Adding 2 more 6 v

[Billinwoodland]

Hi friends. When I bought my A, I had the dealer replace the older 6 v batteries with new ones, as shown in the photograph. I'm planning an extended boondocking trip this fall and want to increase my capacity. While I have not crunched the numbers on power use, I will be using my 12v water pump, satellite TV, some lights, and power needed for frig which will be on propane but draws a small amount. I plan to add solar at some point. I have plenty of room in my battery bay to add 2 more 6v. I understand that adding 2 new batteries to a bank of "weak" batteries is not prudent. But the pictured batteries are only 6 months old. Thoughts on adding 2 new ones to this system? Maybe load test the old ones first? Thanks for your thoughts.
Bill
[img][/img]

[Billinwoodland]

pnichols wrote:
Your left diagram above is not a balanced inter-connection of 4 12 volters.

Your right diagram above is a balanced inter-connection for 4 6 volters.

This tutorial may help on how to inter-connect a multiple bank of 12 volt batteries:
http://www.smartgauge.co.uk/batt_con.html

Thanks, will check it out

[pnichols]

Your left diagram above is not a balanced inter-connection of 4 12 volters.

Your right diagram above is a balanced inter-connection for 4 6 volters.

This tutorial may help on how to inter-connect a multiple bank of 12 volt batteries:
http://www.smartgauge.co.uk/batt_con.html

[Billinwoodland]

wa8yxm wrote:
If you are adding batteries in series (those two are in series) they MUST be TWINS of each other.. All identical,Same age,make,model,size,and so on and so on.

IF adding in parallel there is a lot more freedom..I would (DID in fact) not worry about multiple age in parallel

just remember Each pair of six volt has to be indentical within the pair since each pair is effectively a single 12 volt battery.

But the pairs need not be identical.

wa8yxm, when you say in pairs, is that defined by the neg to pos connection on the series graphic on the right?

[wa8yxm]

If you are adding batteries in series (those two are in series) they MUST be TWINS of each other.. All identical,Same age,make,model,size,and so on and so on.

IF adding in parallel there is a lot more freedom..I would (DID in fact) not worry about multiple age in parallel

just remember Each pair of six volt has to be indentical within the pair since each pair is effectively a single 12 volt battery.

But the pairs need not be identical.

[RJsfishin]

AH capacity make no difference. A grp 24 will charge and discharge equally paralleled w/ a grp 27 or 31. Its controlled by voltage, not amps.

For myself, I dry camp only, and 4-5 months a year, and I still see no need for more than a 225 AH battery bank, especially since I got 300 watts of solar.
Batteries, like horses, eat hay, and they are dead weight when you don't need them. But, JMO.

[Billinwoodland]

RoyB wrote:
Install the two groups of 6V BATTERIES like this. The idea is to get all batteries seeing the same CHARGE VOLTAGES levels when being charged. All "LIKE" DC CABLES should be the same length.



Roy Ken

Hey RoyB, attachement did not show up.
Bill

[time2roll]

I like US Battery configuration 2



http://usbattery.com/info-center/configuration/

[RoyB]

Install the two groups of 6V BATTERIES like this. The idea is to get all batteries seeing the same CHARGE VOLTAGES levels when being charged. All "LIKE" DC CABLES should be the same length.



Roy Ken

[time2roll]

I would get same from the same supplier.

[jrnymn7]

That would preferable, I believe. Others would know better than me.

[Ron3rd]

Add your 2 6v batteries and don't worry about the age of the other ones. I see no problem at all. Though not 1000% theoretically ideal, you will not notice any difference. Great set-up, go for it.

[Billinwoodland]

Thanks fellas. Do the amp hours on the new batteries need to match the old ones?
Thanks
Bill

[jrnymn7]

Bill, do a good top charge on those existing 6's, and an EQ if necessary, after checking SG levels. If things look good, simply parallel the old pair with the new pair, and you should not have any worries.

You'll need to do the same on the new ones... both before putting them into service, and after a few good cycles on their own. (as a 12v string, that is).

You may find each string's ocv (resting open circuit voltage, i.e; no loads whatsoever) must be very, very close, to get them to balance out nice, at first. I split my bank for a while, and found it a little tricky getting the two strings to play nice with each other, afterwards. But a few tries, involving short bursts of charge followed by a good rest, eventually brought things close enough to not make one string leach off the other when paralleled.

[time2roll]

Assuming you have not tortured your batteries during the first six months you are fine to add a second pair.

200 to 500 watts of solar will make an amazing difference.