Pulse and glide battery issue/ ideas needed

[brucepick]

Originally Posted by JethroBodine

Two in parallel is ok, big rigs use up to 4 in parallel for starting.

OK I guess if you're going to buy a matching set and always use them together.

But when one of them develops an issue - no battery lasts forever - the other(s) will sacrifice themselves to support the lame one. Big rigs need starting power. A substantial need but not same as what we need. Ask some serious deep cycle users or the manufacturers.

Anyway, you need SOME additional battery capacity for long coasts with lights and/or fan. You need LOTS of deep cycle capacity to run a car without alternator for many hours. There are many good solutions for both scenarios.

[brucepick]

Any lead acid battery lasts longer (lifespan) if you don't discharge it down to a small percentage of its capacity. Many recommend a limit of 50%. If you usually draw off only 10-20% of capacity and keep it on a quality charger the rest of the time it will usually last for many years.

My point here: Buy as much capacity as you can afford and fit, to avoid draining it down far.

Ask California98Civic. His small (16AH?) single, high quality AGM failed after maybe six months of regular deep draining.

[wickydude]

May I suggest this website for better insight in (dis)charging the various battery types:
windsun.com/Batteries/Battery_FAQ.htm

I found it quite enlightening.

[wickydude]

Was not allowed to post a link yet

[wickydude]

Deep Cycle Battery FAQ

Allowed now

[PaleMelanesian]

I use a charger every night on mine. It doesn't help during the drive, but I start every day with a fully charged battery. More capacity is obviously a better solution, but under my hood will only fit a tiny 51R battery. I use the cabin space for people regularly, so that's out as well. In the end, I'm keeping it simple and just plugging in every night.

[Weather Spotter]

well I stopped by my battery dealer and swapped out the big deep cycle for one that fits in my battery bay. the posts are backward from what I had so it was a tight fit to get the cables to fit

I also added the charger and mounted that in the car. after I see how its working I will need to add a second 120v plug on the side of the car. I am thinking of trying the starter battery as the second one, but I will wait and see how the deep cycle works fist. it has less cranking amps (640 vs 690) but a longer reserve (140 min vs 100). it is also designed to be drained more then the old starting battery.

[Daox]

The cranking amps is a non-issue. I think you'll find the deep cycle works just fine.

[brucepick]

Should be excellent for EOC. If going without alternator, usefulness of the battery will depend on the AH capacity and how far you want to drive.

[Weather Spotter]

thanks for all the help folks!

I got a box for the deep cycle but did not use it, so I am finding a place to put it, I can add the starting battery in there for now, add put in a second deep cycle if needed.