Lithium Batteries - Life Cycles Vs Discharge Levels

[peterboat]

4 minutes ago, cuthound said:

 

Good point.

 

How do our friends with DIY lithiums cope with this, other than by putting the  batteries inside a heated cabin?

 

What happens if they have to leave the boat in the middle of a cold snap and it is still below freezing when they return? Presumably wait until the boat warms up?

 

Do proprietary systems use the BMS to prevent the batteries being charged if The temperature is below 5°C? If so putting the batteries in the engine bay could work with lithiums on a leisure, rather than liveaboard boat.

Mine are 2 and a half foot below the waterline where it doesnt normally freeze, they are for drive so I suppose if its frozen on top I wont be needing my batteries to move the boat or charge them.

[cuthound]

12 minutes ago, peterboat said:

Mine are 2 and a half foot below the waterline where it doesnt normally freeze, they are for drive so I suppose if its frozen on top I wont be needing my batteries to move the boat or charge them.

 

I'd have to screw mine to the bottom of the hull to get them that deep! ?

[peterboat]

8 minutes ago, cuthound said:

 

I'd have to screw mine to the bottom of the hull to get them that deep! ?

Might be less now I have taken the engine out ?

[Alan de Enfield]

30 minutes ago, cuthound said:

How do our friends with DIY lithiums cope with this, other than by putting the  batteries inside a heated cabin?

 

What happens if they have to leave the boat in the middle of a cold snap and it is still below freezing when they return? Presumably wait until the boat warms up?

Reading up on this point - Electric cars have a battery heating system that appears to switch on as the temperature drops (powering the heater themselves)

[Dr Bob]

4 hours ago, WotEver said:

iii) They can operate down to negative Celsius. 

The link Ian gave us says that they can only be charged above 0deg C. Same as LiFePo4s.

I had not heard that one before. 

What else don't we know about these batteries? Lots of positive spin from sellers but NO info from anyone's who has used them. It sounds like they are drop in solutions.......but has anyone real experience? 

[peterboat]

2 minutes ago, Dr Bob said:

The link Ian gave us says that they can only be charged above 0deg C. Same as LiFePo4s.

I had not heard that one before. 

What else don't we know about these batteries? Lots of positive spin from sellers but NO info from anyone's who has used them. It sounds like they are drop in solutions.......but has anyone real experience? 

I have found leoch versions of them, trouble is they are the same price as my secondhand LifePo4s so they are pointless to me

[Dr Bob]

3 hours ago, cuthound said:

 

Good point.

 

How do our friends with DIY lithiums cope with this, other than by putting the  batteries inside a heated cabin?

 

What happens if they have to leave the boat in the middle of a cold snap and it is still below freezing when they return? Presumably wait until the boat warms up?

 

Do proprietary systems use the BMS to prevent the batteries being charged if The temperature is below 5°C? If so putting the batteries in the engine bay could work with lithiums on a leisure, rather than liveaboard boat.

Mine are under the bed. Don't forget, LiFePo4's are much smaller than LAs so will fit in much smaller spaces. 

My system auto disconnects at 3deg C and switches to LA only. I will turn the LI's off when I leave the boat anyway. 

[peterboat]

3 hours ago, Alan de Enfield said:

Reading up on this point - Electric cars have a battery heating system that appears to switch on as the temperature drops (powering the heater themselves)

The aircon on some electric cars runs through the batteries as well to cool them down when charging

[WotEver]

9 hours ago, Dr Bob said:

The link Ian gave us says that they can only be charged above 0deg C. 

According to my reading in the past this is incorrect. In fact Battery University directly contradicts that:

”Although larger and heavier than Li-ion, the ALC is low-cost, operates at subfreezing temperatures and does not need active cooling”

https://batteryuniversity.com/learn/article/new_lead_acid_systems

 

[WotEver]

 

That article concludes with the somewhat amusing observation that...

”Battery experts believe that the core limitation of the lead acid battery is the utilization of lead.”

 

Well, yeah...

[nicknorman]

16 minutes ago, WotEver said:

According to my reading in the past this is incorrect. In fact Battery University directly contradicts that:

”Although larger and heavier than Li-ion, the ALC is low-cost, operates at subfreezing temperatures and does not need active cooling”

https://batteryuniversity.com/learn/article/new_lead_acid_systems

 

I think the most relevant point is that it compares the discharge voltage with that of a supercapacitor. In other words, a large and linear decline in voltage as the battery discharges.

[Dr Bob]

1 hour ago, WotEver said:

According to my reading in the past this is incorrect. In fact Battery University directly contradicts that:

”Although larger and heavier than Li-ion, the ALC is low-cost, operates at subfreezing temperatures and does not need active cooling”

https://batteryuniversity.com/learn/article/new_lead_acid_systems

 

That's what I thought too. The data sheet does give a charging range above 0°C.

David from 'Cruising the cut' put 3 lead carbons in a month ago and he found it difficult to get info on absorption and float voltages....so even that data seems sparse. He wont be much help in understanding how they get on as he has no battery monitoring stuff.

[Alan de Enfield]

http://ipwr.net/lead-carbon-batteries/

 

Advantages of Lead Carbon batteries versus Lithium batteries and Lead-Acid:

• No BMS (Battery Management System) is needed to prevent over-charging and under-charging on a per cell basis.
• No thermal run-away risk of individual cells overheating, exploding, and burning.
• Much greater kW storage capacity per dollar compared with lithium. Approximately twice the storage capacity, or about half the price for the same kW capacity.
• Easy to carry modular system where each battery can be carried and put in place, without needing any lifting equipment.
• Suitable for On-Grid Hybrid and Off-Grid systems due to high discharge amperage capacity.  
• No Cooling fans/system needed for lead-carbon batteries.
• Much higher energy density and longer life in the same size (or smaller) package compared with existing AGM / GEL and Flooded Lead Acid Batteries.  
• No harmful and toxic gases coming off lead-carbon batteries.

[IanD]

3 hours ago, nicknorman said:

I think the most relevant point is that it compares the discharge voltage with that of a supercapacitor. In other words, a large and linear decline in voltage as the battery discharges.

The discharge curve on the Ritar datasheet doesn't show this, it's a normal LA-type curve down to 1.75V/cell (10.5V) defined as fully discharged.

 

They look like an excellent solution for narrowboats, but the key will be price -- as peterboat said the ones from Leoch/Northstar/Victron are expensive, but I suspect that's what they think the market will pay for a "new battery technology" not the manufacturing cost.

 

The way to find out if for somebody who's interested in trying them to get a quote direct from Ritar for the 12V 175Ah battery -- for example, 8-off to build a 48V 350Ah or 12V 1400Ah bank -- and see how this compares to the cheapest Victron price (£460 inc VAT for the identical 12V 160Ah cell).

Edited July 10, 2019 by IanD

[WotEver]

3 hours ago, nicknorman said:

I think the most relevant point is that it compares the discharge voltage with that of a supercapacitor. In other words, a large and linear decline in voltage as the battery discharges.

Although that’s not much of a problem for the majority of on board stuff which couldn’t care less what the exact voltage is. Besides, other curves around the web appear to show much more conventional discharge curves. 

[peterboat]

2 hours ago, IanD said:

The discharge curve on the Ritar datasheet doesn't show this, it's a normal LA-type curve down to 1.75V/cell (10.5V) defined as fully discharged.

 

They look like an excellent solution for narrowboats, but the key will be price -- as peterboat said the ones from Leoch/Northstar/Victron are expensive, but I suspect that's what they think the market will pay for a "new battery technology" not the manufacturing cost.

 

The way to find out if for somebody who's interested in trying them to get a quote direct from Ritar for the 12V 175Ah battery -- for example, 8-off to build a 48V 350Ah or 12V 1400Ah bank -- and see how this compares to the cheapest Victron price (£460 inc VAT for the identical 12V 160Ah cell).

I will have a chat with Neil at hellerby batteries and see what they say, they supply to forklifts cherry pickers etc so they will be able to buy  at a good price I would think