270ah DIY LiFePO4 build

[Zing]

Ignition protection refers to the avoidance of sparks and is relevant to environments with potentially explosive fuel-air mixtures. So an engine compartment with a petrol engine, for example but, on a boat also LPG leaks, petrol fumes from spare cans for outboard, hydrogen from overcharging lead acid are possibilities. But Blue Sea Class T are now ignition protected.

Surely you had better get an ignition protected starter motor and solenoid before you start to worry about the fuse. They will spark up on every engine start and are located in a great place for a propane bomb.

 

[noelex]

But Blue Sea Class T are now ignition protected.

That is good news.

Have you a link? I cannot find anything on the BlueSea website about the new classification and approval.

 

[Poey50]

That is good news.

Have you a link? I cannot find anything on the BlueSea website about the new classification and approval.

I stumbled on it on this site. Scroll down for the description. Blue Sea Systems 5502100 Ignition Protected Class-T Fuse Block 225-400A

 

[Poey50]

Surely you had better get an ignition protected starter motor and solenoid before you start to worry about the fuse. They are spark up on every engine start and are located in a great place for a propane bomb.

I'm not worried about it .. my fuse is well away from sources of gas. Unless there's a catastrophe.

 

[Pete7]

Surely you had better get an ignition protected starter motor and solenoid before you start to worry about the fuse. They will spark up on every engine start and are located in a great place for a propane bomb.

The engine is a Volvo Penta diesel. There is a gas detector under the cooker. Small petrol can stored in the cockpit with permanent drains overboard above the waterline.

Is the risk any higher than the tens of thousands of boats with lead acid batteries in the UK?

Pete

 

[noelex]

I stumbled on it on this site. Scroll down for the description. Blue Sea Systems 5502100 Ignition Protected Class-T Fuse Block 225-400A

Thanks for the link. That will be a useful option for some installations.

The max fuse size of 300A and the requirement for 2 x 4/0 awg cable size ((the metric equivalent of 4/0 is 120 mm squared) required to meet the IP rating is a limitation, but there are few choices for fuses with a very high interrupt rating that also have an IP rating.

This is not a great issue with most lead acid battery systems, fuses such as ANL are IP rated and generally have a sufficiently high interrupt rating. A lithium battery system generally requires a much higher interrupt rating.

Boat power systems have become much more sophisticated in recent years, especially in the areas of battery technology and high voltage solar panels. These new systems require more care. Details such as the interrupt rating of circuit protection devices and the voltage rating of switching devices is sometimes wrongly ignored.

 

[Poey50]

The engine is a Volvo Penta diesel. There is a gas detector under the cooker. Small petrol can stored in the cockpit with permanent drains overboard above the waterline.

Is the risk any higher than the tens of thousands of boats with lead acid batteries in the UK?

Pete

I've neither advocated nor argued against the main fuse being ignition protected. I already had my Class T fuse on order before I knew. Noelex enquired about it so I passed on what I knew. But am I pleased that there is one less source of ignition? Yes. Every little helps.

 

[Zing]

The engine is a Volvo Penta diesel. There is a gas detector under the cooker. Small petrol can stored in the cockpit with permanent drains overboard above the waterline.

Is the risk any higher than the tens of thousands of boats with lead acid batteries in the UK?

Pete

My point wasn't to comment on your risk of explosion compared to everyone else, just to suggest that having an ignition protected fuse was less of a priority than having protection for other flame sources.

That said, in respect of risk mitigation you don't mention a gas solenoid, which may well be a good thing to fit.

 

[Kelpie]

I've neither advocated nor argued against the main fuse being ignition protected. I already had my Class T fuse on order before I knew. Noelex enquired about it so I passed on what I knew. But am I pleased that there is one less source of ignition? Yes. Every little helps.

David, did you ever get your Class T fuse? Cactus just told me it would be another month, by which time I should be out of the country. So I've gone with a Victron ANL fuse instead as the next best option, and one that I could actually buy in time.

I did email Victron to ask about the AIC but they weren't able to provide your information, which is a bit disappointing.

 

[Poey50]

David, did you ever get your Class T fuse? Cactus just told me it would be another month, by which time I should be out of the country. So I've gone with a Victron ANL fuse instead as the next best option, and one that I could actually buy in time.

I did email Victron to ask about the AIC but they weren't able to provide your information, which is a bit disappointing.

Mine is said to be coming in after July 27th but I'm not holding my breath. I'm currently using Blue Sea MRBFs which are not a particular concern so don't mind waiting.

On a separate (LFP) topic for anyone else like Vic who is using the 123SmartBMS I have found that the separate boards on each cell does require me to fully charge about once per month to keep everything balanced. Having seen this video from the enjoyable Offgrid Garage series I've bought one of these active balancers which I'll install at the same time as the Class T fuse upgrade. That should enable me to stay around 85-90% SOC and remain balanced.

 

[Poey50]

This, from Ran Sailing, is what a top-quality DIY LFP build looks like using the fully-featured X2 BMS. His previous video covers more of the basics.

 

[vas]

thanks Poey!
shocked to hear the BMS he uses costs 2.5k USD though...
I guess he uses 180Ah prismatic cells, wonder why he didn't go for 280Ah and skip all these connections.
slowly sketching my system after 3 weeks onboard and still stuck on my Victron inverter charger having a single 24V point - not differentiating charge with load :-(

 

[Poey50]

thanks Poey!
shocked to hear the BMS he uses costs 2.5k USD though...
I guess he uses 180Ah prismatic cells, wonder why he didn't go for 280Ah and skip all these connections.
slowly sketching my system after 3 weeks onboard and still stuck on my Victron inverter charger having a single 24V point - not differentiating charge with load :-(

I think he must have got a Swedish mates-rates on the BMS!

Yes, bigger cells to avoid parallel pairs would have been better but cell sizes to fit available spaces may be the deciding factor.

They certainly aren't short of a bob or two. But a lovely build.

Good luck with yours!

 

[mitiempo]

I guess he uses 180Ah prismatic cells, wonder why he didn't go for 280Ah and skip all these connections.

Nordkyn advises that cells for marine use should be no larger than 200 AH for reasons of robustness.
The reason I am using Calb CA180 in 2P4S configuration.

 

[vas]

interesting, robustness in what sense exactly? not in terms of the physical properties of the enclosures I guess.
for a 24V bank that means 16cells, not at all keen if all I want is keep the costs low and size/complications minimal.

I was really expecting prices to drop, but not seen it. Keen to order batteries from the EU and avoid the Greek customs hassle, guess have to wait for after xmas

 

[mitiempo]

and still stuck on my Victron inverter charger having a single 24V point - not differentiating charge with load :-(

Your BMS can control Victron Multiplus inverter/chargers Inverter and charger separately. As far as I know Victron is the only one to allow this.

 

[mitiempo]

interesting, robustness in what sense exactly? not in terms of the physical properties of the enclosures I guess.
for a 24V bank that means 16cells, not at all keen if all I want is keep the costs low and size/complications minimal.

I was really expecting prices to drop, but not seen it. Keen to order batteries from the EU and avoid the Greek customs hassle, guess have to wait for after xmas

It is a lot of cells for 24 volts.

As far as prices buy from a major Chinese distributor instead of a retailer that just adds profit for themselves.
Lythbattery.Com is who I deal with -on second order now. Prices less than half that of US retailers.

 

[vas]

will have another look, mine is an early Multiplus without even the VE.Bus connection, so I doubt it, but will check. You mean as in changing the Multiplus setup to charge only, charge/invert or invert only I guess?

 

[Poey50]

Nordkyn advises that cells for marine use should be no larger than 200 AH for reasons of robustness.
The reason I am using Calb CA180 in 2P4S configuration.

This has been discussed a lot on various forums. Nordkyn is often quoted but provides no data, as far as I am aware. On the other side of the argument are many who are using much larger Winston cells up to 1000ah without apparent problems. Paralleling two cells to be monitored as one does have a downside compared to individual cell monitoring so I think the trend is to go 4S for 12 volt and 8S for 24 volt although physical space may have the final say as it does for Ran, I think.

 

[Poey50]

It is a lot of cells for 24 volts.

As far as prices buy from a major Chinese distributor instead of a retailer that just adds profit for themselves.
Lythbattery.Com is who I deal with -on second order now. Prices less than half that of US retailers.

Yes, quite a few people on the big Lithium Batteries on a Boat Facebook group have a direct factory contact in China for Winston cells.