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Cheap LiFePO4 BMS?


jetzi

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8 hours ago, Tom and Bex said:

Now our system has settled down and performing as we like, we don't bother with ours either. They just sit there and work! No interventions needed from us at all (other than remembering to charge them occasionally in winter!).

Its not just me then

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7 hours ago, Richard10002 said:

Just watched the first half of a Wheeler Dealers episode in the US, where they had bought a 1985 Maserati Bi Turbo which had been converted to electric.

 

They were speaking to a company that repurposes electric car batteries and retrofits electric motors - they also talked of controllers. I wonder if there are such companies here yet... or are they coming soon? Presumably it's as easy to drop repurposed electric car batteries into a boat, rather than a car. They said that they would get the same power from 76kg of Lithium Batteries as half a ton of Trojan LA batteries.

 

Everything being discussed in this thread seems to be pretty much DIY, requiring a knowledge of lots of stuff that the ordinary Joe doesn't know. Hard to see it taking off until you can buy batteries and a gizmo or two that you can just connect with a few wires without knowing how it all works?

 

22 minutes ago, mrsmelly said:

Nail on head. 

My batteries are ex bus and van batteries my electric motor is from a forklift and the controller ans throttle are small car ones from curtis, if i had bought them to fit straight into a new widebeam they would have cost 3.5k which is cheaper than a  diesel engine, so the price of the stuff is relatively cheap. The reality is the people on here re-purposing electric vehicle kit are only like narrowboaters of yesteryear? at first it was a few that came to the cut and then it was in the hundreds, until we became thousands! If you look in canal magazines of 50 years ago boating was very much DIY, so that is what we are doing going back to our roots

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8 hours ago, Richard10002 said:

They were speaking to a company that repurposes electric car batteries and retrofits electric motors - they also talked of controllers. I wonder if there are such companies here yet... or are they coming soon? Presumably it's as easy to drop repurposed electric car batteries into a boat, rather than a car. They said that they would get the same power from 76kg of Lithium Batteries as half a ton of Trojan LA batteries.

 

That's pretty much what we've done. They are used traction cells from Allied Boxer vans. 12 x 210Ah cells with were selected from a set of approx 30 to have similar capacities. As expected, their capacity is reduced somewhat from the rated value, but still more than adequate for a domestic supply. We never fully charge or fully discharge them, so balancing hasn't been an issue so far.

The weight difference caught us off-guard. Ended up getting some storage heater blocks for ballast, and moved the beer to a different cupboard.

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8 hours ago, Richard10002 said:

Just watched the first half of a Wheeler Dealers episode in the US, where they had bought a 1985 Maserati Bi Turbo which had been converted to electric.

 

They were speaking to a company that repurposes electric car batteries and retrofits electric motors - they also talked of controllers. I wonder if there are such companies here yet... or are they coming soon? Presumably it's as easy to drop repurposed electric car batteries into a boat, rather than a car. They said that they would get the same power from 76kg of Lithium Batteries as half a ton of Trojan LA batteries.

 

Everything being discussed in this thread seems to be pretty much DIY, requiring a knowledge of lots of stuff that the ordinary Joe doesn't know. Hard to see it taking off until you can buy batteries and a gizmo or two that you can just connect with a few wires without knowing how it all works?

Yes it is DIY, but it doesn't require that much knowledge. MP is using an Arduino as the brain which is complex. Tom and I are just using off the shelf stuff so quite easy. Peter is only charging with solar so very easy. You need to understand what is needed to protect the batteries....not difficult to learn....and then make sure you follow the rules. I you have a good understanding of LAs then it is pretty easy and as Peter and Tom says, once bedded in they need virtually no attention......i.e. How long do I need to run the engine today? Am I at 100%?

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18 hours ago, mrsmelly said:

Bloomin eck chaps. Whatever happened to the well tried and tested KISS principal. Why introduce huge amounts of unnecessary paraphernalia to make yer lights work :unsure:

These peeps are doing us all a favour working out the various bits and pieces required for this new battery tech, by the time those of us who don't do the bleeding edge of tech are ready to install these bats, all the complex stuff will be sorted, it's a win win

Plus of course they enjoy this stuff, I mean really really enjoy this stuff and good on em :)

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8 hours ago, Richard10002 said:

Hard to see it taking off until you can buy batteries and a gizmo or two that you can just connect with a few wires without knowing how it all works?

I don't think it will take off anytime soon. Every bote set up is different with different charge sources so it would be difficult to design a 'one fits all' solution. However for anyone who can do basic soldering and 50mm battery cable crimps, it becomes a pretty simple project for someone who has time on their hands. Design your own system .....and all the info is in threads in this forum......source your batteries..... and bolt it together. 

I guess with all these new EVs appearing, there will be a surplus of used LiFePo4s on the market looking for homes so the price of 2nd hand batteries will not go up and likely fall. Cost wise, they are no more expensive than LAs if you are changing them every 2-3 years and cost may favour Li's if 2nd hand LiFePo4 become more available/ cheaper. 

Maybe in the future you could get a little man to come and do it for you but that will throw the cost benefit out. Far better to diy it ...... a very good winter project.

 

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30 minutes ago, Dr Bob said:

a very good winter project.

 

Actually I disagree. Mine sat here all last winter NOT being installed because of poor light conditions for grubbing about under beds etc installing them and their wiring. Only when the proper summer light arrived dis I actually connect them up!

 

 

 

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6 minutes ago, Mike the Boilerman said:


Actually I disagree. Mine sat here all last winter NOT being installed because of poor light conditions for grubbing about under beds etc 

 

What you need is some good electric lights. Oh, wait.

 

To the "it's all too complicated my brains HURTZ" crowd. Actually, it's not. The details are complicated, but no more complicated than for LA. Do you understand how the regulator in you existing alternator works? What it does and how it does it? Of course not. You don't need to understand for Li either. Once off-the-shelf systems covering the whole charging and regulation chain exist, it will be just the same as now. In fact it gets easier: no amount of engineering will protect you from LA sulphation if you use the most natural pattern for domestic batteries of never really fully charging them. That problem goes.  An accurate SOC display is much easier to do with Li than LA, and likely to be more accurate, so misuse or surprises due to not knowing SOC is a thing of the past.

 

Li is easier to live with and ignore than LA.

 

MP.

 

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19 minutes ago, MoominPapa said:

What you need is some good electric lights. Oh, wait.

 

To the "it's all too complicated my brains HURTZ" crowd. Actually, it's not. The details are complicated, but no more complicated than for LA. Do you understand how the regulator in you existing alternator works? What it does and how it does it? Of course not. You don't need to understand for Li either. Once off-the-shelf systems covering the whole charging and regulation chain exist, it will be just the same as now. In fact it gets easier: no amount of engineering will protect you from LA sulphation if you use the most natural pattern for domestic batteries of never really fully charging them. That problem goes.  An accurate SOC display is much easier to do with Li than LA, and likely to be more accurate, so misuse or surprises due to not knowing SOC is a thing of the past.

 

Li is easier to live with and ignore than LA.

 

MP.

 

 

My thoughts are the same.

 

A good grasp of Li seems to me to be about the same degree of complexity as a good grasp of LA. Just different in every aspect.

 

The problem with Li is twofold:

 

1) People failing to let go of LA thinking and properly listening to what is needed for Li. 

2) The absence of a large body of experienced users with a ready solution to every problem. There is no consensus yet about what parts to buy and use for even a really basic vanilla Li installation.

 

And a third problem is peeps like that nice mrsmelly chipping in constantly and undermining the whole idea of trying out Li in the first place... :icecream:

 

 

 

 

 

 

Edited by Mike the Boilerman
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28 minutes ago, Mike the Boilerman said:

 

 

 

And a third problem is peeps like that nice mrsmelly chipping in constantly and undermining the whole idea of trying out Li in the first place... :icecream:

 

 

 

 

 

 

Yea but smelly's on shore power so dont need batteries!?

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43 minutes ago, MoominPapa said:

What you need is some good electric lights. Oh, wait.

 

To the "it's all too complicated my brains HURTZ" crowd. Actually, it's not. The details are complicated, but no more complicated than for LA. Do you understand how the regulator in you existing alternator works? What it does and how it does it? Of course not. You don't need to understand for Li either. Once off-the-shelf systems covering the whole charging and regulation chain exist, it will be just the same as now. In fact it gets easier: no amount of engineering will protect you from LA sulphation if you use the most natural pattern for domestic batteries of never really fully charging them. That problem goes.  An accurate SOC display is much easier to do with Li than LA, and likely to be more accurate, so misuse or surprises due to not knowing SOC is a thing of the past.

 

Li is easier to live with and ignore than LA.

 

MP.

 

I am sure you are right but for peeps like me who have a system that works and is reasonably happy with it, it becomes a big move, until a drop in system exists at a sensible cost I will stick to LA.

 

Simply put I don't want to build any sort of monitoring/charging system or learn any more than the basics required to maintain the system, I already have interests that keep me occupied.

 

I do think they are the way forward just not for me yet, happy to offer the boat for some research though :)

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30 minutes ago, Mike the Boilerman said:

 

My thoughts are the same.

 

A good grasp of Li seems to me to be about the same degree of complexity as a good grasp of LA. Just different in every aspect.

 

The problem with Li is twofold:

 

1) People failing to let go of LA thinking and properly listening to what is needed for Li. 

2) The absence of a large body of experienced users with a ready solution to every problem. There is no consensus yet about what parts to buy and use for even a really basic vanilla Li installation.

 

I think you are spot on in what you say.....in the first few paras.

The degree of complexity is the same as LA's. Just different rules but much much easier to stay withing the rules (viz must charge to 100% to avoid sulphation).

 

You just need to understand the new rules.

 

I think the experience Tom, MP and i have gained this year coupled to Peterboats 'more than one year' experience however does take us forward to the point where there is a solution and good concensus on what kit to buy.

For the more knowledgeable amongst us with understanding of electronics then MP's arduino system looks the best system....cheap, robust, fit with most set ups. Craig's RasPi is another option here.

For the 'muppets' with no grasp of electronics but with an alternator then a system similar to Tom's or mine, using off the shelf kit as Tom identified earlier in this thread (or what I identified in earlier threads) does the job. There are now choices of what 'boxes' to use. Which box to use for what....is a choice when you design your system. 4 of us on here can advise. We are all thinking the same way and I dont think there is any disagreement on 'this box is better than that box'.

For peeps only using solar as a charge source then it is even easier and Peter's solution works well.

 

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13 minutes ago, tree monkey said:

I am sure you are right but for peeps like me who have a system that works and is reasonably happy with it, it becomes a big move, until a drop in system exists at a sensible cost I will stick to LA.

 

I agree. The 'big move' will put most peeps off.

My LA's were working fine. 90% capacity after 2 years (cheapo mix of 3 sealed LAs and 3 open LAs!). The snakes wedding of wires in the 'electrics' cupboard and back into the engine bay said dont touch it. So I didnt. I just bolted the 480Ahr of Li's on in parallel, so they can be isolated and I can run on the original LA's. If I screwed up then, I could easily revert to the LAs. I therefore didnt have a 'big move' like Tom and MP have done.

I thought I was taking a big risk moving to Li's as I knew nothing about them in January this year, but by having the 'hybrid' system that risk is now non-existant. By the time I installed them in March, it was obvious it was going to be a big success.

Putting LiFePo4s on board doesnt have to be a 'big' project.

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33 minutes ago, tree monkey said:

I am sure you are right but for peeps like me who have a system that works and is reasonably happy with it, it becomes a big move, until a drop in system exists at a sensible cost I will stick to LA.

 

 

A sensible Monkey. The perfect strategy. The drop is systems do exist: see Victron for example. All you have to do is wait until Victron et al  have finished recouping the development costs by selling at massive margins to "early adopters". The costs will then settle down to a mark up which makes it economically better to use Li for liveaboards like you, once you take into account lifetime battery costs, diesel use and engine wear and a small premium for the extra convenience.

 

The final stage is when this stuff becomes commodity, I don't think it will make sense for holiday boats 'till then.

 

MP.

 

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3 minutes ago, MoominPapa said:

 

A sensible Monkey. The perfect strategy. The drop is systems do exist: see Victron for example. All you have to do is wait until Victron et al  have finished recouping the development costs by selling at massive margins to "early adopters". The costs will then settle down to a mark up which makes it economically better to use Li for liveaboards like you, once you take into account lifetime battery costs, diesel use and engine wear and a small premium for the extra convenience.

 

The final stage is when this stuff becomes commodity, I don't think it will make sense for holiday boats 'till then.

 

MP.

 

And I will make the swap, I have a fairly simple and clean wiring setup ( only second owner from new and no wierd bodges) and good access so it should be easy

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46 minutes ago, Dr Bob said:

I just bolted the 480Ahr of Li's on in parallel, so they can be isolated and I can run on the original LA's. If I screwed up then, I could easily revert to the LAs.

 

This is what I've done too. Just installed them in parallel with my existing LA battery bank, with an isolator switch.

 

I still use the LA bank as my main source of leccy but I can turn the isolator switch ON when I feel like it to bring the Li into service. And turn it OFF to take them out of service and revert to the old LA system. 

 

Baby steps. 

 

I have connected a cell voltage monitor to each of the Li cells so I know what they are up to.

 

 

E03C8FF2-FBEB-46CD-968F-508CC9D4667A.jpeg

 

 

Next, I need to add in some over-voltage protection. This is the complicated bit, and I haven't decided how to do it yet, exactly.

 

Actually, what I may fit next is a cell balancing device. Finding one that will balance 8 cells is not so easy. I was wondering about just buying two of the four cell balancers mentioned earlier in the thread. One on the first four cells, one on the second four cells. Then at least the max deviation is likely to be better. Could even let one balance the middle four cells first, before fitting both to the eight cells. 

 

 

 

 

Edited by Mike the Boilerman
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1 hour ago, Mike the Boilerman said:

 

This is what I've done too. Just installed them in parallel with my existing LA battery bank, with an isolator switch.

 

I still use the LA bank as my main source of leccy but I can turn the isolator switch ON when I feel like it to bring the Li into service. And turn it OFF to take them out of service and revert to the old LA system. 

 

Baby steps. 

 

I have connected a cell voltage monitor to each of the Li cells so I know what they are up to.

 

 

E03C8FF2-FBEB-46CD-968F-508CC9D4667A.jpeg

 

 

Next, I need to add in some over-voltage protection. This is the complicated bit, and I haven't decided how to do it yet, exactly.

 

Actually, what I may fit next is a cell balancing device. Finding one that will balance 8 cells is not so easy. I was wondering about just buying two of the four cell balancers mentioned earlier in the thread. One on the first four cells, one on the second four cells. Then at least the max deviation is likely to be better. Could even let one balance the middle four cells first, before fitting both to the eight cells. 

 

So.... could I:

 

1) buy 2 or 3 of these used 12v 130Ah batteries:

 

https://www.ebay.co.uk/itm/No1-VALENCE-LiFePO4-12V-BATTERY-130Ah-1-6Kwh-U27-12XP-LITHIUM-LI-ION-SOLAR-BANK/264491336668?hash=item3d94e983dc:g:BhwAAOSwXzxddUH3

 

2) Connect them in parallel with my LA bank with an isolator, (presumably, when the isolator connects them it doesnt isolate the LA bank, so all batteries are being charged or used at the same time?).

 

3) Make sure my mains charger and solar systems are set so they cant deliver more than 14.6V, (turn off equalising in the solar). I dont think my alternator can deliver more than 14.4V, and there is a relay which also charges the starter battery.

 

and Bobs your Uncle? 

 

After 1-3 above, I can then start thinking about refinements, in terms of monitoring and control?

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1 hour ago, Mike the Boilerman said:

 

This is what I've done too. Just installed them in parallel with my existing LA battery bank, with an isolator switch.

 

I still use the LA bank as my main source of leccy but I can turn the isolator switch ON when I feel like it to bring the Li into service. And turn it OFF to take them out of service and revert to the old LA system. 

 

Baby steps. 

 

I have connected a cell voltage monitor to each of the Li cells so I know what they are up to.

 

 

E03C8FF2-FBEB-46CD-968F-508CC9D4667A.jpeg

 

 

Next, I need to add in some over-voltage protection. This is the complicated bit, and I haven't decided how to do it yet, exactly.

 

Actually, what I may fit next is a cell balancing device. Finding one that will balance 8 cells is not so easy. I was wondering about just buying two of the four cell balancers mentioned earlier in the thread. One on the first four cells, one on the second four cells. Then at least the max deviation is likely to be better. Could even let one balance the middle four cells first, before fitting both to the eight cells. 

 

 

 

 

Why not just leave the LA's connected

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3 minutes ago, Richard10002 said:

 

So.... could I:

 

1) buy 2 or 3 of these used 12v 130Ah batteries:

 

https://www.ebay.co.uk/itm/No1-VALENCE-LiFePO4-12V-BATTERY-130Ah-1-6Kwh-U27-12XP-LITHIUM-LI-ION-SOLAR-BANK/264491336668?hash=item3d94e983dc:g:BhwAAOSwXzxddUH3

 

2) Connect them in parallel with my LA bank with an isolator, (presumably, when the isolator connects them it doesnt isolate the LA bank, so all batteries are being charged or used at the same time?).

 

3) Make sure my mains charger and solar systems are set so they cant deliver more than 14.6V, (turn off equalising in the solar). I dont think my alternator can deliver more than 14.4V, and there is a relay which also charges the starter battery.

 

and Bobs your Uncle? 

 

After 1-3 above, I can then start thinking about refinements, in terms of monitoring and control?

Richard ask the seller whether its flashing green or red, these batteries are what I have in my domestic bank and Mega van. Now your solar has to be set at 13,8 volts and float at 13,6 volts, these batteries have an internal BMS but nobody really knows whether it works on its own or it needs the master to control them, these are tough batteries and are 2.5k new, I have the lead and software to read them

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1 minute ago, ditchcrawler said:

Why not just leave the LA's connected

He did, I think. You may be getting confused between protection from voltage spikes due to alternator load-dump at disconnection, and cell overvoltage due to bad balance or overcharging or regulation failure.

 

MP.

 

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2 minutes ago, MoominPapa said:

He did, I think. You may be getting confused between protection from voltage spikes due to alternator load-dump at disconnection, and cell overvoltage due to bad balance or overcharging or regulation failure.

 

MP.

 

If I understood Mike, he has an isolator between the Lis and the LAs. He uses the LAs most of the time, but connects the Lis from time to time. Presumably, for charging, he has them all connected, with the LAs taking what they want, and the Lis taking what they want.

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12 minutes ago, peterboat said:

Richard ask the seller whether its flashing green or red, these batteries are what I have in my domestic bank and Mega van. Now your solar has to be set at 13,8 volts and float at 13,6 volts, these batteries have an internal BMS but nobody really knows whether it works on its own or it needs the master to control them, these are tough batteries and are 2.5k new, I have the lead and software to read them

:)

 

Whether what is flashing green or red? Presumably green means they are OK, and red that they are not? It would be just my luck for them to be flashing green on collection, and red on connection :( Clearly, they are just an example I've found, and there would need to be some way of assessing how "used" a particular battery is.

 

The wires coming out of the middle of the casing on the top seem to suggest they need to be connected to some kind of gizmo for BMS

 

I'm just trying to get a grip of how to get started, and whether it is as complicated as it reads, or whether it can be as complicated as you want it to be :)

 

I like Mikes "Baby Steps" idea.

Edited by Richard10002
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1 hour ago, Mike the Boilerman said:

 

 

Next, I need to add in some over-voltage protection. This is the complicated bit, and I haven't decided how to do it yet, exactly.

 

You first need a high powered switch.

Seems to be 2 options.

1) the BEP motorised switch (which Tom and I have) ...£150. This works with any relay.

or 2) a tyco 200A switch .....£70 new, £30 2nd hand from car breakers yard.....but this needs a latching relay.

 

Then you need a cell level monitoring system to activate the disconnect switch at low and high voltage of an individual cell.

I use the

https://www.zeva.com.au/index.php?product=125

board from Austrailia for £70. Tom also has this. Problem here is that it does not work a latching relay so you either go with the BEP switch or build a circuit to do the latching and get the tyco. I think there is one commercially available for around £75.

Tom linked to a similar board further up this thread for £130 (ish IIRC) which will work directly with the tyco switch so that may be the ideal solution for cell level monitoring but it wont do the total voltage disconnect below.

 

Then you need a total voltage disconnect at high or low voltage ie 12.0V and 13.9V (my system) and high and low temp. I use the relay on my Victron BMV to activate the BEP switch so that is an easy solution. If no BMV then a cheap board from amazon for £20 will work. The issue again though is the latching relay. Easy if you have the BEP switch but you would then need the interface to do the latching if using the Tyco switch.

 

The above gives you 3 levels of comfort.

i) audible alarm

ii) total voltage disconnect

iii) cell level disconnect.

 

For my system, the above only activates in an emergency. It does not activate each day. In fact it has never activated except on testing in the 6 months I have had the batteries.

 

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