Lagondaforum

Subject: Battery advice for LG45

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I need some help in choosing batteries (6 volt) for an LG45.
My understanding of what I need are virtually zero. Ah rating seems to be the the measure of output. What sort of figure do I need to look for. Size is a restriction but I can cope with that. . . .
I have found batteries with 71Ah and 85Ah that would fit (the 85Ah is a bit tight). Anything else I need to take into account?
Any help appreciated.
David

Subject: Re: Battery advice for LG45

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Hi David,

Amp / hours I think is not so much output as an indication of how long the battery can sustain under load. The original equipment for my V12 and LG6 was 2 Lucas SLTSR15E batteries, and I daresay the same for the LG45. Unfortunately I've tried previously to find a specification for that number, but without success; even the classic batterymaker (Lincon I think) I spoke to had no clue!
Firstly, I think I'm correct in saying the Ah won't increase, just the voltage, with a pair of batteries, necessarily connected in series. When I bought my V12, it came with a huge pair of Crompton Parkinson batteries, which must have been seriously larger than those originally specified. Quite why the previous owner fitted those I'm unsure; modern batteries are more efficient so a smaller battery would undoubtedly be just as good. All I can say is that the CP batteries ensured starting was never a problem!
My LG6 came fitted with a DETA 77Ah battery, which worked fine, and was probably unnecessarily powerful. I ran the car for severald days on the Champagne rally with no charging due to a fault with the regulator. That battery of course didn't survive my LG6 being laid up 2000 -2016, so I used the Shield 291 battery from my RMB, which had thoughtfully run a big end. The Shield battery is 58Ah, and had no problem starting the LG6 ... with the proviso that compressions are low due to idiot "professional engineers" machining out the bores too far. I've run the car day and night over considerable mileages, and never had a problem. Given that, I think the 71Ah one would give you sufficient margin.

I am still recommissioning my V12, and ideally hope to find 6v batteries for that that are dimensionally correct, have original appearance (visible bus bars), and ideally will be correct enough for the original battery retaining bars to be used. I've measured up, and the batteries would need to be 26-27cm long at the top surface, have a maximum body width below the top of 20cm, and be 16 - 18cm tall, measured from the battery base to the top surface of the battery.

Hopefully this is of some help to you. Do your dimensions tally with mine?!

If anyone has come across a battery supplier able to supply such dimensionally correct batteries, please let me know!

Laurence

Subject: Re: Battery advice for LG45

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I am no expert on batteries but surely you need to look at the "CC" (cold Cranking) figure to see if the batteries will be sufficient to start the engine. From memory I think you should need cold cranking of 600 CC plus ?
The AH rating is something different and relates to the capacity of the battery (Amps per hour) i.e. 65AH is 65 amps drain for one hour. If you therefore left the headlights and a lot of other things on totalling a discharge of 65 amps (assuming that the engine is not running i.e. no charging) then at the end of one hour the battery would be flat.
Therefore ( and I stand to be corrected by more knowledgeable members) a 65AH battery should be fine for an LG45 but you need to look carefully at the cold cranking figure.

Subject: Re: Battery advice for LG45

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Hi Laurence,

Many thanks. The original batteries according to the build sheet were Z4166 Lucas Twin. Spec now unknown?
Maximum space that the battery tray will allow is 230 x 173 x 190 mm high. The height of 190 mm is to the top of the body to allow room for a cover. Any higher would hit the underside of the bonnet. I will probably go with the 71Ah battery. Need to check if the quoted height includes the terminals, presumably it does.

David

Subject: Re: Battery advice for LG45

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Hi David,
Z4166 is a completely different style of reference, possibly an earlier iteration of the ones for the V12, as your dimensions aren't markedly different to mine.

I sent you an email from your profile on here, did you receive that? I aimed to include a scan of a 1940 Lucas battery advert, which depicts a battery with holes in the casing edges which I suspect the centre battery retaining bar would engage with. Interestingly, the battery is shown without a cover, so presumably Lucas had stopped supplying these, perhaps as a nod to wartime necessities. That said, I have one of these covers, a good inch or more deep. It would be great to see a period photo of the batteries in late 30s Lagondas! If you didn't receive my email, you can find mine in the Register, email and I'll respond.
Laurence

Subject: Re: Battery advice for LG45

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Cold cranking amps (CCA).
Most of the ones I've been looking at don't quote CCA and those that do are much lower 395 to 450. I did find one that quoted 360 with the comment: "This battery incorporates High Cranking Amps (CCA) for superior starting power".

The highest I can find is 500 but that is a 12 volt battery and enormous.

David

Subject: Re: Battery advice for LG45

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Hi Laurence,

I didn't get your email but sounds interesting. Perhaps you could send again?
Photo from The Autocar (April 10th 1936) shows the batteries in an LG45 with battery covers which look the same as the other photo of a period battery ad.
The battery tray of my LG45 had the remains of a leather strap riveted to it one end, presumably to hold the battery down in some way.
David

Thumbnails of attached images:

Subject: Re: Battery advice for LG45

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Hi David,
Problem was my file size was too large to download here, too much faffing to sort it. But whilst yours is a different advert and view, that's pretty much the same battery in the 1940 advert ... and now I've magnified it, it does show a lid.
Your other photo is just the job ... except, for me, not much help! I assumed a similar arrangement, but the V12 battery compartment is one long "box", with the batteries mounted sideways, whereas mine would have been end to end.
I doubt a leather strap would have been used by the factory, as I would imagine acidic battery fumes would rot that pretty quickly. If original, maybe it held a tool/tools?
Unfortunate Arnold's " ... in Detail" book doesn't extend to battery compartment photos. Likewise my book of reprint road tests doesn't help, although there is another LG45 battery photo. I can't detect any straps or bars, and to me, the neatest solution would have been to run a long screw down from those holes in the battery lid and casing, down to captive nuts in the box floor.
Laurence

Subject: Re: Battery advice for LG45

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Hi Laurence,
The remnants of leather look original although seems unlikely as a fixing. They are front and back of the battery riveted to the battery tray at the base of where the battery sits. Can't see they could have held tools etc down there?
David

Subject: Re: Battery advice for LG45

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Hi David,
Ah, I see. Interesting! But I can't see how leather straps, presumably with buckles, would have provided the precise and strong tension needed to retain such heavy items. Those photos don't show straps, either. We need a time machine!
Laurence