Starter battery question

[lxs602]

Hi,

 

A question regarding a new starter battery.

 

I have a starter battery, which managed to start the engine on one day, but after a full day of cruising, then failed to start the engine on the following day. Someone helpfully lent me a multimeter, and the reading was only 12.2V. They also remarked the starter wires were a bit on the thin side, which I understand would increase resistance. The boat and the engine had not been used for a few months. The battery ratings were 45Amp Hours and 370 CCA SEA. The engine is a Sabb 10hp diesel single cylinder. I didn't manage to start it with the hand crank.

 

I asked at a battery shop, and they have a 45AH / 450 CCA AGM battery, and  55AH / 550 CCA AGM battery for a fair bit more.

 

I have read that cold crank amps are more important than amp hours for a starter battery, given the way that starter batteries work by delivering a short but high amount of current to the starter motor.

 

It does seem that most people have batteries that are about 70+ amp hours, though... I'm not sure about the specifications. Do you think the 45 AH / 450 CCA battery would be enough? Would the 55AH / 550 CCA battery bring any extra benefit in cold weather, etc.?

 

Thanks.

 

Edited December 29, 2022 by lxs602

[MtB]

I'd have thought the battery you bought was on the small side but perfectly capable of doing the job for a little single cylinder Sabb. 

 

How is it charged? How do you know the alternator works? 

 

But in particular, in what way did it fail to start the engine the following day? Did it turn over ever slower? Or turn over fine but never actually fire? Or something else?

 

 

[lxs602]

Hi, it tried to turn over, but it then wouldn't start. Then a few times it only clicked. I waited a while and it was the same cycle subsequently. I am not sure about the alternator set up unfortunately, 

Edited December 29, 2022 by lxs602

[BEngo]

A battery at 12.2v after resting  for an hour or more is about 50% charged.  It should get a fairly small engine going if all is well. IIRC the Sabb single uses starting 'cigarettes' for cold weather.  Do you have any of these and are you using them?  They will make the battery work less hard.

 

Also worth checking the cables.  They want to be at least 25mm squared in cross section area. There will probably be numbers on the crimped terminals, like 8-16 or 10-25.  The second one is the cross section area.  Places like 12v planet and vehicle wiring products will sell you made to length replacements.

 

You do not really need an AGM battery for starting.  Their strength is in resisting sulphation by having the minimum amount of acid.  You will find them ina  modern cars because  they can be left part discharged for short periods  without coming to too much harm.

 

As far as CCA, once you have enough for the starter motor any extra are superfluous.  CCA are measured at a temperature something like that of Michigan yesterday.  See if you can find out what your starter motor is, and then its lock torque current. 

 

I would say that if you can find an ordinary (not AGM)  lead acid battery with 370 CCA or better and as big in capacity as will fit your battery storage and your pocket then you will be fine.  Tayna, Battery Megastore and Shield Batteries all have decent reports on here.

[MtB]

3 minutes ago, lxs602 said:

Hi, it tried to turn over, but it then wouldn't start. Then a few times it only clicked. I waited a while and it was the same cycle subsequently. I am not sure about the alternator set up unfortunately, 

 

That sounds to me as though the battery is pancake-flat. What terminal voltage doe it have now, after it doing that?

 

I suspect you might be about to be learning a whole lot about the alternator setup, shortly! Can you post some photos of it, perhaps? Then you'll get some concrete advice.

Or best of all, a video of it failing to start. Upload to FB or youtube?

[Alan de Enfield]

The advantage of a bigger capacity battery is that you get 'more gos' at trying to start the engine.

If it is cold and the diesel a 'bit thick' then you may need several attempts, if there is a problem with the fuel supply, you may need several attempts. and you still need enough ooompf to turn the engine over once you have fixed the problem.

 

Better to have (too many Ah) and not to need, than need and not to have.

[lxs602]

46 minutes ago, BEngo said:

A battery at 12.2v after resting  for an hour or more is about 50% charged.  It should get a fairly small engine going if all is well. IIRC the Sabb single uses starting 'cigarettes' for cold weather.  Do you have any of these and are you using them?  They will make the battery work less hard.

 

Also worth checking the cables.  They want to be at least 25mm squared in cross section area. There will probably be numbers on the crimped terminals, like 8-16 or 10-25.  The second one is the cross section area.  Places like 12v planet and vehicle wiring products will sell you made to length replacements.

 

You do not really need an AGM battery for starting.  Their strength is in resisting sulphation by having the minimum amount of acid.  You will find them ina  modern cars because  they can be left part discharged for short periods  without coming to too much harm.

 

As far as CCA, once you have enough for the starter motor any extra are superfluous.  CCA are measured at a temperature something like that of Michigan yesterday.  See if you can find out what your starter motor is, and then its lock torque current. 

 

I would say that if you can find an ordinary (not AGM)  lead acid battery with 370 CCA or better and as big in capacity as will fit your battery storage and your pocket then you will be fine.  Tayna, Battery Megastore and Shield Batteries all have decent reports on here.

 

I don't have any starter 'cigarettes', that I know of. I am new to the boat and the engine. I will buy some for future cold weather if it will help.

 

The temperature on Wednesday was about 10C ? so not that cold.

 

I was wondering about buying a higher specification battery, as at 50% it clearly failed to do the job or to charge up properly.

 

I will return to the boat on Saturday and I will get some new thicker cables also, as they were a lot thinner than 25mm, more like 10mm I think. 
 

Edited December 29, 2022 by lxs602

[Machpoint005]

A higher capacity battery will take longer to recharge art a given rate. 

 

[Tony Brooks]

46 minutes ago, lxs602 said:

Hi, it tried to turn over, but it then wouldn't start. Then a few times it only clicked. I waited a while and it was the same cycle subsequently. I am not sure about the alternator set up unfortunately, 

 

There are all sorts of things it might be but first clean ALL the battery terminals so they mate bright metal to bright metal. A smear of Vaseline would not go amiss. That clicking sounds like low battery charge with undersized start cables, but it is an old engine so there are all sorts of other possible problems.

 

However unfair this sounds the fact is that unless you are very rich you are going to have to get down and dirty to find out exactly how the systems on YOUR boat work. If you don't we can only be of very limited help so you will end up paying again and again. We can help if photos are posted, for instance lets see a photo of your batteries showing all the wires. from that we will get a pretty good idea  if it is two banks (start and domestic) or just one, as it may well be on a boat with that engine. If it is just a single bank system then there will be no charge splitting but the battery sizes you talk about are likely to be several times too small for domestic AND starting use.

 

I am sure I asked you for two voltages and await the answer. I know that you may not have a multi-meter, but if you are going to need one (or be very rich) and know how to use it. Some help in the electrical notes here http://www.tb-training.co.uk .

 

You will need the engine manual to see where and how you screw the "cigarettes" into the engine and you do NOT have any heater/glow plugs, the "cigarettes" do a similar job.

 

If you don't understand anything by all means ask but please, post photos and and answer to the best of your ability any questions you get asked - even if you think the questions are pointless. Often such questions are to try to eliminate certain possibilities.

 

 

[Tony Brooks]

2 minutes ago, Machpoint005 said:

A higher capacity battery will take longer to recharge art a given rate. 

 

 

Not true.  A large capacity battery discharged to a given percentage of charge will take longer than a smaller one discharged to the same percentage, but a large capacity battery and a smaller capacity battery will take broadly the same amount of time to recharge if they had both been discharged by the same number of Amp hours. In fact I have a sneaky feeling that the larger plate area in the higher capacity battery may allow it to recharge marginally faster but I am far from sure on that.

[MtB]

13 minutes ago, lxs602 said:

I was wondering about buying a higher specification battery, as at 50% it clearly failed to do the job or to charge up properly.

 

Yes agreed, a bigger battery will turn the engine over for longer before going flat. 

 

I'm not sure that will be any help with your engine's starting problem though. A correctly working diesel will start within a few seconds of starting to turn over, so just beating it for longer until the battery goes flat won't get you far. I'm just concerned that you day-long cruise with the new battery failed to charge it. 

 

Unless it supplies your domestic services too, and you just ran it down again overnight. 

 

So many unanswered questions!!

 

 

[David Mack]

If it started fine one day, and the engine was then running for a full day, but wouldn't start the next my money is on the battery being too flat. That points to two possible causes.

1) The battery was not charging during the day's running.

2) Something else has used the battery power overnight.

Do you have a separate battery for domestic uses (lighting, water pumps etc)?

How is the charging current directed from the alternator to the domestic and start batteries? Do you have an automatic relay system, or one of those off-1-2-both switches? Or do you have a battery master switch with a removable red plastic key?

 

The existing battery may or may not be goosed. But if your charging system is not working correctly there is no point in replacing the battery, as the new one could be just as goosed in a few days/weeks/months time.

Edited December 29, 2022 by David Mack

[Tony Brooks]

4 minutes ago, MtB said:

I'm not sure that will be any help with your engine's starting problem though. A correctly working diesel will start within a few seconds of starting to turn over, so just beating it for longer until the battery goes flat won't get you far. I'm just concerned that you day-long cruise with the new battery failed to charge it. 

 

I suppose that keeping on turning on the starter would gradually warm the piston, head and bore so eventually it reached combustion temperature - until the battery was flattened or the starter motor failed due to heating, but I agree with everything you say.

 

I wonder if there is a can of Easystart hide away somewhere from the last owner. If so a worn out engine would be a good bet. I thought the "cigarettes" were only intended for subarctic temperatures and a direct injection engine is usually a very good starter, even in the cold.

2 minutes ago, David Mack said:

If it started fine one day, and the engine was then running for a full day, but wouldn't start the next my money is on the battery being too flat. That points to two possible causes.

1) The battery was not charging during the day's running.

2) Something else has used the battery power overnight.

Do you have a separate battery for domestic uses (lighting, water pumps etc)?

How is the charging current directed from the alternator to the domestic and start batteries? Do you have an automatic relay system, or one of those off-1-2-both switches?

 

The existing battery may or may not be goosed. But if your charging system is not working correctly there is no point in replacing the battery, as the new one could be just as goosed in a few days/weeks/months time.

 

All so true but the OP seems to have no idea what he has bought and can't answer those questions. If he could it would be easier to give him good advice. I fear we may have another "LadyG" here.

[Rob-M]

8 minutes ago, David Mack said:

or one of those off-1-2-both switches

I would be checking whether you have one of these switches to ensure the battery is getting charged whilst the engine is running and that you aren't discharging the engine battery once the engine is stopped.

[PaulJ]

@lxs602

Theres still  some manuals for your engine if it helps -available on the Sabb website - you  should find one here  https://www.frydenbo-industri.no/brukermanualer/fremdriftsmotor

If you are on facebook , join the small but perfectly formed (and very friendly) Sabb Owners Group where you should find the manual in the Files section

 

[MtB]

27 minutes ago, Tony Brooks said:

 

All so true but the OP seems to have no idea what he has bought and can't answer those questions. If he could it would be easier to give him good advice. I fear we may have another "LadyG" here.

 

To be fair he did say he's not on the boat but will be returning on Saturday.

 

On the other hand he also said he plans to fix it by getting a bigger battery and fitting fatter battery cables. Hopefully he will read the subsequent posts here and respond before wasting his money.

 

Reading between the lines I reckon his original battery was fine but discharged due to a duff alternator or absence of a domestic battery bank. The new battery only worked the once because it came fully charged from the shop, and his subsequent pattern of use has drained it too, just as it drained the first battery. 

[Tony Brooks]

Just now, MtB said:

 

To be fair he did say he's not on the boat but will be returning on Saturday.

 

On the other hand he also said he plans to fix it by getting a bigger battery and fitting fatter battery cables. Hopefully he will read the subsequent posts here and respond before wasting his money.

 

Reading between the lines I reckon his original battery was fine but discharged due to a duff alternator or absence of a domestic battery bank. The new battery only worked the once because it came fully charged from the shop, and his subsequent pattern of use has drained it too, just as it drained the first battery. 

 

Absolutely probably scenario, especially if it is just one battery bank for both start and domestic use. As far as the charging is concerned I think that he needs to use a decent voltmeter and see what happens to the voltage before starting, during starting, and once revving.

[nicknorman]

To answer the original question I wouldn’t get an AGM battery because they are a more expensive technology than you need. I get the feeling you went to a car battery shop - in which case you are likely to get a battery optimised for a car, not one optimised for a boat. I would just get a big standard sealed lead acid battery from a chandlers or battery specialist shop that does all sorts of batteries, not just for cars.

 

I’d be inclined to get a battery of similar Ah to the one you are replacing.

 

As to the underlying problem, as other have said it could be alternator not working or finger trouble (battery selector switch in the wrong place. Electricity is invisible so you need an instrument to measure it. I would advise getting your own multimeter, they are not expensive. Then you will know eg if the battery is being charged when the engine is running (voltage over 14v) or not (voltage 12.something).

 

If you install a new battery without checking and fixing any underlying problem, you just kick the can down the road - you will get a few starts out of it, and then you will be back to square one and probably have damaged the new battery by leaving it in a low state of charge.

[blackrose]

1 hour ago, lxs602 said:

 

I will return to the boat on Saturday and I will get some new thicker cables also, as they were a lot thinner than 25mm, more like 10mm I think. 
 

 

The recommendation was for 25mm2. That's a cross section, not diameter just in case that's what you were thinking. 

 

If the existing cables look to be 10mm dia then their cross sectional area excluding the insulation could be 60mm2. However, since you mentioned that someone told you the cables looked thin you probably meant 10mm2, in which case ignore everything I've just said.

39 minutes ago, Tony Brooks said:

All so true but the OP seems to have no idea what he has bought and can't answer those questions. If he could it would be easier to give him good advice. I fear we may have another "LadyG" here.

 

Hahaha. How to slag off two people with one barbed comment! 🤣

[BEngo]

OP.  Roughly where are you? 

Johnathan Hewitt (Johnno) at UCC Braunston is an acknowledged sage on the running and repairing of Sabb engines.  If you are close, or passing,   it would be worth having a chat with him.  UCC run one or two smaller hire boats with Sabb single cylinder engines in their smaller hire boats  so they must be reliable and easily started if well installed.

 

N

[Tony Brooks]

1 hour ago, blackrose said:

 

The recommendation was for 25mm2. That's a cross section, not diameter just in case that's what you were thinking. 

 

If the existing cables look to be 10mm dia then their cross sectional area excluding the insulation could be 60mm2. However, since you mentioned that someone told you the cables looked thin you probably meant 10mm2, in which case ignore everything I've just said.

 

Hahaha. How to slag off two people with one barbed comment! 🤣

 

Not really, I am sure the OP has little idea about his boat and the chances are that he will soon learn. I don't think he has any idea about just how much has to be taken into account to get a half decent diagnosis. that is not his fault, he is new to the game, it is how he reacts from now on. As for the other person I am fed up with requests for help and being told they can't answer questions for a variety of reasons. I know if one is less able it makes things difficult but you either want to learn and make the effort or pay. I don't see ask for help, kick the thing about a bit, pay a "professional" and then complain about the "professional" is any way to go on .

 

If I am honest I think I have been mixing up Lx602s with the chap with the "ignition" problem, but at lest no he has posted a photo se we know its an Isuzu so progress on both fronts.

[Richard T]

41 minutes ago, BEngo said:

OP.  Roughly where are you? 

Johnathan Hewitt (Johnno) at UCC Braunston is an acknowledged sage on the running and repairing of Sabb engines.  If you are close, or passing,   it would be worth having a chat with him.  UCC run one or two smaller hire boats with Sabb single cylinder engines in their smaller hire boats  so they must be reliable and easily started if well installed.

 

N

Agree with BEngo - Johnno is the man for all things Sabb. It would be worth getting the engine serviced by him. You would have to pay travelling time for him to come to the boat but it could save you a lot of money and angst!!

[lxs602]

Thanks a lot for the replies. This really is very helpful and there is a lot of information here.

 

A lot of fair questions and probably some information I should have mentioned to start with. I hope I have responded to everything.

 

The current starter battery is not new. I think the seller said he replaced it earlier this year, but I think it might not have been used much in the last few months.  There was also a "new" unused unconnected 12V leisure battery. When we measured it, I think it was something like 6.5V!

 

 

3 hours ago, Tony Brooks said:

 

Absolutely probably scenario, especially if it is just one battery bank for both start and domestic use. As far as the charging is concerned I think that he needs to use a decent voltmeter and see what happens to the voltage before starting, during starting, and once revving.

 

There are two separate leisure batteries to the starter battery. I did use the radio and one light for about an hour and a half in the evening. I think this shouldn't affect the starter battery if the system is wired properly. I will check out the set-up and the alternator, and also the voltage before / during / after - thanks for this.

 

 

3 hours ago, nicknorman said:

To answer the original question I wouldn’t get an AGM battery because they are a more expensive technology than you need. I get the feeling you went to a car battery shop - in which case you are likely to get a battery optimised for a car, not one optimised for a boat. I would just get a big standard sealed lead acid battery from a chandlers or battery specialist shop that does all sorts of batteries, not just for cars.

 

I’d be inclined to get a battery of similar Ah to the one you are replacing.

 

As to the underlying problem, as other have said it could be alternator not working or finger trouble (battery selector switch in the wrong place. Electricity is invisible so you need an instrument to measure it. I would advise getting your own multimeter, they are not expensive. Then you will know eg if the battery is being charged when the engine is running (voltage over 14v) or not (voltage 12.something).

 

If you install a new battery without checking and fixing any underlying problem, you just kick the can down the road - you will get a few starts out of it, and then you will be back to square one and probably have damaged the new battery by leaving it in a low state of charge.

 

It was a battery shop that I suppose probably did mostly cars, but it did have marine and traction batteries, so not aimed just at cars. They had wet batteries at similar ratings to AGM batteries that were a lot cheaper, so thanks for the recommendation as you'll have saved me a fair amount if I get a new battery.

 

I haven't changed any of the settings. I did buy a multimeter today, as well as some jump leads. I don't know why I didn't think to ask someone for a jump start. There were plenty of other boats around.

2 hours ago, BEngo said:

OP.  Roughly where are you? 

Johnathan Hewitt (Johnno) at UCC Braunston is an acknowledged sage on the running and repairing of Sabb engines.  If you are close, or passing,   it would be worth having a chat with him.  UCC run one or two smaller hire boats with Sabb single cylinder engines in their smaller hire boats  so they must be reliable and easily started if well installed.

 

N

 

I am in Birmingham, but it is moored outside Alvecote marina, so hello to anyone there. Thanks for the recommendation. If I don't get it working I will know who to call. I will probably try badgering the previous owner a bit.

 

2 hours ago, Tony Brooks said:

 

Not really, I am sure the OP has little idea about his boat and the chances are that he will soon learn.

 

You're right there. I have just noticed the tags at the bottom of your posts. I was just on your website this afternoon looking for information to start reading. Sorry to hear you don't do courses any more. I found some in Leicester (which I don't mind heading over to), but they are two days over the weekend, and I can't do Sundays. I found an online one  https://www.allabroad-sailing-academy.co.uk/learn-online/ but I don't know if that will be as good.

 

3 hours ago, blackrose said:

 

The recommendation was for 25mm2. That's a cross section, not diameter just in case that's what you were thinking. 

 

If the existing cables look to be 10mm dia then their cross sectional area excluding the insulation could be 60mm2. However, since you mentioned that someone told you the cables looked thin you probably meant 10mm2, in which case ignore everything I've just said.

 

Hahaha. How to slag off two people with one barbed comment! 🤣

 

The starter wires were visually about 10mm diameter including housing. Do you include the housing when mentioning thickness, or just the actual metal cable? The other wires to the terminals of the batteries were much thicker though, about 25mm thickness.

 

4 hours ago, Tony Brooks said:

 

There are all sorts of things it might be but first clean ALL the battery terminals so they mate bright metal to bright metal. A smear of Vaseline would not go amiss. That clicking sounds like low battery charge with undersized start cables, but it is an old engine so there are all sorts of other possible problems.

 

However unfair this sounds the fact is that unless you are very rich you are going to have to get down and dirty to find out exactly how the systems on YOUR boat work. If you don't we can only be of very limited help so you will end up paying again and again. We can help if photos are posted, for instance lets see a photo of your batteries showing all the wires. from that we will get a pretty good idea  if it is two banks (start and domestic) or just one, as it may well be on a boat with that engine. If it is just a single bank system then there will be no charge splitting but the battery sizes you talk about are likely to be several times too small for domestic AND starting use.

 

I am sure I asked you for two voltages and await the answer. I know that you may not have a multi-meter, but if you are going to need one (or be very rich) and know how to use it. Some help in the electrical notes here http://www.tb-training.co.uk .

 

You will need the engine manual to see where and how you screw the "cigarettes" into the engine and you do NOT have any heater/glow plugs, the "cigarettes" do a similar job.

 

If you don't understand anything by all means ask but please, post photos and and answer to the best of your ability any questions you get asked - even if you think the questions are pointless. Often such questions are to try to eliminate certain possibilities.

 

 

 

Happy to try and investigate. It would have been a good idea to take pictures or a video but that was something else I didn't think of. For the voltages, a reading of 12.2V was taken across the terminals, after trying to start it a few times, if that is what you meant?

 

How would you use the EasyStart? I'll pick up a can on the way.

 

I will check if the alternator is charging the batteries if I can get the engine running. I think I would need a new starter battery to get that far though, unless I maybe hope I can get a jump start. I was hoping to get the boat to Birmingham before new year while I have time to be moving it.

4 hours ago, PaulJ said:

@lxs602

Theres still  some manuals for your engine if it helps -available on the Sabb website - you  should find one here  https://www.frydenbo-industri.no/brukermanualer/fremdriftsmotor

If you are on facebook , join the small but perfectly formed (and very friendly) Sabb Owners Group where you should find the manual in the Files section

 

 

Thanks for this. I have avoided Facebook but I might make the sacrifice. I think I left the printed instruction booklet on the boat unfortunately but I think it was a model G. I will have a look over the manual tomorrow.

[Tony Brooks]

1 minute ago, lxs602 said:

There are two separate leisure batteries to the starter battery. I did use the radio and one light for about an hour and a half in the evening. I think this shouldn't affect the starter battery if the system is wired properly. I will check out the set-up and the alternator, and also the voltage before / during / after - thanks for this.

 

 

 

It was a battery shop that I suppose probably did mostly cars, but it did have marine and traction batteries, so not aimed just at cars. They had wet batteries at similar ratings to AGM batteries that were a lot cheaper, so thanks for the recommendation as you'll have saved me a fair amount if I get a new battery.

 

I haven't changed any of the settings. I did buy a multimeter today, as well as some jump leads. I don't know why I didn't think to ask someone for a jump start. There were plenty of other boats around.

 

I am in Birmingham, but it is moored outside Alvecote marina, so hello to anyone there. Thanks for the recommendation. If I don't get it working I will know who to call. I will probably try badgering the previous owner a bit.

 

 

You're right there. I have just noticed the tags at the bottom of your posts. I was just on your website this afternoon looking for information to start reading. Sorry to hear you don't do courses any more. I found some in Leicester (which I don't mind heading over to), but they are two days over the weekend, and I can't do Sundays. I found an online one  https://www.allabroad-sailing-academy.co.uk/learn-online/ but I don't know if that will be as good.

 

 

The starter wires were visually about 10mm diameter including housing. Do you include the housing when mentioning thickness, or just the actual metal cable? The other wires to the terminals of the batteries were much thicker though, about 25mm thickness.

 

 

Happy to try and investigate. It would have been a good idea to take pictures or a video but that was something else I didn't think of. For the voltages, a reading of 12.2V was taken across the terminals, after trying to start it a few times, if that is what you meant?

 

How would you use the EasyStart? I'll pick up a can on the way.

 

I will check if the alternator is charging the batteries if I can get the engine running. I think I would need a new starter battery to get that far though, unless I maybe hope I can get a jump start. I was hoping to get the boat to Birmingham before new year while I have time to be moving it.

 

Thanks for this. I have avoided Facebook but I might make the sacrifice. I think I left the printed instruction booklet on the boat unfortunately but I think it was a model G. I will have a look over the manual tomorrow.

 

 

It seems that you have one alternator but it might be a dynamo or daynostart. The latter two are no longer much use for charging most leisure boats. It might even be an alternator and a dynostart, in which case the dynostart would both start the engine and then charge the start battery, so in that case the charge part might not be working. Lets assume you have a proper starter motor and an alternator charging both  banks, if so this means the charge must be split between both banks in a way that prevents one bank discharging into the other when the engine is not running. This might be a big four position rotary switch that you have to twist to the correct position, a relay of some sort of a split charge diode system. The latter two shoudl be automatic buyt may be malfunctioning - hence the request for voltages.

 

Agree, no need for an AGM start battery, open cell will do and it will be easier for you to diagnose with a hydrometer.

 

No reason that you should not OCCASIONALLY jump start from the domestic bank as long as they are well enough charged, but be aware most retail jump leads do not have a thick enough conductor unless they are for diesel trucks. I make my own for welding cable.

 

12.2V after a few attempts to start indicates the battery is about a true half charged (for battery longevity consider it fully discharged). I would expect a battery at 12.2V rested voltage to start a diesel. The readings I would want to see are as follows, all between the start battery positive and negative:

 

1. Battery voltage before attempting to start.

2. The voltage as you try to start it with the starter working. Expect a minimum of 10 volts but I find 9.5 is often OK.

3. The voltage soon after the engine is started and revved up. The voltmeter should jump up to above reading 1. I would expect around 13.5 or more and then gradually rising to around 14.2 to 14.4 volts as the battery charges.

 

Easystart is the work of the devil in most peoples hands, If the engine will not start without it, it soon won't stat at all. My mention of it was because if you did find some  it could indicate the engine is well worn, nothing more than indicate. Do not get Easystart anywhere near your engine unless it is proven the engine is worn out. You would be likely to damage it even more.

 

 

 

 

 

 

 

[LadyG]

6 hours ago, MtB said:

I'd have thought the battery you bought was on the small side but perfectly capable of doing the job for a little single cylinder Sabb. 

 

How is it charged? How do you know the alternator works? 

 

But in particular, in what way did it fail to start the engine the following day? Did it turn over ever slower? Or turn over fine but never actually fire? Or something else?

 

 

I read it as he is buying a replacement, asking about which to buy?