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Post by Deleted on Oct 28, 2020 16:54:15 GMT
Thanks Peter, those sound pretty good. How much does your friend charge for 200ah of batteries? Are you recommending that 200ah is not enough? On the point of leaving the existing batteries in place until they expire, in principle it sounds fine. I dont have enough technical know-how to be sure of any of this, but one thing that occurs to me is this: I'm trying to reduce the engine running time needed for recharging, and my aim is to use no more than 150ah of charge each day. So I don't really need the extra capacity that the LAs would add, and if I do use them, it will mean running the engine for longer each day to recharge them. I can see them getting into pretty bad shape by me not recharging them properly, as I'll be focused on charging the lithiums. Maybe if I use some clever wiring to ensure the lithium always get used first and charge first, so the LAs would sit unused and inert until the occasional day they were used. That could work.... The batteries are 138 ah so you would require two for what you need, as Nick says the LAs will end up always being charged anyway.. The extra reserve will let you know if two batteries are enough, Nick is making an alternator controller which I would fit if I was an engine driven boat. I can have a word with James and see what he has if you would like?
Thanks Peter, yes two would be needed, if you can get a rough idea of the price that would be great. I'm guessing they dont have built in BMS, right? So yes, if I understand it right, I also need to add in the cost of a system like Nick's to manage the charging.
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Post by Deleted on Oct 28, 2020 16:57:46 GMT
Its quite interesting this whole lithium battery thing. People talk about control circuits, Arduino and raspberry pies but at the end of the day the average consumer probably things a raspberry pi is a pudding of some sort. People probably just want a fit and forget system. But this will be expensive if your main power source is diesel engine/alternator. There is quite a strong argument for quality AGM batteries in this case. I am tempted to make up banks with these rather appealing Victron blocks. 4 of them to replace the engine-charged batteries. And keep the Lithium batteries for the solar. www.intellitecmv.com/products/12-25ah-agm-super-cycle-batteryYes there is LiFe after Lead but Lead is not dead
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Post by Deleted on Oct 28, 2020 17:24:47 GMT
Thanks Nick- can I ask how the recharging would work with this setup? E.g. would the lithiums draw most of the incoming charge until they were almost full, and then allow the LAs to take most of charge? Or would they all recharge at an equal rate? Either way, it sounds like it all works fine in practice, as borne out by John V's experience. In my case I wouldn't use the LA's most days- but when I did, I would obviously have to accept that recharging everything would take longer than normal. I keep thinking it comes down to whether you want that extra capacity as an occasional fall- back, and to be honest I dont have enough experience to know. In the couple of months since I started cruising, I've managed ok with using 100-150ah of charge each day, and I do like the idea of a simpler set up with a single 200ah lithium battery... but I guess you never know. Dr Bob on CWDF put up a control circuit for what you require I will ask him for it if that would help? Thanks for the kind offer Peter, but tbh my electrical knowledge is not good enough to construct this sort of device from a diagram, even a good one. What I'll probably do is look for an off-the-shelf BMS system. Although that said, I've just remembered I do have a half-decent charger so I'll check that before I leave town tomorrow- it might already have a charge mode or setting that will work for lithium batteries.
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Post by Deleted on Oct 28, 2020 17:29:09 GMT
Its quite interesting this whole lithium battery thing. People talk about control circuits, Arduino and raspberry pies but at the end of the day the average consumer probably things a raspberry pi is a pudding of some sort. People probably just want a fit and forget system. But this will be expensive if your main power source is diesel engine/alternator. There is quite a strong argument for quality AGM batteries in this case. I am tempted to make up banks with these rather appealing Victron blocks. 4 of them to replace the engine-charged batteries. And keep the Lithium batteries for the solar. www.intellitecmv.com/products/12-25ah-agm-super-cycle-batteryYes there is LiFe after Lead but Lead is not dead I dont mind Lead based batteries as such, but the faster recharging times of the lithiums do look very appealing.... But as you say, electrical ignoramuses like me ideally want to have an easy to manage system if possible, or there is every chance I could ruin them very quickly, and throw away a grand
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Post by Deleted on Oct 28, 2020 17:33:17 GMT
I suspect this factor is used in marketing. Like that Shunbin battery you linked to earlier. It looked lovely. Nice metal casing, heavy-looking BMS on there but at the end of the day if the cells are factory QC fails, which is possible, they will let you down regardless of what BMS is on there and never mind how shiny the box is. Lithium batteries are an interesting and slightly financially risky situation. I reckon for diesel engine/alternator basic existing setup there is still an argument for recycling el cheapo "110 leisure" batteries. Just replace them often and don't waste too much diesel trying to fully charge them each time. At some stage, if the diesel engine is your main power supply even when moored up, there will be an overlap where the cost of fuel ends up being greater than the cost of batteries. Lead acid batteries are one of the most well recycled products in existence (at least pikeys are good for something ) so replacing often is not an environmentally arduous thing to do.
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Post by kris on Oct 28, 2020 17:33:23 GMT
The batteries are 138 ah so you would require two for what you need, as Nick says the LAs will end up always being charged anyway.. The extra reserve will let you know if two batteries are enough, Nick is making an alternator controller which I would fit if I was an engine driven boat. I can have a word with James and see what he has if you would like?
Thanks Peter, yes two would be needed, if you can get a rough idea of the price that would be great. I'm guessing they dont have built in BMS, right? So yes, if I understand it right, I also need to add in the cost of a system like Nick's to manage the charging. you’d be in the same position as me, although I seem to remember you have travel power? So a good battery charger with lifepo4 setting will help. I was going for charging from solar and then battery charger for now then sort the alternator issues out later . Peter I’d be interested in the plan for that circuit, if you don’t mind. I also bought mine from James, the same person as peter and he is a lovely man and I can’t recommend him enough. Im at the position where I have to decide to buy or not this £200 relay, that might not do the job of high voltage and low voltage cutout. I’ll stop the procrastination and make a decision soon.
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Post by Telemachus on Oct 28, 2020 17:44:04 GMT
On the subject of low voltage cutoff and BMS, 10v is 2.5v per cell which is the minimum as specified by most manufacturers. Of course by 10v, the LAs will be well flat too! Yes 2.5v is critically low but not disastrous low. As with LA batteries, one should keep an eye on SoC and not over-discharge. So maybe the extant BMS is ok as it just there for emergency disconnect when you have seriously cocked up, not as a normal “target” minimum SoC.
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Post by Deleted on Oct 28, 2020 17:49:22 GMT
The high voltage cutout seems more of an interesting problem to me.
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Post by Deleted on Oct 28, 2020 17:50:16 GMT
The high voltage cutout seems more of an interesting problem to me. Oops wrong login ! It's this idea of holding the LFP batteries at 14.4v+ for an extended time which is concerning. I couldn't immediately find the high voltage cutout for LFP but I seem to recall it is more like 15v. Apparently keeping them that high is detrimental to their 'cycle life. So maybe relying on the built in BMS to take the battery out of circuit is a faulty theory. The BMS are not very easy to adjust if the thing is inside a sealed box which is usually the case.
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Post by Deleted on Oct 28, 2020 18:45:09 GMT
Thanks Peter, yes two would be needed, if you can get a rough idea of the price that would be great. I'm guessing they dont have built in BMS, right? So yes, if I understand it right, I also need to add in the cost of a system like Nick's to manage the charging. you’d be in the same position as me, although I seem to remember you have travel power? So a good battery charger with lifepo4 setting will help. I was going for charging from solar and then battery charger for now then sort the alternator issues out later . Peter I’d be interested in the plan for that circuit, if you don’t mind. I also bought mine from James, the same person as peter and he is a lovely man and I can’t recommend him enough. Im at the position where I have to decide to buy or not this £200 relay, that might not do the job of high voltage and low voltage cutout. I’ll stop the procrastination and make a decision soon. Hi Kris, no I don't think I have a travelpower, but its a decent Sterling charger called an 'Advanced digital alternator to battery charger', and something else called an 'Advanced digital software controlled charger/powerpack'. Nemesis pointed out to me that the second one has a range of modes including desulphation, and there is a charging mode suitable for lithiums, but I dont know what the high and low cutoff voltages are yet- but in theory I might already have a suitably safe charging system for Lithiums. I remember the previous owner saying something like it was set up so that it could get the batteries up to 80% in like half an hour, which suggests it can charge at maybe 100 amps, but its possible he misunderstood its capability. I cant be arsed getting the deck board up now but I'll take a look tomorrow. AS far as I know it has the standard canaline 38 setup with a 50 amp alternator, but if there's more capability than that then great.
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Post by Deleted on Oct 28, 2020 18:52:32 GMT
The high voltage cutout seems more of an interesting problem to me. Oops wrong login ! It's this idea of holding the LFP batteries at 14.4v+ for an extended time which is concerning. I couldn't immediately find the high voltage cutout for LFP but I seem to recall it is more like 15v. Apparently keeping them that high is detrimental to their 'cycle life. So maybe relying on the built in BMS to take the battery out of circuit is a faulty theory. The BMS are not very easy to adjust if the thing is inside a sealed box which is usually the case. Given that lithiums are gradually becoming more popular, I'm surprised some ingenious person hasnt devised an add-on type device to cut off the batteries when they reach the required voltage. The current built in BMS units dont seem to cover that very well from what I can see. If I was cruising I'd have to remember to keep checking them, and manually disconnect them at the correct point. There'd be a good few times I'd forget, and they'd be around 14.4 for half the day....
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Post by kris on Oct 28, 2020 18:53:36 GMT
you’d be in the same position as me, although I seem to remember you have travel power? So a good battery charger with lifepo4 setting will help. I was going for charging from solar and then battery charger for now then sort the alternator issues out later . Peter I’d be interested in the plan for that circuit, if you don’t mind. I also bought mine from James, the same person as peter and he is a lovely man and I can’t recommend him enough. Im at the position where I have to decide to buy or not this £200 relay, that might not do the job of high voltage and low voltage cutout. I’ll stop the procrastination and make a decision soon. Hi Kris, no I don't think I have a travelpower, but its a decent Sterling charger called an 'Advanced digital alternator to battery charger', and something else called an 'Advanced digital software controlled charger/powerpack'. Nemesis pointed out to me that the second one has a range of modes including desulphation, and there is a charging mode suitable for lithiums, but I dont know what the high and low cutoff voltages are yet- but in theory I might already have a suitably safe charging system for Lithiums. I remember the previous owner saying something like it was set up so that it could get the batteries up to 80% in like half an hour, which suggests it can charge at maybe 100 amps, but its possible he misunderstood its capability. I cant be arsed getting the deck board up now but I'll take a look tomorrow. AS far as I know it has the standard canaline 38 setup with a 50 amp alternator, but if there's more capability than that then great. The easiest solution for you probably, although don’t take this as gospel I’m sure one of the adults will be along to correct me. Would be have a lead acid starter battery charged from the alternator then a Sterling battery to battery charger. As I say you’d have to check this.
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Post by Telemachus on Oct 28, 2020 19:00:01 GMT
Hi Kris, no I don't think I have a travelpower, but its a decent Sterling charger called an 'Advanced digital alternator to battery charger', and something else called an 'Advanced digital software controlled charger/powerpack'. Nemesis pointed out to me that the second one has a range of modes including desulphation, and there is a charging mode suitable for lithiums, but I dont know what the high and low cutoff voltages are yet- but in theory I might already have a suitably safe charging system for Lithiums. I remember the previous owner saying something like it was set up so that it could get the batteries up to 80% in like half an hour, which suggests it can charge at maybe 100 amps, but its possible he misunderstood its capability. I cant be arsed getting the deck board up now but I'll take a look tomorrow. AS far as I know it has the standard canaline 38 setup with a 50 amp alternator, but if there's more capability than that then great. The easiest solution for you probably, although don’t take this as gospel I’m sure one of the adults will be along to correct me. Would be have a lead acid starter battery charged from the alternator then a Sterling battery to battery charger. As I say you’d have to check this. This is a satisfactory solution for charging, except that a B2B with decent current rating is very expensive.
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Post by kris on Oct 28, 2020 19:04:27 GMT
The easiest solution for you probably, although don’t take this as gospel I’m sure one of the adults will be along to correct me. Would be have a lead acid starter battery charged from the alternator then a Sterling battery to battery charger. As I say you’d have to check this. This is a satisfactory solution for charging, except that a B2B with decent current rating is very expensive. That is the drawback, I did find those other alternator regulators that where exspensive as well. What do you think about that mosfet regulator? Sorry to keep going on about it but two hundred quid is a lot of money to me. I thought about just using it as low voltage cutout as I know this is how the victron ones are recommended to be used. So no charging currents running through it.
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Post by Deleted on Oct 28, 2020 19:07:03 GMT
I bought some heavily discounted Mastervolt 20ah LFP batteries recently.
MLS 260/12. Built in BMS on them. £100 each. It was an angling centre. They no longer stock them. Maybe Chinese junk but Mastervolt sounded good.. I reckon they wanted shelf space as the Covid thing made people go fishing more... Anyway !
Not very big batteries but I use hardly any power anyway so it works ok for me.
Nothing to do with engine charging they are on a large solar panel.
I put a wire in where I can plug them into the engine room batteries as an experiment (2 engine starters and one domestic battery all basic cheap lead acid) and because of the higher voltage of the LFP batteries you get a flow of current out of the LFP to the lead acid batteries.
I don't really understand why one would need a B2B charger when a wire does the job...
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