26 minutes ago, ojeysky said:

I think it will be 38 hours versus 12 hours since we should be working with a 48v Lead Acid as well

Sigh. Indeed it would; thanks for pointing that out. I remember being surprised at the magnitude of the difference. I've edited my original post.

On 2020/02/15 at 9:12 AM, plonkster said:

I can imagine that working quite well in some areas! In December we spent a few days on a golf course on the South coast, I mean, one of those places that really lends credence to the "white monopoly capital" conspiracy theory. Sunshine all the time, and golf-carts all over, driven inside the estate, parked outside the club house...

🙂

 

My Cart solution - I do think they all have to go this way - and then lithium batteries.....

Hallo everybody

I'm reading a lot on this forum, but this is my first post. I'm planning to replace my AGM batteries with at least 12Kw lithium batteries from Bain Viljoen. I have 2 questions:

First one is for Bain: What is the possibility of bringing 240ah or larger batteries in? I've looked at similar batteries with similar cycles and when I do the calculation (I'm an accountant🤣) of price per ah in USD, the 240ah and 300ah batteries are cheaper per ah vs the price per ah for 120ah batteries.

The second is open for anybody: Where can I get a piece of equipment to measure the DoD of a battery bank. I do use ICC on an Axpert Inverter, but the Axpert SOC is a calculated figure based on the battery type settings.

Thank you,

Herman

18 hours ago, hjr said:

The second is open for anybody: Where can I get a piece of equipment to measure the DoD of a battery bank. I do use ICC on an Axpert Inverter, but the Axpert SOC is a calculated figure based on the battery type settings.

Hallo,

 

I do not know the other brands, but Victron have the BMV battery monitor, that measure the actual energy passing.

Best regards,

Herman

NS, I just had to answer you, Herman!

20 hours ago, hjr said:

Hallo everybody

I'm reading a lot on this forum, but this is my first post. I'm planning to replace my AGM batteries with at least 12Kw lithium batteries from Bain Viljoen. I have 2 questions:

First one is for Bain: What is the possibility of bringing 240ah or larger batteries in? I've looked at similar batteries with similar cycles and when I do the calculation (I'm an accountant🤣) of price per ah in USD, the 240ah and 300ah batteries are cheaper per ah vs the price per ah for 120ah batteries.

The second is open for anybody: Where can I get a piece of equipment to measure the DoD of a battery bank. I do use ICC on an Axpert Inverter, but the Axpert SOC is a calculated figure based on the battery type settings.

Thank you,

Herman

@hjr best is to contact Bain on his contact number. 

Jip, its cheap if you work out to the per ah in USD, but add the shipping to it and you can call me again  He did import 150ah but the manufacturing company stop making because the demand is to low with the covid going on. 

 

On the DoD, you can use a Victron BMV to check it, or you can get a Smart ant BMS like i'm using and some other guys on the forum that give you all the info. If you got a bit of python skills for a Pi, then you can pull the data from the BMS and export it.   

1 hour ago, Gerlach said:

@hjr best is to contact Bain on his contact number. 

Will do....

 

1 hour ago, Gerlach said:

Quote

Jip, its cheap if you work out to the per ah in USD, but add the shipping to it and you can call me again  He did import 150ah but the manufacturing company stop making because the demand is to low with the covid going on.

 

Shipping as separate shipments will be a killer but not as part of the same container

 

 

Starting my own DIY battery build now.  16s3p of Baine's 2nd life cells with a 250A BMS.  With any luck I can collect the cells from Bain tomorrow, and some pre-cut aluminium plates from NK Cutting as well.

Daly Smart BMS just arrived.  Build quality looks amazing, and connectivity up the wazoo. This one has bluetooth, USB, RS232 and RS485.  Also has CAN outputs, but I did not order that, so I doubt it is connected.  Now I just need to get comms specs out of Daly...

For fun, I have also included a picture of the start of my 'play' BMS.  Using grab bag Aliexpress parts to see what can be achieved.  So far this one has cycled that tiny LiPo at the end a few dozen times, tracking and limiting voltage to within 10mV quite reliably.  Unlikely that I will ever finish/use it, but fun to play with.

@JustinSchoeman looking nice!!! 

OOooooo yes. I forgot to add photos. Over the lockdown time I got my second setup up and running. My second BMS I order got stuck with the lockdown "it's still stuck in at JHB HUB", so I ordered a 3de one via Courier with a friend in lockdown level 4. My first lifepo4 setup is running 200 days know and the second one 40days, no problems. Planning to add 3de setup when I can get my hands on that BMS that is stuck in JHB. 

Gerlach, that's a very impressive install!

I've also been running a 16s2p '48V' 12kWh 2nd life DIY battery using Bain's parts since May. I used the dumb BMS option, so no cell info on the BMS, just protection.

 I did get a ISDT 8s display that I can plug into either the lower or upper block of 8 2p cells, which was useful for the final top balancing of the cells - along with a homemade watercooled 3.5V 60A load. You'll laugh if I showed you a pic of that. 

I used Bain's cell connecting parts to start, but replaced the aluminium links with homemade ones  from flattened copper pipe. That way I could connect 4 terminals with one bar, and copper pipe is a heck of a lot easier to get out here than copper bar..  I also built up a 4s3p '12V' battery for my neighbour, and could then make one bar to connect 6 terminals.

I have a Victron setup (Multiplus, MPPT and GX), and it took a bit of tweaking to get it all running nicely, but I'm super chuffed with the result. This time of the year we need about 6kWh to get through the night, and GX will usually tell me the system has gone from 95% to 45%.  We had a cloudy day yesterday, so the batteries were at 50%, and got down to 0% according to the GX at 8am today, but the BMS had still not disconnected. The battery voltage was still 49V, but I was surprised that the cells are reasonably well bottom-balanced as well for the BMS not to have kicked in due to the worst cell having gone below 2,5V.  It was about 5C outside, and I was too warm in bed to go and check the cell voltages:) Same story today, so maybe I'll force myself to brave the elements and go down to the storeroom tomorrow morning.

I have considered a smart BMS, but now that everything is running properly, I don't really need it.

It's certainly been a fun project, and the cost saving over a commercial unit has been immense.

Cheers

Edited August 5, 20205 yr by Ian

8 hours ago, Gerlach said:

OOooooo yes. I forgot to add photos. Over the lockdown time I got my second setup up and running. My second BMS I order got stuck with the lockdown "it's still stuck in at JHB HUB", so I ordered a 3de one via Courier with a friend in lockdown level 4. My first lifepo4 setup is running 200 days know and the second one 40days, no problems. Planning to add 3de setup when I can get my hands on that BMS that is stuck in JHB.

Very impressive and neat. Thanks for sharing your journey.

@Gerlach - wow!  I have a lot to live up to here!

Thanks @Ian I see you on the other side of the mountain. lekker man!!! Sounds you got your setup up and running correctly. What is your charging volt settings on your setup?  Just check your GX for any ripple errors. We founded on TTT setup that he gets ripple errors with his DALY on his setup. The problem is between the MPPT and Inverter and BMS. Short discharge DC  the BMS discharge FIT's don't close so then the Victron MPPT sits with this power that runs between the inverter and MPPT that gives ripple errors. The inverter caps work over time with this then. OOOoooo yes, other thing is, this 2nd life batteries is actually 140ah. They where 150ah in there first life, so there is some extra AH hiding there. 

@JJS is running a 16s2p setup to, you must check his bus bar setup on his. Looks really nice. Post some photos @JJS

What i like about this smart BMS is, you can adjust a lot of settings on the BMS, and it's got to balancing settings that kicks in on it's own, and the Bluetooth app is really nice. I can check on the screen what the BMS is doing and the cells info.  I can stay in the bed and check the battery cells info and SOC. We use about between 3 to 5 kwh a night, depends what we doing. I will like to add a 3de unit, then i don't have to stress for the cold nights running panel heater or something. 

Edited August 6, 20205 yr by Gerlach

Re Ripple errors. TTT had me running for days and I kept forgetting that when the BMS disconnect, the capacitors on the DC bus is the only thing holding the ripple down.

The ripple, btw, is completely normal and all inverters have it. When shaping a 50Hz AC voltage, it draws current from the battery cyclically, creating a 100Hz ripple on top of the DC. With a nice strong battery this ripple is maybe a 100mV, but when the BMS decides to disconnect, that ripple goes to over 1V and at least Victron inverters will complain about it.

Ideally you should keep the cells connected for them to work... 🙂

Also, I need to say something about dissimilar metals. Please research carefully what you use for the busbars and what bolts you use to tie it down, and ideally also use a torque spanner (suitably insulated of course) to get it right. Watch out for stainless steel bolts, the chromium oxide top layer is not the most conductive. Rather use nickel-plated. You should also consider using some kind of contact compound on the cell terminals. Otherwise you create a high impedance situation which worsens the ripple, but also causes the battery voltage to drop out under relatively low current (eg I have 90Ah 12V batteries here that has this problem, I can hardly get 25A out of them without the voltage dropping out).

If anyone knows a good contact paste/compound that you can actually find in this country, let me know. The stuff that I know works really well is Burndy Penetrox A-13, but i can't find it in SA.

31 minutes ago, plonkster said:

...Also, I need to say something about dissimilar metals. Please research carefully what you use for the busbars and what bolts you use to tie it down, and ideally also use a torque spanner (suitably insulated of course) to get it right. Watch out for stainless steel bolts, the chromium oxide top layer is not the most conductive. Rather use nickel-plated. You should also consider using some kind of contact compound on the cell terminals. Otherwise you create a high impedance situation which worsens the ripple, but also causes the battery voltage to drop out under relatively low current (eg I have 90Ah 12V batteries here that has this problem, I can hardly get 25A out of them without the voltage dropping out).

If anyone knows a good contact paste/compound that you can actually find in this country, let me know. The stuff that I know works really well is Burndy Penetrox A-13, but i can't find it in SA.

I was planning on using plain old zinc plated hardware.  It provides very nearly the best galvanic compatibility between copper, steel and aluminium. (Cadmium would be the best, but that is unobtanium here, but zinc is second best, so will have to do.) As a bonus, zinc is also generally used on mild steel screws, which have much better conductivity than high carbon or stainless steels.

Stainless is the worst of everything.  It has the lowest conductivity, and it reacts naturally with aluminium to oxidize any contact surface.

I have also been looking for contact grease, but no luck so far.  Will stick with buffing the aluminium immediately before clamping, and rely on that for a good bond.

Some questions for other builders out there:

1) Anybody know the correct torque spec for the terminals on these cells?  Most manufacturers spec it on the datasheet, but I can not find it on the images on the website.

2) What is the preferred way of routing the balance wires?

a) birds nest (just route directly to the terminals), or

b) channeled wire bundles.

(a) is a lot simpler, and electrically superior (lowest resistance and lowest noise), but does not look great, and is more susceptible to damage if you ever do need to poke around inside the battery.

(b) takes a lot of effort, but looks neat and keeps the wires out of the way, but wires become very long, and long parallel wire runs are very bad for electrical noise.

14 minutes ago, JustinSchoeman said:

correct torque spec

The figure I have is 14Nm.

16 minutes ago, plonkster said:

The figure I have is 14Nm.

That seems a tad excessive?  Most seem to be in the 2-4Nm range?

3 minutes ago, JustinSchoeman said:

That seems a tad excessive?  Most seem to be in the 2-4Nm range?

Oh I agree, that seems mighty tight. But I have in my possession the actual construction documentation of a battery maker and that is what they actually use...

This forum post suggests that 11Nm is good on an M8 bolt. It depends on the quality of the alloy and of the bolt of course. This shop page says 9Nm.

I have never done this before, I merely collected the information so long for a job that has to follow later... once I can source the compound required for the job.

2 hours ago, plonkster said:

If anyone knows a good contact paste/compound that you can actually find in this country, let me know. The stuff that I know works really well is Burndy Penetrox A-13, but i can't find it in SA.

Many years ago, we used to put Spanjaard high temperature copper compound on lead-acid battery terminals. It's basically grease with loads of copper particles mixed in. I know on lead-acid batteries, having grease on the terminals helps prevent corrosion of the connections caused by the acid. I'm not sure if it is a good enough conductor for what you want though.

Edit: here is a link to the product description

https://www.spanjaard.biz/product/copper-compound-500g-tin/

Edited August 6, 20205 yr by Stanley

If I am correct the 280Ah cell has a 6mm bolt and the 120/100Ah has a 4mm?

 

I've been looking at getting 280Ah cells recently myself. For that I have seen 9Nm bandied about on forums. So less than than seems reasonable for the smaller cell.

Speaking about the 280Ah cell specifically, but I have no reason to think the smaller cell is immune either:

The hole depth is 10mm and when you fit more substantial busbars and a BMS lug and perhaps a washer, there is a concern that insufficient thread gets purchase with the original bolts.

So unless you get longer nuts stripping the thread is a real danger.

12 minutes ago, Stanley said:

Many years ago, we used to put Spanjaard high temperature copper compound on lead-acid battery terminals. It's basically grease with loads of copper particles mixed in. I know on lead-acid batteries, having grease on the terminals helps prevent corrosion of the connections caused by the acid. I'm not sure if it is a good enough conductor for what you want though.

The SADF tiffies believed in vaseline. ( for battery terminals, that is).

I just looked up Penetrox A-13 and this is the description:

Synthetic (nonpetroleum) base compound with evenly suspended zinc particles

Which sounds very similar to the high temperature copper compund, except that they use zinc instead of copper.

Spanjaard also has Chrome compound and Nickel compound, for situations where copper is no good.

One of these products may just do the trick if the Penetrox A-13 is not available.

52 minutes ago, plonkster said:

Oh I agree, that seems mighty tight. But I have in my possession the actual construction documentation of a battery maker and that is what they actually use...

This forum post suggests that 11Nm is good on an M8 bolt. It depends on the quality of the alloy and of the bolt of course. This shop page says 9Nm.

I have never done this before, I merely collected the information so long for a job that has to follow later... once I can source the compound required for the job.

Thanks. 9Nm for M6 seems OKish... Will chat to Bain when I collect, and see if he has any factory specs.