cells and repack them using the same BMS. NOTE, it is VERY easy to fry a BMS, so care & caution.

Ideally for 24V System, you want to do Straight 8S battery packs, each with a BMS & Fuse rated to the max anticipated load & charge that you will be using. Each battery pack then set into parallel to equally share the load & charge potentials. If packs are matched in AH Capacity this all plays out fairly evenly. If you have a 150AH Battery & 250AH battery in the bank, that is FINE (no lead-isms here) but you will see a difference in charge & discharge handling relative to the pack capacity which is also fine. One gotcha that folks must pay attention to though, is once the 150 hit's Low or High Volt disconnect, the 250 will keep going. This is where a key point has to be accounted for, each battery BMS should be able to handle the FULL Load/Charge potential as a standalone battery. This is also Failsafe/Fallback protection in case one or the other decides to cut off.

Also have a look at this doc, starting on page 17 about setting up batteries properly in parallel within a bank.
VICTRON Wiring-Unlimited-EN.pdf

Have a good look at the links in my signature, there is info in there you will want and spend a heap of time looking for.

 

[luckielab]

Also have a look at this doc, starting on page 17 about setting up batteries properly in parallel within a bank.
VICTRON Wiring-Unlimited-EN.pdf

This is a great doc!!!

 

[KJU]

OK, the 18 to 30 Amps with a burst to 40 occasionally shouldn't affect the capacity much. I was just curious if you were running it at 100A or more at which point power losses in the batteries and cables could make it look like lower capacity.

If you have two BMSs in series, then during charging, one battery would start balancing before the other one finished charging. The charge current would then be the balancing current of 3A and it could actually go open circuit if the voltage goes high enough on one of the cells. This would leave the other battery unbalanced.

If the BMS was configured correctly, then there shouldn't be any damage to the cells as the under-voltage cut-out will disconnect the cell to avoid further discharge. Just make sure you charge it so that it doesn't eventually self-discharge below its minimum voltage.

Once you connect the 16S BMS, you should be fine. You could also charge the two 24V batteries separately with a 24V charger.

Lead-acid batteries are self-balancing when in series, so you never have to deal with this complexity.

Hope that helps.

Hi HG,
Well, my capacity tests have drawn very modest amperages, and all loads including losses go through a shunt for measurement. By reputation, the capacity should be virtually the same for any (non-damaging) current for LiFePO4 batteries.

Right on about BMS cutoffs preventing identical charging and cell balancing, not to mention access to the capacity of the battery that still has some.

Yes, I always leave these batteries at a medium state of charge. Also, if I were more prone to adding to my investment, I'd have bought two 24V chargers by now. But I already have two 48V ones.
Cheers,
KJU

 

[KJU]

I believe that Luyuan Tech on Alibaba has sent cells to members in NZ. The Shipping Guestimator on Baba "sux" you need to talk with Amy Wan in their chat / messenger app. Shenzhen Luyuan Technology Co., Ltd. - Lifepo4 battery, LTO battery (alibaba.com) Just because a vendor site does not indicate NZ, check with the reps to make sure. We KNOW Good Vendors as well as BAD Vendors here, tons of experience, so search the forum if in doubt on any vendor.

Your descriptions in the thread are indicative of Unmatched / Unbalanced cells misbehaving in your existing battery packs. This is not unusual for that type of "Bulk Commodity cells". Active Balancers can mitigate some minor deviations but no balancer or BMS can "fix" bad or weak cells. I am also unaware of any JBD BMS with built-in Active Balancing, a few have Passive Balancing. Li-Ion BMS - White Paper - Dissipative vs. nondissipative balancing (a.k.a.: Passive vs. Active balancing) It may be possible to extract the cells & BMS (disconnect BMS Harness from BMS prior to disconnecting any other wires) and perform a Top Balance on the cells and repack them using the same BMS. NOTE, it is VERY easy to fry a BMS, so care & caution.

Ideally for 24V System, you want to do Straight 8S battery packs, each with a BMS & Fuse rated to the max anticipated load & charge that you will be using. Each battery pack then set into parallel to equally share the load & charge potentials. If packs are matched in AH Capacity this all plays out fairly evenly. If you have a 150AH Battery & 250AH battery in the bank, that is FINE (no lead-isms here) but you will see a difference in charge & discharge handling relative to the pack capacity which is also fine. One gotcha that folks must pay attention to though, is once the 150 hit's Low or High Volt disconnect, the 250 will keep going. This is where a key point has to be accounted for, each battery BMS should be able to handle the FULL Load/Charge potential as a standalone battery. This is also Failsafe/Fallback protection in case one or the other decides to cut off.

Also have a look at this doc, starting on page 17 about setting up batteries properly in parallel within a bank.
VICTRON Wiring-Unlimited-EN.pdf

Have a good look at the links in my signature, there is info in there you will want and spend a heap of time looking for.

Hi Steve_S,
I'll thank you first for what I've learned from your many posts not directed to me. You've shared a valuable lot of experience and hard-won info - I'd even say wisdom, so... Thanks!

I found stores on AliExpress which offered to ship to NZ, but the combined purchase and shipping was too high. It would be a delight to start with really high quality cells. I may look again for propulsion use, and relegate the 24V marginal (?) Micromall batteries to another use.

Soon I should know more about those units. I have a JBD Bluetooth adaptor now, so I'll try it in each of their UART ports. Software permitting, I may be able to check the BMS for balancing and all the parameters, and possibly even watch the mythical 'active balancer' at work, if it does exist.

Those cells are welded to contacts, so they'll probably stay in place if I do siamese-twin them. Got your reminder about sequence of disconnection. Yeah.

I don't know if you caught that our propulsion system is 48V, so the 24Vs are in series. But in another context, it's good to know the possibilities of parallel setups. Victron is great.

Cheers from a Canadian expat,
KJU

 

[Whats_per_question]

Hi HG,

Starting with MicroMall...
I have two of their 24V 130AH batteries. Paul opened one up for me - they have JBD 8s BMSs, and the advert says 'Install 3A Active Balancing' - I don't know if it's in there or not. Wired in series for our 48V yacht propulsion, they discharge quite unevenly. One of the units hits a cell LVD early enough to yield <110AH in real-propeller tests. The boxes are pretty, but I can't entirely vouch for the quality or capacity of the cells, or their balancing.

I have a new ANT 16s BMS that I may use to siamese-twin the two 8s units. I'll probably concentrate on those for practical purposes, and on the 24 used cells for entertainment, so I'll be ordering nothing for now.

Thanks for your shipping stories.

KJU

Super late to this party, but ... in most cases, unless the BMS manufacturer specifically states that the BMS is designed to work in series, these BMS are not warranted to work in series. In parallel they will (should?) be fine, although some BMS manufacturers do put a limit such as "up to 12 in parallel". This is probably counter-intuitive to many - it certainly was to me years ago but luckily someone gave me the heads-up before i purchased 2 x 12v for a 24v system thinking it would give me more options to change things around in the future. You might think that each battery is independent, and doesn't know (or even need to know) if there are energy sources ahead or behind it on the series string of batteries, but compare this model to a series of resistors in a voltage divider situation - each resistor (other than thermal effects) keeps its nominated resistance at all times, especially with different applied voltages, whereas a battery's internal resistance is (1) low, (2) changes with temperature, (3) changes with SOC, (4) changes with age, (5) changes with chemistry, (6) changes with capacity, (7) changes with applied voltage?
I'm not absolutely sure on #7, but all the others are demonstrable. So now you have a situation where under charge, due to #1, tiny changes in one battery's internal resistance will mean that there is a much lower voltage drop across that battery and therefore similar to charging a battery at a very low charging voltage. The other battery (presuming 2 in the series string) gets the balance of the charging voltage, and this might be enough to cook the BMS.
Also a note about MicroMall - not sure about back in 2021, but here in 2023 their reputation has not been stellar regarding accurate, honest specs in their TradeMe listings, and also not stellar in their customer's comments (online and offline). YMMV. I'm about to make another post about their wind turbines that they claim are 500w

 

[Alkaline]

Luyuan Alibaba.