nicklee
New member
Installing a couple of lifepo4 batteries inside the main cabin, where I sleep. Are there any special ventilation requirements that I need to consider?
Batteries in the cabin
- Thread starter nicklee
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geem
Well-known member
DangerousPirate
Active member
nicklee
New member
Hahaha
Neeves
Well-known member
I have no direct experience, hence an earlier thread, but was under the distinct impression keeping the batteries cool (or not letting them become hot) was a good idea. Which is why SOME 'such' batteries are not recommended for use in motor vehicles (but maybe the advice is focussed at other 'lithium' batteries).
Hope to be educated.
On the other hand keeping all electrical devices as cool as is practicable seems a good idea.
Much might depend on what you mean when you say you are to keep the batteries where you sleep - in an enclosed location without ventilation under the berth or ......?? and may also de[end own how they are charged and used.....
You can live and learn...
Jonathan
Hope to be educated.
On the other hand keeping all electrical devices as cool as is practicable seems a good idea.
Much might depend on what you mean when you say you are to keep the batteries where you sleep - in an enclosed location without ventilation under the berth or ......?? and may also de[end own how they are charged and used.....
You can live and learn...
Jonathan
Seashoreman
Well-known member
As I presume the OP is on the British Isles I guess its pretty cool around the electrical parts these days.I have no direct experience, hence an earlier thread, but was under the distinct impression keeping the batteries cool (or not letting them become hot) was a good idea. Which is why SOME 'such' batteries are not recommended for use in motor vehicles (but maybe the advice is focussed at other 'lithium' batteries).
Hope to be educated.
On the other hand keeping all electrical devices as cool as is practicable seems a good idea.
Much might depend on what you mean when you say you are to keep the batteries where you sleep - in an enclosed location without ventilation under the berth or ......?? and may also de[end own how they are charged and used.....
You can live and learn...
Jonathan
(But of coarse I am (sort of) willing to be corrected)
geem
Well-known member
In the UK, there is no issue with unventilated lithium (lifepo4) batteries.
Out here in the Caribbean, its a different matter. The perfect temperature for lithium is around 25degC, for maximum life. We have a constant 30/31degC battery temperature here, even with mechanical ventilation. The sea is 30degC. The air temperature during the day is circa 30/31. Nothing you can do about battery temperature here without battery cooling. A future project
We ventilate the lead battery box and the lithium battery box. We have 4 computer fans, in total, doing the ventilation. We would turn them all off in the UK
Seashoreman
Well-known member
In the UK, there is no issue with unventilated lithium (lifepo4) batteries.
Out here in the Caribbean, its a different matter. The perfect temperature for lithium is around 25degC, for maximum life. We have a constant 30/31degC battery temperature here, even with mechanical ventilation. The sea is 30degC. The air temperature during the day is circa 30/31. Nothing you can do about battery temperature here without battery cooling. A future project
We ventilate the lead battery box and the lithium battery box. We have 4 computer fans, in total, doing the ventilation. We would turn them all off in the UK
You, Boy, is it Summer or Winter?
Neeves
Well-known member
In the UK, there is no issue with unventilated lithium (lifepo4) batteries.
Out here in the Caribbean, its a different matter. The perfect temperature for lithium is around 25degC, for maximum life. We have a constant 30/31degC battery temperature here, even with mechanical ventilation. The sea is 30degC. The air temperature during the day is circa 30/31. Nothing you can do about battery temperature here without battery cooling. A future project
We ventilate the lead battery box and the lithium battery box. We have 4 computer fans, in total, doing the ventilation. We would turn them all off in the UK
In our current project/investigation we will factor in computer fans in the same way we use extra computer fans for our refrigeration/deep freeze. These computer fans are wired into the compressor wiring and only operate when the compressor operates. We duct cool air from the anchor locker, which always faces to windward, for the fridge and route the warm air from the compressors into the ventilated engine bay. I'll add to the ducting and add a route to the battery location. Temperatures, air and water, in our tropics are not much different to those that Geem enjoys, in Sydney air temps can reach mid 30s but water temps are, historically, mid to low 20s. Reading and watching of current European/med temps make me think adding, at least, computer fans to any, 'lithium', design might be a precautionary act. Most batteries, or any type, that I see are located in, effectively, un ventilated spaces
Computer fans draw very little and come in a variety of sizes from having 3cm - 15cm housings (and probably larger). I happen to have 2 x 15cm housings 'spare' and looking for a home and I may simply use one.
Jonathan
lustyd
Well-known member
The heat of Lithium isn't always due to ambient temps. While charging them hard they will get hot and should have some ventilation regardless of geography.
The issue in the UK is winters where you'd want a heat pad either built in or installed below them to gently warm them.
geem
Well-known member
Of course, but in the UK with water temperatures is in the teens, Charging with solar really doesn't create much heat in the lithium. The boat is naturally fairly cool.
The internal resistance is so low that they don't create much heat unless you are charging at very high amps. To do this, you need a high output alternator and smart regulator. Most people don't go this route as it carries about a £1500 price tag. Charging from a B2B or even two of them, really doesn't heat the batteries up much.
An hour long motor a couple of days ago saw us putting about 1400w in to the lithium with no measurable increase in battery cell temperature
The BMS is the main source of heat. I don't like drop in replacement batteries for this reason. Locating the BMS inside a sealed box in close contact with some of the battery cells is not a good idea for long term battery life.
Monitoring my installation, the cells don't go above 31/32 when being discharged at circa 2kw. The BMS, however will hit 40degC fairly quickly. This is in an ambient air temperature of 30 degC.
If you are UK based with an ambient of 15degC there is little to worry about with charging in most applications. Unless you are installing a very large alternator
lustyd
Well-known member
Not everyone is a liveaboard don't forget. Alternator + solar can be capable of generating heat but add in an over-specced shore charger and there could be a lot of heat damaging the cells. It's not that unusual to over-rate a charger to bring charge times down with Lithium.
The problem isn't that the cells overheat, it's that when warm they degrade faster and can produce gas, so in any circumstances it's better to do what you can to keep them in the goldilocks zone.
I don't disagree with your general point, I think you're probably right that in the UK they'll usually be fine. It could be misleading to people who don't understand the subject though so I thought worth adding some extra detail.
The problem isn't that the cells overheat, it's that when warm they degrade faster and can produce gas, so in any circumstances it's better to do what you can to keep them in the goldilocks zone.
I don't disagree with your general point, I think you're probably right that in the UK they'll usually be fine. It could be misleading to people who don't understand the subject though so I thought worth adding some extra detail.
geem
Well-known member
Very few people over size chargers. They are expensive. Most people who have a legacy charger for their lead batteries will have sized them for lead. Apart from the fact that most have an inappropriate charge profile, they are inherently smaller than you can use on lithium. Very unlikely anybody will have an oversized lithium shorepower charger. If you were to install a very small lithium battery and a very large shorepower charger then yes, you could run high amps, but even so, lithium has a very low internal resistance. They won't heat up as much as a similar sized lead battery.
They don't gas unless they in failing unlike a lead battery that gases when charging
lustyd
Well-known member
I think you may be viewing the world through your own experience. Chargers are not that expensive and the difference between appropriate and oversized isn't very much in the grand scheme of lithium installs. When specifying devices like Multiplus it would be pretty easy to overspec based on AC needs and end up with hundreds of amps of charge capacity. Add in a 1KW solar array giving you ~80A additional input and you'll certainly be getting warm batteries.
Neeves
Well-known member
An example of why thread drift can be useful.
The OP has not provided enough information for anyone to offer a single concise answer to his question as we have no idea where he sails nor how big his 'Lithium' house battery and might be nor how he is charging this resource. I suspect the OP has not made a search and has no idea of the wealth of information that you both, Lusty/Geem, have posted and have no idea of your details.
I did wonder, based on Geem's posts, if conditions in a nicely sheltered Med marina might not be similar (or worse) for the OP to Geem's Caribbean environment.
Its all here if you are prepared to search.
Jonathan
The OP has not provided enough information for anyone to offer a single concise answer to his question as we have no idea where he sails nor how big his 'Lithium' house battery and might be nor how he is charging this resource. I suspect the OP has not made a search and has no idea of the wealth of information that you both, Lusty/Geem, have posted and have no idea of your details.
I did wonder, based on Geem's posts, if conditions in a nicely sheltered Med marina might not be similar (or worse) for the OP to Geem's Caribbean environment.
Its all here if you are prepared to search.
Jonathan
geem
Well-known member
Do you have lithium? If you install small lithium batteries with their own BMS, in parallel, they share the load. They don't get hot. Lithium batteries have charging parameters, just like lead. If you want to exceed manufacturers recommendations, that's an entirely different thread
ean_p
Well-known member
Have you a link to info that shows the extent of the impact of increasing temperatures on the well being of the cells please Geem.In the UK, there is no issue with unventilated lithium (lifepo4) batteries.
Out here in the Caribbean, its a different matter. The perfect temperature for lithium is around 25degC, for maximum life. We have a constant 30/31degC battery temperature here, even with mechanical ventilation. The sea is 30degC. The air temperature during the day is circa 30/31. Nothing you can do about battery temperature here without battery cooling. A future project
We ventilate the lead battery box and the lithium battery box. We have 4 computer fans, in total, doing the ventilation. We would turn them all off in the UK
I've seen plenty detailing the reduction in life cycles with increased cycle use % but not seen any detail on the 'effects' of use in temperatures above 30 degree etc just oem statements around operational temps being for example -20 to +60 degrees etc...
geem
Well-known member
ean_p
Well-known member
Mmmm yes that study really put it in to context and tends to imply that high ambient locker temperatures may be as impactful as 100% cycling regimes on cell life expectancy etc... thanks for the info!
geem
Well-known member
Are you UK based?
I can't see it being a problem if you battery box benefits from cooling from the hull. My battery box is under the saloon seat on the starboard side. We have our old lead bank and the new lithium battery adjacent, in seperate boxes. The lead bank( 4xTrojan T105RE) are on permanent float by vertue of a Victron orion. Ditto the generator battery. They sit at a constant 30degC. The lithium battery is being charged by solar, up to 28A at 24v and being discharged at upto 1800w when running the watermaker, immersion heater or induction hob. The ambient air temperature today is 30degC and the water temperature is the same. Current lithium battery temperature is 31degC just after midday. It will drop to about 30degC over night if I leave the little computer fan running. The BMS does get hotter. It goes up to circa 40degC when we are cooking or making water. If you use drop in batteries with the BMS in the battery case, then the heat from the BMS will heat the battery cells. This may hold the battery temperature up more than a DIY battery where the BMS is in a larger box and there is an opportunity for heat to be lost to the surroundings.
When I was using my Trojans as the main house bank, in this hot environment, they would often hit 35degC under normal solar charging unless I left the battery box lid off. They would still hit 33degC. The low resistance of lithium really helps
