Ian Comerford Posted January 5 Posted January 5 Hopefully this is of interest. If any of you were following my last couple of road trips to France you will recall a battery/starting problem that reared its ugly head from time to time. The problem turned out to be a mismatch between what the starter motor needed and what the battery could supply. Many years ago I fitted an Odyssey PC680 lightweight battery. It was less than half the weight of the standard boat anchor and did its job well for ages. Then, four years, ago I fitted a beautiful Brise Co-axial high torque start motor. I didn’t realise at the time that it required 330 CCA to do its job and thanks to my clever neighbour Peter (930 owner) I now know that is couldn’t always provide sufficient oomph to start the car, having nowhere near 330. I bought a bigger Odyssey 925 AGM which provided enough and off we went. Everything was ok until the weather got a bit colder a few weeks ago. The battery conditioner said the charge was good, it turned over a little sluggishly but not bad, but wouldn’t start. I slaved the Lancia battery to it which isn’t very big but still no start. Bugger! Today, Peter came round to join the diagnostics. There was enough power to turn the engine over well, we smelt fuel so that side was working. Next was to check for spark, so I removed a plug and cranked it over. The spark was a bit yellow, not a nice strong blue one. Peter suggested trying the battery from his 930, a lithium iron one apparently less susceptible to the cold. He kindly removed it from his car and I fitted it. It literally took half a turn of the engine to start, really quick! So, whilst the battery can provide sufficient power to the starter, it struggles to do this when cold. It seems the starter motor takes the lion’s share of the power and there isn’t enough for the CDI to do its job (thought I had fixed this with the bigger 925……). And I guess this could apply to any of you that have fitted high torque starters over the years. Has anyone compared what the original starter requires against a high torque one? I have attached a picture of Peter’s Li battery which is very light but fitted in a large case which includes a fitted voltmeter. The big question is, what do I replace it with? I would like to keep it light if possible, but really want to avoid inducing starting issues by having something that cannot perform when it gets a little colder. Peter has ordered a sodium battery which it seems is new technology. But I really want reliability (with less weight…). Any recommendations gratefully received and hopefully Peter will chime in with detail of his current Li battery and also the new one he has inbound.
mean in green Posted January 5 Posted January 5 It’s called Cold Cranking Amps with good reason: the energy required to crank increases as the ambient temperature drops (and battery condition to some extent), so really you want the highest CCA rating you can find. Also in the smallest battery packaging, which would be nice if it was also the lightest and oh, as many Amp hours as possible too please. It’s all a compromise.
Ian Comerford Posted January 5 Author Posted January 5 Thanks Simon, I just hadn’t thought about this detail at the time. Any recommendations?
carrpet Posted January 5 Posted January 5 The Lithium Battery that Ian is referring to is now 3 years old. Lithium batteries are affected by cold but the CCA spec is so high at 1800, even at 5C is has loads of surplus umph, so the voltage drop impact on the ignition is virtually non existent. Voltage 12.8v Capacity 62AH CCA 1800 Weight 10kg from memory Ian's Lead AGM battery is dropping voltage in the cold so that the ignition spark we observed was noticeably weak
carrpet Posted January 5 Posted January 5 Just now, carrpet said: The Lithium Battery that Ian is referring to is now 3 years old. Lithium batteries are affected by cold but the CCA spec is so high at 1800, even at 5C is has loads of surplus umph, so the voltage drop impact on the ignition is virtually non existent. Voltage 12.8v Capacity 62AH CCA 1800 Weight 10kg from memory Ian's Lead AGM battery is dropping voltage in the cold so that the ignition spark we observed was noticeably weak However, if I were to purchase today I would go with Sodium Ion rather than Lithium. Sodium batteries operate as standard over a much wider temperature range, and can operate at < -20C. They are also much lighter and smaller with a similar high CCA (slightly lower weight for weight than Li). Sodium batteries are not yet available in the UK via normal channels. Voltage 12.8V Capacity 60AH CCA 1300 Weight 7.5kg Size: 230*175*162mm Operating Temperature range -30C to +70C Warranty 5 years Cost including a sodium ion trickle charger is £150
Roy M Posted January 5 Posted January 5 Is it just me being tight (I'm northern) but wouldn't it be worth buying Peter's Lithium battery if he's replacing it (if he wants rid) and giving it a prolonged test?
carrpet Posted January 5 Posted January 5 1 hour ago, Roy M said: Is it just me being tight (I'm northern) but wouldn't it be worth buying Peter's Lithium battery if he's replacing it (if he wants rid) and giving it a prolonged test? I was born in Northumberland Roy so almost as tight as a Scotsman !!
carrpet Posted January 5 Posted January 5 12 minutes ago, Roy M said: Born Sunderland so not that far away! Your a Mackem then !
Roy M Posted January 5 Posted January 5 (edited) Not a .mag are you?? Believe it or not I've got a friend who's a mag so I'm very tolerant. Edited January 5 by Roy M
Ian Comerford Posted January 5 Author Posted January 5 56 minutes ago, carrpet said: I was born in Northumberland Roy so almost as tight as a Scotsman !! Which means I would never by anything from either of you due to the price!! Meanwhile, back on topic, any battery recommendations?
mean in green Posted January 5 Posted January 5 3 hours ago, Ian Comerford said: Thanks Simon, I just hadn’t thought about this detail at the time. Any recommendations? Sorry, not recently Ian. I’ve always thought Varta or Bosch were the go to brands, but I wonder if it is still the case going by online chat around their ownership. I don’t think sodium ion car batteries are far off.
Roy M Posted January 5 Posted January 5 My Bosch Silver is probably 14 years old and still going strong. Keep it on a Ctek charger when parked and had no issues. I did replace the wife's BMW battery with a Duracell one and it seems a quality item.
Ian Comerford Posted January 6 Author Posted January 6 Thanks Roy, I hoping not to go back to lead acid but let’s see what other feedback comes. Does anyone else have experience of Li batteries or other less weighty AGM ones?
Ian Comerford Posted January 6 Author Posted January 6 Has anyone had experience of Optima AGM batteries, or are they really just the same capability as Odyssey?
hagarep Posted January 7 Posted January 7 Ian. I have a Lightweight High Torque Starter from Stuttgart Classica, powered by a Varley Red Top RT35, specs below: I keep it on a Noco trickle charger and watch it via BMS. I have never had a starting issue, but the batteries don't last if you don't keep them charged. Voltage: 12V Capacity: 28Ah CA: 530A CCA: 410A Terminals: M6 Female Weight: 10.7kg Dimensions(mm) LxWxH: 165 x 176 x 125 Jason
Ian Comerford Posted January 7 Author Posted January 7 Thanks Jason, that’s really useful detail. The AHC of your battery is quite low relative to what is recommended for our cars, which I assume is why it needs constant trickle charging. Seems it’s all about compromise if I stick with lead acid.
Ian Comerford Posted January 11 Author Posted January 11 Any more thoughts on recommended batteries? Thank you
mean in green Posted January 12 Posted January 12 More of an observation than a recommendation: having lived with this for a while, I found the novelty of a compact lightweight lead acid battery soon wore off. Not sold as a starter battery, so no CCA rating but it does crank ok. 21 amp hours implies maybe around ten useable standby hours, but in reality I found that it was less than that. It was so bad it was almost like running total loss ignition. The only way to be sure it would start when coming back to the car was to manually disconnect it. Every. Single. Time. Put up with it for a while, but gone back to full fat 740CCA 80Ah Yuasas.
Ian Comerford Posted January 12 Author Posted January 12 Thank you, again. It’s useful to hear something that is along my current line of thinking. I really like the idea of a small light battery but it seems you cannot get it if you require high ish CCA (due to my starter motor)and also want it to be able to go a decent time without charging (road trip/touring holiday scenario). My current Odyssey just doesn’t like the cold…..
Beaky Posted January 13 Posted January 13 (edited) out of curiously , how much weight are you saving and is that really noticeable in the real world? I have just changed the batteries on my SLK and sons Boxster and gone for Yausa versions. The previous batteries were Bosch and probably 10 years old just starting to have cold weather issues. Edited January 13 by Beaky
Ian Comerford Posted January 13 Author Posted January 13 Withe the first Odyssey battery it was a 10kg saving……at the wrong end of the car! I’m fully supportive of the concept of the aggregation of marginal gains, so it made sense.
Jonny Hart Posted January 14 Posted January 14 Batteries don't last forever! Depends on use but 5 years is normal. I'm on my second PC 925 (first one replaced after 5 years) but don't have any issues. I have a normal starter motor but my car regularly has a 80 amp constant load from the AC / Heating. Mostly, this load is covered by the high output 175A alternator. You generally only need a big battery if your alternator cannot cover the load of the car. My '68 Alfa also has a PC925 and a Wosp lightweight starter. If it has sat for while, due to carbs and a mechanical pump, it can take 30 seconds of cranking to start but the battery copes ok. I don't use a battery conditioner but do occasionally top them up if they've been sitting more than 6 weeks.
ROBINWILD Posted January 14 Posted January 14 On 13/01/2025 at 08:19, Beaky said: out of curiously , how much weight are you saving and is that really noticeable in the real world? I have just changed the batteries on my SLK and sons Boxster and gone for Yausa versions. The previous batteries were Bosch and probably 10 years old just starting to have cold weather issues. Just like Beaky says, how much weight saving is really being achieved? I was in the market recently for a new battery and looked at all the options. In the end I just went for the easiest option at the right price. Yuasa 3000 for £90 from GSF, to replace a 15 year old PowerBull, same spec. Delighted with it, the car starts first turn again...
Ian Comerford Posted January 16 Author Posted January 16 I always thought 10kgs wasn’t a bad amount to lose but have other priorities now…….
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