Conflicting info on batteries - starter plus auxiliary

[Stereo]

I'm wiring my starter battery to my camper battery with an SCR/isolator between. I'm reading conflicting information about whether the batteries have to be of like type. Currently, I am still using wet cell batteries in both, but my starter battery is getting weak. Both batteries get light use. The truck sits for at least a week at a time. We do travel back country but the worst we tackle is rough forest roads.

What kind of battery can I combine with my almost-new flooded cell auxiliary battery?

If I need to keep it flooded cell, can it be maintenance free?

Is there any reason I wouldn't want maintenance free?

I'm reading that batteries have turned to crap. What's your advice on longer-lasting, reliable batteries? Some are suggesting Deka is still well made.

Thanks for the advice.

 

[dwh]

They only have to be alike (brand, type, size, age) when wired together into a permanent full-time battery bank.

When only tied part-time during charging, you can mix and match whatever.

Except don't mix gel type with anything but gel. Gels usually require a slightly lower voltage than agm/flooded.

 

[Stereo]

Thank you for clarifying, dwh. I'm curious what the auto parts stores are evaluating with their hand-held device that they clip on. (The salespeople didn't know. Geez.) Voltage, obviously, and that was fine, but the device said to replace it. Of course, I'm suspect since they sell batteries. What else can they read on a battery that's not under load?

My battery holds a charge but feels a little weak on the start. I used a hydrometer and it said to replace the battery but then I later read that specific gravity is not a good indicator. How do I know for sure that the battery needs replacement...before it's completely dead?

 

[DEnd]

The store uses a conductance tester. It puts a small AC current through the battery and tests it. It's basically the same thing a car dealer would use to check your battery though maybe not as well made or as accurate. If it says to replace the battery it's a good idea to replace the battery. AC conductance testing isn't perfect, but it is still pretty good.

Batteries haven't turned to crap. Our expectations has increased, as well as the loads we place on them. Today the battery is likely to be the first major problem we see on a vehicle, that didn't used to be the case. Yes average battery life has decreased, but the battery is also much more highly loaded, it is doing a lot more work than it used to. The more work a battery does then the shorter its life is. The way to improve your battery life on your truck is to disconnect it and/or place it on a tender.

Your isolator doesn't totally isolate your batteries, the only way to truly do this is to completely disconnect them. That said I doubt you will have any issues with it, most isolators still do a pretty darn good job. The main issue is that it may shorten the lifespan of your starting battery ( since it's another maybe large load on the electrical system), the way to solve that is to go with an isolated charging system for your camper's house battery.

 

[Stereo]

Yes average battery life has decreased, but the battery is also much more highly loaded, it is doing a lot more work than it used to. The more work a battery does then the shorter its life is.

That makes sense. Thank you for that information and the tips to extend the life of my battery.

 

[broncobowsher]

I don't worry about mixing batteries so long as they are being charged. Gel takes a lower voltage? Did you do anything to the alternator to change the voltage for a gel? Nobody does, and they work just fine.

Now mixing them with the engine off for extended times, I won't do that.

 

[dwh]

Just a boilerplate warning. Like "don't mix electricity and water" - which actually happens pretty frequently with relatively little mayhem.

And most gel's specs do call for lower bulk/absorb voltages.