Using say a multi-meter or plug in cigarette type 12V starter/crank battery reader, is the link shown below a good indication of the state of the battery;
Hopefully a chart will be attached to this post (I'm new here so hope it works). It's a chart for standard voltage at 20 deg C and battery left standing for 5 hours at least.
Close to yours in most respects: ie within about 0.3 volts except lower range and 0 volts.
Do readings vary with deep cycle 12V batteries or are the readings the same?
oldtrack123 said
10:28 AM Nov 9, 2012
Hi
The tables give a GUIDE to % of battery capacity
But that battery capacity decreases with age
An OLD 100Ahrs deep cycle or a 100A cca battery could only have 20% of it's ORIGINAL capacity available
But that can still be fully charged & give the volt readings as indicated in the tables for SOC
That will be reasonably correct % of the REDUCED capacity
20% of 20Ahrs or 20% of 20CCA
In addition the readings at all times are best taken when the battery has been at rest [no charge oe discharge for at least several hours
Note even a 0.2v error in the volt reading is significant when using voltage as a SOC indicator
Peter
-- Edited by oldtrack123 on Friday 9th of November 2012 10:32:04 AM
Baz421 said
04:39 PM Nov 9, 2012
Hi Duh
I think they are close, but not really 100% sure, maybe someone else can with more technical expertise can help.
From my experience a 12 V wet cell is technically "flat" at about 12.3 - 12.2 V ( shouldn't go down to 12 V or battery life is reduced), whilst a deep cycle is technically flat at 50% of its capacity.
I take my caravan batteries (4X100AH deep cycle) to 12V regularly which shows about 40% capacity remaining. We were on the road full time for 3 years and now batteries are just over 5 1/2 years old. One failed at about 2 years but it must have ben a dud.
What application is your battery used for, as modern chargers help to keep batteries fully charged BUT a car alternator for example generally only charges a battery to about 70% of its capacity. So you can see that modern multi stage chargers/solar chargers and regulators are far better than a simple charge from a car alternator.
Hope this helps.
Cheers Baz
Duh said
07:37 PM Nov 9, 2012
Thanks for the feedback Baz and OT, I bought one of those plug into cigarette lighter type readers and was testing an old campervan which had a new but completely flat battery, been tested and the experts reckon it is ok, all connections checked tight etc, was being given a good weekly run, but had died a couple of time and the RAC had to restart it (only after a week sitting idle, once started is ok for restarting). Alternator has been checked ok, according to the experts, so not sure if it has a dud battery or not.
The house battery (not sure how old or if deep cycle, hard to read the labels, but fully sealed) after being charged by onboard 240V charger off mains shows only 12.2 volts after a week of being charged (which according to those charts is about 60%) I haven't given it a "rest" check again yet but will do so. This battery was in this old campervan when it was bought (1997 Mazda).
The crank battery is new, but is a very small battery which is the original size, the cradle cannot be modified to take a larger one. The cradle is under the floor of the front seat.
Was thinking maybe another battery could be put under the campervan seating behind the front seat and hooked up in parallel does this make sense or is it possible?
Thanks
oldtrack123 said
11:23 PM Nov 9, 2012
Hi yes ,you can parallel two batteries with heavy cables , but they should be the same type & preferably near the same capacity.
The battery which, the "Experts" tested & said Ok has definitely lost capacity ,from sitting in a discharged condition & is now useless, even though it may charge up to the fully charged voltage I suspect the experts did not do a load test on it, just a voltage test
The battery that has only reached 12.2 volts has suffered the same fate
Peter
Duh said
01:52 AM Nov 10, 2012
Thanks Peter,
The house battery that originally showed 12.2V after a week on 240V charge is now showing 10.5V, so I take it that is zero charge and is a sign it is stuffed.....
The crank battery has a 3 year warranty, so hopefully the owner can get it replaced, they bought it through the RAC but they hummed and harred last time they were contacted about it, I wish I was allowed to take it up with them but I am on a short lease! LOL !
Baz421 said
04:36 AM Nov 10, 2012
Hi again Duh
My advice is NOT to put your 2 batteries in parallel. The reason is if you flatten one in paralllel YOU THEN FLATTEN BOTH.
No matter how careful you are it's Murphy waiting to strike. Friends years ago accidentally flattened all caravan batteries and both batteries in 4WD as they inadvertantly connected all to a heavy load , including inverters to solve a problem and in the end forgot about it (beer was cold). It happens when you least expect it.
As you are in Perth someone could give you the name of a good auto elec or go to a specialised 4 WD place and get good advice, plus shop around is good too.
In simple terms you need the ability to charge both batteries and discharge (even flatten) the house battery WITHOUT flatenning your starting battery. This can be done relatively cheaply with simple manual switching systems up to fully auto systems.
Someone will know someone in Perth - maybe a new topic - HELP me find a good auto electrician in Perth.
Cheers Baz
Duh said
06:32 AM Nov 10, 2012
Thanks Baz, the campervan doesn't belong to me and I have suggested the auto electrician bit so have to bite my lip now but good advice.
The house battery is not linked to the crank/starting battery so one is not affected by the other. But he house battery is ancient I think, because it is enclosed in a wooden framed box without disconnecting things I can't read what is on the sides but I would say it needed replacing some time ago. But the crank battery is new, the owner taking it up with the RAC at present, but not forceful enough IMHO.
Santa said
08:49 AM Nov 11, 2012
Duh wrote:
Using say a multi-meter or plug in cigarette type 12V starter/crank battery reader, is the link shown below a good indication of the state of the battery;
Thanks for the link Duh, handy little reference, I have a volt meter attached to my MH batteries and up to this point was wondering exactly what it was telling me, so, correct me if I'm wrong but it seems to me that if the volt meter ever dips to 12v or lower the batteries are in urgent need of some erg's
-- Edited by Duh on Thursday 8th of November 2012 06:14:35 PM
-- Edited by Santa on Sunday 11th of November 2012 08:53:22 AM
Duh said
08:23 PM Nov 11, 2012
From what the others on here have said Santa that seems to be the case.
My techo knowledge is zero (Duh) but we are lucky to have some experienced and qualified people on GN who would be better to answer your query. See their earlier posts.
oldtrack123 said
01:16 AM Nov 12, 2012
Duh wrote:
Thanks Baz, the campervan doesn't belong to me and I have suggested the auto electrician bit so have to bite my lip now but good advice.
The house battery is not linked to the crank/starting battery so one is not affected by the other. But he house battery is ancient I think, because it is enclosed in a wooden framed box without disconnecting things I can't read what is on the sides but I would say it needed replacing some time ago. But the crank battery is new, the owner taking it up with the RAC at present, but not forceful enough IMHO.
Hi Bazz
Yes quite correct, if is the 2nd battery is for another use[Auxillary]
The best way then is to have automatic Isolation by a good VSR battery isolator
Traxide, Red arc etc all good units & simple to install.
Peter
oldtrack123 said
01:25 AM Nov 12, 2012
Santa wrote:
Thanks for the link Duh, handy little reference, I have a volt meter attached to my MH batteries and up to this point was wondering exactly what it was telling me, so, correct me if I'm wrong but it seems to me that if the volt meter ever dips to 12v or lower the batteries are in urgent need of some erg's
Hi
If you take your motor home batteries[house ] THAT level on a regular basis,they will have a very short life
They would need to be FULLY charged ASAP
Momentary dips due to heavy loads are ok but sustained use at low voltage should be avoided if you want long battery life
Suggest you consider a low voltage cutout
Peter
-- Edited by Duh on Thursday 8th of November 2012 06:14:35 PM
-- Edited by Santa on Sunday 11th of November 2012 08:53:22 AM
jimricho said
03:42 AM Nov 12, 2012
oldtrack123 wrote:
Momentary dips due to heavy loads are ok but sustained use at low voltage should be avoided if you want long battery life
Suggest you consider a low voltage cutout
Peter
I use a Baintech LVC low voltage cut-out in my rig and can recommend it. It has a 30 second time delay to allow for momentary voltage dips due to heavy loads such as a compressor fridge starting.
Duh said
03:27 AM Nov 13, 2012
Thanks for that Jim and OT, will pass that onto the owner of the campervan in question!
Esperian said
12:38 PM Nov 15, 2012
Duh wrote:
Thanks Baz, the campervan doesn't belong to me and I have suggested the auto electrician bit so have to bite my lip now but good advice.
The house battery is not linked to the crank/starting battery so one is not affected by the other. But he house battery is ancient I think, because it is enclosed in a wooden framed box without disconnecting things I can't read what is on the sides but I would say it needed replacing some time ago. But the crank battery is new, the owner taking it up with the RAC at present, but not forceful enough IMHO.
Did you try desulfator for your house battery?
Here is a link to the Ebay where you can get it, with delivery costs included:
This may solve y problem for good, and cheaply. The battery will run as new.
90% of the time, battery gets sulphated, what this causes loss of ability to hold power, even if it will show sometime even great volatege, but only for short time...
Almost every battery can be rescued, if you'll connect to it a battery desulphator while charging, and/or leave it on even permanently - if it only still shows voltage and doesn't have shorted plates. I had problem with battery ones, myself, when I bought second hand car some time ago. Battery was flat, and didn't want to hold power at all. In the winter time, just overnight stay depleted it so bad it hardly could turn the starter motor.
Finally, when I needing to ask for a jump-start, after just short visit at my friends' I went straight to near-by Jayco shop, and bought the desulphator for about 50.00 bucks. I put in on immediately (it has just two crocodile connectors), and... I forgot since them I ever had a problem.
I left it permanently, till I finally sold the car, when (of course) I removed the desulphator, and now use it on my new car. It is just as simple as connecting two crocodile connectors to your battery, and problem is gone... If you just lease the van, you don't have to leave it with the van when you give it back. I use it now for years, and plan to get another one for solar charging my auxiliary battery too. It is an excellent maintenance tool, for affordable price.
-- Edited by Esperian on Thursday 15th of November 2012 12:56:22 PM
Duh said
04:22 AM Nov 16, 2012
Thanks Esperian, I will definitely pass that on, I had never heard of them before!
jimricho said
02:54 PM Nov 16, 2012
I use a Redarc Dual Battery "Smart Start" isolator to connect my van's 12v system to the car battery. This is an example of a VSR that Peter (OT123) is referring to. (VSR = Voltage Sensitive Relay, we techies love acronyms!). The main purpose of these devices is to ensure that the starting battery gets charging priority and that the second battery is not connected to the main battery until the main is first recharged.
I also have installed a Rotronics solid state dual battery isolator (VSR) between the main car battery and the auxiliary battery in the car.
Duh said
10:36 PM Nov 16, 2012
Thanks Jim,
I had a similar set up in my Hi Ace campervan when I had it in my possession (currently being sold on consignment) worked well.
Using say a multi-meter or plug in cigarette type 12V starter/crank battery reader, is the link shown below a good indication of the state of the battery;
http://www.marxrv.com/12volt/voltchart1.gif
-- Edited by Duh on Thursday 8th of November 2012 06:14:35 PM
Duh
Hopefully a chart will be attached to this post (I'm new here so hope it works). It's a chart for standard voltage at 20 deg C and battery left standing for 5 hours at least.
Close to yours in most respects: ie within about 0.3 volts except lower range and 0 volts.
Cheers Baz
Thanks Baz,
Do readings vary with deep cycle 12V batteries or are the readings the same?
Hi
The tables give a GUIDE to % of battery capacity
But that battery capacity decreases with age
An OLD 100Ahrs deep cycle or a 100A cca battery could only have 20% of it's ORIGINAL capacity available
But that can still be fully charged & give the volt readings as indicated in the tables for SOC
That will be reasonably correct % of the REDUCED capacity
20% of 20Ahrs or 20% of 20CCA
In addition the readings at all times are best taken when the battery has been at rest [no charge oe discharge for at least several hours
Note even a 0.2v error in the volt reading is significant when using voltage as a SOC indicator
Peter
-- Edited by oldtrack123 on Friday 9th of November 2012 10:32:04 AM
Hi Duh
I think they are close, but not really 100% sure, maybe someone else can with more technical expertise can help.
From my experience a 12 V wet cell is technically "flat" at about 12.3 - 12.2 V ( shouldn't go down to 12 V or battery life is reduced), whilst a deep cycle is technically flat at 50% of its capacity.
I take my caravan batteries (4X100AH deep cycle) to 12V regularly which shows about 40% capacity remaining. We were on the road full time for 3 years and now batteries are just over 5 1/2 years old. One failed at about 2 years but it must have ben a dud.
What application is your battery used for, as modern chargers help to keep batteries fully charged BUT a car alternator for example generally only charges a battery to about 70% of its capacity. So you can see that modern multi stage chargers/solar chargers and regulators are far better than a simple charge from a car alternator.
Hope this helps.
Cheers Baz
Thanks for the feedback Baz and OT, I bought one of those plug into cigarette lighter type readers and was testing an old campervan which had a new but completely flat battery, been tested and the experts reckon it is ok, all connections checked tight etc, was being given a good weekly run, but had died a couple of time and the RAC had to restart it (only after a week sitting idle, once started is ok for restarting). Alternator has been checked ok, according to the experts, so not sure if it has a dud battery or not.
The house battery (not sure how old or if deep cycle, hard to read the labels, but fully sealed) after being charged by onboard 240V charger off mains shows only 12.2 volts after a week of being charged (which according to those charts is about 60%) I haven't given it a "rest" check again yet but will do so. This battery was in this old campervan when it was bought (1997 Mazda).
The crank battery is new, but is a very small battery which is the original size, the cradle cannot be modified to take a larger one. The cradle is under the floor of the front seat.
Was thinking maybe another battery could be put under the campervan seating behind the front seat and hooked up in parallel does this make sense or is it possible?
Thanks
yes ,you can parallel two batteries with heavy cables , but they should be the same type & preferably near the same capacity.
The battery which, the "Experts" tested & said Ok has definitely lost capacity ,from sitting in a discharged condition & is now useless, even though it may charge up to the fully charged voltage
I suspect the experts did not do a load test on it, just a voltage test
The battery that has only reached 12.2 volts has suffered the same fate
Peter
Thanks Peter,
The house battery that originally showed 12.2V after a week on 240V charge is now showing 10.5V, so I take it that is zero charge and is a sign it is stuffed.....
The crank battery has a 3 year warranty, so hopefully the owner can get it replaced, they bought it through the RAC but they hummed and harred last time they were contacted about it, I wish I was allowed to take it up with them but I am on a short lease! LOL !
Hi again Duh
My advice is NOT to put your 2 batteries in parallel. The reason is if you flatten one in paralllel YOU THEN FLATTEN BOTH.
No matter how careful you are it's Murphy waiting to strike. Friends years ago accidentally flattened all caravan batteries and both batteries in 4WD as they inadvertantly connected all to a heavy load , including inverters to solve a problem and in the end forgot about it (beer was cold). It happens when you least expect it.
As you are in Perth someone could give you the name of a good auto elec or go to a specialised 4 WD place and get good advice, plus shop around is good too.
In simple terms you need the ability to charge both batteries and discharge (even flatten) the house battery WITHOUT flatenning your starting battery. This can be done relatively cheaply with simple manual switching systems up to fully auto systems.
Someone will know someone in Perth - maybe a new topic - HELP me find a good auto electrician in Perth.
Cheers Baz
Thanks Baz, the campervan doesn't belong to me and I have suggested the auto electrician bit so have to bite my lip now but good advice.
The house battery is not linked to the crank/starting battery so one is not affected by the other. But he house battery is ancient I think, because it is enclosed in a wooden framed box without disconnecting things I can't read what is on the sides but I would say it needed replacing some time ago. But the crank battery is new, the owner taking it up with the RAC at present, but not forceful enough IMHO.
-- Edited by Santa on Sunday 11th of November 2012 08:53:22 AM
From what the others on here have said Santa that seems to be the case.
My techo knowledge is zero (Duh) but we are lucky to have some experienced and qualified people on GN who would be better to answer your query. See their earlier posts.
Hi Bazz
Yes quite correct, if is the 2nd battery is for another use[Auxillary]
The best way then is to have automatic Isolation by a good VSR battery isolator
Traxide, Red arc etc all good units & simple to install.
Peter
I use a Baintech LVC low voltage cut-out in my rig and can recommend it. It has a 30 second time delay to allow for momentary voltage dips due to heavy loads such as a compressor fridge starting.
Thanks for that Jim and OT, will pass that onto the owner of the campervan in question!
Did you try desulfator for your house battery?
Here is a link to the Ebay where you can get it, with delivery costs included:
http://www.ebay.com.au/sch/i.html?LH_BIN=1&clk_rvr_id=410862555763&_nkw=battery+desulfator&rt=nc&LH_FS=1
This may solve y problem for good, and cheaply. The battery will run as new.
90% of the time, battery gets sulphated, what this causes loss of ability to hold power, even if it will show sometime even great volatege, but only for short time...
Almost every battery can be rescued, if you'll connect to it a battery desulphator while charging, and/or leave it on even permanently - if it only still shows voltage and doesn't have shorted plates. I had problem with battery ones, myself, when I bought second hand car some time ago. Battery was flat, and didn't want to hold power at all. In the winter time, just overnight stay depleted it so bad it hardly could turn the starter motor.
Finally, when I needing to ask for a jump-start, after just short visit at my friends' I went straight to near-by Jayco shop, and bought the desulphator for about 50.00 bucks. I put in on immediately (it has just two crocodile connectors), and... I forgot since them I ever had a problem.
I left it permanently, till I finally sold the car, when (of course) I removed the desulphator, and now use it on my new car. It is just as simple as connecting two crocodile connectors to your battery, and problem is gone... If you just lease the van, you don't have to leave it with the van when you give it back. I use it now for years, and plan to get another one for solar charging my auxiliary battery too. It is an excellent maintenance tool, for affordable price.
-- Edited by Esperian on Thursday 15th of November 2012 12:56:22 PM
Thanks Esperian, I will definitely pass that on, I had never heard of them before!
I also have installed a Rotronics solid state dual battery isolator (VSR) between the main car battery and the auxiliary battery in the car.
Thanks Jim,
I had a similar set up in my Hi Ace campervan when I had it in my possession (currently being sold on consignment) worked well.