GSL
Well-Known Member
C'mon Jimmy, the suspense is killing us here
Graham
Graham
Why do my batteries show 16v?
- Thread starter jimmy_the_builder
- Start date
jimmy_the_builder
Well-Known Member
The Optimate I've got has a desulphate indicator, but this didn't come on when the charger was switched on (although it does, dimly, when the charger is connected but not powered).
Cheers
Jimmy
jimmy_the_builder
Well-Known Member
Things are obviously a bit quiet on the forum when the most exciting thing seems to be my dodgy voltmeter! Cue Haydn...
Cheers
Jimmy
david_bagshaw
Well-Known Member
I have had siilar experiance with a cheap chineese voltmeter, as the meters internal battery fails, the meter overreads.
had siimlar readig, 12.4 batt showed 17 volts.
had siimlar readig, 12.4 batt showed 17 volts.
jimmy_the_builder
Well-Known Member
Should I be offended at your suggestion that my £4.99 meter from Maplin might (a) be cheap and (b) be of far eastern manufacture?
Maybe I should stick to quality gear. From Lidl.Cheers
Jimmy
rbcoomer
Well-Known Member
I usually wire a 21W car indicator lamp across the terminals and leave overnight A 100Ah battery should power this for 60 hours or a 50Ah for 30. Don't leave them there too long as the batteries don't like being completely flattened, but if after say 12 hours the lamp is barely lit then the battery's scrap! It will be dimmer, but should still give a reasonable light if the battery is >35Ah. For lower rated batteries a 10W lamp will suffice, but you'll have to wait longer on bigger ones. A couple of 21W and you can half the wait. If you stick too much load on it may not give a true reflection on how well it will 'hold' the charge however. If it's a starting battery, I'd also hook it up to the car on it's own and see how well it turns over/starts! Don't try that bit if you have a fussy car alarm or keycoded stereo however...
Somewhere like a tyre centre can test, but in my experience they always say they're duff regardless! Their testers use a load and measure the voltage drop - similar to using the car's starter really.Pinnacle
Well-Known Member
J-T-B
My oh my.......haven't you got anything better to do????
And there was me thinking the Brighton was home to lots of "interesting" people.........
Oh, I almost forgot......when are you planning another trip to the civilised West? It would be good to see if we could meet up!
My oh my.......haven't you got anything better to do????
And there was me thinking the Brighton was home to lots of "interesting" people.........
Oh, I almost forgot......when are you planning another trip to the civilised West? It would be good to see if we could meet up!
sarabande
Well-Known Member
Jimmy - when you mention Optimate, is that the m/cycle charger ?
I have a couple of the 4s with the clever charging routines for the bikes, but the output is only designed for batteries up to 50 AHr with a charge current of 0.8 Amp.
I suspect they will take for ever to charge you 170Ahrbatts - if they ever manage to do it.
I have a couple of the 4s with the clever charging routines for the bikes, but the output is only designed for batteries up to 50 AHr with a charge current of 0.8 Amp.
I suspect they will take for ever to charge you 170Ahrbatts - if they ever manage to do it.
jimmy_the_builder
Well-Known Member
Oh, I almost forgot......when are you planning another trip to the civilised West? It would be good to see if we could meet up!
Hi P, yip we are deffo overdue. If the weather permits in a couple of weeks time we'll be heading your way; if it doesn't, I'm going to go and get lost in the SoF with my mobike instead...
Cheers
Jimmy
jimmy_the_builder
Well-Known Member
I do, altho I think mine is a 3, not a 4. Hang on, I'll go and check.
...
It is a 3. I didn't think about it's capacity, I just thought that it was prolly the cleverest charger that I'd got. Hmmm. Voltage is still showing as 13.1v. I might try and have a go at rbcoomers load test tonight and see what the voltage is tomorrow.
Cheers
Jimmy
VicS
Well-Known Member
Re Maplins cheap multimeters
I have two. ( Two for the price of three offer or something like that a while back.)
Quite adequate for general puposes but you might want something better for an electronics laboratory.
You have to be aware that they will give silly readings if the battery start to go though!
For a 170Ah battery you should be using a charger with max output getting on for 16amps.
A smaller one will do it but take a long time. 3 amps though just is not in the game at all. Suitable for batteries below 40Ah really or as a maintenance charger for larger ones.
Get them on a decent sized charger and charge them each until you can get a reading of at least 12.7 volts 24 hours after coming off charge. Preferably nearer 12.8V.
Monitor them for a week or so. A good battery will take several weeks to fall below 12.6v
Even if they seem OK on this basis it does not guarantee them to be good for service but if they fail the above they are not likely to be much good.
I have two. ( Two for the price of three offer or something like that a while back.)
Quite adequate for general puposes but you might want something better for an electronics laboratory.
You have to be aware that they will give silly readings if the battery start to go though!
For a 170Ah battery you should be using a charger with max output getting on for 16amps.
A smaller one will do it but take a long time. 3 amps though just is not in the game at all. Suitable for batteries below 40Ah really or as a maintenance charger for larger ones.
Get them on a decent sized charger and charge them each until you can get a reading of at least 12.7 volts 24 hours after coming off charge. Preferably nearer 12.8V.
Monitor them for a week or so. A good battery will take several weeks to fall below 12.6v
Even if they seem OK on this basis it does not guarantee them to be good for service but if they fail the above they are not likely to be much good.
jimmy_the_builder
Well-Known Member
I think I've learned that lesson!
Thanks for this - useful info. In fact these two batts were being charged by the 50a charger on the boat until yesterday afternoon when I brought them home. Stuck one on the optimate yesterday evening for a couple of hours until it said it was fully charged. Now, 24 hours later it's showing 13.1v. Sounds like I need to monitor it for a decent period of time to determine if it is healthy or not.m Of course, if it _is_ healthy, then the much bigger question is - what is causing my domestic bank to fail after only a few hours.
Cheers
Jimmy
sarabande
Well-Known Member
Devices such as security stuff, gas detectors, pumps, even a fridge, may be wired permanently live.
If you have a clamp ammeter or can scrounge the use of one, you will be able to trace if there are any demands being made when the main switch is off.
A decent clamp ammeter (e.g. Kewtech 2056R) is invaluable on board for tracking where the juice is going, and has AC and DC volts, continuity, and temperature as well. Worth considering.
If you have a clamp ammeter or can scrounge the use of one, you will be able to trace if there are any demands being made when the main switch is off.
A decent clamp ammeter (e.g. Kewtech 2056R) is invaluable on board for tracking where the juice is going, and has AC and DC volts, continuity, and temperature as well. Worth considering.
jimmy_the_builder
Well-Known Member
Good point about the 'secret' loads. I don't have a clamp ammeter though, and although the model you recommend looks rather lovely, it is expensive. Whilst it's very much less convenient, is there a reason why I couldn't just wire a shunt in series with the domestics and use a regular ammeter? It's hopefully not something I'll be doing too often so I don't mind a bit of scrambling around in the battery box if it's going to save me the thick end of £150.
Cheers
Jimmy
jfm
Well-Known Member
Yes you can do that but is an ammeter not already fitted to the boat?
jimmy_the_builder
Well-Known Member
It is, but I don't know where the shunt is that it is (presumably) driven off. Sarabande makes a good point about direct-wired items - I think my Eberspacher is direct-wired, frexample, cos when the domestic master is off it is still powered (and the ammeter shows nuffink). So I presume that the ammeter perhaps only catches items that are correctly wired into the Fairline schema proper.
Anyway: ebay might be my friend, again:
http://cgi.ebay.co.uk/New-DIGITAL-C..._Measurement_Equipment_ET&hash=item3a655631e7
Cheers
Jimmy
jimmy_the_builder
Well-Known Member
VicS
Well-Known Member
You ceratinly could wire a shunt in the domestic battery circuit.
The meter to go with it would be a millivoltmeter which could be your multimeter on its lowest range ( 200mv)
shunts are typically rated by the current required to produced a potential difference of 50mv
If you fitted a 100 amp shunt, for example, 100 amps would give you a reading of 50mV.
The resolution of the meter is 0.1mV. That would be produced by 0.2 amps.
0.2 amps is the smallest current you could detect using the multimeter on its 200mV range and a 100 amp shunt. That may or may not be sufficient sensitivity. You may need to break in to the circuit and use one of the low current ranges directly.
The idea of a permanently fitted shunt that could be used in conjunction with a multimeter for trouble shooting does appeal I must admit.
rule the waves
Active Member
Optimate
If it's the kind of optimate I presume, it's what they call an "intelligent" charger, which means: it charges well above the normal mark, and then discharges and this in a continuous cycle. This keeps the batteries "alive" if not used for extended periods. I use it for my motor bike in wintertime. Unfortunately, I don't exactly know by heart to what voltage they charge in the "up"-cycle. They also discharge well under 11 volts.
If it's the kind of optimate I presume, it's what they call an "intelligent" charger, which means: it charges well above the normal mark, and then discharges and this in a continuous cycle. This keeps the batteries "alive" if not used for extended periods. I use it for my motor bike in wintertime. Unfortunately, I don't exactly know by heart to what voltage they charge in the "up"-cycle. They also discharge well under 11 volts.