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200 amp lithium


luggsy

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I bought 200Ah cells from BLS, shipped from China. All went absolutely according to plan.

 

https://blslifepo4battery.com
 

Generally you get what you pay for, if Li batteries are too good to be true they are probably factory rejects with below spec performance.

Edited by nicknorman
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25 minutes ago, luggsy said:

Has anyone bought a 200amp lithium of alibaba they seem cheap if so did you actually receive it ? Where is the best place to buy one ? Should I be cautious? Any help appreciated 

I think alibaba is bulk purchase only.

 

Keith

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1 hour ago, luggsy said:

Has anyone bought a 200amp lithium of alibaba they seem cheap if so did you actually receive it ? Where is the best place to buy one ? Should I be cautious? Any help appreciated 

 

Just read the small print as to what you actually get - they are not like a FLA battery and just 'plug-and-play' makes sure you get (or know that you need) all the electronic control BMS stuff.

Cheap batteries are unlikely to have the BMS incorporated into 'the box'.

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The other thread running at the moment there is a video where someone bought this 200ah lithium 'drop in' battery complete with a BMS. I quite like the way their site is not full of marketing crap. I have a few questions about it though and no doubt Nick will home in on the main question! 

 

https://www.lifebatteries.co.uk/product-page/12v-200ah-bluetooh-bms

 

 

 

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23 minutes ago, MtB said:

The other thread running at the moment there is a video where someone bought this 200ah lithium 'drop in' battery complete with a BMS. I quite like the way their site is not full of marketing crap. I have a few questions about it though and no doubt Nick will home in on the main question! 

 

https://www.lifebatteries.co.uk/product-page/12v-200ah-bluetooh-bms

 

 

 

£860 for 200Ah at 12v is not a bad price. If they last as long as we expect, a couple, (400Ah), would sort out many of us for a long time to come.

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8 minutes ago, Richard10002 said:

£860 for 200Ah at 12v is not a bad price. If they last as long as we expect, a couple, (400Ah), would sort out many of us for a long time to come.

 

Particularly with the Overkill BMS and Bluetooth adaptor. Pretty sure my Overkill was about £160 with no Bluetooth as they were sold out!

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1 hour ago, Richard10002 said:

£860 for 200Ah at 12v is not a bad price. If they last as long as we expect, a couple, (400Ah), would sort out many of us for a long time to come.

The 200Ah cells I got come out at £578 for 4. So you are paying an extra £282 for the box and BMS. Which is not unreasonable, but not especially cheap either.

 

Personally I wouldn’t want a built in BMS with a mind of its own, in case it decided to isolate from the alternator at an inconvenient (alternator-destroying) moment. And the BMS doesn’t support a 1C discharge. I also wonder what happens if you have more than one, each with its own BMS. Do they talk to each other?

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2 hours ago, nicknorman said:

The 200Ah cells I got come out at £578 for 4. So you are paying an extra £282 for the box and BMS. Which is not unreasonable, but not especially cheap either.

 

Personally I wouldn’t want a built in BMS with a mind of its own, in case it decided to isolate from the alternator at an inconvenient (alternator-destroying) moment. And the BMS doesn’t support a 1C discharge. I also wonder what happens if you have more than one, each with its own BMS. Do they talk to each other?

 

Having one myself, there is no way i can see for them to talk to each other. 

 

The plan is, connect in parallel to a LA battery so the alternator is protected. 

 

This is all dead simple "Lithium for Dummies" end of the spectrum stuff, easily understandable by most boaters nervous of messing with innards of their alternator.

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5 minutes ago, MtB said:

 

Having one myself, there is no way i can see for them to talk to each other. 

 

The plan is, connect in parallel to a LA battery so the alternator is protected. 

 

This is all dead simple "Lithium for Dummies" end of the spectrum stuff, easily understandable by most boaters nervous of messing with innards of their alternator.

Yes, fudging by using an LA battery to cover for the sins of the system! But if connecting an LA battery in parallel fixed the problems, I wouldn’t object so much! In fact connecting a LA battery in parallel only addresses the issue of sudden disconnection. It doesn’t address the issue of alternator overheating nor sub-optimal charging profile.

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Just now, nicknorman said:

Yes, fudging by using an LA battery to cover for the sins of the system! But if connecting an LA battery in parallel fixed the problems, I wouldn’t object so much! In fact connecting a LA battery in parallel only addresses the issue of sudden disconnection. It doesn’t address the issue of alternator overheating nor sub-optimal charging profile.

 

Nope, but adding ten metres of 16mm CSA cable fixes the alternator overheating problem is an equally cheap and simple way. Adjust length to adjust alternator running temp! 

 

An easy-to-implement quick and dirty lithium installation that saves running the engine for hours to get the batts up to 100% once a week is the goal for most liveaboards, remember? Not all of us wants a boat that would be better served by a nuclear power station... ;) 

 

 

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  • 7 months later...
On 22/01/2022 at 23:12, MtB said:

 

Nope, but adding ten metres of 16mm CSA cable fixes the alternator overheating problem is an equally cheap and simple way. Adjust length to adjust alternator running temp! 

 

Would you mind elaborating on this? I'd like to know why/how this works, and how to implement it exactly (i.e. where does the cable go?)

 

I'd really like to use this solution.

 

Thanks

 

(sorry for the old thread necro, if that is an issue here)

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9 minutes ago, 170968 said:

Would you mind elaborating on this? I'd like to know why/how this works, and how to implement it exactly (i.e. where does the cable go?)

 

I'd really like to use this solution.

 

Thanks

 

(sorry for the old thread necro, if that is an issue here)

 

Broadly speaking, the internal resistance of a lithium battery is so low that the alternator gets to deliver it's full output current all the time when charging. As most boats have automotive alternators only rated for short bursts of full output (after starting the engine, to replace the charge used by cranking it over), running them at full output for long periods makes them overheat, hence the need for some sort of output current control.

 

Now Nick Norman's method of current limiting is very elegant, but complex to implement and unnecessary when using a lithium batt as a hybrid with the original LA batts still in service. Start off by just wiring your lithium batt in parallel and see how your alternator behaves. Watch carefully. Or more accurately measure its temperature carefully over a couple of hours of full output charging into the lithium to see if it has an overheating problem in the first place. It might not, depending on the resistance of your existing cabling. 

 

If the alternator overheats, a very low resistance inserted into the lithium connecting cable will reduce the peak charge current a little, thus protecting the alt. Start with a randomly selected long-ish length of cable inserted and test again. Use a clamp meter to measure the actual charge current, and say an infrared 'point and measure' thermometer to monitor the alt temp. If the alt is still overheating, add more wire. If the charge current is too low for your taste and the alt is running cool, reduce the length.

 

The resistance of the length of wire will be significant in relation to the internal resistance of the lithium batt and varies with length, obvs, so will have an effect on the charge current. Use Ohm's Law if you are minded to do some calcs. 

 

Nick hates this method as it is 'down and dirty' as the Yanks would say, but it broadly works. It does not negate the need for all the normal protections to be installed against over and under charging. It is purely to limit alternator overheating.

 

 

Just now, MtB said:

(i.e. where does the cable go?)

 

Arrange the cable anywhere convenient. Bear in mind it will get warm as a little power will be getting dumped into it and it needs to stay cool, so don't coil it up and box it in! 

 

 

 

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15 minutes ago, MtB said:

 

Nick hates this method as it is 'down and dirty' as the Yanks would say, but it broadly works. It does not negate the need for all the normal protections to be installed against over and under charging. It is purely to limit alternator overheating.

 


No I don’t “hate it” but it only addresses one of several problems with using an LA charging system to charge Li, and does so as a rather blunt tool. But hey, better than nothing!

 

Just to clarify, the general idea is that the LA battery + is connected directly to the alternator (well, via the isolator switch if you want to comply with BSS) and then the positive of the LA is connected to the positive of the Li via a length of wire that has some slight resistance so will drop some voltage when high current is flowing, thus reducing the maximum alternator output to something the alternator can tolerate long term. Li and LA battery negative can be connected together in the usual way.

 

Wire needs to be fat enough so as not to get too hot at whatever current is desired, and as MtB says don’t coil it up or otherwise prevent it from dissipating heat. This length of wire presents some safety hazard so if there is any possibility of it chafing and touching hull or other negative connection, it should be fused at both ends. If I was a BSS inspector I’d certainly want it fused at both ends.

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3 minutes ago, nicknorman said:


No I don’t “hate it” but it only addresses one of several problems with using an LA charging system to charge Li, and does so as a rather blunt tool. But hey, better than nothing!

 

Just to clarify, the general idea is that the LA battery + is connected directly to the alternator (well, via the isolator switch if you want to comply with BSS) and then the positive of the LA is connected to the positive of the Li via a length of wire that has some slight resistance so will drop some voltage when high current is flowing, thus reducing the maximum alternator output to something the alternator can tolerate long term. Li and LA battery negative can be connected together in the usual way.

 

Wire needs to be fat enough so as not to get too hot at whatever current is desired, and as MtB says don’t coil it up or otherwise prevent it from dissipating heat. This length of wire presents some safety hazard so if there is any possibility of it chafing and touching hull or other negative connection, it should be fused at both ends. If I was a BSS inspector I’d certainly want it fused at both ends.

 

 

And all those junctions involved in having fuses both ends AND going through a possibly low quality isolator switch probably add enough resistance to chop down alternator output to about two thirds of rated anyway! 

 

Although weirdly on my own installation (24v, nominal 30A alternator), I'd sometimes see up to 38A charge current out of it into the lithium. And no overheating!

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I accept that the lithium hybrid is a low cost simple way of doing things but I can't get enthused by it.

It is the ultimate mixing of new and old batteries and we are always told not to do this, if the LA fails with a shorted cell all that lithium energy dumps into the LA.

If the LA is a proper battery like a Trojan then the charging voltage is not high enough. If the lithium and LA's both discharge then the lithium charges first (???) so it will take ages to get the LAs fully charged.  The current limiting length of cable is a bit naff.

I suppose if its a lithium bank with a single LA as a surge surpressor then its maybe just about ok.

My intuition is that if you want to go lithium then do it properly, but this is expensive.

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Thanks all. Very helpful.

 

Do these drop in replacement type lithium batteries protect themselves from overcharging, or do I still need to add this?

 

What I'm thinking of doing is using one of these drop in batteries as a temporary measure, until I can get a proper system installed. Otherwise I am going to need to buy some lead acids to tide me over anyway. I really want to avoid this if possible.

So if I dropped in a 100ah lithium, in place of the mostly dead LA batteries, do I even need to worry about overheating my alternator? Lets say I charge the lithium when it reaches 50%, using a 90amp alternator? So approximately a half hour charge.

 

ETA: the LA starter will still be in place.

 

Edited by 170968
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22 minutes ago, 170968 said:

Thanks all. Very helpful.

 

Do these drop in replacement type lithium batteries protect themselves from overcharging, or do I still need to add this?

 

What I'm thinking of doing is using one of these drop in batteries as a temporary measure, until I can get a proper system installed. Otherwise I am going to need to buy some lead acids to tide me over anyway. I really want to avoid this if possible.

So if I dropped in a 100ah lithium, in place of the mostly dead LA batteries, do I even need to worry about overheating my alternator? Lets say I charge the lithium when it reaches 50%, using a 90amp alternator? So approximately a half hour charge.

 

ETA: the LA starter will still be in place.

 

Typically drop in replacement type lithium batteries are protected from over charging and over discharging. However in doing so they let the cells get right to the limit of what is tolerable before rapid damage occurs. It is not an exact science but IMO this means they can be routinely in the zone where a bit of unnecessary damage occurs, and doing that routinely means the life is shortened. Of course the life is very long, so maybe a reduction by say 50% isn’t a huge deal, but it is still wasteful!

 

A lot depends on your usage pattern. If you mostly only run your engine to charge the batteries, you can stop the engine when they become charged and that is fine. But if you often cruise for many hours a day, the batteries will sit there fully charged and being held up at the charging voltage (14.4v or whatever) and that is not good for them.

 

I find my alternator will run flat out for about 5 minutes before my over temperature protection kicks in and starts to reduce alternator output. Mind you that is set quite low at about 85C, but the 85C is the temperature of the case and cooling air exiting the alternator, presumably there are bits inside that are a lot hotter. So I think the “thermal time constant” is only 5 mins or so. By 30mins the alternator will long since have stabilised at whatever the plateau temperature is. Whether this is too hot depends on the alternator and the environment (ambient temperature of engine bay) so for example if you start this process with a cold engine and cold engine bay, it will be better than starting it with an already hot engine. And the rpm. Better to run the alternator faster than the minimum to get more cooling air throughput (faster fan speed).

 

As MtB says, there will already be some resistance in the circuit through battery isolators and just through connections, so maybe you should suck it and see before adding the long cable.

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It all depends on the alternator. Mine can run flat out for quite a time (charging Trojans with an Adverc) but it does run much hotter than I would like.  If you don't have temperature protection (which you won't) then you need to limit current and hence temperature to a safe value, but this is a pretty arbitrary number that you can only guess at.  Lithiums take their full charge current (whatever the alternator can deliver) at any state of charge so starting charging at 50%, or any value, makes no difference.

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10 minutes ago, 170968 said:

Would the diameter of the wire be specific to the output (amps) of the alternator, or is it a product of the diameter and length?

 

I'm thinking it would be a set diameter and an adjustable length depending on the amount of overheating, but I'm not sure at all.

The diameter (or more properly the cross sectional area) determines how much current the cable can take without overheating. So it would be best to go for a cable whose maximum current rating matches the maximum alternator output (note that the maximum current rating of a cable depends on how it is installed, because ultimately it has to be able to dissipate heat created by the current and its specific resistance. So a cable installed inside trunking, within an insulated space etc will have a lower current rating than one installed in an open space).

 

Having chosen a cable size which won’t overheat, you then adjust the length to obtain the desired resistance to reduce the alternator current to an acceptable long term value.

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12 minutes ago, Mike Hurley said:

 

Interesting to see. Makes it look very simple. Though I thought her cable seemed too thin. And maybe too long judging by her alternator temp?

 

9 minutes ago, nicknorman said:

The diameter (or more properly the cross sectional area) determines how much current the cable can take without overheating. So it would be best to go for a cable whose maximum current rating matches the maximum alternator output (note that the maximum current rating of a cable depends on how it is installed, because ultimately it has to be able to dissipate heat created by the current and its specific resistance. So a cable installed inside trunking, within an insulated space etc will have a lower current rating than one installed in an open space).

 

Having chosen a cable size which won’t overheat, you then adjust the length to obtain the desired resistance to reduce the alternator current to an acceptable long term value.

 

Thanks, this makes perfect sense.

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4 hours ago, MtB said:

 

Broadly speaking, the internal resistance of a lithium battery is so low that the alternator gets to deliver it's full output current all the time when charging. As most boats have automotive alternators only rated for short bursts of full output (after starting the engine, to replace the charge used by cranking it over), running them at full output for long periods makes them overheat, hence the need for some sort of output current control.

 

Now Nick Norman's method of current limiting is very elegant, but complex to implement and unnecessary when using a lithium batt as a hybrid with the original LA batts still in service. Start off by just wiring your lithium batt in parallel and see how your alternator behaves. Watch carefully. Or more accurately measure its temperature carefully over a couple of hours of full output charging into the lithium to see if it has an overheating problem in the first place. It might not, depending on the resistance of your existing cabling. 

 

If the alternator overheats, a very low resistance inserted into the lithium connecting cable will reduce the peak charge current a little, thus protecting the alt. Start with a randomly selected long-ish length of cable inserted and test again. Use a clamp meter to measure the actual charge current, and say an infrared 'point and measure' thermometer to monitor the alt temp. If the alt is still overheating, add more wire. If the charge current is too low for your taste and the alt is running cool, reduce the length.

 

The resistance of the length of wire will be significant in relation to the internal resistance of the lithium batt and varies with length, obvs, so will have an effect on the charge current. Use Ohm's Law if you are minded to do some calcs. 

 

Nick hates this method as it is 'down and dirty' as the Yanks would say, but it broadly works. It does not negate the need for all the normal protections to be installed against over and under charging. It is purely to limit alternator overheating.

 

 

 

Arrange the cable anywhere convenient. Bear in mind it will get warm as a little power will be getting dumped into it and it needs to stay cool, so don't coil it up and box it in! 

 

 

 

I have about 2 mts and it's a bit too long which is a shame as it represents a nice neat cable run

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3 hours ago, 170968 said:

Thanks all. Very helpful.

 

Do these drop in replacement type lithium batteries protect themselves from overcharging, or do I still need to add this?

 

What I'm thinking of doing is using one of these drop in batteries as a temporary measure, until I can get a proper system installed. Otherwise I am going to need to buy some lead acids to tide me over anyway. I really want to avoid this if possible.

So if I dropped in a 100ah lithium, in place of the mostly dead LA batteries, do I even need to worry about overheating my alternator? Lets say I charge the lithium when it reaches 50%, using a 90amp alternator? So approximately a half hour charge.

 

ETA: the LA starter will still be in place.

 

Will the LA be constantly connected to the alternator?

If you have a diode splitter as opposed to a relay you may be dropping half a volt already.

Also you can run the long cable from the split charge device to the Lithium and not back to the alternator. So depending what you have installed already you may or may not need a longer wire.

 

 

If you connect a digital voltmeter between the B+ terminal of your alternator and the positive battery terminal of your domestic batteries on your existing system, then run the engine while your batteries are well depleted you will see what sort of volt drop you have in your charge circuit already. The inefficiency of some systems from new may mean you don't need to do anything

Edited by ditchcrawler
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