best way to test house batteries ?

[Sir_Traveller]

Hello Everyone…

I have a 2003 Ford F-53 RV

What’s the most accurate way to test house batteries using multimeter and hydrometer? Disconnect from shore power then keep few lights on inside the RV to give a bit of load? Do I have to disconnect the 2 batteries from each other and test each one separately? or no need to disconnect anything ?
I appreciate any suggestions…

[pianotuna]

Sir Traveller wrote:
So I disconnected the shore power and turned off the house battery switch, I waited an hour then tested the batteries, and the measurements were as follows: the voltage ( using a millimeter was 12.83 , and when I used the hydrometer, every cell in the first battery tested 1.3 and every cell in the second parallel battery was 12.65 , are these too high? Is it possible to be because of overcharging?

12.65 is ideal. It would be better to wait 24 hours before testing, with no loads and no charging.

[Sir_Traveller]

So I disconnected the shore power and turned off the house battery switch, I waited an hour then tested the batteries, and the measurements were as follows: the voltage ( using a millimeter was 12.83 , and when I used the hydrometer, every cell in the first battery tested 1.3 and every cell in the second parallel battery was 12.65 , are these too high? Is it possible to be because of overcharging?

[Sir_Traveller]

ArchHoagland wrote:
How old are the batteries?

Are they the original batteries?

no they are not
the batteries are exactly 3 years old, Duracell deep cycle batteries ( plus or ultra )

[wallynm]

Get a load tester, fully charge all of the batteries and then use the load tester on each battery. If one is bad replace all of them at the same time!

[ArchHoagland]

How old are the batteries?

Are they the original batteries?

[Gjac]

MountainAir05 wrote:

opnspaces wrote:

MountainAir05 wrote:
I test with them separate. Then check each with the hydrometer after they set for an hour or so. I also check each cell with the volt meter after the hydrometer test.

How do you check an individual cell with a volt meter?

Saves writing and it has a video. Wash off the lead when you are finish.

https://www.youtube.com/watch?v=_8qgZoovWHI&ab_channel=BatteryChem%E2%84%A2LeadAcidBatteryDesulfatorandReconditioner

This is how I check mine also except I leave the positive probe on the pos battery terminal and dip the negative probe into each cell and subtract the difference. When ever I see a low cell I run an Equalization on the battery and also a desulphation cycle also. My batteries are not on a slide and it is difficult to get a hydrometer in there to check. I have two hydrometers and have not had accurate readings, the voltmeter is good enough for what I need.

[time2roll]

First evaluate the system and post the battery age and the measured charging voltage.

I would start with a full charge. This would be charging at about 14.4 volts until amps drop to less than one amp per battery. This could take 2 to 8 hours.

After fully charging disconnect all batteries to separate. Let them sit 24 to 48 hours. Check resting voltage is 12.6+ and full charge on the hydrometer. Post the results.

If they hold a charge and are evenly matched just use them. If the capacity seems much lower than previous then it is probably time to get some new batteries. If the life seemed short it is a good time to evaluate your usage, charging and maintenance routine.

[MountainAir05]

Chum lee wrote:

opnspaces wrote:

MountainAir05 wrote:
I test with them separate. Then check each with the hydrometer after they set for an hour or so. I also check each cell with the volt meter after the hydrometer test.

How do you check an individual cell with a volt meter?

With most modern automotive wet cell batteries, . . . you can't. You can only check the total individual battery voltage. (without damaging the battery casing) With some older automotive wet cell batteries, like pre 1970's, you quite easily could. With some modern industrial wet cell batteries you still can. Tesla, Hybrid batteries (Li-ion), . . . you usually can. These batteries aren't generally used in RV applications.

Chum lee

The OP stated to test with a multimeter and hydrometer so it would work for him. If you can check using a hydrometer then you can also check using a volt meter.

[GIB2]

dieseltruckdriver said it all .
Click on word these and shows Midtronics tester
There are others as well I have Snap on .
The beauty of these is they send impulses though the battery and remove no power from the battery
The message you receive could say good battery needs charge or bad battery or bad cell replace battery. If it says bad battery you don't waist your time and electricity. load testers sell batteries. Electronic testers diagnose batteries. In the end they save you money from misdiagnosing.

[Chum_lee]

opnspaces wrote:

MountainAir05 wrote:
I test with them separate. Then check each with the hydrometer after they set for an hour or so. I also check each cell with the volt meter after the hydrometer test.

How do you check an individual cell with a volt meter?

With most modern automotive wet cell batteries, . . . you can't. You can only check the total individual battery voltage. (without damaging the battery casing) With some older automotive wet cell batteries, like pre 1970's, you quite easily could. With some modern industrial wet cell batteries you still can. Tesla, Hybrid batteries (Li-ion), . . . you usually can. These batteries aren't generally used in RV applications.

Chum lee

[MountainAir05]

opnspaces wrote:

MountainAir05 wrote:
I test with them separate. Then check each with the hydrometer after they set for an hour or so. I also check each cell with the volt meter after the hydrometer test.

How do you check an individual cell with a volt meter?

Saves writing and it has a video. Wash off the lead when you are finish.

https://www.youtube.com/watch?v=_8qgZoovWHI&ab_channel=BatteryChem%E2%84%A2LeadAcidBatteryDesulfatorandReconditioner

[pianotuna]

wopachop,

If the owner has an inverter, that is an easy way to ramp up to quite a high load, especially if each battery is tested as an individual.

[wopachop]

Sir Traveller wrote:
What’s the most accurate way to test house batteries using multimeter and hydrometer?

Depends what you are trying to test. The hydrometer works great to determine how much of a charge the batteries will accept. Which will also give a rough idea of capacity remaining for the batteries.

It wont really tell you the voltage drop under load. For that you could buy a load tester. Or you could load test at home. Put a multimeter on the batteries and then have someone flip on lights and run the water pump. Note how much voltage drop occurs. I dont want to give out voltage numbers because i dont know the correct numbers to give. But lets say you turn on the water pump and your voltage drops to 11.9V. That would indicate the batteries are getting older and sagging too much under load.

[garyemunson]

https://www.harborfreight.com/100a-612v-battery-load-tester-61747.html?_br_psugg_q=battery+tester