virtual7 Posted December 10, 2003 Posted December 10, 2003 i'm interested in fitting a bigger battery in my cat sv 140. after a couple of weeks in the garage the battery is completely flat.does anyone know what size and how do u fit the battery? thx.
Irrelevant Posted December 10, 2003 Posted December 10, 2003 Why not just fit an isolator switch - i.e. as on race cars? J351 TPE . . . battered old X/Flow
Chris W Posted December 10, 2003 Posted December 10, 2003 A bigger battery won't help. The battery is flat because the immobiliser is drawing around 40mA continuously. Buy a "battery conditioner" (eg: Draper "Battery Master" for around £16 from Halfords) and leave it connected 365 days a year. It will keep your battery in a fully charged condition (without overcharging it) and will counteract the current draw from the immobiliser. You can change the croc clips supplied for a more convenient connector to enable you to plug it in instantly without lifting the bonnet. Don't ever let your battery go completely flat as it does degrade its life, expecially if you leave it discharged. Chris 2003 1.8K SV 140hp see it here
Normans_Ghost Posted December 10, 2003 Posted December 10, 2003 Virtual7, I've run 2 wires direct off battery to a cigar lighter under dash and put the female end on a battrey conditionr. Put car in garage, plug cigar lighter in, jobs a good 'un. norman verona 1989 BDR
Graham Sewell Posted December 10, 2003 Posted December 10, 2003 nverona, If you have put the female connector on the battery conditioner, your dashboard must look mighty wierd with the male connector sticking out....
Sheds Moderator Posted December 11, 2003 Posted December 11, 2003 Possibly Graham, or maybe it's just that Norman's been doing it wrong all these years. 😳
virtual7 Posted December 11, 2003 Author Posted December 11, 2003 thx guys, had thought about the battery conditioner, but there is no power in the building's garage... what about hawker odyssey batteries? would this help at all?
Gary G Posted December 11, 2003 Posted December 11, 2003 I think that you will have the same problem regardless of what battery you use. I took Chris W's advice and bought a battery conditioner. I don't have power in my garage either, so I have to take it out of the car and bring it into the house. Sounds like a pain, but I'm either driving the car frequently in the summer so that I don't have to do it, or I'm not driving it at all in the winter, so I just bring it in and leave it for months on end.
Chris W Posted December 11, 2003 Posted December 11, 2003 Virtual You WILL have the same problem regardless of the battery size..... and allowing the battery to slowly discharge all the time will kill its lifespan. You could buy a solar panel from Maplins for example and trickle charge the battery at a few tens of mA if you have no power in the garage. Chris 2003 1.8K SV 140hp see it here
KenEvans Posted December 11, 2003 Posted December 11, 2003 I'm marketing an automatic battery isolation switch with a hillclimbing business partner (albeit owning a TVR). It's perfect for the situation you describe. Find the "cars" section here. 10% off to Lotus Seven Club members. It'll automatically disconnect your battery once the voltage drops to 11.9 volts below which starting capability becomes marginal. It will then automatically reconnect when you get into the car and operate the ignition, lights or brake pedal. It weighs about..............180gm. Ken Edited by - KenEvans on 11 Dec 2003 13:00:28
virtual7 Posted December 11, 2003 Author Posted December 11, 2003 chris, have found at maplins a solar charger. do u think 12v 1.8w will be enough? ken, once it has automatically cut the battery, is there enough power to restart the car after a few weeks? thx.
KenEvans Posted December 11, 2003 Posted December 11, 2003 Virtual7, as long as the battery itself is on good condition then the voltage will recover a little once the drain is disconnected. The duration of this recovery depends upon the condition of the battery and whether it has suffered a deep discharge at any time (which PriorityStart would have prevented, a deep discharge can reduce the life of a battery by 40%). So basically the answer is it depends upon the condition of your battery not forgetting there will be zero external drain. The product obviously can't boost a battery nor repair an already damaged one, but it helps look after them in the first place. Ken
KenEvans Posted December 11, 2003 Posted December 11, 2003 Don't forget, a solar charger must be capable of creating a current greater than the drain on the battery or the net result is the same. Solar chargers are good on boats on a hot summer's day but are less effective in the winter and, of course, at night time. Ken
virtual7 Posted December 11, 2003 Author Posted December 11, 2003 the solar panel seems a good idea as there is 24/7 strong lighting in the garage...
Chris W Posted December 11, 2003 Posted December 11, 2003 Virtual In theory, the 1.8W, 12v solar panel would be ideal as the charging current is just about right. (150mA). However..... I presume the 1.8W is specified in strong (sun)light. You would need to try it in a real situation to be sure you're getting enough oomph in winter with the lighting you have available. So long as it delivers, say, 80mA or so, it will counteract the drain from the immobiliser and provide a small current to keep the battery topped up. Re the automatic isolation switch.............. although this will indeed switch off all external drains when the battery volts drop to a predetermined level, the device will not prevent the self-discharge inherent in all batteries which is worse in winter. So you cannot fit one of these devices and then just leave the battery for weeks... it will still be flat due to self discharge (a chemical effect within the physics of the battery). Chris 2003 1.8K SV 140hp see it here
KenEvans Posted December 11, 2003 Posted December 11, 2003 Chris, a battery actually retains its charge longer in COOL (rather than cold) storage. Here's something I posted some weeks ago in a similar thread. Depending on the type of battery and temperature, batteries have a natural self discharge or internal electro chemical "leakage" at a 1% to 25% rate per month. Over time the battery will become sulphated and fully discharged. Higher temperatures will significantly accelerate this process. A battery stored at 95° F (35° C) will self-discharge twice as fast than one stored at 75° F (23.9° C). The best way to prevent sulphation is to keep a lead-acid battery fully charged because lead sulphate does not form. This can be accomplished three ways. The best solution is to use a charger that is capable of delivering a continuous "float" charge at the battery manufacturer's recommended float or maintenance voltage for a fully charged battery. 12-volt batteries, depending on the battery type, usually have fixed float voltages between 13.2 VDC and 13.8 VDC, measured at 80° F (26.7° C) with an accurate (.5% or better) digital voltmeter. Based on the battery type you are using, charging can best be accomplished with a microprocessor controlled, three stage (for AGM or Gel Cell batteries) or four stage (for wet batteries) "smart" charger or by voltage-regulated float charger to "float" or maintain fully a charged battery. A cheap, unregulated "trickle" charger or manual two stage charger can overcharge a battery and destroy it. A second and less desirable method is to periodically recharge the battery when the State-of-Charge drops to 80% or below. Maintaining a high State-of-Charge (SoC) tends to prevent irreversible sulphation. The recharge frequency is dependent on the parasitic load, temperature, the battery's condition, and plate formulation (battery type). Temperature matters! Lower temperatures slow down electro chemical reactions and higher temperatures speed them up. I'm quite sure batteries stand in wholesalers for weeks and retain their factory charge. Ken Edited by - KenEvans on 11 Dec 2003 18:11:10
Chris W Posted December 11, 2003 Posted December 11, 2003 Ken The reason that batteries lose their usefulness quicker in winter though is that there is not so much charge to lose. ie: the battery's chemical process is far less efficient in cold conditions so that the loss of a given amount of charge is a higher proportion of the total charge available. Thus, a 30AH battery (like the Banner supplied) will not be a 30AH battery in cold conditions. At normal temperatures the charging process is about 70% efficient. ie: given a totally flat battery, you need to put in around 43AH of charge to end up with 30AH. In cold weather the amount of charge needed to be put back to achieve 30AH rises considerably. So while I agree with you that the internal leakage resistances are indeed smaller in value at elevated temperatures, if you leave two batteries disconnected, one in normal temperatures and one in cold temperature, the cold temperature one will be the most likely one to fail. This is also due to the fact that in cold temperatures the convection flow in the electrolyte is severely reduced and therefore the time to recover from an attempted engine start (when the acid in the vicinity of the plates is converted to water and needs a finite time to remix) is lengthened considerably in cold weather. The main point though is that leaving a battery to sit on its own without keeping it topped up is detrimental to its eventual lifespan. I agree that a "trickle charger" should not be left ON continuously as the current supplied is too high for 24x7 use. However if the current is limited to around 100 - 150mA a "conditioner" supplying this current can indeed be left connected 24x7. I wasn't trying to pour cold water (excuse the pun) on your automatic isolators which I am sure have great potential (aargh... another pun). I was trying (poorly) to make the point that abusing the battery in the first place will eventually cause it to fail anyway. Chris 2003 1.8K SV 140hp see it here
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