charging batteries

[kemer]

I need to put a charger on my house batteries. There are 2 batteries that run in parallel. The fluids are all full. The charger I have will charge AGM, STD, or GEL batteries. I'm assuming these would be STD batteries? Also, with two batteries, there are two positive posts and two negative posts. Do I attach to two of the posts on the same battery? Right now, my voltage meter shows around 5.00 on each battery.

THANKS

BTW, what are AGM and GEL batteries?

[Executive45]

Ok, we've determined they are 12VDC batteries. Now how did you "test" them to determine they were at 5VDC? Did you use a meter? If so, are you familiar with the meter? Have you checked them with a hydrometer? Assuming you are correct with your finding of 5VDC then the batteries are most likely done. Next will be battery size. Somewhere on either battery or both they will be a size i.e. 31, 27 etc. That will determine how many CCA are needed for your coach if you don't have the manual and assuming someone has not changed them. Since you have no information in your profile and you haven't told us what kind of coach you have it's difficult to offer any more info. Please provide Coach name, model, year and make. Someone who has a similar coach can help you tremendously. Good luck...keep posting....Dennis

[wa8yxm]

RoyF wrote:
If the batteries are connected in parallel then the two positive posts are directly connected to each other, so a connection to one positive is a connection to both. The same goes for the negative posts. So connecting to the positive and negative of just one battery will charge both.

What he said.

NOW: I hear from time to time that you should use positive on one and negative on the other but for most battery chargers (Under 100 amps) ignore that talk and go with what He said.

[rk911]

GordonThree wrote:
5 volts? Maybe you have two 6 volt batteries wired in series, not two 12 volt wired in parallel. What are the markings on the batteries?

either that or the batts are kaput. how many cells per batt...3 or 6?

[time2roll]

Yes at 2 volts per cell you definitely have 12v batteries. Charging is same regardless.

[wolfe10]

As suggested, a smart charger will not charge a 12 VDC battery at 5 VDC. Connect charger to either positive and either negative.

So, either use a cheap charger or jump from another battery/vehicle to get it started.

VERY likely you will be replacing them.

[kemer]

Executive wrote:
First determine what batteries you have. 12VDC will have six caps and 6VDC will have three. AGM batteries are maintenance free batteries so there will be no caps on them. Since you indicate fluids are full you have STD or wet cell batteries. Finally, look at the batteries and let us know if the positive of one connects to the positive or negative post of the other....a google search will give you lots of info on AGM and Gel....Dennis

Each battery has six caps so I'm assuming they are both 12 volts. The positive of one does connect to the positive of the other

[time2roll]

GELL and AGM have similar chemistry but the electrolyte is a bit different. Both are considered sealed. GELL is more commonly used for standby service. AGM is fairly similar to flooded with certain advantages like faster charging and can be used tipped on its side.

As for your batteries they are overly discharged and sulfating badly. Charge them asap but they might be shot. You may need to jump start them for the charger to even begin.

[wolfe10]

Yup, if in parallel, they will be 12 VDC batteries.

If connected in series, they will be 6 VDC.

And, many smarter chargers will NOT charge a totally dead battery. You will need to use a "less smart"/less expensive charger to start.

And, if they have been dead for very long, they are likely DEAD.

[Executive45]

First determine what batteries you have. 12VDC will have six caps and 6VDC will have three. AGM batteries are maintenance free batteries so there will be no caps on them. Since you indicate fluids are full you have STD or wet cell batteries. Finally, look at the batteries and let us know if the positive of one connects to the positive or negative post of the other....a google search will give you lots of info on AGM and Gel....Dennis

[theoldwizard1]

kemer wrote:
There are 2 batteries that run in parallel. (Positive to positive, negative to negative)
.
.
.
Right now, my voltage meter shows around 5.00 on each battery.

Your batteries are dead. You need new ones.

[GordonThree]

5 volts? Maybe you have two 6 volt batteries wired in series, not two 12 volt wired in parallel. What are the markings on the batteries?

[Lwiddis]

At five volts your batteries, 6 or 12 volts, are irreparably damaged. Read a basic online paper on fundamental RV electricity. GEL and AMG batteries are good but expensive and you need to understand more before you buy them.

[midnightsadie]

for safty, learn what you have before just guessing. you could cause some real problems. check water level. clean post. p.s 5v sounds like the batteries are shot. before removing any cables take a pic, draw a map. put tags on , use wire tye,s.

[RoyF]

If the batteries are connected in parallel then the two positive posts are directly connected to each other, so a connection to one positive is a connection to both. The same goes for the negative posts. So connecting to the positive and negative of just one battery will charge both.