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Cheap LiFePO4 BMS?

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Another BMS - unbranded from China - Bluetooth - Instructions apparently not too clear.

 

https://www.ebay.co.uk/itm/Smart-Lifepo4-li-ion-Lipo-LTO-Battery-Protection-Board-BMS-48V-72V-Bluetooth-20S/192880341024?_trkparms=aid%3D111001%26algo%3DREC.SEED%26ao%3D1%26asc%3D20131017132637%26meid%3Db511157a3c944ab2b90b1a7eca6d97b4%26pid%3D100033%26rk%3D1%26rkt%3D8%26mehot%3Dpp%26sd%3D192880341024%26itm%3D192880341024%26pmt%3D0%26noa%3D1%26pg%3D2045573&_trksid=p2045573.c100033.m2042

 

along with a video with it in action in a 48V 40Ah system. He's a bit excitable, but works his way through getting the BMS to work. He seems to think the BMS controls everything it needs to, but you guys will know if something is missing if you watch the video.

 

 

 

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1 hour ago, WotEver said:

Gosh, he’s excitable!

Agreed... but he does seem to make things look relatively straightforward, and not averse to revealing his own learning curve. I also presume he is making some kind of a living out of it?

 

I dont think I can justify spending £1200 or so on a 200Ah bank of individual cells from Sinopoly, from a financial point of view. However, if I could introduce some fun/interest/hobby element, then it could be worth doing.

 

In all of the discussions by our early adopters here, it seems that Battery Management is the major issue and, if this little hundred quid box can deal with all of that, (including temperature), it only leaves the initial capital expense of the batteries as an issue, (for me, anyway).

Edited by Richard10002

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Given #276 where I identify this BMS and a video to go with it, is there any reason I couldn't buy it and practice with my Lead Acid bank - 3 x Rolls 130Ah 12V batteries, (capacity probably around 180Ah total :( )? Assuming I could, I would be up to speed, risking nothing, by the time I stump up for lithiums.

 

https://www.ebay.co.uk/itm/Smart-Lifepo4-li-ion-Lipo-LTO-Battery-Protection-Board-BMS-48V-72V-Bluetooth-20S/192880341024?_trkparms=aid%3D111001%26algo%3DREC.SEED%26ao%3D1%26asc%3D20131017132637%26meid%3Db511157a3c944ab2b90b1a7eca6d97b4%26pid%3D100033%26rk%3D1%26rkt%3D8%26mehot%3Dpp%26sd%3D192880341024%26itm%3D192880341024%26pmt%3D0%26noa%3D1%26pg%3D2045573&_trksid=p2045573.c100033.m2042

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1 hour ago, Richard10002 said:

Agreed... but he does seem to make things look relatively straightforward, and not averse to revealing his own learning curve. I also presume he is making some kind of a living out of it?

 

I dont think I can justify spending £1200 or so on a 200Ah bank of individual cells from Sinopoly, from a financial point of view. However, if I could introduce some fun/interest/hobby element, then it could be worth doing.

 

In all of the discussions by our early adopters here, it seems that Battery Management is the major issue and, if this little hundred quid box can deal with all of that, (including temperature), it only leaves the initial capital expense of the batteries as an issue, (for me, anyway).

Your price for the Sinopoly cells is twice what Tom, MP and  myself paid. £1000 for 480Ahrs was typical this spring.

Your 'BMS' will run between £200 and £500 dependent on what level of protection you need.

Putting Li's in has been fun/interesting/become a hobby.

 

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1 hour ago, Richard10002 said:

Given #276 where I identify this BMS and a video to go with it, is there any reason I couldn't buy it and practice with my Lead Acid bank - 3 x Rolls 130Ah 12V batteries, (capacity probably around 180Ah total :( )? Assuming I could, I would be up to speed, risking nothing, by the time I stump up for lithiums.

 

https://www.ebay.co.uk/itm/Smart-Lifepo4-li-ion-Lipo-LTO-Battery-Protection-Board-BMS-48V-72V-Bluetooth-20S/192880341024?_trkparms=aid%3D111001%26algo%3DREC.SEED%26ao%3D1%26asc%3D20131017132637%26meid%3Db511157a3c944ab2b90b1a7eca6d97b4%26pid%3D100033%26rk%3D1%26rkt%3D8%26mehot%3Dpp%26sd%3D192880341024%26itm%3D192880341024%26pmt%3D0%26noa%3D1%26pg%3D2045573&_trksid=p2045573.c100033.m2042

Just looked at the video.

From an overview point of view, it seems to be everything you need with its own cell monitoring and auto disconnect .....but I guess the devil is in the detail. He is only using it with a solar charger so isnt interested in overcharging or over voltage. I assume it can manage both of them....but he didnt give enough detail about what can be adjusted and by how much. Lets assume it does do high voltage disconnection....otherwise it is pointless.

 

How are you going to set your system up? Will it be with an alternator? If so then how are you going to handle the alterntor charge on high voltage disconnect? I assume you will have a lead acid in parallel? The start battery perhaps? If it is the start battery then what is the current this unit is likely to see? Will the solid stage relay in it take the current then? The unit is wired on the negative battery lead. I have my isolation switches on the positive lead. Not sure if this would be an issue.

Think through how the high voltage disconnect and re-connect works. I have a voltage sensor on the alternator/LA side of the disconnect so when the voltage is high, it isolates and then when the alternator stops, the sensor detects the voltage is low enough and reconnects. I suspect this unit just measure the voltage of the Li's. May need a bit of thinking through.

 

If I was in your position and want a new hobby, then get one of these boards but buy a 2nd hand 160Ahr LiFePo4 12V (for around £300) and wire it in parallel with your current ageing set of LAs to see how it works.

If you use the module to connect to your LAs then you can play and see if it cuts out at low voltage or temperature but dont try it with the alternator otherwise you will blow it up by disconnecting it at full whack as you watch the voltage rise towards the constant voltage stage.

As per my previous post, the Winston Thunderskys are half the price of the Sinopoly ones.

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56 minutes ago, Dr Bob said:

Your price for the Sinopoly cells is twice what Tom, MP and  myself paid. £1000 for 480Ahrs was typical this spring.

Your 'BMS' will run between £200 and £500 dependent on what level of protection you need.

Putting Li's in has been fun/interesting/become a hobby.

 

I was aware that you had got good deals on your battery cells, but presumed the source had dried up. Where did you get them from?

 

If I could get 400Ah for £1000, I'd order them tomorrow :) 

 

I can't find any cells for less than the Sinopoly ones, and a 12v battery seems to have no facility to connect to individual cells.

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20 minutes ago, Dr Bob said:

Just looked at the video.

From an overview point of view, it seems to be everything you need with its own cell monitoring and auto disconnect .....but I guess the devil is in the detail. He is only using it with a solar charger so isnt interested in overcharging or over voltage. I assume it can manage both of them....but he didnt give enough detail about what can be adjusted and by how much. Lets assume it does do high voltage disconnection....otherwise it is pointless.

 

How are you going to set your system up? Will it be with an alternator? If so then how are you going to handle the alterntor charge on high voltage disconnect? I assume you will have a lead acid in parallel? The start battery perhaps? If it is the start battery then what is the current this unit is likely to see? Will the solid stage relay in it take the current then? The unit is wired on the negative battery lead. I have my isolation switches on the positive lead. Not sure if this would be an issue.

Think through how the high voltage disconnect and re-connect works. I have a voltage sensor on the alternator/LA side of the disconnect so when the voltage is high, it isolates and then when the alternator stops, the sensor detects the voltage is low enough and reconnects. I suspect this unit just measure the voltage of the Li's. May need a bit of thinking through.

 

If I was in your position and want a new hobby, then get one of these boards but buy a 2nd hand 160Ahr LiFePo4 12V (for around £300) and wire it in parallel with your current ageing set of LAs to see how it works.

If you use the module to connect to your LAs then you can play and see if it cuts out at low voltage or temperature but dont try it with the alternator otherwise you will blow it up by disconnecting it at full whack as you watch the voltage rise towards the constant voltage stage.

As per my previous post, the Winston Thunderskys are half the price of the Sinopoly ones.

My immediate thoughts are that I would set it up using solar and the genny via the Sterling Charger and not have it connected to the alternator. Most of my charging is via solar or genny, so little would change in this respect.

 

I would keep my existing bank and starter connected to the alternator, and the sterling can be set up to charge two different types of battery bank.

 

I could have a switch to  select domestic power from the Lithium or the LA banks.

 

Over time I could resolve the alternator/lithium issue.

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9 minutes ago, Richard10002 said:

I was aware that you had got good deals on your battery cells, but presumed the source had dried up. Where did you get them from?

 

If I could get 400Ah for £1000, I'd order them tomorrow :) 

 

I can't find any cells for less than the Sinopoly ones, and a 12v battery seems to have no facility to connect to individual cells.

We got ours from

Jeremy Bloomfield

[email protected]
07736467455
www.ev-support.co.uk

He is based in Colchester.

Give him a ring. If he hasnt got any then he will know where to get some from. Ours are Winston thundersky bare cells.

He does not deliver. You have to arrange collection yourself. I drove down there.

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3 minutes ago, Richard10002 said:

My immediate thoughts are that I would set it up using solar and the genny via the Sterling Charger and not have it connected to the alternator. Most of my charging is via solar or genny, so little would change in this respect.

 

I would keep my existing bank and starter connected to the alternator, and the sterling can be set up to charge two different types of battery bank.

 

I could have a switch to  select domestic power from the Lithium or the LA banks.

 

Over time I could resolve the alternator/lithium issue.

 

 

This is what I've done, except my switch just adds the lithium in parallel with the domestic LA, or disconnects the lithium.

 

 

Don't underestimate the cost of cabling to do this, given you want the lithiums inside the boat in the warm, not out the back in the nasty cold with the LA batts.

 

 

 

  • Greenie 1

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9 minutes ago, Mike the Boilerman said:

 

 

Don't underestimate the cost of cabling to do this, given you want the lithiums inside the boat in the warm, not out the back in the nasty cold with the LA batts.

 

 

 

I think I paid £80 for 10M of 50mm cable. It does add up (5M of black and 5m of red)

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12 minutes ago, Dr Bob said:

I think I paid £80 for 10M of 50mm cable. It does add up (5M of black and 5m of red)

 

ISTR needing 20m! 

 

But I bought 35mm, being a cheapskate and a low power user. And my bank is 24v so half the current of a 12v installation.

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1 hour ago, Dr Bob said:

We got ours from

Jeremy Bloomfield

[email protected]
07736467455
www.ev-support.co.uk

He is based in Colchester.

Give him a ring. If he hasnt got any then he will know where to get some from. Ours are Winston thundersky bare cells.

He does not deliver. You have to arrange collection yourself. I drove down there.

Snap! Same person. He was very helpful, and even made us the cabling and connectors.

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48 minutes ago, Mike the Boilerman said:

I'm finding that lad in the videos virtually unwatchable. The clichés come too thick and fast. 

OMG!

No way!

I can't believe it!

Check this out!

This is so cool!

 

I'm a grumpy git today....

I must be just as grumpy because I eventually switched it off before the end - I simply couldn’t stand listening to him any longer. 

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1 minute ago, WotEver said:

I must be just as grumpy because I eventually switched it off before the end - I simply couldn’t stand listening to him any longer. 

 

Me too. And I wasn't even going to mention his whiny annoying voice. 

 

Oh...

  • Haha 1

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24 minutes ago, Mike the Boilerman said:

 

Either that or all my domestic stuff is 12v using a step down device.

 

Or feed them with 24v via a resistor the same value as the actualing coils. 

 

 

 

I have a a step down transformer but run the fridge freezer at 24 volts 

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7 minutes ago, Mike the Boilerman said:

 

You've invented a DC transformer???? 

 

I'm impressed!!!

 

 

 

That's what the nice seller on Ebay called it?

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48 minutes ago, Mike the Boilerman said:

 

You've invented a DC transformer???? 

 

I'm impressed!!!

 

 

 

 

I think he is bucking the trend. ?

Edited by cuthound
  • Haha 3

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3 hours ago, Mike the Boilerman said:

 

 

This is what I've done, except my switch just adds the lithium in parallel with the domestic LA, or disconnects the lithium.

 

 

Don't underestimate the cost of cabling to do this, given you want the lithiums inside the boat in the warm, not out the back in the nasty cold with the LA batts.

 

 

 

My charger, solar controller, and domestic switch panel, are all at the rear of the cabin, just above an unused space which would suit lithiums ideally. So I'm guessing I wont need much cable, although a quick think produces close to 5 metres each of red and black.... without connecting to the alternator.

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On 22/10/2019 at 16:05, Dr Bob said:

In normal operation, my charge sources would cut back on voltage to below 13.4V when I get to 13.6V (at 30-40A charge) so I never get to point A. If you have charge sources that will go to 14.4V, then the Li's will rise in voltage to 14.4V and get wrecked unless the inbuilt battery BMS (which I would not trust) isolated them. The disconnect is best if it is only used in an emergency.

 

Charging LiFePo4s is totally different to the bulk, absorption and float used in LA's.  The voltage rises as they get charged and it is easy to estimate SoC from the voltage/current.Stop when you get to your target voltage.

 

The trickiest thing about all of this, is how to get your alternator to turn off at 13.6V or at least by 13.9V. My alternator never got above 13.9V so would be fine on its own but I bought a Sterling AtoB to get it to 14.4V for my lead acids and that has multiple settings that let me access max voltages between 13.6V and 13.9V. Tom has a different alternator controller. MP does his control via his Arduino. Peter doesnt have an alternator.

 

 

 

 

 

Why can't he use an isolator switch connected to a Victron BMV to cut the charge at 13.9V like you did?

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