How low can you go?

[hairyneep]

No not a suspension query and definitely not limbo, it's batteries.

I've got two starter batteries which were fitted new when I bought the Bongo from Wheelquick. I've got a split charge relay fitted so use the second battery as a leisure. We don't have a conversion so only use the leisure battery for lights, blinds, stereo and phone charging. We've been off hook up for up to four days in the past and never had any problems but am wondering how low the battery can go before it gets to the point of being damaged, mainly so I can use a 12v cool box (I shouldn't have bought a plug in volt meter, my paranoia was fine before )

I'll be replacing the battery at some point for a proper one but only once it's knackered.

Thanks

[francophile1947]

Using a 12v cool box will flatten your battery in just 4/5 hours, unless you run your engine at the same time.
How low can you go? - how long is a piece of string It will depend on the capacity and state of the battery, but anything less than 12v is flat - much lower will cause some damage to the battery, if it's left flat for any length of time. Starter batteries are not meant to be flattened, although I have had them successfully recover from totally flat i.e.not even the interior light would work.

[g8dhe]

If you take a lead acid battery below 10.5volts then it will start to be damaged very rapidly, best not to go below 10.8 if at all possible and a good number to remember is 11 volts!

[hairyneep]

Perfect, thanks for the replies.
I ran the cool box yesterday for 5 1/2 hours and the voltage dropped to 11.3 so I'm happy with that, means I can keep my beer cool for a bit longer

[The_Gordons]

I fitted a cheapy LCD panel voltmeter from fleabay. This is conected to the leisure battery via a switch so that it is not permanently switched on. Its good enought to alllow me to keep an eye on the charge level of the leisure battery when parked up and also to keep an eye on the alternator when the engine is running.