Fed up with flat leisure battery will this help?

[cornishpete]

After spending a week camping near a windy and cold Padstow with a flat leisure battery (30amp fuse blown between split charge relay and battery) now I know where to look won't be a problem again!! I would like to keep an eye on the leisure battery. Has anyone tried one of these http://www.tcschandlery.co.uk/7704/Nasa ... nitor.html or got any thoughts on them, apart from the price

[dannyg1985]

dude i used to work on a bass boat in weymouth, we used to run twin 12v batteries for our electrics, n we had the monitor, very usefull on the boat so cany see no probs on ya camper, n it saves goin without a brew when ya in the middle of nowhere

[neil3965]

Just bought one of these off ebay, arrived today (brand new, £79 incl postage). The guy who sells them puts one up for auction every couple of days, but they rarely go for less than £80 (plus £8.95 postage). The cheapest I have found them outside ebay is here:

http://www.mailspeedmarine.com/power-po ... 7961.bhtml" onclick="window.open(this.href);return false;

for £84.99 plus £6.99 postage. I looked at making my own unit, but buying good quality parts (digital voltmeter, shunt resistor, switches and cable) was going to cost £40-50, plus at least half a day making the damn thing, so I reckoned getting a neat, professional package for £80 was reasonable value.

The cheapest way to keep an eye on the state of your battery, apart from manually checking it with a multimeter, would be to buy a cheap digital voltmeter (around £15 on ebay), mounting it on a panel and wiring it to your leisure battery. With no other load on the battery (ie with everything switched off) the reading will give a fair idea of the state of charge (12.6v or above = 100%, 12.4v = 75%, 12.2v = 50%, roughly speaking). When there is a load on the battery (eg with lights or other equipment switched on) the voltage will drop slightly depending on how much current is being drawn.

The NASA unit uses microprocessor wizardry to measure current draw, voltage and time to calculate a fairly accurate measure of remaing battery capacity at any time, as well as how long it will take to fully recharge the battery.

Won't have time to install this beastie until July, probably, but will let you know how it goes.

[Oldiebut goodie]

After spending a week camping near a windy and cold Padstow with a flat leisure battery (30amp fuse blown between split charge relay and battery)

This is exactly why I said to uprate split charge relay system to a mininmum of 70A, preferably 100A system on another thread. If your leisure battery is flat it is going to want to pull the max from your alternator - 45A,65A or 90A or whatever it is rated at - people poo-pooed the idea but did not have the ability to see that the 30A system is not up to the job.(As you have proved!)