Poey50
Well-known member
Can you give links to fuse and holder?
270ah DIY LiFePO4 build
- Thread starter Poey50
- Start date
Can you give links to fuse and holder?
Zing
Well-known member
I just searched for NH fuses between 100 and 400A. You will need to study the peak current rating and certifications too. Farnell has a better filter search I think.
Centred Tag Fuses | RS Components
Also try Farnell and Mouser etc.
Poey50
Well-known member
I think you gave those links before. I'm not clear on the holding arrangements and that was what informed my decision to go with Class T.
Zing
Well-known member
It sounds like you are already sorted out, but this website I just found is pretty good with links to further info on holders etc. Start here and browse:
NH Fuses Explained
Poey50
Well-known member
I'm sorted but others are likely to be interested in alternatives.
mitiempo
Member
No mention of amp interrupt rating that I can see. That is the main advantage of class T fuses @ 20,000 amps
Zing
Well-known member
You need to look at the datasheets. See here and follow the links. Those are rated to 30kA at DC voltages.
Swe-Check sell Battery Protection Fuses. Low Prices. Fast delivery.
Alan S
Well-known member
How about an HRC (high fupturing capacity) eg Bussman 100LET
Farnell have them ln stock for unde £20.
Interrupt rating is 200kA if I am reading the data sheet correctly.
Farnell have them ln stock for unde £20.
Interrupt rating is 200kA if I am reading the data sheet correctly.
gregcope
Well-known member
Rereading this thread and I have this in my notes @vas
Storage of LIFEPO batteries in my RV
This person is using two profiles on their victron kit for storage and use. Not sure if you can have more (Storage, Use, FullCharge).
Poey50
Well-known member
I recently came across this method of using drop-ins which avoids the sudden loss of power through BMS disconnect (and dangers to the alternator, marine electronics and boat safety) but allows charging through alternator and external regulator and keeps the lead acid start battery charged. The device itself is available though Rod Collin's firm - Compass Marine. Sadly Rod has recently had a stroke so the business seems out of action for the moment but the method is food for thought for anyone considering drop-ins. The wiring diagram is very clear.
Load Dump Stay Alive Protection Solenoid Manual.pdf
Load Dump Stay Alive Protection Solenoid Manual.pdf
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Pete7
Well-known member
Looks like a contactor. I have one which I am thinking of using rather than a battery master switch to isolate the LFP when not on board. There are several types including temporary and sustained connections. Alternatively just stick an AGM battery in parallel with the LFP.
12v contactor - Google Search
vas
Well-known member
it also looks like a simple contactor to me as well... Are we missing something?
I'm afraid text was way too boring to read and started skipping bits after the second page.
Also even less relevant to a twin screw mobo with starter bank charged from different engine to service bank (and which are only bridged in emergency via a similar contactor to start the engines when engine bank is dead).
I'm afraid text was way too boring to read and started skipping bits after the second page.
Also even less relevant to a twin screw mobo with starter bank charged from different engine to service bank (and which are only bridged in emergency via a similar contactor to start the engines when engine bank is dead).
JohnGC
Active member
Looks rather like one of these.
Trombetta 684-1221-212-02 12V Powerseal DC Contactor, 150A | Waytek
Trombetta 684-1221-212-02 12V Powerseal DC Contactor, 150A | Waytek
Poey50
Well-known member
I haven't looked at it closely as I won't be going down that road but it seems to me that a certain amount of effort has been put in to speccing it for the particular job. Mr Collins does take a fair amount of care over these matters. It is another automatic solution to LFP being taken offline by the BMS and avoiding a load dump. It is cheaper than a B2B for maintaining the start battery. It is not a simple contactor.
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Poey50
Well-known member
The idea of hybrid systems has come up a few times. The appeal is that it is one of the only safe ways of using drop-ins (since there is always a battery left in the system in the event of a BMS disconnect) and that not all lead acid batteries need to be switched over to LFP. The downside has always been the problem of ensuring that the lead acid gets an adequate charge because of the differing charging needs. So this development be of interest to some. Expect other similar gizmos to come on the market as LFP prices drop,
Emily & Clark's Adventure - BBMS System
Emily & Clark's Adventure - BBMS System
Kelpie
Well-known member
If I'm understanding correctly, the other downside of a hybrid/parallel system is that the BMS will have to work a lot harder. It's no longer just a failsafe mechanism in this kind of setup.
Pete7
Well-known member
Are you thinking generally or referring to the video Clark posted last night?
Kelpie
Well-known member
General comment about systems where LFP and lead acid are wired permanently in parallel.
The Clark system is interesting, but I did raise an eyebrow where they say "a BMS will not prevent overcharging". It can and it does. Best practice is to have the charging sources themselves cut off but a functioning BMS will disconnect in event of overcharge.
Poey50
Well-known member
The Zwerfcat hybrid model works that way but, my understanding of this proposed system is that the device itself controls charging not the BMS but it wasn't completely clear. I thought there was some slightly misleading description of how alternators operate - as if they all the ability to drop into float. Most are dumb and have a single regulated voltage. The other problem that I can see for drop-ins is his most recent gizmo is that selecting of charging between say 20 and 80%, while good for longevity, may be problematic for balance. Battleborn advise charging regularly to full in order to keep cells in balance and without this there is effective loss of capacity since one cell may hit full well before the others. In fairness he does mention that drop-ins will need to be charged to full from time to time but it will require those using the system to be fully aware of the needs of their batteries. Not all drop-ins supply good information and not all drop-in owners are likely to be interested.
Charge controllers operating on amperage rather than voltage does seem a very good idea for LFP and is the reason why the Wakespeed 500 seems to be the external regulator of choice for more sophisticated systems - at least for those who have £500 approx to spend. Unfortunately not me - but the Balmar MC614 is no slouch.
I think well-built DIY systems are still the way to go for most who want to change to LFP but this certainly has some promise.
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sailaboutvic
Well-known member
I've posted several graft showing how well my 400ah lithium bank been work thought out the summer since April .
There only been twice or three time I had to used the B2B to help charge the batteries these have been on cloudy days when we didn an over night sail ,
the rest of the time my 750W panels have kept them up every day without a problem , if anything we had tons of power to waste .
It's now the end of sept and here in the Med , we had six days of overcast weather in a row,
As you can see from the latest graft each day the batteries have got lower to a point of 35% ,
We been at anchor over this time .
We expecting a full day of sun to day so with a bit of luck we will replace the 200A we need , as well as our Daly uses so the batteries will be back to 98% by the end of the day .
Our consumption is high with freezer and fridge going to 24/7 add to that microwaves,kettle , induction hob and heating the hot water when we have power to waste.
Having some way to replace the power used on several days of cloudy weather is some thing that need to be thought about carefully ,
The option are a much bigger bank of a faster charger.
Yes using less power would help but if your as we are full time cruisers using less power can be difficult for us the only option is to use the gas and not use the induction hob or the kettle for them without gas there is no options .
Another day of overcast and I guess we would need to turn on the Gen and at only 30a input through our B2B , seen a waste of fuel , as it will be a very long time to replace 300A especially when at the same time using the very less 7A . Stick the kettle or induction hob on for 15 mins and see the amps diminish .
So we see how the next few months go and then decide if we need to add another charger to boost the charge when we using the Gen for less running time .
There only been twice or three time I had to used the B2B to help charge the batteries these have been on cloudy days when we didn an over night sail ,
the rest of the time my 750W panels have kept them up every day without a problem , if anything we had tons of power to waste .
It's now the end of sept and here in the Med , we had six days of overcast weather in a row,
As you can see from the latest graft each day the batteries have got lower to a point of 35% ,
We been at anchor over this time .
We expecting a full day of sun to day so with a bit of luck we will replace the 200A we need , as well as our Daly uses so the batteries will be back to 98% by the end of the day .
Our consumption is high with freezer and fridge going to 24/7 add to that microwaves,kettle , induction hob and heating the hot water when we have power to waste.
Having some way to replace the power used on several days of cloudy weather is some thing that need to be thought about carefully ,
The option are a much bigger bank of a faster charger.
Yes using less power would help but if your as we are full time cruisers using less power can be difficult for us the only option is to use the gas and not use the induction hob or the kettle for them without gas there is no options .
Another day of overcast and I guess we would need to turn on the Gen and at only 30a input through our B2B , seen a waste of fuel , as it will be a very long time to replace 300A especially when at the same time using the very less 7A . Stick the kettle or induction hob on for 15 mins and see the amps diminish .
So we see how the next few months go and then decide if we need to add another charger to boost the charge when we using the Gen for less running time .
