Canal water temperature

[booke23]

This is a random question, but does anybody monitor the temperature of the canal water? If so is it fairly stable or does follow the air temperature (obviously lagging behind quite a bit I imagine) and get quite variable?  

[Tony Brooks]

12 minutes ago, booke23 said:

This is a random question, but does anybody monitor the temperature of the canal water? If so is it fairly stable or does follow the air temperature (obviously lagging behind quite a bit I imagine) and get quite variable?  

 

As it is sometimes warm to the touch in summer and frozen so solid boats can't eve rock as you walk about it is very variable. Canal tend to be shallow compared with rivers so can heat faster.

[booke23]

Yes that makes sense @Tony Brooks. My lithium battery sits on the Uxter plate, and when I was at the boat yesterday despite the air temperature being 8 degrees C the Lithium battery was only 3 degrees C (and therefore couldn't be charged as it was below 5 degrees C). I surmised the water was still very cold from the recent cold spell and so the battery was effectively being chilled from below. I'm pondering cutting a piece of Celotex or similar and putting the battery on that.

[Detling]

the water below about 6 inches is almost always above freezing and doesn't really go below 4 degrees, due to the laws of physics. In a hot summer the top few inches can reach into the 20's but more normally the upper teens.  The air temperature inside the boat/engine hole on a cruiser stern can go low enough for the diesel in the filter to wax (about -10) as I found out a few years ago.

 

Insulation does not warm things up, it merely slows the rate of temperature change both up and down. For your batteries look at putting them on or wrapping them in carbon heat mats, sold to keep food warm, and seedling germination loads available a lot are 12 volt. Just turn on before you want to charge the batteries. Insulation outside to keep the heat in.

[ditchcrawler]

2 minutes ago, Detling said:

 Insulation does not warm things up, it merely slows the rate of temperature change both up and down. For your batteries look at putting them on or wrapping them in carbon heat mats, sold to keep food warm, and seedling germination loads available a lot are 12 volt. Just turn on before you want to charge the batteries. Insulation outside to keep the heat in.

So many don't understand that

[booke23]

5 minutes ago, Detling said:

Insulation does not warm things up, it merely slows the rate of temperature change both up and down.

 

Exactly. Which is why I'm considering a layer of insulation under the battery. That way I wouldn't be faced with the situation of the battery being kept cold by the Uxter plate while the air temperature is above the required temperature for charging. 

[Alan de Enfield]

28 minutes ago, booke23 said:

the Lithium battery was only 3 degrees C (and therefore couldn't be charged as it was below 5 degrees C)

 

 

New edition of the big book of excuses - No 683 :

.................. sorry C&RT I know I have been on the 48 hour mooring for 3 days but is is too cold to charge my batteries

[BEngo]

I would be surprised if your Li battery cannot be charged at all at 3deg C.  Usually they can accept a low rate of charge.  The need is to harge slowly enough to get the charge reactions going, but not the permanently damaging Li plating reaction.

 

There are some examples of acceptable  low temperature charge rates in the Li BMS thread.

 

N

 

 

[booke23]

2 minutes ago, Alan de Enfield said:

New edition of the big book of excuses - No 683 :

.................. sorry C&RT I know I have been on the 48 hour mooring for 3 days but is is too cold to charge my batteries

 

I hope not!....I think most lithium users still have a lead acid starter battery so no excuse not to get the engine running.

 

3 minutes ago, BEngo said:

I would be surprised if your Li battery cannot be charged at all at 3deg C.  Usually they can accept a low rate of charge.  The need is to harge slowly enough to get the charge reactions going, but not the permanently damaging Li plating reaction.

 

There are some examples of acceptable  low temperature charge rates in the Li BMS thread.

 

N

 

 

 

Possibly, but Victron say don't do it below 5 Degrees!

[roland elsdon]

So if I had spent a fortune on lithium batteries I would have to disconnect them from the solar in winter, as my engine room can easily get get below 5 degrees in a cold snap.

Yet another good reason not to buy them.

[nicknorman]

15 minutes ago, roland elsdon said:

So if I had spent a fortune on lithium batteries I would have to disconnect them from the solar in winter, as my engine room can easily get get below 5 degrees in a cold snap.

Yet another good reason not to buy them.

The reality is that li batteries can be charged normally down to 0C and they can be charged very slowly at -20C, and on a sliding scale in between. Victron are playing it safe by limiting charging to 5C. The other thing to consider is that many people install the Li batteries in habitable (heated) space, since unlike LA batteries there is no risk of nasty gases coming off the batteries.

55 minutes ago, BEngo said:

I would be surprised if your Li battery cannot be charged at all at 3deg C.  Usually they can accept a low rate of charge.  The need is to harge slowly enough to get the charge reactions going, but not the permanently damaging Li plating reaction.

 

There are some examples of acceptable  low temperature charge rates in the Li BMS thread.

 

N

 

It seems the built in BMS disallows charging below 5C. Apparently you can change that to a lower temperature but the warranty is voided.

[nicknorman]

I recently bought this stuff, yet to install it but it seems good…

 

https://www.ebay.co.uk/itm/263094394766

[booke23]

40 minutes ago, roland elsdon said:

So if I had spent a fortune on lithium batteries I would have to disconnect them from the solar in winter, as my engine room can easily get get below 5 degrees in a cold snap.

Yet another good reason not to buy them.

Not quite. The BMS does this automatically! But it's usually only overnight that the temperature drops too low for charging when your solar is doing nothing anyway. 

Although I have lithiums, they were fitted by the previous owner. I am still on the fence about them. The low temperature thing is an irritation, however I am a leisure boater so it doesn't trouble me too much and It could be easily fixed if I lived aboard (by moving it into the boat as @nicknorman suggests). Charging them directly from an alternator is problematic as they are designed for lead acid batteries. Equipment to rectify this is pricy. (hence why most still have a lead acid battery to get around the alternator problem)

However their quoted capacity in AH is fully useable unlike a lead acid battery and with the correct setup they can be charged from flat to full in 2hrs, something you definitely can't do with lead acids. Pros and cons. I think on balance for me they are worth it, especially as someone else forked out for the conversion!!

[MtB]

2 hours ago, Alan de Enfield said:

 

 

New edition of the big book of excuses - No 683 :

.................. sorry C&RT I know I have been on the 48 hour mooring for 3 days but is is too cold to charge my batteries

 

Eh? 

 

Somebody here was on the 48hr moorings for about nine months before moving off. 

 

Promptly replaced by a near-identical boat that stayed for only three months. 

 

 

[TheBiscuits]

1 minute ago, MtB said:

Somebody here was on the 48hr moorings for about nine months before moving off. 

 

Promptly replaced by a near-identical boat that stayed for only three months. 

 

The enforcement team - sorry, licence support - will be getting bonuses.  Their performance has improved threefold!