BMC 1.5 engine issues

[Tony Brooks]

27 minutes ago, The Alchemist said:

Are you thinking that maybe why I'm having issues with starting the engine in a morning?

 

If the engine battery is failing or if it is not getting fully charged then yes, because of slow cranking speed, BUT, as I understand your set up the alternator must be connected to the start battery so unless the lithium load has dramatically depressed the charging voltage it should always be well charged. However, having said that, I am concerned about the 13.8 volts you told us about. That would take a very long time to fully charge a LA battery.

 

Cna you measure the start battery voltage while you are cranking the engine? It should not drop below 10 volts (Lucas), although I would be happyish with 9.8V

1 minute ago, The Alchemist said:

The split chargers purpose is to charge two lead acid battery's, the primary is the starter battery and the secondary is the leisure battery. The lithium battery has to have a lead acid battery between itself and the alternator as the output of the alternator is not adequate for lithium batteries.

The dc to dc charger then adjusts the output from the lead acid battery to the charge requirements of the lithium battery so that they are then charged through the system.

 

I understand now, so which battery is the alternator connected to, the engine LA or the domestic LA? If it is the domestic LA then that warm relay might indicate volt drop which would not help start battery charging.

[The Alchemist]

54 minutes ago, hider said:

 

How do you eventually get the engine started in the morning?

It took me a while to resolve that. After removing the solenoid I eventually discovered a broken solder joint on a wire coming out of it which wasn't making a good contact. I carry a small blow torch with me with which I was able to melt the solder to improve the contact. 

Which you've kindly just reminded me that I need to apply some more fluxed solder as I lost a little while heating it up. 👍

57 minutes ago, Tony Brooks said:

 

If the engine battery is failing or if it is not getting fully charged then yes, because of slow cranking speed, BUT, as I understand your set up the alternator must be connected to the start battery so unless the lithium load has dramatically depressed the charging voltage it should always be well charged. However, having said that, I am concerned about the 13.8 volts you told us about. That would take a very long time to fully charge a LA battery.

 

Cna you measure the start battery voltage while you are cranking the engine? It should not drop below 10 volts (Lucas), although I would be happyish with 9.8V

 

I understand now, so which battery is the alternator connected to, the engine LA or the domestic LA? If it is the domestic LA then that warm relay might indicate volt drop which would not help start battery charging.

The alternator charges both batteries that is the purpose of a split charger however now you've raised this issue then I think I may switch to a different type of split charger. The current split charger as you suggest priorities the one with the highest demand which is going to be the lead acid which is connected to the lithium battery so it will be prioritising that and only charging the starter battery when the demand from the lithium battery drops (i.e. when it's almost charged). But there is another split charge relay that only begins charging the secondary battery when the primary battery has been fully charged.

I need to switch my charger to that type so as the starter battery becomes fully charged before the charging of the secondary battery(s) kick's in.

Thank you. 👍

[Mikexx]

1 hour ago, The Alchemist said:

The split chargers purpose is to charge two lead acid battery's, the primary is the starter battery and the secondary is the leisure battery. The lithium battery has to have a lead acid battery between itself and the alternator as the output of the alternator is not adequate for lithium batteries.

The dc to dc charger then adjusts the output from the lead acid battery to the charge requirements of the lithium battery so that they are then charged through the system.

 

Can you confirm the wiring is like:

 

 

In which case there isn't a need for the LA leisure battery. Given the DC-DC load is within the alternator capacity I doubt the alternator would suffer any damage from extended charging.

[Tony Brooks]

22 minutes ago, The Alchemist said:

It took me a while to resolve that. After removing the solenoid I eventually discovered a broken solder joint on a wire coming out of it which wasn't making a good contact. I carry a small blow torch with me with which I was able to melt the solder to improve the contact. 

Which you've kindly just reminded me that I need to apply some more fluxed solder as I lost a little while heating it up.

 

My guess is that it was probably the pull in coil that was not soldered properly, that would prevent the solenoid pulling in with a good clunk. It would be relying on the much weaker (lower current) hold in coil to try to move the solenoid. The other solder pad has two wires in it.

 

If it has stopped playing up then well done, I doubt there is anything else wrong with it, and if it started when an engineer was there

I doubt they would have found or noticed it.

 

8 minutes ago, Mikexx said:

 

Can you confirm the wiring is like:

 

 

In which case there isn't a need for the LA leisure battery. Given the DC-DC load is within the alternator capacity I doubt the alternator would suffer any damage from extended charging.

 

That is why I was questioning his setup. I have no idea why he needs the leisure LA battery UNLESS the alternator is connected to it, but that is relatively easy to alter to the engine battery. He may be simply wearing out the LA battery. I agree the DC to DC converter, as it is set up, will prevent overloading the alternator

[The Alchemist]

15 minutes ago, Tony Brooks said:

 

My guess is that it was probably the pull in coil that was not soldered properly, that would prevent the solenoid pulling in with a good clunk. It would be relying on the much weaker (lower current) hold in coil to try to move the solenoid. The other solder pad has two wires in it.

 

If it has stopped playing up then well done, I doubt there is anything else wrong with it, and if it started when an engineer was there

I doubt they would have found or noticed it.

 

 

That is why I was questioning his setup. I have no idea why he needs the leisure LA battery UNLESS the alternator is connected to it, but that is relatively easy to alter to the engine battery. He may be simply wearing out the LA battery. I agree the DC to DC converter, as it is set up, will prevent overloading the alternator

Yes. Your diagram pretty much displays my set up. I was given a similar diagram of the recommended layout for a lithium battery system when I purchased it from the supplier and it included a lead acid battery in the diagram. I assumed it was to encourage the alternator to continue putting out a charge into the system and so that when the lithium battery was at full charge the dc to dc charger would cut out allowing the lead acid to fully charged as a means to kickstart the dc to dc charger when the system starts. I never questioned the reason behind it!

[GBW]

It seems likely this is too late but it is possible to buy a cast aluminium rocker cover that is in a different league to the tin one.

Refer to my relevant post in this forum;- That leaky rocker box.

Edited October 17 by GBW
addendum

[Ex Brummie]

On 16/10/2024 at 18:43, The Alchemist said:

It took me a while to resolve that. After removing the solenoid I eventually discovered a broken solder joint on a wire coming out of it which wasn't making a good contact. I carry a small blow torch with me with which I was able to melt the solder to improve the contact. 

Which you've kindly just reminded me that I need to apply some more fluxed solder as I lost a little while heating it up. 👍

The alternator charges both batteries that is the purpose of a split charger however now you've raised this issue then I think I may switch to a different type of split charger. The current split charger as you suggest priorities the one with the highest demand which is going to be the lead acid which is connected to the lithium battery so it will be prioritising that and only charging the starter battery when the demand from the lithium battery drops (i.e. when it's almost charged). But there is another split charge relay that only begins charging the secondary battery when the primary battery has been fully charged.

I need to switch my charger to that type so as the starter battery becomes fully charged before the charging of the secondary battery(s) kick's in.

Thank you. 👍

is it not just a case of swapping the charging leads on the relay?

[Tony Brooks]

1 minute ago, Ex Brummie said:

I need to switch my charger to that type so as the starter battery becomes fully charged before the charging of the secondary battery(s) kick's in.

 

I don't think that you do, start batteries only have to supply a few Ah to start an engine in tolerable condition, so they are always more or less fully charged. They only need a few Ah top up. The only thing that might cause this not to be so is if you connect the alternator to a lithium battery, so the high charging current pushes the voltage down to below about 13.8 volts, but this does not apply to your system, you are charging a LA battery with a B2B preventing high charging currents to the lithium.

 

Split charge relays prioritise nothing, relative battery voltage does that. As log as you have a simple split charge relay between the domestic LA battery and engine LA battery, the battery with the lower voltage (domestic probably) will draw more of the charging current than the battery with the higher charge (start battery probably). As above, as long as the voltage is above about 13.8 then both will charge.

 

 

[Mikexx]

On 16/10/2024 at 19:40, The Alchemist said:

Yes. Your diagram pretty much displays my set up. I was given a similar diagram of the recommended layout for a lithium battery system when I purchased it from the supplier and it included a lead acid battery in the diagram. I assumed it was to encourage the alternator to continue putting out a charge into the system and so that when the lithium battery was at full charge the dc to dc charger would cut out allowing the lead acid to fully charged as a means to kickstart the dc to dc charger when the system starts. I never questioned the reason behind it!

 

You are correct in that when Lithium battery's BMS system disconnects the batteries you still need to present a load to prevent the alternator output voltage from climbing to high values and destroying anything connected to it.

 

However you already have the starter battery that will limit voltage and present a load in these circumstance. So there is no need for the second LA leisure battery. It's one time a split charge relay or voltage sensitive relay or a DC to DC converter should work well with a single alternator.

 

I, for instance, have a second alternator and should I change to lithium I would leave a lead acid for those occasions where load dumps would destroy anything connected to the alternator, and quite possibly the alternator itself.

 

 

[Tony Brooks]

11 minutes ago, Mikexx said:

However you already have the starter battery that will limit voltage and present a load in these circumstance. So there is no need for the second LA leisure battery. It's one time a split charge relay or voltage sensitive relay or a DC to DC converter should work well with a single alternator.

 

Not sure a VSR would work to limit the charging current drawn by the lithium battery, that is where the B2B comes in. I agree with what you say, keeps it simple.

[Mikexx]

10 minutes ago, Tony Brooks said:

 

Not sure a VSR would work to limit the charging current drawn by the lithium battery, that is where the B2B comes in. I agree with what you say, keeps it simple.

 

They seem to kick in around 13.8V and disconnect below 13V. I'm not sure how accurate they are.Some claim to be 'software controlled'. It does generally ensure the starter battery gets a chunk of current first.

 

The usual technique top limit current to lithium batteries is to use a long cable of a cross-sectional area to cope with the target current to introduce some resistance in the charging circuit. Some say that method is a bodge and frown upon it. If a suitably sized cable is used and clipped appropriately I don't see the issue. In practice the length chosen by trial and error and it's not very long.

[The Alchemist]

2 hours ago, GBW said:

It seems likely this is too late but it is possible to buy a cast aluminium rocker cover that is in a different league to the tin one.

Refer to my relevant post in this forum;- That leaky rocker box.

Yes. I was expecting this on Saturday but it turned up today. 😊

It came with a cork gasket but I've applied heat resilient silicone which appears to have worked well. 

[dmr]

A chinese MG in a boat 😀 That will upset a few purists.

[The Alchemist]

1 minute ago, dmr said:

A chinese MG in a boat 😀 That will upset a few purists.

It's done the trick!

[Peugeot 106]

Repeat. That’s what I hope the forum is for. Long may it continue

[GBW]

15 hours ago, dmr said:

A chinese MG in a boat 😀 That will upset a few purists.

No - its genuine MGB (and maybe A).

[dmr]

1 hour ago, GBW said:

No - its genuine MGB (and maybe A).

 

Yes, just after I posted I thought a bit more and could not think why China would be making rocker box tops for the old B series.  I assume that are not still making that engine ? 😀

[hider]

30 minutes ago, dmr said:

 

Yes, just after I posted I thought a bit more and could not think why China would be making rocker box tops for the old B series.  I assume that are not still making that engine ? 😀

1.5D was made in India and the 1.8D in Turkey. I suspect that production may well have ceased. India used the engines in the Ambassador cars which were based on the old pre Farina Morris Oxford.

[Tony Brooks]

2 hours ago, GBW said:

No - its genuine MGB (and maybe A).

 

I thought he MGA had a very different engine - twin overhead cam possibly.

[hider]

41 minutes ago, Tony Brooks said:

 

I thought he MGA had a very different engine - twin overhead cam possibly.

No, straight B series OHV 4 cylinder in various capacities and stages of tune.  Twin cam was a different model.

[NURDLE]

MGA had both a single and twin cam version.  There is a great MGA website that has lots of good info about the petrol version.  Some applies to diesels.  https://mgaguru.com/mgtech/engine/en1.htm

 

[The Alchemist]

Thank you. 👍

[Peugeot 106]

Phew! I thought for a moment you were going to say it was leaking again!