LiFe batteries (again...)

OK so I've been looking at batteries and BMS all evening and now my brain hurts.
What does the hive mind here think will happen to prices? How quickly are they falling, and if I wait a year or two is that likely to make much difference?
 
Kelpie said:
OK so I've been looking at batteries and BMS all evening and now my brain hurts.
What does the hive mind here think will happen to prices? How quickly are they falling, and if I wait a year or two is that likely to make much difference?
Click to expand...

I suggest you ask the question on DIY Solar. DIY Solar Power Forum. You will get more informed opinion there. People like Ghostwriter have been buying cells regularly for years and have their fingers on the pulse and know what the trends are.

My view is the cells will continue to drop in cost but you need to price up a total system including BMS and all chargers / controllers and re-wiring costs - all of those will hold their price.. One way to prepare while you are waiting is to gradually swap over any legacy chargers for ones that are highly configurable and can manage lead acid and LFP. (In practice this probably means Victron Bluetooth units.)

But one data point for falling prices is the fact that I paid 720 US dollars for my cells in March. The cells I linked to above are 450 USD for the same capacity (280ah) including transport. Now I'm not sure if the costs are equivalent shipped costs (cells + all taxes + transport + PayPal extra or credit card for security) but, if so, this is a substantial drop. Top tip: to compare prices always get quotes on this total shipped cost and if you buy get it in writing to ensure no hidden taxes are added at the end.
 
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Poey50 said:
I mentioned this very simple sounding hybrid model on another thread. I'm not advocating it, as I haven't tried to explore it in any depth, but they sound like they know what they are talking about.

Lithium-Hybrid

The promise of the system is that you don't need to upgrade any chargers / alternators, the LFP does literally drop in to a lead acid system. Whereas with a dual bus system like mine the BMS is used only as a last resort to prevent catastrophic damage, in this set-up the low voltage and high voltage disconnect are a routine part of the day to day operation. It sounds too good to be true - but it very possibly isn't. You might need to take some care in choosing a suitable drop-in battery however as some have high voltage disconnect above 3.65 volts per cell which would shorten its life.
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sorry, bit late on this was meant to reply on your own thread Poey50.
Contacted this guy (Frank) he's actually running his custom BMS on a hybrid LifePO4 together with FLA for the last year.
I offered to help and he's interested but will come back to me after xmas as he's too busy with a real life/work project he's involved.
Will keep contact with him and let you know.

My main problem is how I can get a set of LiFePO4 for my 24V system (8 pieces) so that I can test the whole thing without spending a lot (not too keen to get into this for the next season) rather wait for prices to drop.
It's not like I can get a 50Ah 24V system for 200quid to try it and then flog that (or reuse that somehow as a 100Ah 12V?) and get a 270Ah system in 2022, is it?

we'll see

V.
 
If I get the Q right, simple answer is by getting a system with a decent BMS that wont throttle I/O to 20-30A
if you mean dropping voltage due to the load, if you check the voltage/SOC plot, it's fairly flat throughout the usable SOC range, so not an issue. It's not like our Trojans where a 80A load drops voltage way too low in half an hour only to recover a few mins afterwards.
 
Most BMS is 100a some 200a anything over that your looking at big buck .


If I go to lithium one thing I will want to do is run my water maker motor 230v pump . My Gen shows it use 11A at 230/240v that's around 220A @12 v if I Calu that right ,

So even a 200a BMS isn't going to do the job .
I guess there must be another way around this when drawing a large loads.
 
yep, go 24V :-)
my watermaker is also drawing 11A@230V, which is approx80A@25V+ 10-12A from solar (always run watermaker on sunny noons!)
My T105REs (in not v.good health) manage 30mins at that (through a Victron Multiplus3000VA) before dropping to 23V (and Amps shooting up)
I recon a decent 280Ah LifePO4 pack would fare much better...
 
vas said:
yep, go 24V :)
my watermaker is also drawing 11A@230V, which is approx80A@25V+ 10-12A from solar (always run watermaker on sunny noons!)
My T105REs (in not v.good health) manage 30mins at that (through a Victron Multiplus3000VA) before dropping to 23V (and Amps shooting up)
I recon a decent 280Ah LifePO4 pack would fare much better...
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Changing to 24v means putting in a load of droppers to work everything else it also mean my plain of 2x200Ah bank given me 400ah , will end up only being a 200ah bank if put them in serial to make a 24v bank which isn't going to be enough .
 
it was a tongue in cheek comment Vic, not a thing you can really do (unless you change boat to a 24V one...)
otoh, the capacity of the bank is the same whether it's 400Ah@12 or 200Ah@24, just the cabling to the the inverter and the potential losses/Amps drop.
 
vas said:
it was a tongue in cheek comment Vic, not a thing you can really do (unless you change boat to a 24V one...)
otoh, the capacity of the bank is the same whether it's 400Ah@12 or 200Ah@24, just the cabling to the the inverter and the potential losses/Amps drop.
Click to expand...
So back to the original question , there must be a away people are running all sorted of loads
 
Daly do a low cost smart BMS rated up to 250amps Vic. I don't know it as I'm not a heavy user but i think there are some videos on YouTube. It has been discussed a lot on the DIY Solar forum.
 
Poey50 said:
Daly do a low cost smart BMS rated up to 250amps Vic. I don't know it as I'm not a heavy user but i think there are some videos on YouTube. It has been discussed a lot on the DIY Solar forum.
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I quite interested in GWL stuff and their 123 smart bms but two things
One is they only seen to be rated at 100a
And two after three emails to them with question about their batteries I not had one rep,y back , thats very bad show .
 
sailaboutvic said:
I quite interested in GWL stuff and their 123 smart bms but two things
One is they only seen to be rated at 100a
And two after three emails to them with question about their batteries I not had one rep,y back , thats very bad show .
Click to expand...

I'm surprised GWL are slow - may be lockdown problems? Try going direct to 123 Electric at this email address - info@123electric.eu

There are people on Lithium Batteries on a Boat Facebook group with big systems and that will be a good place for this kind of question. You can get contactors / relays up to 500amps so you just need a BMS which will control those. I'm not sure 123Smart would go higher than 200 amps.
 
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sailaboutvic said:
Most BMS is 100a some 200a anything over that your looking at big buck .


If I go to lithium one thing I will want to do is run my water maker motor 230v pump . My Gen shows it use 11A at 230/240v that's around 220A @12 v if I Calu that right ,

So even a 200a BMS isn't going to do the job .
I guess there must be another way around this when drawing a large loads.
Click to expand...
Hi Vic,

We have 400AH Winston LiFePo4 at 12V and we can run our watermaker no problem.

We have an Orion Jr BMS for our system, it is not the cheapest but it is very good. We can configure multiple inputs and outputs to switch on/off at different cell voltages to control all the main charging sources and the inverter.

In most cases the BMS does not actually switch the battery current on/off - it just sends a signal to a heavy duty contactor that will disconnect the battery if necessary. We have a 500A shunt and a 500A main contactor so our BMS can control up to 500A but I think if you use a suitable shunt and contactor it can control up to 1000A. Our main contactor will only be turned off by the BMS if we get to a dangerously low or high battery voltage or if the current discharge limit is exceeded. Before that we have other control steps in the BMS that turn things off before we get to any of those "final limits" - the operation of the main contactor by the BMS is the "last resort" function to protect the battery. The only time this has operated in nearly 2 years is when we had guests on board who turned the electric kettle on when the watermaker was running - so the inverter wanted to draw about 380A and this was above the current discharge limit in the BMS and so it turned the contactor off exactly as it should have done.

Even a 200A BMS is not actually going to do the switching for 200A it will just send a signal to a suitable contactor - so it may be possible to just use a larger contactor with it to control more load.

For a boat system I would say you should have 500A contactor and shunt - you will hopefully never get close to that but it gives plenty of safety overhead.

There are many BMS units that offer many different levels of functionality and control - the Orion is one of the best and gives me the best control over our system. I would recommend that you do not try and cut corners with a cheap BMS - ultimately the BMS is there to protect your expensive battery bank and a cheap BMS may not do that adequately.
 
crisjones said:
Hi Vic,

We have 400AH Winston LiFePo4 at 12V and we can run our watermaker no problem.

We have an Orion Jr BMS for our system, it is not the cheapest but it is very good. We can configure multiple inputs and outputs to switch on/off at different cell voltages to control all the main charging sources and the inverter.

In most cases the BMS does not actually switch the battery current on/off - it just sends a signal to a heavy duty contactor that will disconnect the battery if necessary. We have a 500A shunt and a 500A main contactor so our BMS can control up to 500A but I think if you use a suitable shunt and contactor it can control up to 1000A. Our main contactor will only be turned off by the BMS if we get to a dangerously low or high battery voltage or if the current discharge limit is exceeded. Before that we have other control steps in the BMS that turn things off before we get to any of those "final limits" - the operation of the main contactor by the BMS is the "last resort" function to protect the battery. The only time this has operated in nearly 2 years is when we had guests on board who turned the electric kettle on when the watermaker was running - so the inverter wanted to draw about 380A and this was above the current discharge limit in the BMS and so it turned the contactor off exactly as it should have done.

Even a 200A BMS is not actually going to do the switching for 200A it will just send a signal to a suitable contactor - so it may be possible to just use a larger contactor with it to control more load.

For a boat system I would say you should have 500A contactor and shunt - you will hopefully never get close to that but it gives plenty of safety overhead.

There are many BMS units that offer many different levels of functionality and control - the Orion is one of the best and gives me the best control over our system. I would recommend that you do not try and cut corners with a cheap BMS - ultimately the BMS is there to protect your expensive battery bank and a cheap BMS may not do that adequately.
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Hi Chris
I'm too looking at Wilson cells although the we doing some research on GWL
They do GBS cells pack , still trying to find out more , I wish they answer there emails .
The BMS I looking at using is the 123smart and at just under €300 I would say I cutting corners:) .
I drop you an email as we both wonder how thinks are going with you both .
Vic
 
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