Breakdown due to dead battery

Not familiar with multiple batteries in a big rig yet. Are the batteries wired in parallel or series? In series the amp hours don't really need to match as long as the lowest rated battery meets the maximum amp hour rating. Example would be 4X100ah-12v in series equals 48v @100ah. If the maximum amp hour requirement is 100ah,then you're good. You could run 2X200ah and 2X100ah and still never exceed the max. In parallel the amp hours of all batteries need to match. An example 4X100ah-12v in parallel equals one big 12v-400ah battery. Because in this case you are stepping up the amps, you need the balance of Ah to prevent any of the cells or batteries from heating to the point that the acid mix evaporates (sealed batteries will bulge and worst case burst). Hope this helps a little bit.

 

No different ratings are NOT the problem, what is ... is replacing two out of the three or three out of the four.

REPLACE all of them.

Electricity is all the same, auto, truck, train, it is all the same.

 

Batteries are in parrallel to get the amps/ Usually 4 batteries.
In my book, it is better to replace them all. Yet bad batteries wont affect electronics. That would be a bad charging system providing too much voltage and cooking the batteries. A cheap way to figure out (if you dont trust the gauge in your truck) if voltage is correct? 14.7 is the usual voltage from an alternator.
https://www.amazon.com/Palumma-Char...teway&sprefix=12v+outlet+usb+,aps,500&sr=8-22

 

Replace all the batteries and have the charging system checked for both proper voltage output and amperage output.

 

12 volt batteries on a fully 12 volt system HAVE to be hooked in parallel. Parallel keeps the voltage the same, amp capacity increases. (Not going to go into 12V charge/24 volt series parallel. Too complicated to explain lol.)

Hooking batteries in series you increase the voltage (by adding the voltages of each battery together). Amp capacity stays the same as (I believe, not 100% sure) the lowest battery amp rating.

Mixing different battery CCA or AH ratings shouldn't hurt electronics and electrical. What will hurt them is incorrect voltage. If you were to hook four, 12 volt batteries in series on a 12 volt system, you WILL destroy electronics.

As a rule of thumb, if one battery in a group fails a load test, replace all the batteries in the group. Replacing only one or two weak ones will just drag the new ones down to the level of the weakest remaining battery. Its just like sticking a brand new tire next to a worn out one. Just wasting money.

 

Ah batteries are one of those things that you really can’t predict when they will go out even with a thorough inspection.

#### happens, don’t worry about it. I’ve had my front tire blowout and I was going 70 on the left lane. Had my alternator belt snap (you can usually tell when the voltage gauge goes wild or stays at 12v). Had my main belt snap going up the hill fully loaded. And lots of other things.

As far as batteries, I have a mechanic that checks them every Saturday so I can at least say the only time my batteries died was when that -50 wind hit during the polar vortex.

 

Are they sealed batteries, or do they have fill caps? Do you know if they have ever been reconditioned? If they have water caps, and we’re new when originally installed, you can probably recondition them with electrolyte. They sell it in bags at most major auto parts stores. For about $9.00 you get a bag with enough-to do one battery. It’s a lot cheaper than $120.00 replacements. Just make sure to follow the instructions, and put a full 24hr. Trickle charge on them before use. I’m running batteries that are 12 yrs. old, and have been reconditioned twice.

 

Good for you, glad you are back up and running.

Hell I know CDL holders who can't figure out how to check the oil - which should be a requirement to demonstrate a knowledge of what an oil dipstick looks like and how the markings work.