I have 2 x 100AGM in my battery bank. Should I connect source and load to the same diagonals or to opposite diagonals? For the sake of this question source is solar input or mains battery charger and load is house load and/or inverter. I've read a few threads on RV, boating and solar forums and some say one way and the others say do it the other way without giving a reason. Many of the examples talk about banks of 4 or more batteries and the issues about balancing the 'middle' batteries which makes sense to me - but with only 2 batteries this is not an issue (I think...)
I can see that having source and load on different diagonals makes practical sense in terms of being able to more easily identify what is what but does it make a difference to how the batteries charge/ discharge or battery life? And just for curiosity should the connection method be different for a two battery bank vs a bank with multiple batteries?
dabbler said
02:21 AM Nov 26, 2020
Parallel configuration. Source and load to the same battery posts/poles for positive and negative respectively. Positives to first battery in bank, negatives to last battery in bank. Batteries connected in either parallel or series should be viewed by as one larger single battery and it becomes clearer.
Whenarewethere said
09:38 AM Nov 26, 2020
As said about, source & load from the same battery.
& Fuse everything on the positive side.
For setups with 4 batteries, connect them in pairs, then connect each of those sets as you would if you had only 2 batteries.
Or connect all 4 batteries to a common junction with the same length or wire. The same as if you had an odd number of batteries.
kgarnett said
08:54 PM Nov 26, 2020
If you will be using a battery monitor or similar with a shunt to measure current (charge & discharge) then both charge and discharge currents should flow through the shunt. This implies source and load connections are connected to the same battery terminal via the load side of the shunt.
Ken
Cooch said
08:57 PM Nov 27, 2020
Thanks for clarifying. Connections appear to be mostly as you suggest. Previous owner has a couple of (low draw) things connected to the 'wrong' side; one of them seems to be power to the brake controller, I will have to trace the other to find out what it is.
Jaahn said
12:03 PM Nov 28, 2020
Cooch wrote:
Thanks for clarifying. Connections appear to be mostly as you suggest. Previous owner has a couple of (low draw) things connected to the 'wrong' side; one of them seems to be power to the brake controller, I will have to trace the other to find out what it is.
Hi Cooch
If it was mine I would get rid of the wrong connections, they often cause problems in the long run. As said if you have a current shunt to monitor the use then all current should come and go through that anyway. So connect them properly with heavy cables and connectors, positive on one battery, negative on the other, so there is no voltage difference on the two batteries and no odd "low current" draws to upset the balance. You only need to do it once to get it right.
Jaahn
Cooch said
11:32 PM Nov 29, 2020
Some of the cables have no slack so doing it right will take a bit of work Jaahn. Stacking multiple ring terminals gets a bit untidy too. What i'd like is to tidy it up a bit so I can see what's what and find the fuse when I need to so i'm thinking of getting a marine type fuse box with bus bar to take care of some of the connections. Or is there a better way of doing this? There is a shunt and I have deflection type panel meters for volts and amps. These are factory install and pre technojiggery so I can only see discharge. Down the track i'd like to add a battery monitor to let me see how many amps the solar is putting back in (plus the other useful info). Could this be installed using the existing shunt or will it likely interfere with panel meters?
kgarnett said
08:54 AM Nov 30, 2020
If the planned battery monitor can be set up to use the existing shunt Amps/mV then you can use the existing shunt for the monitor. You can also connect the existing analog ammeter to the shunt.
The analog ammeter measures the mV across the shunt and is scaled in Amps. If the analog meter is of reasonably high input resistance then it will only take an insignificent current from the shunt and readings on the monitor or analog ammeter will not be affected.
Ken
Jaahn said
10:49 AM Nov 30, 2020
Cooch wrote:
Some of the cables have no slack so doing it right will take a bit of work Jaahn. Stacking multiple ring terminals gets a bit untidy too. What i'd like is to tidy it up a bit so I can see what's what and find the fuse when I need to so i'm thinking of getting a marine type fuse box with bus bar to take care of some of the connections. Or is there a better way of doing this? There is a shunt and I have deflection type panel meters for volts and amps. These are factory install and pre technojiggery so I can only see discharge. Down the track i'd like to add a battery monitor to let me see how many amps the solar is putting back in (plus the other useful info). Could this be installed using the existing shunt or will it likely interfere with panel meters?
Hi Cooch
A bit of good work now will be forever and avoid a bit of work when you do not want it
Stacking is not good and a bus bar for each + and - is a good idea. You do not need fancy expensive ones. Go to your local electrical supplier and get them. Called active link and neutral link, multi hole, several sizes, and get one with a black cover and one with a red cover. Cheap and good enough for your home 240V power. On ebay too ! Then some good connecting cables between the links and shunt and the battery terminals and lugs. Place the links where you need them. This is what I did for my MH with a 6x circuit breaker board.
As said the shunt will be ok with two meters run off it, but the meters may specify the shunt resistance to get the right reading. So see if there is some identification on the shunt or the existing meter. EG 50mv FS or something like that. Get back to us and ask questions other may be interested also.
Cheers jaahn
-- Edited by Jaahn on Monday 30th of November 2020 10:51:26 AM
-- Edited by Jaahn on Monday 30th of November 2020 10:53:36 AM
Cooch said
11:15 AM Jan 17, 2021
Ok, i've finally had a chance to look at my wiring set up a bit more. As mentioned previously there are some 'extra' loads connected directly to the battery ie they do not register on the amp meter. One is power for the auxiliary brake controller, the other is power to a 12v socket. I don't know why the brake controller is connected to the house batteries as I think this is a 'vehicle system' and ought to be connected to the vehicle battery. I occasionally use the 12v socket to power a waeco portable fridge and it would be helpful if this load showed on the meter. So a couple of things to fix.
I'm not quite sure what is going on in my battery compartment but I think the picture shows a VSR (vehicle is 2005) to control charge to house batteries and a shunt (or is it a fusable link??) for house loads. I can't see any specs on the shunt. The two red cables seem to go to the house fuse panel. Amp meter is 60A but house fuses add up to 160A, then there is an additional 40A for loads connected directly to the battery.
Looking for advice on how to proceed before I tackle this. I figure I need to know the capacity of the existing shunt before I go connecting additional loads to it. Bus bars are part of the solution here, thanks Jaahn. Other option is to add a battery monitor now with an appropriate sized shunt and hopefully with equivalent spec that will also drive the existing amp meter.
-- Edited by Cooch on Sunday 17th of January 2021 11:49:30 AM
Ok, i've finally had a chance to look at my wiring set up a bit more. As mentioned previously there are some 'extra' loads connected directly to the battery ie they do not register on the amp meter. One is power for the auxiliary brake controller, the other is power to a 12v socket. I don't know why the brake controller is connected to the house batteries as I think this is a 'vehicle system' and ought to be connected to the vehicle battery. I occasionally use the 12v socket to power a waeco portable fridge and it would be helpful if this load showed on the meter. So a couple of things to fix.
I'm not quite sure what is going on in my battery compartment but I think the picture shows a VSR (vehicle is 2005) to control charge to house batteries and a shunt (or is it a fusable link??) for house loads. I can't see any specs on the shunt. The two red cables seem to go to the house fuse panel. Amp meter is 60A but house fuses add up to 160A, then there is an additional 40A for loads connected directly to the battery.
Looking for advice on how to proceed before I tackle this. I figure I need to know the capacity of the existing shunt before I go connecting additional loads to it. Bus bars are part of the solution here, thanks Jaahn. Other option is to add a battery monitor now with an appropriate sized shunt and hopefully with equivalent spec that will also drive the existing amp meter.
-- Edited by Cooch on Sunday 17th of January 2021 11:49:30 AM
Hi Cooch
The two items is see in the pics are I believe ; the big shiny one is a connecting relay controlled by some switch, hence the two smaller terminals. Most likely controlled by the ignition circuit to charge using the car alternator. It is not a VSR(voltage controlled relay).
the second one looks to me like an over load protection unit called auto resetting over load relay. It is not a meter shunt.
They were used commonly on headlight circuits as they continuously switch of and on to reduce the overload current (so you do not loose your lights completely) They usually have a current rating on them. An old fashioned protection method.
A meter shunt will have two main big meaty connections for the main wires to carry the current and two tiny connections which go to the meter. It is possible the meter may not use a shunt. What is its max reading.
Jaahn
-- Edited by Jaahn on Sunday 17th of January 2021 07:54:19 PM
Derek Barnes said
09:22 AM Jan 18, 2021
Jaahn wrote:
Cooch wrote:
Some of the cables have no slack so doing it right will take a bit of work Jaahn. Stacking multiple ring terminals gets a bit untidy too. What i'd like is to tidy it up a bit so I can see what's what and find the fuse when I need to so i'm thinking of getting a marine type fuse box with bus bar to take care of some of the connections. Or is there a better way of doing this? There is a shunt and I have deflection type panel meters for volts and amps. These are factory install and pre technojiggery so I can only see discharge. Down the track i'd like to add a battery monitor to let me see how many amps the solar is putting back in (plus the other useful info). Could this be installed using the existing shunt or will it likely interfere with panel meters?
Hi Cooch
A bit of good work now will be forever and avoid a bit of work when you do not want it
Stacking is not good and a bus bar for each + and - is a good idea. You do not need fancy expensive ones. Go to your local electrical supplier and get them. Called active link and neutral link, multi hole, several sizes, and get one with a black cover and one with a red cover. Cheap and good enough for your home 240V power. On ebay too ! Then some good connecting cables between the links and shunt and the battery terminals and lugs. Place the links where you need them. This is what I did for my MH with a 6x circuit breaker board.
As said the shunt will be ok with two meters run off it, but the meters may specify the shunt resistance to get the right reading. So see if there is some identification on the shunt or the existing meter. EG 50mv FS or something like that. Get back to us and ask questions other may be interested also.
Cheers jaahn
-- Edited by Jaahn on Monday 30th of November 2020 10:51:26 AM
-- Edited by Jaahn on Monday 30th of November 2020 10:53:36 AM
If you use the above links make sure you get ones with the correct current rating. Most of the above type links seem to be limited to 100A max. If you use a high power inverter with your battery system you can easily draw 200A or more.
Jaahn said
10:26 AM Jan 18, 2021
Derek Barnes wrote:
Jaahn wrote:
Cooch wrote:
If you use the above links make sure you get ones with the correct current rating. Most of the above type links seem to be limited to 100A max. If you use a high power inverter with your battery system you can easily draw 200A or more.
If you are going to use a high power inverter(say > 300W) I would not wire it to anything but direct to the battery terminals. Possibly only include a shunt in the circuit. Every connection will cause voltage drops at high current use, so make all connections 120% good and short wiring.
The above links do not have holes big enough for the wire size needed for big current but suit all the normal things you use. They have a couple of size holes in them usually for a couple of larger wires.
Jaahn
-- Edited by Jaahn on Monday 18th of January 2021 02:19:11 PM
Cooch said
10:39 AM Jan 19, 2021
Googled the auto reset circuit breaker and will have a closer look at mine for a rating and see if perhaps it's manual reset as that would seem to offer better protection in short circuit situation. Panel meter has 60A max reading. Trying to get more info on this from manufacturer. I have 300w inverter, currently wired direct to battery. Considering adding it to the metered circuit but think my life will be easier if I leave it alone and just sort the other low amp loads for now.
Personally, I would NEVER fit an auto reset circuit breaker.
If a circuit breaker trips, I want to know why and fix that before power is reconnected.
Cheers,
Peter
I have 2 x 100AGM in my battery bank. Should I connect source and load to the same diagonals or to opposite diagonals? For the sake of this question source is solar input or mains battery charger and load is house load and/or inverter. I've read a few threads on RV, boating and solar forums and some say one way and the others say do it the other way without giving a reason. Many of the examples talk about banks of 4 or more batteries and the issues about balancing the 'middle' batteries which makes sense to me - but with only 2 batteries this is not an issue (I think...)
I can see that having source and load on different diagonals makes practical sense in terms of being able to more easily identify what is what but does it make a difference to how the batteries charge/ discharge or battery life? And just for curiosity should the connection method be different for a two battery bank vs a bank with multiple batteries?
As said about, source & load from the same battery.
& Fuse everything on the positive side.
For setups with 4 batteries, connect them in pairs, then connect each of those sets as you would if you had only 2 batteries.
Or connect all 4 batteries to a common junction with the same length or wire. The same as if you had an odd number of batteries.
Ken
Hi Cooch
If it was mine I would get rid of the wrong connections, they often cause problems in the long run. As said if you have a current shunt to monitor the use then all current should come and go through that anyway. So connect them properly with heavy cables and connectors, positive on one battery, negative on the other, so there is no voltage difference on the two batteries and no odd "low current" draws to upset the balance. You only need to do it once to get it right.
Jaahn
The analog ammeter measures the mV across the shunt and is scaled in Amps. If the analog meter is of reasonably high input resistance then it will only take an insignificent current from the shunt and readings on the monitor or analog ammeter will not be affected.
Ken
Hi Cooch
A bit of good work now will be forever and avoid a bit of work when you do not want it
Stacking is not good and a bus bar for each + and - is a good idea. You do not need fancy expensive ones. Go to your local electrical supplier and get them. Called active link and neutral link, multi hole, several sizes, and get one with a black cover and one with a red cover. Cheap and good enough for your home 240V power. On ebay too ! Then some good connecting cables between the links and shunt and the battery terminals and lugs. Place the links where you need them. This is what I did for my MH with a 6x circuit breaker board.
As said the shunt will be ok with two meters run off it, but the meters may specify the shunt resistance to get the right reading. So see if there is some identification on the shunt or the existing meter. EG 50mv FS or something like that. Get back to us and ask questions other may be interested also.
Cheers jaahn
-- Edited by Jaahn on Monday 30th of November 2020 10:51:26 AM
-- Edited by Jaahn on Monday 30th of November 2020 10:53:36 AM
Ok, i've finally had a chance to look at my wiring set up a bit more. As mentioned previously there are some 'extra' loads connected directly to the battery ie they do not register on the amp meter. One is power for the auxiliary brake controller, the other is power to a 12v socket. I don't know why the brake controller is connected to the house batteries as I think this is a 'vehicle system' and ought to be connected to the vehicle battery. I occasionally use the 12v socket to power a waeco portable fridge and it would be helpful if this load showed on the meter. So a couple of things to fix.
I'm not quite sure what is going on in my battery compartment but I think the picture shows a VSR (vehicle is 2005) to control charge to house batteries and a shunt (or is it a fusable link??) for house loads. I can't see any specs on the shunt. The two red cables seem to go to the house fuse panel. Amp meter is 60A but house fuses add up to 160A, then there is an additional 40A for loads connected directly to the battery.
Looking for advice on how to proceed before I tackle this. I figure I need to know the capacity of the existing shunt before I go connecting additional loads to it. Bus bars are part of the solution here, thanks Jaahn. Other option is to add a battery monitor now with an appropriate sized shunt and hopefully with equivalent spec that will also drive the existing amp meter.
-- Edited by Cooch on Sunday 17th of January 2021 11:49:30 AM
-- Edited by Jaahn on Sunday 17th of January 2021 07:54:19 PM
If you use the above links make sure you get ones with the correct current rating. Most of the above type links seem to be limited to 100A max. If you use a high power inverter with your battery system you can easily draw 200A or more.
__________________________________________________________________________________________________________
Hi
If you are going to use a high power inverter(say > 300W) I would not wire it to anything but direct to the battery terminals. Possibly only include a shunt in the circuit. Every connection will cause voltage drops at high current use, so make all connections 120% good and short wiring.
The above links do not have holes big enough for the wire size needed for big current but suit all the normal things you use. They have a couple of size holes in them usually for a couple of larger wires.
Jaahn
-- Edited by Jaahn on Monday 18th of January 2021 02:19:11 PM
Googled the auto reset circuit breaker and will have a closer look at mine for a rating and see if perhaps it's manual reset as that would seem to offer better protection in short circuit situation.
Panel meter has 60A max reading. Trying to get more info on this from manufacturer.
I have 300w inverter, currently wired direct to battery. Considering adding it to the metered circuit but think my life will be easier if I leave it alone and just sort the other low amp loads for now.
If a circuit breaker trips, I want to know why and fix that before power is reconnected.
Cheers,
Peter