gregcope
Well-known member
thanks
270ah DIY LiFePO4 build
- Thread starter Poey50
- Start date
gregcope
Well-known member
Is that your intended BMS or are you going something different?
sailaboutvic
Well-known member
Year me , I given myself a right head Ach read and watching stuff and the more I learn the more I going off them .
I now rackon a 400Ah bank with a good BMS , b3b charger relay and god know what else is going to set me back a good 3k at the very less .
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sailaboutvic
Well-known member
This may be some help to some its a reply I got from 123 smart , still not got a reply back Fromm GWL so if I did go the lithium route I won't be useing them .
Hi Vic,
Do you have a pack made of separate 3.3V cells or is it a complete 12V battery block? If it is a 12V battery block and you have no access to the individual cells of 3.3V each, then you cannot use the SmartBMS (or any other cell BMS).
If you have two banks, then you need 1 complete BMS per bank. That means that you need a SmartBMS set for 4 cells per bank. Alternatively you can reconfigure the two banks to one bank with double the capacity by placing each two cells parallel. Then you will get 2P4S, so each 2 cells parallel, these parallel branches in series to get 4 in series. For this configuration, you only need 1 SmartBMS where each branch of 2 cells parallel gets 1 cell board. The voltage over two batteries in parallel is always the same.
Please see the FAQ at 123\SmartBMS gen3 - 123electric - section "Can I place multiple cells or packs parallel"
Besides you need a power efficient power relay like the SmartBMS (max 120A) or the Kilovac EV200 which you need to connect to the SmartBMS. If the BMS detects a voltage or temperature error, the BMS cuts the relay off after 8 seconds. For example if you draw so much power that the pack goes below the configured Vmin (2.9V for example) for 8 seconds long, then the BMS will cut off the load. If your load always let the cells drop below this value even when the pack is partly charged, then either the pack capacity is not sufficient for your load, the terminals are oxidated (always clean cell poles with sanding paper before mounting) or the power cables may need to have a bigger diameter (mm2).
It is recommended that a qualified technician installs the SmartBMS because a wrong installation can damage the battery pack and/or the SmartBMS.
For futher support/ordering, please contact one of our international shipping dealers: Where to buy - 123electric
Best regards,
Sebastiaan Adamo
Hi Vic,
Do you have a pack made of separate 3.3V cells or is it a complete 12V battery block? If it is a 12V battery block and you have no access to the individual cells of 3.3V each, then you cannot use the SmartBMS (or any other cell BMS).
If you have two banks, then you need 1 complete BMS per bank. That means that you need a SmartBMS set for 4 cells per bank. Alternatively you can reconfigure the two banks to one bank with double the capacity by placing each two cells parallel. Then you will get 2P4S, so each 2 cells parallel, these parallel branches in series to get 4 in series. For this configuration, you only need 1 SmartBMS where each branch of 2 cells parallel gets 1 cell board. The voltage over two batteries in parallel is always the same.
Please see the FAQ at 123\SmartBMS gen3 - 123electric - section "Can I place multiple cells or packs parallel"
Besides you need a power efficient power relay like the SmartBMS (max 120A) or the Kilovac EV200 which you need to connect to the SmartBMS. If the BMS detects a voltage or temperature error, the BMS cuts the relay off after 8 seconds. For example if you draw so much power that the pack goes below the configured Vmin (2.9V for example) for 8 seconds long, then the BMS will cut off the load. If your load always let the cells drop below this value even when the pack is partly charged, then either the pack capacity is not sufficient for your load, the terminals are oxidated (always clean cell poles with sanding paper before mounting) or the power cables may need to have a bigger diameter (mm2).
It is recommended that a qualified technician installs the SmartBMS because a wrong installation can damage the battery pack and/or the SmartBMS.
For futher support/ordering, please contact one of our international shipping dealers: Where to buy - 123electric
Best regards,
Sebastiaan Adamo
Poey50
Well-known member
It's also possible to import Winston cells direct from China. That could be cheaper than GWL . Someone on Lithium Batteries on a Boat Facebook Group has the details. $1800 for 4 x 3.2 volt 400 ah cells and $350 for delivery is quoted. Not sure how that compares like for like to GWL. They are good cells and more suitable for the marine environment but .. you have to pay a lot more than aluminium cased ones. But about 1/3 of the people on that group have bought from GWL without complaint so unless the price advantage is quite large I think you would be better sticking with GWL for the cells just because European firms have better trading ethics on the whole than Chinese ones.
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sailaboutvic
Well-known member
You Mr have a lot to answer for
I was fine with my crappy Trojan until you started posting haha .RJ Energy give me a quote for their batteries a while back USD 787 for 4x271ah cells but not sure about there cells how good they are 30/40 days by train ( yes train)
Edit USD 787 included transport and taxed to Italy , batteries are 185US per cell
Poey50
Well-known member
You Mr have a lot to answer for
RJ Energy give me a quote for their batteries a while back USD 787 for 4x271ah cells but not sure about there cells how good they are 30/40 days by train ( yes train)
Sorry about that Vic! If you can hang on 10-15 years I can let you know how well the RJ Energy 271s hold up. They've been great for the first three months, is all I can say.
sailaboutvic
Well-known member
Are your from R J Energy ?
Not sure I be sailing in 15 years time
Poey50
Well-known member
Ha ha! You caught me.
True answer - I wouldn't be hanging around here if I could make a small fortune flogging cells off the back of a lorry (or whatever).
sailaboutvic
Well-known member
No I mean did you buy your from RJ Energy ?
sailaboutvic
Well-known member
OK no need to answer just read your first posting again .
How did you find them to deal with ?
Did they balance the batteries before sending them out?
How did you find them to deal with ?
Did they balance the batteries before sending them out?
Poey50
Well-known member
Very easy to deal with - Carl Wu is the main guy and has good English.
The batteries should be matched for capacity but they aren't balanced. Sometimes people get them and notice that they are all the same voltage - 3.2volts typically - and then think they don't need to balance. But inbalances only show up at the high end of the charge and that is why it's called a top balance.
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sailaboutvic
Well-known member
i was dealing with someone called Alce , very quick to reply to email , as it happen she still emails me , i keep telling her i am taken
i been temped to go with them if i did buy .
am still in two minds
might drop you a pm at some time not to driff this thread if thats ok
i been temped to go with them if i did buy .
am still in two minds
might drop you a pm at some time not to driff this thread if thats ok
Poey50
Well-known member
i was dealing with someone called Alce , very quick to reply to email , as it happen she still emails me , i keep telling her i am taken
i been temped to go with them if i did buy .
am still in two minds
might drop you a pm at some time not to driff this thread if thats ok
Feel free to PM me.
I'm not sure if RJ Energy are now offering the best deals. Have a look at the cells that Neil bought in posts #167 and #178. They look good.
Kelpie
Well-known member
I've re-read this thread from the beginning, thanks again to Poey50 for his excellent write up and willingness to answer so many questions.
You said that the cells, delivered, cost £620. And the finished article came to £1500, with £1100 being the pack, case, BMS, and various connectors (if I'm reading it right).
£620 for 270Ah is a fantastic price, cheaper per usable Ah than Trojans. But obviously the extra costs fairly add up and change the whole equation.
It would be very interesting to see where the extra money goes, and what options might exist to keep the budget down. Obviously these would come with their own downsides. I'm thinking things like running without a BMS, manually isolating the bank when necessary, accepting a lower maximum current draw, not using the alternator as a charging source, etc etc. Yes these are probably bodges, but I'd be willing to sacrifice a bit of user-friendliness if it keeps the budget in check.
You said that the cells, delivered, cost £620. And the finished article came to £1500, with £1100 being the pack, case, BMS, and various connectors (if I'm reading it right).
£620 for 270Ah is a fantastic price, cheaper per usable Ah than Trojans. But obviously the extra costs fairly add up and change the whole equation.
It would be very interesting to see where the extra money goes, and what options might exist to keep the budget down. Obviously these would come with their own downsides. I'm thinking things like running without a BMS, manually isolating the bank when necessary, accepting a lower maximum current draw, not using the alternator as a charging source, etc etc. Yes these are probably bodges, but I'd be willing to sacrifice a bit of user-friendliness if it keeps the budget in check.
Poey50
Well-known member
Hmm ... I wouldn't feel able to support with information an installation on a boat with no BMS. (Not the same issues for a trolling motor.) People have done it by manual intervention but LFP gives you no credit at all for the hundreds of times you remember. i used to have a dog that had no off switch when it came to gobbling down food. It always needed us to set limits. One day it came across a lot of food and gorged and gorged ... and gorged.. It's the same with LFP except dogs don't go into thermal runaway and burn the house down. Quite properly people distinguish LFP from other less stable lithium ion chemistries but that assumes the use of a BMS.
So costs are for a lithium system not for cells. There is an unavoidable upfront hit but a good system will last for many years - no one knows quite how many.
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Kelpie
Well-known member
Haha nice analogy. Maybe going with no BMS at all is a bridge too far. But it's a bit bewildering as a newbie choosing one.
E.g. is this BMS( 100A 12V BMS 4S Li-ion LiFePO4 LiFe LMO Lithium Battery Protection Circuit Board | eBay) at £6 going to do the job, or do I need to spend £250 on a 123Smart?
E.g. is this BMS( 100A 12V BMS 4S Li-ion LiFePO4 LiFe LMO Lithium Battery Protection Circuit Board | eBay) at £6 going to do the job, or do I need to spend £250 on a 123Smart?
sailaboutvic
Well-known member
The more research I do the more ways I found to cost cutting , but it all comes with a risk ,
I guess if you going to spend that type of money as chris said it's not worth cutting corners,
If I Knew more about then I may take a change with used cells , if you only got 8 year for cheap batteries that not a bad deal , but all the bottom and top balance would drive me mad plus it the balancing that I'm a bit not sure off plus there the investment of buying a charger you only going to use once and being full time liveaboard we have enough junk on board without storing more .
There lot of much cheaper BMS then the 123 although if I when to the expense of building a bank I think I too would use the BMS 123
Poey50
Well-known member
Two things in reply. First I think your questions are too high level. You need first to more basically work out what kind of lithium system to have on your boat - how all the parts of that work together safely and, as far as possible, automatically. I spent about 18 months researching before spending anything and the most useful series of articles were the 6 by Nordkyn Design which I reference near the beginning. My system has four levels from oversight to catastrophic level protection. For me that was the minimum and that has weaknesses as I have shown in different posts. It is not in the same league as Chris's system which requires little human intervention. It is said that the best systems are where people forget where they installed their LFP. Anything that needs human intervention is a weakness. If you are going to spend a lot of money on cells then you need to keep yourself safe and have a long life from your investment.
So second, I don't believe it is possible to drop safely below £1500 spend, and in the end with fully upgraded alternator charging I spent twice that. I'm happy to be proved wrong (a Zwerfcat hybrid system shows promise here) but for a permanent installation it has to have an upfront investment.
Zing
Well-known member
I’ve just ordered the CPM BMS from GWL. It looks like it will do all I need. High and low cell monitoring and a pulse to a latching relay to a cut off. No balancing, which I see as an advantage. Not too expensive either at EUR 138 plus vat. 16 cell monitoring.
