Lithium Batteries installation

[IanD]

13 minutes ago, MtB said:

 

Thanks. That's actually what I thought but didn't want to have people say I was overstating the case. 

 

So spend £6,000 to get it exactly right or £350 to get it pretty close. 

 

Hmmm.... now which option will the average tightwad boater think looks better value? 

 

The second one of course, which is why this option is becoming increasingly popular with boaters -- at least, until the insurance companies stick their oar in... 😉

 

Just don't expect that the LFP batteries will last as long as promised, or that your alternator won't cook itself, or your LA batteries won't die from sulphation.

 

If you're starting from an existing system based round "dumb" alternator/LA/shore/genny charging it's much cheaper to drop in an LFP as you say, because it's always expensive to replace something that's already there and working whether it's batteries or an engine.

 

For a new build/fitout the tradeoff is very different, LFP has many advantages, and is not that much more expensive than a *good* LA-based system.

 

Since the OP is looking to upgrade an existing LA/alternator-based system, adding drop-in LFP is the cheapest and simplest option, but he needs to be aware of the potential pitfalls, and that things may not be as rosy as some of the vloggers make out... 😉

 

[nicknorman]

57 minutes ago, MtB said:

 

Thanks. That's actually what I thought but didn't want to have people say I was overstating the case. 

 

 

So spend £6,000 to get it exactly right or £350 to get it pretty close. 

 

Hmmm.... now which option will the average tightwad boater think looks better value? 

Not sure where the £350 comes from. I have 600Ah which cost around £1800. I guess £350 might get you the cheapest 100Ah battery but that is only any use if you wished you had been born as a caveman. People who are looking at Li probably have electrical demands greater than one rusty candle and a sink foot pump for water.

[Naughty Cal]

7 minutes ago, nicknorman said:

Not sure where the £350 comes from. I have 600Ah which cost around £1800. I guess £350 might get you the cheapest 100Ah battery but that is only any use if you wished you had been born as a caveman. People who are looking at Li probably have electrical demands greater than one rusty candle and a sink foot pump for water.

We certainly don't live like cavemen on the van. That manages just fine with a single 100ah lithium battery.

[nicknorman]

12 minutes ago, Naughty Cal said:

We certainly don't live like cavemen on the van. That manages just fine with a single 100ah lithium battery.

Cavewoman then? But seriously, a van is a much smaller space and has less “stuff” than a modern narrowboat. I also have 100Ah in my caravan.
Camper vans tend not to be parked up “off grid” for several days or weeks - they either get driven or are on a site with hookup - as a generalisation.

 

On the boat we tend to use about 200Ah a day, although we are certainly not frugal.

[jonathanA]

I think I'm going to have to re-read this thread several times...  so what is a 'reasonable' way to 'drop in' some lithium.

 

Here's a real life situation. (not me but someone I know)

 

bank of 3 LA, replaced with 3 lifos 105Ah.  canaline dual alternator engine, 175A iskra (I think) domestic,  Sterling 3KW combi and some solar (less than a KW probably). 

LA starter remains. 

The boat does not move a lot, although they may do more cruising in the better weather. currently the owner manages his batteries via the lifos blue tooth app to monitor the state of charge and mainly controlling the charging of the lithiums by switching the charger on/off as needed.  

This is fine during the winter when hes not moving, but once he goes for a cruise then I fear he could get the disconnect/alternator spike sceanario, which he is blissfully unaware of...  This is supposedly a professional install done by someone who does this 'all the time for campervans/caravans' 

 

what does the panel think he needs.... 

 

anecdotally the alternator seems quite happy charging the lithiums from low states of charge and seems to be running at a max of about 30A into each lifos battery without issue.  he's never taken them to much above an indicated 95% charge on the app. 

 

 

 

 

[magnetman]

Two separate battery banks is what I like. The alternator charges a decent Lead Acid battery lets say a Victron AGM block. 

 

The solar panels or shore power charge a lithium battery. 

The lithium battery runs 240v loads via an inverter. Inverters have low voltage cutouts. 

 

The Lead battery runs the 12v circuits. 

 

 It depends what is happening in winter but if the Boat is on mains then you just have a charger for both batteries. 

 

You can connect them together if and when you want to but the general plan is for them to be separate. 

 

Some people use a lot more power on their Boats than I do. 

In fact I expect everyone uses less than I do. 

[IanD]

23 minutes ago, magnetman said:

Two separate battery banks is what I like. The alternator charges a decent Lead Acid battery lets say a Victron AGM block. 

 

The solar panels or shore power charge a lithium battery. 

The lithium battery runs 240v loads via an inverter. Inverters have low voltage cutouts. 

 

The Lead battery runs the 12v circuits. 

 

 It depends what is happening in winter but if the Boat is on mains then you just have a charger for both batteries. 

 

You can connect them together if and when you want to but the general plan is for them to be separate. 

 

Some people use a lot more power on their Boats than I do. 

In fact I expect everyone uses less than I do. 

 

How does the LFP battery get charged in winter when there's no sun and you're cruising, not in a marina (no shoreline?)

 

The alternator can only charge the 12V LA (starter? domestic?) battery (doesn't need much power), so the LFP goes flat.

 

Unless you have a 230Vac generator to charge the LFP batteries and provide AC power as a passthrough the inverter.

 

Still can't charge the LFP batteries from alternator while cruising, unless you also add a DC-DC converter between the LA and LFP.

 

"You can connect them together if you want to" -- what, two high-current battery banks at different voltages and SoC? Really?

Edited February 8 by IanD

[magnetman]

1 minute ago, IanD said:

 

How does the LFP battery get charged in winter when there's no sun and you're cruising, not in a marina (no shoreline?)

 

The alternator can only charge the 12V LA (starter? domestic?) battery (doesn't need much power), so the LFP goes flat.

 

Unless you have a 230Vac generator to charge the LFP batteries and provide AC power as a passthrough the inverter.

 

Still can't charge the LFP batteries while cruising, unless you also add a DC-DC converter between the LA and LFP.

 

"You can connect them together if you want to" -- what, two high-current battery banks at different voltages and SoC? Really?

 

'It depends what is happening in winter but if the Boat is on mains then you just have a charger for both batteries. ' 

 

 

....

 

Yes you can connect a 13.6v nominal battery to a 12.6v nominal battery and the former will charge the latter. 

 

 

 

 

 

What do you mean by 'two high-current battery banks' ? 

 

Surely the current is associated with what people are doing. Some people don't use much elastic trickery on their Boats.

 

 

 

 

Everyone knows winter off grid is a challenge. The answer is to consume less but a lot of people don't want to do that. 

 

 

I would say change behaviour in winter and maybe just use the lead battery if the alternator is the only charger. This is when you can connect the lead battery with a wire to the lithium battery to get some charge into it. This has to be a manual intervention with monitoring so would not suit everyone. 

 

 

I don't believe in off grid winter living on Boats with multiple kilowatt consumers using a battery as the main energy source. For that you need a proper generator. 

However for the 'shoulder seasons' and certainly the summer having two separate battery banks can work. 

 

It is possible that my lifestyle is so far removed from the norm that I have no concept of what other people do on their Boats. 

 

I may in fact be an actual caveman ! 

I do not have a hair drier ! 

[IanD]

11 minutes ago, magnetman said:

 

'It depends what is happening in winter but if the Boat is on mains then you just have a charger for both batteries. '

 

Yes you can connect a 13.6v nominal battery to a 12.6v nominal battery and the former will charge the latter. 

 

What do you mean by 'two high-current battery banks' ? 

 

Surely the current is associated with what people are doing. Some people don't use much elastic trickery on their Boats.

 

Everyone knows winter off grid is a challenge. The answer is to consume less but a lot of people don't want to do that. 

 

 

"High-current" means "something that will provide a lot of current" -- if you want to connect LA and LFP batteries together which may be at different SoC/voltages to see how big a spark you get and how much current flows down the cable while they try and equalise voltages, I'd rather not be next to you if that's OK... 😉

 

(yes I know it's what happens when you jump-start a car, but boat batteries are often a *lot* bigger than car ones, and LFP can provide *lots* of current -- at least, until the internal BMS (hopefully) detects overcurrent and disconnects rather than dying...)

 

While you're plugged in nothing is a problem, you don't really need batteries at all. When you're not plugged in is when the problems appear, if you want to keep the LA and LFP separate then you need a way of getting charge from one to the other when out on the canals, since (in your plan) the alternator only charges the LA and the solar only charges the LFP. It's why people do the "drop-in LFP connected via some resistive cable to LA" bodge, because all charge sources can charge both batteries, albeit not especially well-controlled.

 

If you're not going to go out on the canals and stay plugged in all the time, why have a boat? 😉

Edited February 8 by IanD

[magnetman]

I heard that a lot of people take moorings temporarily which sometimes have electric. 

 

As for living on a Boat on a mooring I'd happily live anywhere on my Boat regardless of whether it moves because I want to live on the Boat. It doesn't make a lot of difference to me whether it is moving much its the fact it is a Boat. Very important and it will be 30 yars on 4th April since I moved onto my first Boat so I think I know by now. 

 

 

Give me a million pounds I'll still live on my little Boat not buy property or land. Not my bag. 

 

 

[IanD]

1 minute ago, magnetman said:

I heard that a lot of people take moorings temporarily which sometimes have electric. 

 

As for living on a Boat on a mooring I'd happily live anywhere on my Boat regardless of whether it moves because I want to live on the Boat. It doesn't make a lot of difference to me whether it is moving much its the fact it is a Boat. Very important and it will be 30 yars on 4th April since I moved onto my first Boat so I think I know by now.

 

Give me a million pounds I'll still live on my little Boat not buy property or land. Not my bag. 

 

 

That's fine for you, but I expect most people want a boat they can take out on the canals where there are no power points (i.e. almost everywhere!) without ending up with flat batteries... 😉

[magnetman]

Yes. Like I said I have no concept of the power use on other peoples Boats. 

 

I would have thought 5 hours engine running with alternator and battery would be enough but I guess some people want household comforts when cruising. 

 

Fair enough but not my thing. 

 

 

 

I'm not worth arguing because I am basically right.

[jonathanA]

35 minutes ago, magnetman said:

Two separate battery banks is what I like. The alternator charges a decent Lead Acid battery lets say a Victron AGM block. 

 

The solar panels or shore power charge a lithium battery. 

The lithium battery runs 240v loads via an inverter. Inverters have low voltage cutouts. 

 

The Lead battery runs the 12v circuits. 

 

 It depends what is happening in winter but if the Boat is on mains then you just have a charger for both batteries. 

 

You can connect them together if and when you want to but the general plan is for them to be separate. 

 

Some people use a lot more power on their Boats than I do. 

In fact I expect everyone uses less than I do. 

to some extent that is what he has a LA starter and lithium domestic bank.  the issues are the usual ones - how to stop the alternator cooking, although that doesn't seem to be an problem and how to deal with the 100% charge disconnect situation when running the engine...  its the latter that is the concern in this situation as charger/solar are doing the job they are supposed to.

 

so would simply parallelling the alternators (and therefore connecting the batts together) ensure there was always an LA battery taking charge when the engine is running (and only when the engine is running) ?

[IanD]

8 minutes ago, jonathanA said:

to some extent that is what he has a LA starter and lithium domestic bank.  the issues are the usual ones - how to stop the alternator cooking, although that doesn't seem to be an problem and how to deal with the 100% charge disconnect situation when running the engine...  its the latter that is the concern in this situation as charger/solar are doing the job they are supposed to.

 

so would simply parallelling the alternators (and therefore connecting the batts together) ensure there was always an LA battery taking charge when the engine is running (and only when the engine is running) ?

 

Why would the alternator cook, it's only attached to the LA battery like on any old-school boat?

 

Why would there be any (LFP) charge disconnect when running the engine, the alternator doesn't connect to it?

 

(there's only one alternator according to the posts...)

 

Having half the charge sources (alternator, solar) connected to each battery and half the loads (AC, DC) connected to each doesn't make sense unless you have a way to get charge from one to the other (bidirectional?), because one battery might have more charge coming in than going out and the other one vice versa, depending on where the charge is coming from and where the loads are drawing power from.

 

It works if you're plugged into shore with a charger for each, but not otherwise.

Edited February 8 by IanD

[magnetman]

37 minutes ago, IanD said:

 

"

 

Edited February 8 by magnetman
double post see below

[jonathanA]

11 minutes ago, IanD said:

 

Why would the alternator cook, it's only attached to the LA battery like on any old-school boat?

 

Why would there be any (LFP) charge disconnect when running the engine, the alternator doesn't connect to it?

 

(there's only one alternator according to the posts...)

 

Having half the charge sources (alternator, solar) connected to each battery and half the loads (AC, DC) connected to each doesn't make sense unless you have a way to get charge from one to the other (bidirectional?), because one battery might have more charge coming in than going out and the other one vice versa, depending on where the charge is coming from and where the loads are drawing power from.

 

It works if you're plugged into shore with a charger for each, but not otherwise.

I think you've slightly misunderstood/got confused with the other posts (easily done 🙂 ).  in my scenario its a dual alternator system, with the domestic bank having been replaced by lithiums.  (so potential for alternator cooking) 

[magnetman]

35 minutes ago, IanD said:

 

" if you want to connect LA and LFP batteries together which may be at different SoC/voltages to see how big a spark you get and how much current flows down the cable while they try and equalise voltages, I'd rather not be next to you if that's OK... 😉

 

Have you actually tried it? 

 

I know there is the theory that there will be a terribly large discharge from the lithium battery and sparks and melted wires but have you actually done it and found out what happens? 

 

I have. It doesn't go crazy and make sparks or burn anything. 

 

Maybe it would with an enormous battery bank but I am not advocating for tonnes of lithium batteries. 

[IanD]

7 minutes ago, magnetman said:

Have you actually tried it? 

 

I know there is the theory that there will be a terribly large discharge from the lithium battery and sparks and melted wires but have you actually done it and found out what happens? 

 

I have. It doesn't go crazy and make sparks or burn anything. 

 

Maybe it would with an enormous battery bank but I am not advocating for tonnes of lithium batteries. 

 

No I haven't tried it, I've got more sense 😉

 

(also, no LA battery -- except the small genny starter battery which is trickle-charged by a DC-DC converter)

 

If the LFP has a good robust BMS (maybe not a cheapo Chinese one then...) then with different SoC/voltages it should just overcurrent disconnect with no damage. If not, best of luck... 🙂

 

11 minutes ago, jonathanA said:

I think you've slightly misunderstood/got confused with the other posts (easily done 🙂 ).  in my scenario its a dual alternator system, with the domestic bank having been replaced by lithiums.  (so potential for alternator cooking) 

Indeed, I thought you were talking about the system @magnetman has. Alternator cooking is a real hazard with a dumb automotive alternator, LFPs, and no alternator temperature sensor or extra cooling...

Edited February 8 by IanD

[Jon57]

What's the experts opinion on this dc to dc chargers and solar controller. https://uk.renogy.com/dcc50s-12v-50a-dc-dc-on-board-battery-charger-with-mppt-new-version/?Rng_ads=86111fb344f6897c&kw=&ad=77103447420750&gr=1233653057195912&ca=483526763&pl=bing&r_u_id=151300468&msclkid=2ffb358f1c011c2e93d6504c5e03c5ad

[IanD]

3 minutes ago, Jon57 said:

What's the experts opinion on this dc to dc chargers and solar controller. https://uk.renogy.com/dcc50s-12v-50a-dc-dc-on-board-battery-charger-with-mppt-new-version/?Rng_ads=86111fb344f6897c&kw=&ad=77103447420750&gr=1233653057195912&ca=483526763&pl=bing&r_u_id=151300468&msclkid=2ffb358f1c011c2e93d6504c5e03c5ad

Looks OK if it meets your requirements, but some currents might be a bit small for a narrowboat:

 

Alternator 660W max (50A)

Max solar Vin/Pin 50V/660W

Max charging current 50A (25A alternator/25A PV)

[magnetman]

2 hours ago, IanD said:

 

No I haven't tried it, I've got more sense 😉

 

(also, no LA battery -- except the small genny starter battery which is trickle-charged by a DC-DC converter)

 

If the LFP has a good robust BMS (maybe not a cheapo Chinese one then...) then with different SoC/voltages it should just overcurrent disconnect with no damage. If not, best of luck... 🙂

 

 

You only find out what happens if you try it. are you saying if you connected a charged nominal 13.2v LFP 100Ah battery  to a discharged 100Ah LA at lets say 12v the LFP would try to discharge into the LA at 100A? How do you know this if you have not tried it? Are you basing this on theoretical calculations of internal resistance?

[GUMPY]

30 minutes ago, magnetman said:

You only find out what happens if you try it. are you saying if you connected a charged nominal 13.2v LFP 100Ah battery  to a discharged 100Ah LA at lets say 12v the LFP would try to discharge into the LA at 100A? How do you know this if you have not tried it? Are you basing this on theoretical calculations of internal resistance?

 

It will discharge at whatever rate the LA battery will accept.

Watch the video!

[rusty69]

....Including what might be quite a high discharge rate into a LA battery with one or more faulty cells.

[magnetman]

7 hours ago, rusty69 said:

....Including what might be quite a high discharge rate into a LA battery with one or more faulty cells.

There is that. One would hope that in an arrangement where "This has to be a manual intervention with monitoring so would not suit everyone. " as noted in a previous post the individual carrying out the procedure would be aware of the elf of the batteries. 

 

I did mention previously this is not a fit and forget system and would need manual intervention and monitoring. 

 

I guess it is rather unusual for people to have a close relationship with their batteries. 

[rusty69]

4 hours ago, magnetman said:

 

I did mention previously this is not a fit and forget system and would need manual intervention and monitoring. 

I would think so. When thousands of people have fitted these hybrid systems, manual intervention will be required to remove them again when our proactive BSS and insurance providers deem them not fit for purpose.