Smallest starter battery.

[pandos]

I have an original VP MD21b ( 2.1L 4 cylinder) . It has good compression (new rings) and starts pretty quickly, (new starter )

My existing starter battery is a 16 year old 130ah AGM. It is tird and past time to replace.

I have just bought some new AGMs for the house bank 2x120ah.

I wonder what is the smallest capacity starter battery I could safely get away with. ?

I have a 1/2both switch, so if the fuel system needed to be bled I have that back up.

 

[LadyInBed]

Google around to see what batteries are supplied with 2.1 ltr vehicles.

 

[pandos]

Google around to see what batteries are supplied with 2.1 ltr vehicles.

I think that will give me the normal, and will include a conservative reserve for cold starts or even sufficient to deal with bleeding the system etc.

As I will also have access to up to 240ah in the house bank I know I could use a smaller battery,

Just how small is the question.

 

[Tranona]

Red Flash 1100 - assuming you mean the smallest physically. This is a high output starter only so not comparable in terms of Ah at 37 with a conventional battery for which you will be looking at around 100Ah, but will start your engine. Do away with that awful switch and have an automatic charge system, individual isolators and an emergency parallel switch then you have all bases covered.

This is what I shall be installing in my project boat but with a 1000 (28Ah) one for a 40hp 3 cylinder engine. Did the same in the last boat I rewired and also have a Red Flash in my Morgan - 18 years and still going strong.

 

[QBhoy]

You'll likely be aware already, but its not so much about the AH...more the CCA. So a dedicated starter battery of 80ah but with a cca of 700, will start your diesel much better than a 110ah leisure battery, that may not even have a cca rating to start with. these days you can get dual purpose starter and leisure batteries.

 

[pandos]

Thanks for the replies.

The red start are absolutely the dogs bollox of batteries and super for small spaces and weight reduction etc but at stg.237 I won't be buying one.

Maybe I should rephrase my question.

I am building a new battery box and I want to have a snug fit and ideally to be able to put the 3 batteries side by side.

I'd rather have a conventional 100quidish AGM starter battery. (Which can be easily and cheaply replaced if needs be)

I have never really managed to get my head around CCA other than to understand that a bigger number means more power...

I was once told that engineering was not about how strong something needed to be to survive but was really about how weak it could be,

I wonder how small /weak in terms of ah/CCA a 12v AGM battery can I get away with to start my engine.

I would have been nervous with anything less than 80 ah without a good recommendation, but given the replies so far, maybe I should be looking at cca and if so what would be the Minimum in CCA.?

 

[QBhoy]

Thanks for the replies.

The red start are absolutely the dogs bollox of batteries and super for small spaces and weight reduction etc but at stg.237 I won't be buying one.

Maybe I should rephrase my question.

I am building a new battery box and I want to have a snug fit and ideally to be able to put the 3 batteries side by side.

I'd rather have a conventional 100quidish AGM starter battery. (Which can be easily and cheaply replaced if needs be)

I have never really managed to get my head around CCA other than to understand that a bigger number means more power...

I was once told that engineering was not about how strong something needed to be to survive but was really about how weak it could be,

I wonder how small /weak in terms of ah/CCA a 12v AGM battery can I get away with to start my engine.

I would have been nervous with anything less than 80 ah without a good recommendation, but given the replies so far, maybe I should be looking at cca and if so what would be the Minimum in CCA.?

Hi. So a good relevant example might be that a 2.2l Honda diesel car requires 680 cca recommended. Diesels take a fair load of current to turn them over. Especially in colder weather. Just with their very high compression. The very thing that enables them to fire up. Very different from a petrol engine of the same size. I’d have a look for a good dual purpose marine battery. I’m sure you can get them around the 100/110ah size that will be rated to about 700 cca.
There is no doubt that a big big leisure purpose battery…may just start your engine. But it certainly won’t be as lively at it, as a battery that’s designed for it. Have a look at something like this. This is a dual purpose. 800 cca but also a bit of a leisure battery too.
LEISURE Battery > MARINE LOW HEIGHT PROFILE > 12 V > 115Ah > 850CCA 115 AH 110 | eBay

 

[pandos]

Hi. So a good relevant example might be that a 2.2l Honda diesel car requires 680 cca recommended. Diesels take a fair load of current to turn them over. Especially in colder weather. Just with their very high compression. The very thing that enables them to fire up. Very different from a petrol engine of the same size. I’d have a look for a good dual purpose marine battery. I’m sure you can get them around the 100/110ah size that will be rated to about 700 cca.
There is no doubt that a big big leisure purpose battery…may just start your engine. But it certainly won’t be as lively at it, as a battery that’s designed for it. Have a look at something like this. This is a dual purpose. 800 cca but also a bit of a leisure battery too.
LEISURE Battery > MARINE LOW HEIGHT PROFILE > 12 V > 115Ah > 850CCA 115 AH 110 | eBay

Thanks for that... My house bank is two of these.

12v 110ah Leoch AGM Leisure battery - Sunstore Solar

They seem cheap but reviews are good and I bought them from a guy who upgraded to lithium so he can cook and run his coffee machine ..

Should be more than enough, if stuck.. But I will do some poking around for 800+cca in non leisure.
Thanks .

 

[QBhoy]

Thanks for that... My house bank is two of these.

12v 110ah Leoch AGM Leisure battery - Sunstore Solar

They seem cheap but reviews are good and I bought them from a guy who upgraded to lithium so he can cook and run his coffee machine ..

Should be more than enough, if stuck.. But I will do some poking around for 800+cca in non leisure.
Thanks .

Just read the specs for that battery you mention there. They seem to be a dual purpose and have a cca of 800. Plenty for you. Not cheap though. You’ll get similar for under £100 for sure.

 

[PaulRainbow]

Thanks for that... My house bank is two of these.

12v 110ah Leoch AGM Leisure battery - Sunstore Solar

They seem cheap but reviews are good and I bought them from a guy who upgraded to lithium so he can cook and run his coffee machine ..

Should be more than enough, if stuck.. But I will do some poking around for 800+cca in non leisure.
Thanks .

If you go for the lowest possible CCA rating, when the battery is slightly tired it won't start the engine and you'll need a new one. A borderline CCA will also give your starter motor a hard time. I'd suggest one of these: Hankook SA57020 AGM Leisure Battery

Ignore the "leisure" part of the description, it's a stop/start battery. Will be a good fit for your engine and the AGM domestics.

 

[syvictoria]

I don't understand why you're trying to get the 'smallest' possible battery if not restricted by size or weight? It seems as if you're purposely trying to introduce jeopardy! And having to replace a battery that proves to be too small/problematic would ultimately be false economy.

I've used Tayna in the past and would recommend on both price and service.

 

[pandos]

I don't understand why you're trying to get the 'smallest' possible battery if not restricted by size or weight? It seems as if you're purposely trying to introduce jeopardy! And having to replace a battery that proves to be too small/problematic would ultimately be false economy.

I've used Tayna in the past and would recommend on both price and service.

I have a 130ah starter which is physically large and wold not fit neatly into my newly chosen location. I knew a motor cycle battery would not be suitable , but easily fit in anywhere .

So the query was aimed at addressing the Goldylocks point between being too small and being unnecessarily large.

Trahnona's suggestion of Restarts, highlighted the need to restrict the solutions to being only as expensive as needs must.

Paul's suggestion at 70ah, with just about 800 cca will physically fit just the way I want , whilst not introducing jeopardy.

Now it's a case of finding a similarly speced battery over here...(Tanya do not deliver here...but thanks for the recommendation.)

 

[PaulRainbow]

I have a 130ah starter which is physically large and wold not fit neatly into my newly chosen location. I knew a motor cycle battery would not be suitable , but easily fit in anywhere .

So the query was aimed at addressing the Goldylocks point between being too small and being unnecessarily large.

Trahnona's suggestion of Restarts, highlighted the need to restrict the solutions to being only as expensive as needs must.

Paul's suggestion at 70ah, with just about 800 cca will physically fit just the way I want , whilst not introducing jeopardy.

Now it's a case of finding a similarly speced battery over here...(Tanya do not deliver here...but thanks for the recommendation.)

Try a Google search for "096 AGM Start Stop Car Battery"

 

[ChromeDome]

The owners handbook only states "Standard battery capacity" (114 ah.)

Personally would go for the highest CCA and physical size you can fit (into boat and budget), Longer warranty commonly indicates better quality but technology (AGM, Optima, Silver Oxide, Dual purpose and then some that might not fit your need anyway) will influence price too.

 

[Alex_Blackwood]

I have an original VP MD21b ( 2.1L 4 cylinder) . It has good compression (new rings) and starts pretty quickly, (new starter )

My existing starter battery is a 16 year old 130ah AGM. It is tird and past time to replace.

I have just bought some new AGMs for the house bank 2x120ah.

I wonder what is the smallest capacity starter battery I could safely get away with. ?

I have a 1/2both switch, so if the fuel system needed to be bled I have that back up.

How about.
Mercedes SLC 2.1 D Diesel battery to fit (2016-2017) compatible part Torq X AGM Car Battery 12V 95Ah 850CCA Type 019

 

[LadyInBed]

Have a read here Pick the Best 1000 CCA (Cold Cranking Amps) Marine, Automotive and Industrial Battery
then make a decision.

 

[PaulRainbow]

Have a read here Pick the Best 1000 CCA (Cold Cranking Amps) Marine, Automotive and Industrial Battery
then make a decision.

1000cca is waaaaaaay over the top for the OPs engine.

My car has 3.0 litre V6 diesel engine and only has a 800CCA AGM battery

 

[LadyInBed]

1000cca is waaaaaaay over the top

That's just the title provided by the link.
The chart in the article shows various batteries with CCA's from 800 to 1700!
The OP said

I have never really managed to get my head around CCA other than to understand that a bigger number means more power...

The article might help shed a little light.

 

[pandos]

Have a read here Pick the Best 1000 CCA (Cold Cranking Amps) Marine, Automotive and Industrial Battery
then make a decision.

Interesting link.thanks.

The decision is made based on Paul's recommendations, instinct, euros and space...

Thanks to all.

 

[Tranona]

Agree with PaulRainbow that an automotive stop start AGM is the way to go. This what Bavaria fit, only the bigger 95ah Exide which is normally used on such cars as Jaguar XF and Range Rovers. Bit OTT but presumably they get a good deal as the boat has 5 of them, one start, 3 house and one bow thruster.

In my GH I shall be fitting 2 Exides and a Red Flash 1000 which fit the box - there is not room for another bigger AGM