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Cheap LiFePO4 BMS?


jetzi

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1 hour ago, peterboat said:

I have before I put on a video  of it on charge and discharge, if I have time before I go to Egypt I will, do you want that Article by the way? I go on 2 weeks holiday from Monday

Where was the video? I missed it.

Not heard back from Chris yet. I will remind him.

5 minutes ago, mrsmelly said:

 Sticking several hundred pounds into batteries and associated paraphanalia only makes sense if you are deffo not selling for several years so you are partly locking yourself into something uneccesarily. If I change boats I would not be paying extra money out for someones battery choice just like I wouldnt give extra if the tanks happened to be full of diesel, another consumable.

I'd take mine with me and leave the existing LA's in circuit.

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4 minutes ago, Dr Bob said:

Where was the video? I missed it.

Not heard back from Chris yet. I will remind him.

I'd take mine with me and leave the existing LA's in circuit.

With your system can you just attache/detach lithiums with ease without messing with charging system etc?

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12 minutes ago, mrsmelly said:

Not realy? I am on my eighth boat as I buy one that suits my lifestyle at any given time. Sticking several hundred pounds into batteries and associated paraphanalia only makes sense if you are deffo not selling for several years so you are partly locking yourself into something uneccesarily. If I change boats I would not be paying extra money out for someones battery choice just like I wouldnt give extra if the tanks happened to be full of diesel, another consumable.

 

 A big downside to installing lithiums is selling the boat.

 

I would be totally put off buying a boat with a lithium battery bank were I not interested in such stuff. So much so that I would 100% rule out any boat powered by lithiums, and I suspect 99% of the boat buying public are likely to think similarly. 

 

 

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7 minutes ago, mrsmelly said:

Ahh, so your standard alternater thingie doesnt knacker em if you just wire lithiums in line sort of?

I would disconnect the +ve lead and the -ve lead to the Li's and change the dip switch on the AtoB back to the flooded LA setting. The boat will be back to what it was before I put the Li's in. This is what I did when my son borrowed the boat in August.

Prolly take me a day to unscrew all the Li BMS components and stick 'em in the car with the batteries ready for the new boat.

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18 hours ago, Tom and Bex said:

https://www.ebay.co.uk/i/192880341024?ul_noapp=true&var=493362285172

 

I can't see that it's been mentioned yet, but it looks like that bms requires a minimum of 7 cells connected to it? Fine for 24v system but not 12v. Not liked any closer at it though. 

You're right :( I was failing to understand the relevance of the capital S, for Series, and just thought you could attach as many batteries as you had. back to the drawing board then. What is needed is a 4S BMS with under and over voltage protection/cut off and under and over temperature protection/cut off.

 

Perhaps the BMS that Ivan referred to in the first post of this thread is the way to go, although it does have a max Charge Current of 20A printed on its front:

 

https://www.ebay.co.uk/i/192880341024?ul_noapp=true&var=493362285172

 

Plus some kind of temperature switch - I wonder if a simple thermostat could do this?

 

https://www.amazon.co.uk/gp/product/B01429KIJ2/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

 

???

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On 31/10/2019 at 15:55, Dr Bob said:

How are you going to set your system up? Will it be with an alternator?

Been thinking about this, and I think I have the solution to using the alternator, for me, but not necessarily for everyone.

 

As well as a Sterling Procharge Ultra charger, where I can set a custom setting for Lithiums, I also have a Sterling 2500W Pro Combi S inverter charger, which charges my LA bank when connected to the shore power socket. I could fairly easily provide a 240V socket whereby the inverter supplies the Pro Charge Ultra, when the engine is running, thus removing the need for any control of the alternator bit of the system.

 

This actually runs contrary to common sense as, having the inverter running to charge the batteries has always been a no no, for obvious reasons but, in this situation, with 2 separate battery banks, it seems to make sense.

 

This wouldn't work for everyone, although the addition of a relatively cheap inverter to power the shore power battery charger from the alternator might actually be easier than controlling the alternator.

 

If I am correct, just need to resolve the BMS and temp issues. Having said that, on temperature, given that I only charge from my genny, (or engine?), if the temp is too cold, I can just choose not to charge until it warms up. a temp sensor on the side of the batteries, with a readout near the charger, would make this quite a simple rule.

 

Or could I just wire something like this in the charger +ve wire?: 

 

https://www.amazon.co.uk/gp/product/B01429KIJ2/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

 

Thoughts welcomed from anyone.

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15 minutes ago, Richard10002 said:

 

This actually runs contrary to common sense as, having the inverter running to charge the batteries has always been a no no, for obvious reasons but, in this situation, with 2 separate battery banks, it seems to make sense.

 

 

Well that's a bit of out the box thinking!

.....er yes!

The load that the inverter pulls on the LA bank should keep the alternator working hard, but I bet it wouldnt be as hard as if direct into the Li bank....but that is good as the alternator would overheat at high current. It might work if the load was similar to to the normal alternator output and worth a try.

One thing to watch though is the Sterling setting for LiFePO4s. I bet it is set at a high voltage ie 14.6V and it might not go into float. Be very careful. Instead I would pick a customisable setting if it has one or the lowest voltage setting ie like the US gel setting on mine. Just because it says lithium doesnt mean it works. My Victron IP22 charger has a LiFePO4 setting which keeps pumping the voltage/current in as  we are well down the tail current at 100% SoC with no sign of letting up. Play around with the different settings and you may find one that suits.

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2 minutes ago, Dr Bob said:

Well that's a bit of out the box thinking!

.....er yes!

The load that the inverter pulls on the LA bank should keep the alternator working hard, but I bet it wouldnt be as hard as if direct into the Li bank....but that is good as the alternator would overheat at high current. It might work if the load was similar to to the normal alternator output and worth a try.

One thing to watch though is the Sterling setting for LiFePO4s. I bet it is set at a high voltage ie 14.6V and it might not go into float. Be very careful. Instead I would pick a customisable setting if it has one or the lowest voltage setting ie like the US gel setting on mine. Just because it says lithium doesnt mean it works. My Victron IP22 charger has a LiFePO4 setting which keeps pumping the voltage/current in as  we are well down the tail current at 100% SoC with no sign of letting up. Play around with the different settings and you may find one that suits.

We've already discussed the Sterling settings. On the Pro Charge Ultra, you can set absorption and float at any level from about 12.5V to 15.1V, so I could set absorption at 13.7V, (or anything I like), and float at 13.0V, (or anything I like). I can get more specific if/when I actually get some cells :) 

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13 hours ago, Richard10002 said:

Been thinking about this, and I think I have the solution to using the alternator, for me, but not necessarily for everyone.

 

As well as a Sterling Procharge Ultra charger, where I can set a custom setting for Lithiums, I also have a Sterling 2500W Pro Combi S inverter charger, which charges my LA bank when connected to the shore power socket. I could fairly easily provide a 240V socket whereby the inverter supplies the Pro Charge Ultra, when the engine is running, thus removing the need for any control of the alternator bit of the system.

 

This actually runs contrary to common sense as, having the inverter running to charge the batteries has always been a no no, for obvious reasons but, in this situation, with 2 separate battery banks, it seems to make sense.

 

This wouldn't work for everyone, although the addition of a relatively cheap inverter to power the shore power battery charger from the alternator might actually be easier than controlling the alternator.

 

If I am correct, just need to resolve the BMS and temp issues. Having said that, on temperature, given that I only charge from my genny, (or engine?), if the temp is too cold, I can just choose not to charge until it warms up. a temp sensor on the side of the batteries, with a readout near the charger, would make this quite a simple rule.

 

Or could I just wire something like this in the charger +ve wire?: 

 

https://www.amazon.co.uk/gp/product/B01429KIJ2/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

 

Thoughts welcomed from anyone.

That's what I was trying to suggest in this post. You can even automate the whole process using a Victron BMV relay which would:

 

  • Isolate the Li bank on engine start.
  • Turn on the inverter at the same time, which feeds the charger
  • On engine stop, reverse the above leaving your Li connected back up to your LA and loads.

 

 

12 hours ago, Richard10002 said:

We've already discussed the Sterling settings. On the Pro Charge Ultra, you can set absorption and float at any level from about 12.5V to 15.1V, so I could set absorption at 13.7V, (or anything I like), and float at 13.0V, (or anything I like). I can get more specific if/when I actually get some cells :) 

 

What ampage is the charger rated at? I ask this because mine is only 15 amps which makes the above idea pointless (it would take longer to charge than a bank of lead acids)

Edited by eid
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3 hours ago, eid said:

That's what I was trying to suggest in this post. You can even automate the whole process using a Victron BMV relay which would:

 

  • Isolate the Li bank on engine start.
  • Turn on the inverter at the same time, which feeds the charger
  • On engine stop, reverse the above leaving your Li connected back up to your LA and loads.

:) The post you refer to lost me with its' NO's and NCs and stuff - not a criticism, I just tend to get a bit lost with relays and similar. I should try to get my head around them. You were obviously ahead of me with our "out of the box" thinking :) 

 

3 hours ago, eid said:

What ampage is the charger rated at? I ask this because mine is only 15 amps which makes the above idea pointless (it would take longer to charge than a bank of lead acids)

I think my alternator is rated at 55A, but I never see more than about 33A and a max voltage of 14.4V, or something around those figures, (thus around 500 Watts). Your point is the reason I said it could work for me, but not for everyone.

 

I dont go far, so dont often use the engine, and not for long periods so, in my case, any battery charging from the engine running is a bonus, rather than a requirement. 

 

My "vision" is that, if I wanted to charge from the engine/alternator, I would have to reduce the charger max Amps from 60A to 30A, (30A x 14v = 420Watts). The Pro Charge Ultra has a facility to select full power, three quarter power, half power, or quarter power so, in my case, 60A, 45A, 30A and 15A). You are correct with your comment on the time to charge. Even at 30A, it would take 5/6 hours for me to replace the 160Ah I seem to use every couple of days on board - worth it if I did a day of cruising, but not for the hour or two it takes to get to the clubhouse and back to fill up with water and empty the bogs..

 

Having said that, I have been thinking of changing the alternator for one which could provide up to about 90A, (my perceived limit for a narrow belt system), so that is also an option, and this may be a good excuse to justify it :) 

 

I'm currently watching loads of youtube videos, and a few relevant forums, to see what options exist, while I get my head around ordering £1400 worth of batteries from a company in Prague, or waiting to see if some suitable used cells pop up, which might involve a day trip to Colchester, (something I could live without if honest :) )

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10 minutes ago, Richard10002 said:

:) The post you refer to lost me with its' NO's and NCs and stuff - not a criticism, I just tend to get a bit lost with relays and similar. I should try to get my head around them. You were obviously ahead of me with our "out of the box" thinking :) 

 

I think my alternator is rated at 55A, but I never see more than about 33A and a max voltage of 14.4V, or something around those figures, (thus around 500 Watts). Your point is the reason I said it could work for me, but not for everyone.

 

I dont go far, so dont often use the engine, and not for long periods so, in my case, any battery charging from the engine running is a bonus, rather than a requirement. 

 

My "vision" is that, if I wanted to charge from the engine/alternator, I would have to reduce the charger max Amps from 60A to 30A, (30A x 14v = 420Watts). The Pro Charge Ultra has a facility to select full power, three quarter power, half power, or quarter power so, in my case, 60A, 45A, 30A and 15A). You are correct with your comment on the time to charge. Even at 30A, it would take 5/6 hours for me to replace the 160Ah I seem to use every couple of days on board - worth it if I did a day of cruising, but not for the hour or two it takes to get to the clubhouse and back to fill up with water and empty the bogs..

 

Having said that, I have been thinking of changing the alternator for one which could provide up to about 90A, (my perceived limit for a narrow belt system), so that is also an option, and this may be a good excuse to justify it :) 

 

I'm currently watching loads of youtube videos, and a few relevant forums, to see what options exist, while I get my head around ordering £1400 worth of batteries from a company in Prague, or waiting to see if some suitable used cells pop up, which might involve a day trip to Colchester, (something I could live without if honest :) )

I would buy the Valences Richard, they tell you how many cycles they have carried out, 3 of them will get you nearly 400ah, they are well made and will tell you they are in good condition and balanced, no other battery will do that. You will be putting them in parallel so no series charging problems and they really are well priced and will last a lifetime

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1 hour ago, Richard10002 said:

:) The post you refer to lost me with its' NO's and NCs and stuff - not a criticism, I just tend to get a bit lost with relays and similar. I should try to get my head around them. You were obviously ahead of me with our "out of the box" thinking :)

 I probably didn't explain it very well anyway, hence the lack of replies ?

 

 

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18 hours ago, Richard10002 said:

Perhaps the BMS that Ivan referred to in the first post of this thread is the way to go, although it does have a max Charge Current of 20A printed on its front:

Although the specs state 50A:

http://vi.raptor.ebaydesc.com/ws/eBayISAPI.dll?ViewItemDescV4&item=192880341024&category=48619&pm=1&ds=0&t=1567043417000&ver=0

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  • 2 weeks later...
On 06/11/2019 at 13:05, peterboat said:

I would buy the Valences Richard, they tell you how many cycles they have carried out, 3 of them will get you nearly 400ah, they are well made and will tell you they are in good condition and balanced, no other battery will do that. You will be putting them in parallel so no series charging problems and they really are well priced and will last a lifetime

I've bought 4 of the valences!!! Picking them up on Monday, although it will take me a while to sort out the wiring to the position they are going in on the boat.

 

I've chosen the 4 that he says show the lowest cycles on his Valence computer software, 106, 395, 550 and 639 cycles. However, on the phone he tells me that the cycle count may not be representative as, as far as he knows, it only counts a cycle when there is a full charge and discharge, so loads of cycles between say, 20% and 80% wouldnt show - I find that hard to believe, as it would be a pretty pointless measurement.

 

Have you any idea how they counts cycles?

 

The suspicious mind in me suggests that he may be trying to get me to take the ones with higher cell counts, but some other reading that he will say is better. I'm inclined to go with my gut, and with the lowest cell counts that I have already chosen.

 

The thing that swayed me to them was a reading of the user manual:

 

https://drive.google.com/file/d/0ByGOeb9QpNbgbFg2cXdqUE9OLTQ/view

 

)it talks about what the internal BMS does, even if not connected to the official external BMS, and it seems to have upper and lower voltage cutouts, along with some temp sensors which suggest temperature cut outs as well.)

 

as well as this video of a tear down of one, where his intention is to use the cells with a replacement BMS of his own choosing.:

 

 

And a Will Prowse tear down of a green Valence, which showed the internal quality.

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1 minute ago, Richard10002 said:

I've bought 4 of the valences!!! Picking them up on Monday, although it will take me a while to sort out the wiring to the position they are going in on the boat.

 

I've chosen the 4 that he says show the lowest cycles on his Valence computer software, 106, 395, 550 and 639 cycles. However, on the phone he tells me that the cycle count may not be representative as, as far as he knows, it only counts a cycle when there is a full charge and discharge, so loads of cycles between say, 20% and 80% wouldnt show - I find that hard to believe, as it would be a pretty pointless measurement.

 

Have you any idea how they counts cycles?

 

The suspicious mind in me suggests that he may be trying to get me to take the ones with higher cell counts, but some other reading that he will say is better. I'm inclined to go with my gut, and with the lowest cell counts that I have already chosen.

 

The thing that swayed me to them was a reading of the user manual:

 

https://drive.google.com/file/d/0ByGOeb9QpNbgbFg2cXdqUE9OLTQ/view

 

)it talks about what the internal BMS does, even if not connected to the official external BMS, and it seems to have upper and lower voltage cutouts, along with some temp sensors which suggest temperature cut outs as well.)

 

as well as this video of a tear down of one, where his intention is to use the cells with a replacement BMS of his own choosing.:

 

 

And a Will Prowse tear down of a green Valence, which showed the internal quality.

Good choice Richard and stick with low cycles,  mine had stckers on them with the cycles on it, when I checked last cycles have gone up and I never ever do full cycles. As far as I know the temperature sensor works with the master Bms and doesn't do anything to the internal one.  The quality of these batteries is very good and that's why I bought them. 

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3 minutes ago, peterboat said:

Good choice Richard and stick with low cycles,  mine had stckers on them with the cycles on it, when I checked last cycles have gone up and I never ever do full cycles. As far as I know the temperature sensor works with the master Bms and doesn't do anything to the internal one.  The quality of these batteries is very good and that's why I bought them. 

Thanks for that. What you say about cycles makes sense, and I can add in a temp sensing device to cut off the charger circuit if it goes too low.

 

Perhaps a bit cheeky, but have you got a link to where I can download the software, and is there anything special about the battery to PC cable?

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5 minutes ago, Richard10002 said:

Thanks for that. What you say about cycles makes sense, and I can add in a temp sensing device to cut off the charger circuit if it goes too low.

 

Perhaps a bit cheeky, but have you got a link to where I can download the software, and is there anything special about the battery to PC cable?

Not cheeky at all Richard I will WhatsApp or mail it to  you when I get back off holiday you have seen the video of these batteries being checked it's that easy to make the lead, I have spare plugs so can send you one as well. When you install them connect the leads together as its easier to check them 

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8 minutes ago, peterboat said:

Not cheeky at all Richard I will WhatsApp or mail it to  you when I get back off holiday you have seen the video of these batteries being checked it's that easy to make the lead, I have spare plugs so can send you one as well. When you install them connect the leads together as its easier to check them 

Many thanks..... :) 

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Can someone remind me what the issues with the motorised isolator switches is please?

 

Also thoughts on this point please: there needs to be an isolator for when there is an extreme high or low cell voltage to give ultimate protection to the battery. The battery would be completely disconnected.

 

But what about when the battery temperature is below 0 and the engine is started? One wants to keep the battery connected for domestic loads. One also wants to supply boat domestic loads from the alternator. So how should the system handle this? Should it set the alternator regulation voltage to a low value so that, whilst the batteries don’t receive any charge, domestic loads can be supplied by the alternator? (if so what voltage?)   Or should it just isolate the battery and connect the alternator directly to the boat’s services without a battery in circuit (likely to get lots of ripple I suspect)? Or should it isolate the alternator from the batteries and boat services, whilst leaving the battery to supply boat services (requires a second motorised switch)? Or what?

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17 minutes ago, Mike the Boilerman said:

 

It costs £160, and draws a (tiny) current all the time IIRC.

It was something to do with the way they had to be controlled.

 

Edit: I see the Sterling ones use 0.2mA when off and 1.7mA when on, which I suggest is in no way significant. Would flatten a 400AH battery in about 25 years.

Edited by nicknorman
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1 hour ago, nicknorman said:

Can someone remind me what the issues with the motorised isolator switches is please?

 

Also thoughts on this point please: there needs to be an isolator for when there is an extreme high or low cell voltage to give ultimate protection to the battery. The battery would be completely disconnected.

 

But what about when the battery temperature is below 0 and the engine is started? One wants to keep the battery connected for domestic loads. One also wants to supply boat domestic loads from the alternator. So how should the system handle this? Should it set the alternator regulation voltage to a low value so that, whilst the batteries don’t receive any charge, domestic loads can be supplied by the alternator? (if so what voltage?)   Or should it just isolate the battery and connect the alternator directly to the boat’s services without a battery in circuit (likely to get lots of ripple I suspect)? Or should it isolate the alternator from the batteries and boat services, whilst leaving the battery to supply boat services (requires a second motorised switch)? Or what?

Agree with Mike. Price. £160 whereas the Tyco relays are £30-£70. My motorised switch takes very little power. I dont worry about power drain at all - we were away in Asia most of August and it hardly dropped in power.

 

Your strategy for charging/discharging - you have to work out for what you want to achieve. I went for a very simple system, ie batteries under the bed so wont go below 0°C and if they do they are out of the circuit. Tom, MP and I all use an LA as a dump so there is always a battery in circuit to power the appliances with the engine running. Tom uses 2 switches, one on the charge side and one on the discharge side. The more complex you make it (ie not having an LA) and the more you try to cover all eventualities the more foolproof (or idiot proof) it has to be. Its far cheaper to use the Tyco relays if you are going to have more than one switch. I got the motorised switch as I didnt have the skill to build a circuit to activate the latching relay....the BEP switch was very simple to wire up (once Tom showed me how to do it) but is £100 more.

If you are not going to have an LA in circuit then it does become more complex and issues like you are talking about have to be solved.

 

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