Changing to lithium.

[Blueboat]

Hi, I’m thinking about replacing my AGM’s for lithium. Had a quote etc, but as I have three batteries at 10 stone each, two to one side of the engine bay, and one in middle back of engine bay, what do people do to correct balance. 
my boat does sit high in the water at bow, and does struggle in manoeuvres in the wind, would reducing the weight at back help, or make it worse. I’m thinking worse.

pro tem I could keep old batteries as stern ballast till I find better alternative. 
but what are the options, it would have to be done professionally as I can’t bend over for more than a couple minutes.

its an Aqualine semi trad, but what do people normally do when changing to lithium, and is it an issue ?

[PeterF]

I took out about 190kg of AGM batteries and installed about 65kg of lithium batteries, all on the port uxter plate. Luckily, the boat had about 90kg of trim ballast at the bow on the starboard side under the bed. 70kg of this was moved to the stern port side to rebalance the boat both fore-aft and port-starboard. This was half the difference between the AGM and lithium batteries so it worked well.

[JoeC]

My lithium's went inside the boat and I kept the old acid ones in place as ballast.

[blackrose]

I think big old AGM batteries would be perfect as ballast. My understanding is that they're fairly leak-proof. 

 

When I switched to lithium I took out 3 x 39kg lead/acid batteries and installed 2 x 26kg lithium, so the difference was minimal and I'm on a widebeam anyway so I didn't have to do anything.

 

Your AGMs are 63kg each? Wow, what Ah capacity are they? I hope access is good and you get some help if you have to remove any of them. Also it sounds to me like you might need some more ballast at the bow to get a bit more control in the wind. Why not try putting one or two of those AGMs at the bow? Just make sure the terminals are well covered.

Edited December 3, 2025 by blackrose

[Jen-in-Wellies]

I removed about 75kg in lead acid on the starboard side, with the replacement Lithium batt going on the centre line. Removed some ballast and redistributed some heavy stuff in the cabin to balance again. The stern has lifted about an inch as a result. 

[Blueboat]

15 hours ago, blackrose said:

I think big old AGM batteries would be perfect as ballast. My understanding is that they're fairly leak-proof. 

 

When I switched to lithium I took out 3 x 39kg lead/acid batteries and installed 2 x 26kg lithium, so the difference was minimal and I'm on a widebeam anyway so I didn't have to do anything.

 

Your AGMs are 63kg each? Wow, what Ah capacity are they? I hope access is good and you get some help if you have to remove any of them. Also it sounds to me like you might need some more ballast at the bow to get a bit more control in the wind. Why not try putting one or two of those AGMs at the bow? Just make sure the terminals are well covered.

There is nowhere to put them at the bow unfortunately.

 

15 hours ago, blackrose said:

I think big old AGM batteries would be perfect as ballast. My understanding is that they're fairly leak-proof. 

 

When I switched to lithium I took out 3 x 39kg lead/acid batteries and installed 2 x 26kg lithium, so the difference was minimal and I'm on a widebeam anyway so I didn't have to do anything.

 

Your AGMs are 63kg each? Wow, what Ah capacity are they? I hope access is good and you get some help if you have to remove any of them. Also it sounds to me like you might need some more ballast at the bow to get a bit more control in the wind. Why not try putting one or two of those AGMs at the bow? Just make sure the terminals are well covered.

they are 3x220ah , lasted me ten years cc’ing.

I thought there might be a modern way of using ballast that is easy to handle, looks like I will be keeping at least one as ballast and see how it handles.

thanks for replies.

15 hours ago, Jen-in-Wellies said:

I removed about 75kg in lead acid on the starboard side, with the replacement Lithium batt going on the centre line. Removed some ballast and redistributed some heavy stuff in the cabin to balance again. The stern has lifted about an inch as a result. 

with the stern lifting, has that helped or hindered navigation? Presume it is worse on a windy day ?

[Jen-in-Wellies]

3 hours ago, Blueboat said:

ith the stern lifting, has that helped or hindered navigation? Presume it is worse on a windy day ?

On my boat it makes no difference. However narrowboats are not great in wind generally. Have you steered enough different ones to be sure yours is exceptionally bad?

[Blueboat]

Yes,as have steered a few in past, not exceptionallybad  but is more difficult than other boats I have steered. An example is turning onto the middle levels after Denver sluice, never had a problem, but with this boat, it took me three turns to get in, I know that’s flow and not wind, but same effect. [lockie said I can’t believe you never grounded on the sand bank, but I knew I wouldn’t as I knew where it was, and knew my draught was enough to miss it.
Doesn’t seem to be a definitive answer from replies, so I think I will get rid of two batteries[ 20 stone] and keep one as ballast. Could do with sticking one in bow locker, but that’s a fail on bsc.

[Blueboat]

Just a last question on this, is it safe to keep old AGMs as ballast once there disconnected, and for how long?

And would putting say ten stone of steel or lead in the gas locker at the bow be allowed under boat safety cert as it says nothing else to go in there, would ballast be a fail?

and should this be done professionally, or can it be done safely by an amateur[trim, I mean after removing ballast[batteries from the stern]

[nicknorman]

7 minutes ago, Blueboat said:

Just a last question on this, is it safe to keep old AGMs as ballast once there disconnected, and for how long?

And would putting say ten stone of steel or lead in the gas locker at the bow be allowed under boat safety cert as it says nothing else to go in there, would ballast be a fail?

and should this be done professionally, or can it be done safely by an amateur[trim, I mean after removing ballast[batteries from the stern]

Yes it is safe to keep old AGMs in situ. I don't think BSS says nothing else can be in gas locker, what it does say is nothing in there that could either block the vents or move (in a collision) and damage the gas installation.

[MtB]

31 minutes ago, nicknorman said:

Yes it is safe to keep old AGMs in situ. I don't think BSS says nothing else can be in gas locker, what it does say is nothing in there that could either block the vents or move (in a collision) and damage the gas installation.

 

Or create a spark which might ignite all the escaped gas in there.....

[David Mack]

3 hours ago, nicknorman said:

Yes it is safe to keep old AGMs in situ. I don't think BSS says nothing else can be in gas locker, what it does say is nothing in there that could either block the vents or move (in a collision) and damage the gas installation.

This is what the BSS actually says about gas lockers:

I think you might struggle to find an examiner who wouldn't regard slabs of steel as 'heavy items', which could either move or create sparks.

By all means use old batteries as ballast.  But make sure the terminals are properly covered as for batteries in service.

Edited December 14, 2025 by David Mack

[nicknorman]

5 minutes ago, David Mack said:

This is what the BSS actually says about gas lockers:

I think you might struggle to find an examiner who wouldn't regard slabs of steel as 'heavy items', which could either move or create sparks.

By all means use old batteries as ballast.  But make sure the terminals are properly covered as for batteries in service.

It would depend on whether the steel slabs were restrained eg by being too big to slide into the cylinders,mbeingnunder the cylinders etc. I would disagree that some lumps of mild steel could create gas-igniting sparks. Have you ever tried to light a gas burner or even create a spark by clashing lumps of steel together at the sorts of speeds (accelerations) likely to ensue from a canal boat collision?

[David Mack]

11 minutes ago, nicknorman said:

I would disagree that some lumps of mild steel could create gas-igniting sparks.

I agree with you in practice. But do you think an examiner would sign it off?

[nicknorman]

12 minutes ago, David Mack said:

I agree with you in practice. But do you think an examiner would sign it off?

Who knows what an examiner might think. But some would. The text does say open flame or spark inducing equipment. It is a long way from an open flame to a lump of mild steel. And spark inducing equipment suggests to me equipment designed to induce sparks. A lump of steel is not "equipment". Although I would agree that the list is not exhaustive.

[MtB]

Which is easier...?

 

1) Persuading an unreasonable inspector that his belief that unrestrained lumps of mild steel hitting each other can spark-ignite any gas hanging around in a gas locker is wrong

Or... 

2) Taking the unrestrained lumps of mild steel out of the gas locker, or not putting them in there in the first place

 

Pragmatism Roolz OK

 

 

 

 

Edited December 15, 2025 by MtB
Missing word

[blackrose]

20 minutes ago, MtB said:

2) Taking the unrestrained lumps of mild steel out of the gas locker 

 

...for the day of inspection and then putting them back in afterwards.

 

Seems the most pragmatic if that's where they're needed.

[Jen-in-Wellies]

A BSS acceptable restraint of the gas bottles is there to prevent the pillar valves, regulators and other gas carrying fittings being damaged and causing a massive propane leak. They don't have to totally stop any mm long movement of the bottles. It might still be theoretically possible for a spark to come from slight movement of the gas bottle against the locker. The low level vents should clear any small amounts of gas before an explosive mixture can form. 

The bigger concern with unrestrained ballast would be it hitting valves, regulators, hoses, pipes and bubble testers, not sparks. Covering steel ballast with glued on rubber sheet would negate sparks as a potential issue, but would still need to be restrained. 

 

Steel chains are commonly used to restrain gas bottles and are OK with the BSS, despite some movement being possible. I use a ratchet strap, which is very effective in restricting movement, but that happens to suit the way the locker is built

[Jon57]

10 hours ago, nicknorman said:

It would depend on whether the steel slabs were restrained eg by being too big to slide into the cylinders,mbeingnunder the cylinders etc. I would disagree that some lumps of mild steel could create gas-igniting sparks. Have you ever tried to light a gas burner or even create a spark by clashing lumps of steel together at the sorts of speeds (accelerations) likely to ensue from a canal boat collision?

 

10 hours ago, David Mack said:

I agree with you in practice. But do you think an examiner would sign it off?

 

9 hours ago, nicknorman said:

Who knows what an examiner might think. But some would. The text does say open flame or spark inducing equipment. It is a long way from an open flame to a lump of mild steel. And spark inducing equipment suggests to me equipment designed to induce sparks. A lump of steel is not "equipment". Although I would agree that the list is not exhaustive.

Well I've got 15 or more railway line fish plates in my gas locker as well as the usual stuff. The usual stuff is always removed for the BSS and the boat has passed 3. Two by different examiners. They must have come to the judgement that they posed no risk. Just goes to show how stupid the system is. 

[Alan de Enfield]

13 minutes ago, Jon57 said:

Well I've got 15 or more railway line fish plates in my gas locker as well as the usual stuff. The usual stuff is always removed for the BSS and the boat has passed

 

You sound like the sort of guy who'll do anything to avoid complying with guidance - if your car has a 'bald' tyre, do you borrow a wheel off a mate when you go for your MOT ?

[magnetman]

Oh right. 

 

So if one has an object in the gas locker it may suddenly fly out of there at high speed and crash into a coach carrying a load of kids resulting in 12 fatalities and several badly injured innocent youngsters? 

 

A bad tyre could cause this in the real world. 

 

An article in a gas locker could not. Even if there was a combined petrol and gas fire no kids would be killed. 

 

Well possibly the one who rushes to see what is happening and trips over on a loose paving slab then snacks their head in the ground. 

 

 

How would you propose to replicate the outcome of a blowout of a bad tyre on a motorway by putting an object in a narrowboat gas locker?

 

 

 

 

 

 

 

[Tony Brooks]

15 minutes ago, Alan de Enfield said:

 

You sound like the sort of guy who'll do anything to avoid complying with guidance - if your car has a 'bald' tyre, do you borrow a wheel off a mate when you go for your MOT ?

 

I think that was uncalled-for. We don't know what the usual stuff is, it might be hose and rope, neither likely to cause sparks, but Jon simply gave an example where heavy slabs of steel, unrestrained were accepted by two different BSS examiners. This helps @Blueboat answer his own question.

 

I would add that when I no longer needed 3 x 19Kg gas cylinders I made a wooden box with ventilated base the same width, depth and height as a gas bottle and put that in the gas locker to contain spare paint, solvents, and a gas lighter refill canister. It was never questions by a BSS exminer.

Edited December 15, 2025 by Tony Brooks

[Blueboat]

Thanks for answers, the gas locker was just an addendum for later possible trim, I would struggle to get an AGM in and out of that space, my main question is answered ,that it is safe to leave my used AGMs in situ as ballast. 

[LadyG]

4 hours ago, blackrose said:

 

...for the day of inspection and then putting them back in afterwards.

 

Seems the most pragmatic if that's where they're needed.

Just what i do [everyone does] with their chain, anchor, tins of paint, coal scuttle, diesel containers,  hose, and black rubbish bag.

[Alan de Enfield]

13 minutes ago, LadyG said:

Just what i do [everyone does] with their chain, anchor, tins of paint, coal scuttle, diesel containers,  hose, and black rubbish bag.

 

Really ?