Guest The Doctor Posted December 30, 2003 Report Posted December 30, 2003 Got given Halfords car vacuum by wife for Crimbo (get very worked up when kids lose crumbs everywhere when picnicking, so a great gift). Suprised at the suction on the thing, but a bit nervous about drwaing power from the battery, especially in view of the recent threads about battery life. So far I've only used it with the engine running. Does anyone have experience of how long you can draw power off the battery before you start deteriorating battery life/ability? Quote
seatkid Posted December 30, 2003 Report Posted December 30, 2003 Does anyone have experience of how long you can draw power off the battery before you start deteriorating battery life/ability? The deeper you discharge a cars lead acid battery, the more important it is to recharge it quickly. This is because a discharged battery "sulphates", a process which is difficult or impossible to reverse leading to reduced capacity or premature failure. (look up sulfation on the web for more detail) I have read that car batteries are soon damaged beyond repair if they are discharged greater than 75% and not immediately recharged. A Galaxy battery is either 70 or 90Ah depending which variety is fitted. A car vacuum probably draws around 5A, so you could run it for hours and hours before you discharge the battery a lot so don't worry about that. (n.b. I also read that the VW TDi engines suffer damage when left to idle for very long periods) Bear in mind that there is a permanent draw on the battery (I measured mine just under 0.1A) from the cars electronics which are always on (on board computers etc) - in some cases this could be higher (satnav?) which represents approx 2Ah per day. So if you go on holiday for 15 days, your battery could drain a lot (30Ah). This is in addition to the self discharge all batteries have (which gets worse with age). This is where a lot of damage would be done to the battery. Some people would recomend you disconnect the battery in this situation (what about security?) It is good practice to avoid deep discharges without allowing an immediate recharge. e.g. Leaving your sidelights on all night is probably a bad thing to do. Modern lead-calcium batteries are considerably less tolerant to deep discharge than the old lead antimony batteries. Quote
Tigger Posted December 31, 2003 Report Posted December 31, 2003 I Have an inflatable RIB boat, which I pump up with an inflator off the 12v system. This is in fact the same as a Hoover but the other way. If you get my drift. I run the pump for about 10mins to fill the chambers of the boat. I have never had a problem with draining the battery, as has been said I think it would run allot longer if needed Quote
Guest mick Posted January 2, 2004 Report Posted January 2, 2004 Leave a 'mid-sized' cool box plugged in on a fairly regular basis - last time for a good 4hrs or more whilst on a cross channel ferry. Haven't a clue how much current the box draws, but have had no probs with it. Quote
seatkid Posted January 2, 2004 Report Posted January 2, 2004 Approx 5 to 8A (when cooling thermostat demands) depending on size. A lot of cool boxes (not mine) will automatically cut off if the battery voltage drops below a certain level. My Alhambra will automatically cutoff certain electrics after a while (e.g the boot/door lights if left open) and I've a feeling it could do the same for the 12v socket on low battery voltage - anybody know? Quote
Guest mick Posted January 3, 2004 Report Posted January 3, 2004 A lot of cool boxes (not mine) will automatically cut off if the battery voltage drops below a certain level. I did read somewhere that the box I have (Halfords labeled) does auto shut off, but the instructions omit to state this, so I have my doubts. The Ford manual does mention something about isolating electrical items after a time period, but must confess haven't read it that closely! Quote
Guest SA Intruder Posted January 3, 2004 Report Posted January 3, 2004 If the battery voltage drops to a fixed level, the aux socket will permanantly isolate until the engine is next restarted. The idea is to preserve enough power to start the engine. It can be bypassed, but obviously this defeats the object... Quote
Danny Boy Posted January 3, 2004 Report Posted January 3, 2004 SA do you know if the isolation applicable on the Mk1 models or just the Mk2? Happy New Year to you all!!! :) :D Quote
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