Roger Ford Posted June 3, 2012 Share Posted June 3, 2012 Stopping? Does a lithium battery naturally stop charging Yes - when the voltage in the battery equals the voltage being supplied to the battery then it will stop charging. I charge small Lithium Ion batteries on my desk power supply, which has current and voltage limits. I simply set the current limitation appropriately (200mA for AAA size batteries, 1A or so for the bigger 18650 cells) and the voltage to 4.2v. As the battery approaches 4.2v, so the charging current drops towards zero. It's very dangerous to overcharge LiIon batteries much beyond 4.2v, but since the power supply won't supply more than 4.2v, there's no way the battery voltage can possibly exceed 4.2v. Link to comment Share on other sites More sharing options...
Z3MCJez Posted January 7, 2013 Share Posted January 7, 2013 As I'm considering a RBC400 for my race Caterham, I've bumped this for some real-world experience. I have a battery isolator so don't intend to trickle charge. I know that if I let it go dead I've killed it. How are those that bought one finding them 9 months on? Jez Link to comment Share on other sites More sharing options...
Roger Ford Posted January 8, 2013 Share Posted January 8, 2013 Remembering it's the Autosport show this week, does nobody really have any feedback on these batteries? Link to comment Share on other sites More sharing options...
CharlesElliott Posted January 8, 2013 Share Posted January 8, 2013 A Powervamp PVR25 weighs 6.1Kg, an RBC400 equivalent is just over 1Kg so you save about 5Kg. Is it worth it? Link to comment Share on other sites More sharing options...
NoLimits Posted January 8, 2013 Share Posted January 8, 2013 I have sold a number of both the RBC400 and RBC600. Depends on the engine specification as to which is required. I have exchanged a couple of RBC400's for 600's Link to comment Share on other sites More sharing options...
Lee Fowler Posted January 8, 2013 Share Posted January 8, 2013 All good here but I did buy the correct Optimate for the battery. Lee Link to comment Share on other sites More sharing options...
Z3MCJez Posted January 8, 2013 Share Posted January 8, 2013 Charles - I currentlyhave an 8kg Banner, which is standard in the Caterham series. I finished a race at 621kg. Limit is 600kg. I would have gladly paid £250 last year to save 7kg. Given that I would target +5kg anyway, that would have got me to 9kg over, rather than 16. The weight limit next year in grads is also slightly tougher, with the heavier tyres. But I'd like to know that the battery will last a bit! Jez Link to comment Share on other sites More sharing options...
CharlesElliott Posted January 8, 2013 Share Posted January 8, 2013 Limit 605Kg in Sigmax (I assume). Link to comment Share on other sites More sharing options...
NoLimits Posted January 8, 2013 Share Posted January 8, 2013 They are tried and tested in the Superbike and Motor GP race series - used just about everywhere. Also used by all the Super GT Nissan's etc. Sumo Power etc Link to comment Share on other sites More sharing options...
Z3MCJez Posted January 9, 2013 Share Posted January 9, 2013 Thanks NoLimits. I'm not intending to use an Optimate - simply disconnect. I know that the claim is for <2% charge loss annually, but I was just asking for real world performance, rather than sitting in a temperature controlled environment. Anyway, I have a battery master, so full isolation can be achieved and I suspect I'll take the plunge. However, do you think that a 1600 Sigma will need a RBC400 or 600? Jez Link to comment Share on other sites More sharing options...
Lee Fowler Posted January 9, 2013 Share Posted January 9, 2013 RBC400 should be fine. Lee Link to comment Share on other sites More sharing options...
NoLimits Posted January 9, 2013 Share Posted January 9, 2013 Agreed Link to comment Share on other sites More sharing options...
Z3MCJez Posted August 26, 2013 Share Posted August 26, 2013 Bringing this back to the top as a friend has just asked what lithium battery he should buy. My thoughts on the RBC400 (used with a Sigma Supersport car with the lightened flywheel): 1) It's very small and light. You can only appreciate this when you see it next to a normal battery. 2) It starts the car fine when the car is cold or warm. It doesn't really like starting the car when the car is hot (I.e. coming off track, stop in parc ferme, it needs some encouragement to re-fire the car). I think it would be better if the car had the normal flywheel as it doesn't have quite the inertia to get over the compression. It sounds like when you start a car with a battery that is dying, but then when the car is cooler, it starts it well. 3) I've had no problems with the battery going flat, but it is always left disconnected by master switch. If I was buying again, I'd be tempted to to buy the RBC600, but at another £200, that's quite an additional cost! Jez Link to comment Share on other sites More sharing options...
Member Jonathan Kay Posted August 26, 2013 Member Share Posted August 26, 2013 Is that difference between hot and cold starting caused by the ease of starting the engine or the oomph coming out of the battery? Thanks Jonathan Link to comment Share on other sites More sharing options...
Z3MCJez Posted August 26, 2013 Share Posted August 26, 2013 I've always presumed it's due to the engine being hot, leading to slightly higher compression, but I guess I should pay some attention to whether the battery is warm / hot at the end of a session. I'll check that next time I race - Cadwell, w/e of 7/8 September. Jez Link to comment Share on other sites More sharing options...
catastrada Posted August 26, 2013 Share Posted August 26, 2013 I have an RBC400 on my race car (2.0L Duratec 224 hp) and it's working fine. Engine was totaly cold when I did this . I recently bought the correct optimate too. Link to comment Share on other sites More sharing options...
NoLimits Posted August 26, 2013 Share Posted August 26, 2013 The Racing Battery prefers to be hot. It will give more power when it is hot. For the same reason the battery will give more power out on its 3rd or 4th press of the starter button assuming its only for the 5 sec as recommended and it was fully charged. Link to comment Share on other sites More sharing options...
Z3MCJez Posted August 26, 2013 Share Posted August 26, 2013 Interesting Simon. I have religiously followed the rule on not holding the button for more than 5s (and then giving it a short rest, although that is only 10s or so). I haven't had to try that in anger on a circuit though! That suggests that the reluctance to start is linked to the engine, not that battery. Jez Link to comment Share on other sites More sharing options...
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