8d- batterys

[biff]

Well one off my batterys died.so weres the best place to buy new ones? o'reillys have them for 192.00 that sound about right.

[Dave5Cs]

If for starts. I buy 2 Group 31's at Napa for 79.00 each.

[PP]

I got tired of replacing my D's every couple of years. Last year I went to group 31's and the old 892 starts just fine. Plus I have room in the battery compartment for a jug of distilled water, a turkey baster, some jumper cables, and the hygrometer for the house batteries.  I did throw a snit with NAPA when they wouldn't give me a full deposit return on the D's because I wasn't replacing them with same. But we finally came to a compromise LOL.
Will

[mikke60]

I just replaced my 8 d s last week after 5 seasons. Downsized to standard truck batteries and all is still well. I don't do winter camping,so it helps.  Good luck.

[Lin]

Lots of guys have switch from 8d's to group 31.  So far, I have yet to hear of any problems with it.  Get AGM if you can.

[mikke60]

i am also under the impression that having four batteries the approx same size (two bus,two house) that they will charge more evenly. Anyone out there have input on this?  thanks

[John Z]

Just replaced my pair of Apr 03 group 31 start batteries. They have happily existed with the house battery, which is 2 2006, and 2 2007 6v golf cart batteries from Sam's. Both banks are tired together while being charged, either by the engine or a single onboard charger/maintainer. Seems to be working fine.

[TomC]

When I had my 50DN alternator rebuilt (exchanged), I replaced the big black box transistorized regulator with a digital regulator that is about the size of a pack of cigs. Closer voltage regulation. I have 2-31 batteries that are standard wet, but sealed for starting, and two 8D AGM for house batteries. I have a bridging relay to charge all batteries going down the road, or for jump starting myself, etc. Never had a problem with the batteries, even though they are different. My first set of 8D AGM's went 7 years. In that 7 years I did ZERO to those batteries as to maintenance. I will pay the double for AGM batteries everytime now. It's as though they aren't even there. Good Luck, TomC

[Lostranger]

I get great service life from 8D batteries, but I never buy cheap ones. Got 7 years from a pair of Interstate flooded starting batteries in first bus. Sold the bus four years later, and the second set was still strong. Been buying Carquest brand since then. I use two flooded 8Ds to start and four 8D AGMs for house system. We're off-grid solar, and I could not be happier with either bank. I'll probably go AGM the next time I need starting batteries.

I've seen several people claiming short life with 8D batteries, but if they bought good ones, I doubt that the batteries were at fault. Lots of things affect battery life. My only serious complaint is that I don't lift them as easily as I once did.

Jim

[biff]

Got new 8ds o'reillys had two on floor.but thay were dusty and 6 mo. old. thay orderd me two had them in three hours.the ones i took out were 10 and 11 years old. one interstate the other one said alabama battery co.years ago my dad ran a 8d for his house bat. in a winabago lasted 20 years.i ran 31s in diesel van could get around 5 years out of them.

[Ed Hackenbruch]

 Had 8ds in the bus when i got it, one was 7 and the other was 8 when they died. Put in 2 31s and replaced them at 9 years because i thought they were causing a starting problem i had. Replaced them with 2 more 31s,  turned out it was the starter that was bad.

[RoyJ]

i am also under the impression that having four batteries the approx same size (two bus,two house) that they will charge more evenly. Anyone out there have input on this?  thanks

Not an issue at all. In fact, the alternator is a dumb "open loop" DC power source - it provides a constant voltage, and the batteries simply absorb as much current as they need based on their state of charge. 8D, Group 31s, 6V Golfs, are all the same chemistry wise (assuming all flooded).

The exception being modern cars, where the ECU adjust the voltage based on ambient temp. The German luxury cars go a step further and program actual charging algorithms into the alternator to suit their OEM AGM batteries. But unless someone has a 2015 Setra or Volvo I doubt that's a concern for most of us!

You MAY have some minor issues if one bank is AGM and the other is flooded, as AGMs like higher voltage for bulk and absorption charging stages - 14.7v. If that's the case, I'd simply turn up the alternator to 14.6 - 14.7 ish, and cater to the AGMs as they're likely more pricey. This would cause a slight overcharge to any flooded batteries you have, but that does no harm as long as you water them more often. In fact, the slight bubbling would probably de-sulphate the lead plates better.

In conclusion:

- if all batts are flooded, use whatever combo you wish and set your alt for around 14.4v, best balance between charging speed and water loss.

- If you have AGMs on board, cater to them, as they're much harder to "fix" if overcharged (permanent acid loss) or undercharged (sulphated, with no way to desulphate them).

[TomC]

Think of batteries as water tanks. Once you fill one up, it won't get any fuller, then it spills over to the next tank. Batteries don't know where the electricity is coming from (don't have a brain). If you have flooded batteries, set at 14.7. If you have AGM, set at 14.1. I have my alternator set at 14.1 and have no problems with flood batteries for starting (sealed) and AGM for house. Good Luck, TomC