Lithium batteries - EVE cells - and insurance

[TandC]

Any first-hand experience of whether insurance companies are getting wobbly with lithium battery systems where the battery is not an "off the shelf" manufactured unit, but is instead a battery built up out of EVE cells, with a battery management system etc?

 

I had a chat with a large supplier of equipment earlier and they mentioned that where systems use these individual cell batteries, insurers may not cover. 

 

The company I spoke to was pretty open and honest about - sure, they sell manufactured units... so yes, maybe they do have a sales interest....  but regardless, their technician's view was that the warranty you get with manufactured units is better than a EVE cell built battery.  And, he mentioned the potential issue with insurance.

 

Whether there's a difference between being able to evidence that the battery was built and installed by a "competent professional", one with appropriate experience,  public liability insurance, etc - as opposed to me doing it myself? 

 

 

 

 

 

 

 

 

 

 

[mrsmelly]

Aaaaaaarrgghhh Lifium Battwies 😁

[IanD]

17 minutes ago, TandC said:

Any first-hand experience of whether insurance companies are getting wobbly with lithium battery systems where the battery is not an "off the shelf" manufactured unit, but is instead a battery built up out of EVE cells, with a battery management system etc?

 

I had a chat with a large supplier of equipment earlier and they mentioned that where systems use these individual cell batteries, insurers may not cover. 

 

The company I spoke to was pretty open and honest about - sure, they sell manufactured units... so yes, maybe they do have a sales interest....  but regardless, their technician's view was that the warranty you get with manufactured units is better than a EVE cell built battery.  And, he mentioned the potential issue with insurance.

 

Whether there's a difference between being able to evidence that the battery was built and installed by a "competent professional", one with appropriate experience,  public liability insurance, etc - as opposed to me doing it myself? 

 

I had no insurance problems with a system built from individual cells and an external BMS, but this was done by a professional boatbuilder with experience of building such systems -- who is therefore responsible for the quality and safety of the install, and will presumably have professional liability insurance to cover this.

 

I don't know if the same would apply with a DIY system because there's no way of knowing how competent the installer is, it may well vary from one insurance company to another -- and may change in the future. Maybe @nicknorman can comment, since he designed and built his own system?

Edited September 5, 2025 by IanD

[TandC]

Did you "declare" that this was the system on taking out insurance?    Would an insurer request confirmation that it was installed by a pro? 

 

For my new build, it would be installed by a professional - not myself.   So, for clarity, I guess the question is more - if the installation is done by a professional, then such a cell-based system shouldn't cause problems with insurers?   

But yes - it would be interesting to hear from those who have done self-build systems too actually

 

[Ex Brummie]

How do the insurers know what batteries you have? 

Are they now asking in renewals? They did not on my renewal but then I have lead acid anyway.

[Alan de Enfield]

7 minutes ago, Ex Brummie said:

How do the insurers know what batteries you have? 

Are they now asking in renewals? They did not on my renewal but then I have lead acid anyway.

 

If you change from  LA to LI then you are obliged to inform your insurers.

[nicknorman]

50 minutes ago, Alan de Enfield said:

 

If you change from  LA to LI then you are obliged to inform your insurers.

where does it say that in my policy terms and conditions?

[ditchcrawler]

50 minutes ago, Alan de Enfield said:

 

If you change from  LA to LI then you are obliged to inform your insurers.

But what if you start with them

17 minutes ago, nicknorman said:

where does it say that in my policy terms and conditions?

Came through this week

 

"Following any reported incident or modification to the vessel or her engines or electrical systems including
batteries and their connections, we reserve the right to review and adjust the terms of the insurance. We may ask for
a surveyor’s report or valuation following repair, alteration or change to the vessel or her engines, electrical systems
including batteries and their connections, or as a result of a surveyor’s examination which may highlight a risk to the
seaworthiness of the vessel or a change in the sum to be insured. All associated costs in respect of reports requested
by us will be for the owners own account. Some changes agreed by us may result in an additional or increased premium."

[blackrose]

35 minutes ago, nicknorman said:

where does it say that in my policy terms and conditions?

 

I haven't seen that stated in my policy either. If Alan's insurance stipulates that he has to inform them presumably that also applies to other installations such as modifications to his LPG system, AC and 12v systems, etc?

2 hours ago, TandC said:

Any first-hand experience of whether insurance companies are getting wobbly with lithium battery systems where the battery is not an "off the shelf" manufactured unit, but is instead a battery built up out of EVE cells, with a battery management system etc?

 

I had a chat with a large supplier of equipment earlier and they mentioned that where systems use these individual cell batteries, insurers may not cover. 

 

The company I spoke to was pretty open and honest about - sure, they sell manufactured units... so yes, maybe they do have a sales interest....  but regardless, their technician's view was that the warranty you get with manufactured units is better than a EVE cell built battery.  And, he mentioned the potential issue with insurance.

 

Whether there's a difference between being able to evidence that the battery was built and installed by a "competent professional", one with appropriate experience,  public liability insurance, etc - as opposed to me doing it myself? 

 

 

 

 

 

 

 

 

 

 

 

Out of interest, and this may be a stupid question, but what's the point of building your own lithium batteries when they are available off the shelf from reputable companies with all the protection systems built-in? 

 

Is it much cheaper to build them yourself for example, or are there other benefits?

[nicknorman]

Since I installed the Li system, I have had a BSS inspection which passed without comment on the electrics (or anything else) so as far as I am concerned there would be no justification for objection from the insurance company. It is true that there is a “cover all” comment about notifying them of any modifications, but virtually every boat has had some modifications. And what was the original specification? Most boats have a degree of customisation at manufacture. And I think somewhere it says modifications that affect seaworthiness.

42 minutes ago, blackrose said:

 

I haven't seen that stated in my policy either. If Alan's insurance stipulates that he has to inform them presumably that also applies to other installations such as modifications to his LPG system, AC and 12v systems, etc?

 

Out of interest, and this may be a stupid question, but what's the point of building your own lithium batteries when they are available off the shelf from reputable companies with all the protection systems built-in? 

 

Is it much cheaper to build them yourself for example, or are there other benefits?

In my case it was cheaper, but that was quite a few years ago now and the difference is now probably less or zero. In my case it was that I wanted to build my own system integrated with the existing Mastervolt kit, such the charging from both the alternator and the Mastervolt Combi was controlled by the BMS. There was and is no commercial option to achieve that.

[MtB]

2 hours ago, Alan de Enfield said:

 

If you change from  LA to LI then you are obliged to inform your insurers.

 

 

Cobblers.

 

Neither of my Basic-Boat third party policies require this. 

 

[ditchcrawler]

5 minutes ago, MtB said:

 

 

Cobblers.

 

Neither of my Basic-Boat third party policies require this. 

 

This was from Nautical just this week

 

[nicknorman]

1 hour ago, ditchcrawler said:

But what if you start with them

Came through this week

 

"Following any reported incident or modification to the vessel or her engines or electrical systems including
batteries and their connections, we reserve the right to review and adjust the terms of the insurance. We may ask for
a surveyor’s report or valuation following repair, alteration or change to the vessel or her engines, electrical systems
including batteries and their connections, or as a result of a surveyor’s examination which may highlight a risk to the
seaworthiness of the vessel or a change in the sum to be insured. All associated costs in respect of reports requested
by us will be for the owners own account. Some changes agreed by us may result in an additional or increased premium."

But those are your policy’s term and conditions, not mine

[mrsmelly]

With regard any insurance just confide in the insurers before you take the policy up and if you change anything. Paying for a null and void insurance policy is more numptyish

than not even buying one. If there is a major claim you could be in big shit trying to save a few quid. Boat insurance is peanuts anyway. 

[Peanut]

It doesn't matter what your policy says, you have to disclose any, "material fact."  Unfortunately, they decide what is that is, the only way to find out is to ask them.  If you don't, they may choose to decline your claim. It could turn out to be a costly mistake.

[nicknorman]

34 minutes ago, Peanut said:

It doesn't matter what your policy says, you have to disclose any, "material fact."  Unfortunately, they decide what is that is, the only way to find out is to ask them.  If you don't, they may choose to decline your claim. It could turn out to be a costly mistake.

 

This is simply not true. You have to comply with the policy terms. Perhaps the terms say you must disclose any material fact. Or maybe it doesn't. There is no point in issuing opinions about insurance policies unless you have analysed every one of them available on the market and found them to be uniform. Which seems highly unlikely.

And even if it does, requiring one to disclose every material fact has no meaning in law. Is a material fact the amount in kilos of faeces I depositied down the toilet this morning? Or maybe it is the amount of weapons grade plutonium I have in the torpedoes on board. It is a meaningless statement and contracts have to be reasonably clear and specific, otherwise they are not enforceable.

 

Anyway, perhaps you can enlighten us as to how many insurance claims have been refused solely because a correctly installed lithium battery system had been added to the boat? I strongly suspect the answer is zero, and thus I find these sort of comments pure scaremongering.

Edited September 5, 2025 by nicknorman

[Mike Coombes]

6 hours ago, TandC said:

Any first-hand experience of whether insurance companies are getting wobbly with lithium battery systems where the battery is not an "off the shelf" manufactured unit, but is instead a battery built up out of EVE cells, with a battery management system etc?

 

I had a chat with a large supplier of equipment earlier and they mentioned that where systems use these individual cell batteries, insurers may not cover. 

 

The company I spoke to was pretty open and honest about - sure, they sell manufactured units... so yes, maybe they do have a sales interest....  but regardless, their technician's view was that the warranty you get with manufactured units is better than a EVE cell built battery.  And, he mentioned the potential issue with insurance.

 

Whether there's a difference between being able to evidence that the battery was built and installed by a "competent professional", one with appropriate experience,  public liability insurance, etc - as opposed to me doing it myself? 

 

 

 

 

 

 

 

 

 

 

 

Big debate on the YBW forum on the same subject.

 

Does not sound encouraging. Some Insurers are getting difficult, some will not insure with DIY systems.

[Alan de Enfield]

1 hour ago, Peanut said:

It doesn't matter what your policy says, you have to disclose any, "material fact."  Unfortunately, they decide what is that is, the only way to find out is to ask them.  If you don't, they may choose to decline your claim. It could turn out to be a costly mistake.

 

I'm with craftinsure and they state :

 

5.1 Your duty of care
5.1.1 Information Your Insurers need to know.
You must take reasonable care to provide complete and accurate answers to the questions Your
Insurance Adviser or Your Insurers ask when You take out, make changes to or renew Your
Policy. Your Policy may not be valid or may not cover You fully if the information provided by
You is not complete and accurate or if You do not tell Your Insurance Adviser about any changes.
You must let Your Insurance Adviser know if there are any changes to the information set out
in Your Schedule. You must also tell Your Insurance Adviser within 14 days in the event of
any of the following:
i) Any additional people to be insured or any insured person to be taken off the Policy;
ii) Any criminal convictions for any of the people insured or to be insured;
iii) Any change in Your Craft’s mooring or storage location;
iv) Any change to Your Craft’s original specification;
v) Any modifications to Your Craft;

[TandC]

Thanks - I am currently with CraftInsure - I'll give a few of them a ring round anyway to see what the mood music is.  If the system is designed and installed by a professional you'd like to think that an insurer would be content.   

[Rob-M]

My Crafiinsure narrow boat policy states...

 

This policy is based on the information You have given Us about You and/or Your Boat. You must tell Us immediately about

changes to the details You provided for example:

• Any changes to the levels of cover You require

• Any changes to Your contact information

• Any criminal convictions or if You have had any other insurance declined, cancelled or had special terms imposed

 

 

There is nowhere in their questions when taking out the policy that asks about battery type.

[blackrose]

10 hours ago, Peanut said:

It doesn't matter what your policy says, you have to disclose any, "material fact."  Unfortunately, they decide what is that is, the only way to find out is to ask them.  If you don't, they may choose to decline your claim. It could turn out to be a costly mistake.

 

That is total nonsense. How have you managed to arrive at such a complete misunderstanding?

 

As Nick said, you only have to disclose what your insurer requires in order to comply with their policy terms. It is not incumbent on policyholders to determine what those requirements are. 

[pearley]

1 hour ago, Rob-M said:

My Crafiinsure narrow boat policy states...

 

This policy is based on the information You have given Us about You and/or Your Boat. You must tell Us immediately about

changes to the details You provided for example:

• Any changes to the levels of cover You require

• Any changes to Your contact information

• Any criminal convictions or if You have had any other insurance declined, cancelled or had special terms imposed

 

 

There is nowhere in their questions when taking out the policy that asks about battery type.

Mine is Craftinsure too. As they never asked what batteries were fitted from new why tell them you've changed them. Do we tell them if we increase the size of battery bank but keep the same type? Do we tell them we've changed from Lead acid to AGM or lead carbon? Do I tell them I've added a 240v and 12 volt socket in the engine bay.

 

My hot water system has been altered a lot since built to improve the flow and heat at the shower. Is this a material change?

[Tony Brooks]

11 minutes ago, blackrose said:

 

That is total nonsense. How have you managed to arrive at such a complete misunderstanding?

 

As Nick said, you only have to disclose what your insurer requires in order to comply with their policy terms. It is not incumbent on policyholders to determine what those requirements are. 

 

I don't think so. my understanding is the same as Peanuts, however unfair that may sound. Insurances are known as a contract of upmost good faith which require the insuree to disclose all material facts that affect the risk to the insurer so they can properly assess the risk, but it is the insurer who decides what those material facts are, even if they are not stated in the policy.

[blackrose]

Under the Consumer Insurance (Disclosure and Representations) Act 2012, insurers are required to ask all relevant questions to gather the necessary information from those they insure. 

[Peanut]

No scaremongering Nick, the requirement to disclose relevant facts, are covered in the:

 

Consumer Insurance (Disclosure and Representations) Act 2012

 

https://www.legislation.gov.uk/ukpga/2012/6/contents

 

It is simply true. Essentially, you know the risk you wish to insure, the insurance company does not. It is up to you to tell them of what you want to insure, and any change to that, so that they can decide whether to take the risk, or not, or apply different terms and conditions.

 

This is from the GJW insurance.

 

 

Stated in plain English, in case you are unaware of your legal obligation.

 

 

Also from the GJW insurance.

 

 

Emphasis by GJW

 

Para 12. Would be relevant to the installation of lithium batteries, “alteration or addition.”

 

Para 14. Relates to how lithium batteries are to be installed.

I accept that the fire extinguisher seems nonsensical, as no such extinguisher exist.

 

More to follow...