What should voltage read on a cold start?

Hello everyone hope you all had a good new year and that.
I didn’t start my 2005 defender td5 for a few days and this morning it was very cold -4, when I put the ignition on my voltage on my reader said 11.5 and then when I went to start her it was like almost the engine turned over quite slowly so didn’t start first revolution as it normally does, but the second, the battery was only new last year and was the correct one from Tanya bats any ideas peeps?

Sounds low to me, although glow plugs should be on. More importantly you need to watch the voltage while the starter is engaged. If it goes much below 11 then your battery is flat

A reading of 12.65-12.77 volts means your battery has a full charge. 12.45-12.54 volts means you have a 75% charge, 12.24-12.29 is 50% charged, and 11.99-12.06 volts is 25% charged. 11.75-11.89 volts means your battery is dead.
I assume with ignition on there is minimal load, what was it ignition off
And what with engine running at high idle, is alternator working ok
Have you got a drain on the battery overnight

Discodevon said:

new last year and was the correct one from Tanya bats any ideas peeps?

Click to expand...

First thing I'd check is that it is the correct one - the one they recommend for a 300Tdi D1 is 54 Ah - which is hilarious - it might start it twice before the plates buckle .... And, ..... yes, this is probably a mistake on their part, but ......

Thanks lads, the battery is a 1000cca enduroline but seemed to not push the engine over hard enough at -4 my immobiliser light flashes every second would this drain the battery down a tad in 5 days without starting?

Discodevon said:

Thanks lads, the battery is a 1000cca enduroline but seemed to not push the engine over hard enough at -4 my immobiliser light flashes every second would this drain the battery down a tad in 5 days without starting?

Click to expand...

Yes it's a drain but shouldn't impact a healthy battery.
Is your alternator healthy?

My voltmeter (key in stage 2) reads 11.9v 99% of the time. Starts pretty well in the cold and jumps to 14.4v soon as its started. Then down to 13.9v once everythings on and running.

Doesn't sound too bad to me, you're better off checking voltage when the ignition is off, ie no/minimal load

I would check the battery with a good multimeter, your volt meter might not be accurate.

Col

Discodevon said:

Thanks lads, the battery is a 1000cca enduroline but seemed to not push the engine over hard enough at -4 my immobiliser light flashes every second would this drain the battery down a tad in 5 days without starting?

Click to expand...

Enduroline is Tanya's own brand of battery and I'm afraid, like other similar suppliers, are total rubbbish. There is nothing wrong with buying batteries mail order, but just ensure it is a genuine brand from a well known manufacturer. I've had early failure with own brands in both starting batteries and leisure batteries. The websites always push them at you as giving more cranking amps and higher capacity than the genuine brand you are looking at. They are always at a lower price, so it seems like a no brainer, until you realise they are total crap and giving the supplier maximum profit.

My last battery for my TD5 is a Varta brand (made in same factories as Bosch - but cheaper). I can let my truck sit for at least 2 weeks in the winter and it will always fire on the first twitch of the starter with minimal measured voltage drop from full charge.

v8landyman said:

My last battery for my TD5 is a Varta brand (made in same factories as Bosch - but cheaper).

Click to expand...

Strangely i changed a Varta and a Bosch silver both failed in the second winter while i've got a Bullet batt from tanya and it's still going strong in the 5'th winter now.

sierrafery said:

Strangely i changed a Varta and a Bosch silver both failed in the second winter while i've got a Bullet batt from tanya and it's still going strong in the 5'th winter now.

Click to expand...

I know it's strange isn't it, just about everyone has a different experience with starter batteries? Haven't heard of Bullet, is that another own brand?

I dont know who owns the brand i just know that it's a good battery which has survived 4 hard winters here unlike the other branded ones

Thank you for the reply’s everyone! This morning she started first swing at -1 and with the ignition on the voltage read 11.6 or 11.7 and it read 12.4 volts with the ignition on one click so maybe the battery from Tanya isn’t enjoying its self in the cold, it matched the original part number but had 1000 cca so thought it would be plenty

Those readings ar very good actually

I had a look at mine this morning. Ignition on and the voltage drops to around 11.2v, but consider the glow plugs are taking a fair draw. Engine running and it goes straight to 14.5v. By the time I got to work 3 miles away it was on 14.2v. I use Hankook MF31-1000 batteries - 115aH / 1000cca.

Cheers everyone, mine jumps to 14,4v once started so perhaps my landy didn’t like being sat in the cold for days without being started, I’m guessing the colder it is the more power the fuel pump uses as well? The glow plugs haven’t ever been changed either, if these were dodgey would they play silly. Buggers with the voltage ?

Old oil can get quite gloopy when it's cold, that'll make the oil pump harder to turn, leading to extra effort on the starter

Discodevon said:

Cheers everyone, mine jumps to 14,4v once started so perhaps my landy didn’t like being sat in the cold for days without being started, I’m guessing the colder it is the more power the fuel pump uses as well?

Click to expand...

A good batery should not be affected by that cos i doubt that you had below -15*C there and mine starts even after 10 days in such temps

kermit_rr said:

Old oil can get quite gloopy when it's cold, that'll make the oil pump harder to turn, leading to extra effort on the starter

Click to expand...

Good point, I am using a heavy 10w40 so that may be playing a part too

thank you