shenandoah75
Active Member
I'm assuming i have to cut the leads coming out of the m1, and put new connectors on ? any other options?
thx
-brad
thx
-brad
Best way to hook batteries in parallel for ELK
- Thread starter shenandoah75
- Start date
WayneW
Senior Member
Who is "they" and where do we get them?
If you just hook to batteries together like that you are asking for trouble. One of the two will eventually die, when it does it will kill the other. Possibly the charging circuit too, also it won't work when needed. You need the batteries to be isolated, so that either or both and be charged or supply the control but CANNOT drain directly into the other battery.
shenandoah75
Active Member
well i have a hellroaring isolator ($$$) in my tow veicle for similar purposes, but it only isolates one way.... I can see it for my deepcycle applications optimas/trojans involved with a travel trailer, but seems like overkill on a little 8AH that goes for $20? Back to my rv world, the guidance i've seen on parallel (or series for that matter - i use both) connections is that you should use batteries of same manufacturer/type/model/age... My elk batt is a year old, so i'd probably violate that though
I am pretty sure elk states you have to do this (or similar) in the install manual for 24 hour standby in residential fire/burglar applications... ( in conjunction with amperage limits)
I am pretty sure elk states you have to do this (or similar) in the install manual for 24 hour standby in residential fire/burglar applications... ( in conjunction with amperage limits)
ctwilliams
Active Member
I asked the same question awhile back and got this answer from Spanky (Link):
No problem with two 8AH batteries in parallel. Keep in mind that the more battery amp hour capacity is to be recharged, the longer it will take after a battery run down.
FYI:
When putting two batteries in parallel, should a cell in either battery ever short, it will bring down the other battery also. The M1's low voltage battery test will let you know it has a problem.
Ranger Digital
Active Member
Here is a drawing if that helps. Its page 51 of the install manual for the On-Q HMS 1100, pretty much the same I imagine. You may not have access if you are not signed up for access.
http://www.onqlegrand.com/images/pdf/1307593.pdf
http://www.onqlegrand.com/images/pdf/1307593.pdf
Just a note. If you have a defective cell in a parallel string, a voltage test will not tell you anything. Only a capacity test, in this case runtime, or by braking the string apart and testing individually could you tell if you had a bad cell. Also, definitely use batteries of the same capacity and age, otherwise your cells will get out of balance and your total capacity will drop.
murphy
Member
My installation of a large backup-battery.
Pay attention of the "diode", because it takes away a small amount of voltage.
Therefor you will never have the full capacity added, only a part.
Think about the type of the diode.
In my case it is not a single one, but 20 parallel. That helps a little reducing the voltage drop. And they are Ge-diodes, not Si-diodes.
You must have any device, which prohibit a death of the complete powersystem when 1 battery(cell) is sick.
In my solution, the big car-battery can die whenever ...
And the small battery, direkt connected to the ELK-system is watched and regularly tested by the ELK-system.
At least I hope, this will work during long power-losses AND is a safe configuration.
Pay attention of the "diode", because it takes away a small amount of voltage.
Therefor you will never have the full capacity added, only a part.
Think about the type of the diode.
In my case it is not a single one, but 20 parallel. That helps a little reducing the voltage drop. And they are Ge-diodes, not Si-diodes.
You must have any device, which prohibit a death of the complete powersystem when 1 battery(cell) is sick.
In my solution, the big car-battery can die whenever ...
And the small battery, direkt connected to the ELK-system is watched and regularly tested by the ELK-system.
At least I hope, this will work during long power-losses AND is a safe configuration.
@murphy thank you for this post! This is exactly what I'm trying to do, and I was actually going to use a diode to bypass the smaller battery all together. However, I like your set up, and I think I'll go this route instead. However, being ignorant when it comes to isolation and diodes, I don't understand why you had to use 20 diodes, could you elaborate?
I was thinking of using something like this, it's built to work with high capacity batteries already, so i figured it would work just fine:
http://roadmasterinc.com/products/accessories/electrical/diodes.html
For my charger, I'll be using a battery tender
http://products.batterytender.com/Chargers/Water-Resistant-Power-Tender-Plus-12V-5A.html
For the battery, I was planning on using a 100ah SLA AGM battery.
Any suggestions/advice would be greatly appreciated!
I was thinking of using something like this, it's built to work with high capacity batteries already, so i figured it would work just fine:
http://roadmasterinc.com/products/accessories/electrical/diodes.html
For my charger, I'll be using a battery tender
http://products.batterytender.com/Chargers/Water-Resistant-Power-Tender-Plus-12V-5A.html
For the battery, I was planning on using a 100ah SLA AGM battery.
Any suggestions/advice would be greatly appreciated!
murphy said:My installation of a large backup-battery.
battery.jpg
Pay attention of the "diode", because it takes away a small amount of voltage.
Therefor you will never have the full capacity added, only a part.
Think about the type of the diode.
In my case it is not a single one, but 20 parallel. That helps a little reducing the voltage drop. And they are Ge-diodes, not Si-diodes.
You must have any device, which prohibit a death of the complete powersystem when 1 battery(cell) is sick.
In my solution, the big car-battery can die whenever ...
And the small battery, direkt connected to the ELK-system is watched and regularly tested by the ELK-system.
At least I hope, this will work during long power-losses AND is a safe configuration.
Wouldn't recommend this route with a diode. Advised way would be a RIB or similar relay that would connect the larger battery on AC power loss and disconnect the smaller from the panel.
I agree with DEL.
If the voltage delivered by both chargers to the Elk's battery isn't exactly the same, the Elk's charging circuit will fight with the car battery charger, and possibly over charge the battery.
It will also interfere with the Elk's battery load test, so the Elk won't be able to warn you when the Elk's battery needs to be replaced.
Although batteries can be connected in parallel if they are a well matched set, you don't want to have more than one charger trying to charge them.
If the voltage delivered by both chargers to the Elk's battery isn't exactly the same, the Elk's charging circuit will fight with the car battery charger, and possibly over charge the battery.
It will also interfere with the Elk's battery load test, so the Elk won't be able to warn you when the Elk's battery needs to be replaced.
Although batteries can be connected in parallel if they are a well matched set, you don't want to have more than one charger trying to charge them.