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Re: Battery tester for leisure battery.
Posted: Sun Jan 11, 2009 8:51 pm
by daveblueozzie
Have fitted the digital display in the bongo ,and it does exactly what i wanted it to do.
got a reading of about 11.65 just after i fitted the display,when i started the engine it started to go up and read about 13.50. I went back about an hour later (no i didn't leave the engine running

) just to see the blue dial lit up in the dark

(i know sad git) and it was reading about 12.30 so it is doing the job i wanted it to do.
BDC has said we should test what happens when we plug a cool box into the power socket (not 240v don't worry)
(i had a 12v power socket fitted ,and then fitted another myself. the normal ciggy socket wiring is not up to the job) and see what power it draws while the engine is off.
Re: Battery tester for leisure battery.
Posted: Sun Jan 11, 2009 9:38 pm
by Simon Jones
Good news. For a cheap bit of kit, they do the job pretty well don't they?
Re: Battery tester for leisure battery.
Posted: Sun Jan 11, 2009 11:12 pm
by mikeonb4c
Discovered something interesting today. For reasons I won't bother you with I was testing voltage at the battery (using a multimeter and probes) against the reading on my panel mounted digital voltmeter (similar device to Daves). Once a load was applied at the ciggie sockets, I found the reading on the multimeter was up to 0.5v higher than on the panel mounted meter, even though the wiring from LB to ciggie socket is not long and is well rated. Anyone got a thought about what might cause that?
Nice to have a panel mounted voltmeter though - discreet bling
PS - lets have a piccie of yours in place Dave

Re: Battery tester for leisure battery.
Posted: Sun Jan 11, 2009 11:23 pm
by dandywarhol
I've just replaced yet ANOTHER faulty EXIDE leisure battery - one dead cell! The battery would discharge to 11.65v after around 8 hours of sitting in 20 deg. warmth and drop down to 10v when the surface charge was taken off by powering a 21w flasher bulb for 30 minutes.
The motor factor tested it with a fancy Bosch battery teater and declared it u/s. Luckily it was under a 2 year warranty.
Now on number 3 battery in 3 years - both had a problem with a faulty cell. Now wondering if this high charging malarky is causing it despite some sources saying its ok to give them a high initial charge.
Haven't heard from the guy on the forum (forgotten his name now) who was building a regulated charging setup................

Re: Battery tester for leisure battery.
Posted: Sun Jan 11, 2009 11:24 pm
by Simon Jones
The descrepancy in meter readings is probably due a combination of things. The longer the distance from the battery, the greater the voltage drop, so try putting the multimeter at the same point where there panel meter is. The other thing will be that they both have a small degree of inaccuracy which could appear greater if one meter reads high while the other one reads low. The key thing about any gauge or meter is that its the relative value that matters, rather than the actual number. So if your meter shows 13.5v to 14.5v when the engine is running, you'll know that anything outside of this range indicates a problem.
Re: Battery tester for leisure battery.
Posted: Sun Jan 11, 2009 11:25 pm
by clark282
Has anyone used a battery tester which plugs straight into the cig socket?
Regards
Alex
Re: Battery tester for leisure battery.
Posted: Sun Jan 11, 2009 11:31 pm
by mikeonb4c
Simon Jones wrote:The descrepancy in meter readings is probably due a combination of things. The longer the distance from the battery, the greater the voltage drop, so try putting the multimeter at the same point where there panel meter is. The other thing will be that they both have a small degree of inaccuracy which could appear greater if one meter reads high while the other one reads low. The key thing about any gauge or meter is that its the relative value that matters, rather than the actual number. So if your meter shows 13.5v to 14.5v when the engine is running, you'll know that anything outside of this range indicates a problem.
Thanks SImon - good advice. When the days get longer and warmer and I long to be outdoors, I'll do further investigations along the lines you suggest.
Today, I was trying to find out why the clever electric blanket control box invention wot I built works great with a crap 75AhHr starter battery when test it in the house and yet the low voltage (11.5v cutout) protector in it cuts out almost immediately when I try to use the device in the car (doesnt matter whether I try it off the LB or the 95Ah starter battery cig socket). Very strange. I'm at a loss to explain it and its a shame as I think I may have found a way to use an electric blanket for a night or two of cold wild camping (but so far only in my bedroom test regime!)
Re: Battery tester for leisure battery.
Posted: Sun Jan 11, 2009 11:33 pm
by dandywarhol
Get your LB checked out for a duff cell Mike - see my previous post..................
Re: Battery tester for leisure battery.
Posted: Mon Jan 12, 2009 12:19 am
by mikeonb4c
dandywarhol wrote:Get your LB checked out for a duff cell Mike - see my previous post..................
Thanks Dandy. Don't know how I missed your earlier post. Excellent, as it sounds like it could quite possible explain things (or at least I would have said so except that I cannot believe the 95Ah starter battery I used in todays test has got this problem). But I do suspect my LB is not doing its job properly.

Re: Battery tester for leisure battery.
Posted: Mon Jan 12, 2009 12:50 am
by daveblueozzie
As requested Mike a piccy or two of the meter in the dash.

and one in the dark.

Re: Battery tester for leisure battery.
Posted: Mon Jan 12, 2009 12:59 am
by mikeonb4c
Re: Battery tester for leisure battery.
Posted: Mon Jan 12, 2009 9:08 pm
by bigdaddycain
Re: Battery tester for leisure battery.
Posted: Mon Jan 12, 2009 9:34 pm
by francophile1947
mikeonb4c wrote:Today, I was trying to find out why the clever electric blanket control box invention wot I built works great with a crap 75AhHr starter battery when test it in the house and yet the low voltage (11.5v cutout) protector in it cuts out almost immediately when I try to use the device in the car (doesnt matter whether I try it off the LB or the 95Ah starter battery cig socket). Very strange. I'm at a loss to explain it and its a shame as I think I may have found a way to use an electric blanket for a night or two of cold wild camping (but so far only in my bedroom test regime!)
Might just be lightweight wiring, for the cigar socket, not letting a fast enough flow of electric from the 95Ah battery. Did you ever fully charge your LB, with your new charger, for a couple of days?
Re: Battery tester for leisure battery.
Posted: Mon Jan 12, 2009 10:05 pm
by mikeonb4c
francophile1947 wrote:mikeonb4c wrote:Today, I was trying to find out why the clever electric blanket control box invention wot I built works great with a crap 75AhHr starter battery when test it in the house and yet the low voltage (11.5v cutout) protector in it cuts out almost immediately when I try to use the device in the car (doesnt matter whether I try it off the LB or the 95Ah starter battery cig socket). Very strange. I'm at a loss to explain it and its a shame as I think I may have found a way to use an electric blanket for a night or two of cold wild camping (but so far only in my bedroom test regime!)
Might just be lightweight wiring, for the cigar socket, not letting a fast enough flow of electric from the 95Ah battery. Did you ever fully charge your LB, with your new charger, for a couple of days?
Yup. Did that. Its all very strange. I need to set aside some time and do some methodical testing. Alternatively, just get an extra sleeping bag - it'd be less headache
..but it wouldn't be as much fun!

Re: Battery tester for leisure battery.
Posted: Mon Jan 12, 2009 10:12 pm
by You've Been Bongod
i am on my way
