I just had a gentlemen restore my 2 8D start batteries. They were completely dead. Not even a hint of turning over the engine and the low air pressure alarm didn't even sound. I was upset to say the least. All I could here was the sound of a cash register going off. I called "ReNu batteries" in Charleston, SC. The guy came out on his way home to check them at no cost. He check both batteries and determined they were good canidates to be restored. The house batteries were another story(only 2.0 volts out of each of them). He picked up the batteries and had them for about 4 days. I was told that he drained them and replaced the electrolite and charged the crap out of them with his smart charger. I put them back in and it seemed like the engine rolled over and started in less than a second. It used to take several seconds and sometimes multiple tries.

I guess the lesson here is to have a professional take a look at your batteries before you go buying new ones. I got out of the whole deal for 110 bucks. I was so happy.

Rodney

I think it will be interesting to see how long they last with these reboot. From what I know about batteries, the lead plates are sacrificial and over time they build up enough lead residue in the bottom to short out. My guess is the renewing constitutes flushing out the residue and replacing the electrolyte. The real questions I have are how long will a rehabbed battery last and is it worth the $110? Due to the cost of 8Ds, it may be worth it. Then again, if it is just a band aid approach to get a few more months of life, I would just as soon bite the bullet and be good for years to come.

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Originally posted by Moonbeam-Express:
I think it will be interesting to see how long they last with these reboot. From what I know about batteries, the lead plates are sacrificial

Yup. When you use up the lead, it's all over.

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and over time they build up enough lead residue in the bottom to short out.

Yup. You can see it on motorcycle batteries with clear cases. Some of the stuff on the bottom is lead sulfate.

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My guess is the renewing constitutes flushing out the residue and replacing the electrolyte.

There might be more to it.

A lot of batteries can be saved by dumping, flushing out the sediment, and using EDTA to break down the sulfation. I have done it to a number of clear plastic case motorcycle and jetski batteries, and the improvement is clearly visible.

Home Power Magazine has several articles on it, as do some of the electric car sites.

Googling EDTA Batteries will yield a lot of information.

quote:

The real questions I have are how long will a rehabbed battery last and is it worth the $110? Due to the cost of 8Ds, it may be worth it. Then again, if it is just a band aid approach to get a few more months of life, I would just as soon bite the bullet and be good for years to come.

I can't say a lot on my own experience because they involved batteries with an unknown history. Or poorly treated batteries. Now and then, one couldn't be saved, but, for the most part, they seemed to last as long as other cheapie Taiwan or Chinese batteries.

The enemy of batteries is sulfation. Lead and lead dioxide are the 2 normally reacting species. While discharging, the sulfate from the sulfuric acid will react with the lead to form insoluble lead sulfate on the plate surfaces. Normal charging converts the sulfate back to the lead. If left discharged, the lead sulfate can sink to the bottom of the cell. This is the evil sulfation we want to avoid. This depletes the lead from the plates and the sulfate from the electrolyte and will eventually short out the cell plates at the bottom of the cell. This is why it is so hard on batteries to remain discharged for any length of time.

Flushing out the sulfate residue is helpful as well as fresh electrolyte of proper concentration. This will often allow charge/discharge cycling again but usually the charge capacity of the battery is reduced, since the lead plates are still somewhat depleted.

The design of the plates is the major difference between regular and deep cycle. The deep cycle batteries will have fewer but heavier plates, allowing for deep discharge but lower current rates. The starting ones have more light plates, better for high current but lousy for deep cycle. Your deep cycle batteries may be able to function but time will tell.

Modern chargers have occasional short duration high current cycles designed to prevent sulfation and circulate the electrolyte to minimize sedimentation.

Corey is right.. the money may be well spent if the batteries function again, but questions of longevity and capacity remain.

My batteries were badly sulfated when I got my coach. The crank battery never did respond and I replaced it. The deep cycles came back to life and took a charge but the capacity never fully recovered so I eventually replaced them. Good luck with yours!

I will try and remember to update in 6 months or so and let you guys know how it's going.

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Originally posted by Steve VW:
The enemy of batteries is sulfation.

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Modern chargers have occasional short duration high current cycles designed to prevent sulfation and circulate the electrolyte to minimize sedimentation.

Could you mean high voltage?

Occasional high voltage is equalization, which corrects stratification or unequal SG readings. The the physical violence of overvoltage does a little to knock off some sulfation.

I follow Trojan's rec and only equalize when the SG readings vary by .15 or more. If needed, Desulfation is accomplished by using a Vector charger with electronic desulfation, which is an AC current of sufficiently high frequency not to damage the plates too much. I check if desulfation is needed by using a conductance tester.

When boondocking, the batteries get run down to 50% SOC by disconnecting the solar, and then get a really full charge once a week. That means SG all the way up to 1270 (or as high as it will go).

If we are actually living in the house, the batts get the same exercise once a month. This always improves the conductance reading.

This regimen helped our last batteries to still be pretty decent at just over 9 years when I upgraded to a larger bank.

oops! thanks for the editing. Voltage indeed is the term I needed. You have obviously done your homework. Goes to show that appropriate use/care can provide long service.

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Originally posted by Steve VW:
Goes to show that appropriate use/care can provide long service.

The heck of it is, I wanted to go several more years on the old pair of GC batts, just to see how long they would last. The folks at Trojan said I was on borrowed time, as lead depletion was surely gonna get me, but curiosity caused me to really wanna go as long as I could.

But, sadly, I was gifted with a new pair, and took the opportunity to buy two more so I could have a matched set of four. They serve as cranking and house batteries now, due to limited space in the battery drawer.

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The design of the plates is the major difference between regular and deep cycle. The deep cycle batteries will have fewer but heavier plates, allowing for deep discharge but lower current rates. The starting ones have more light plates, better for high current but lousy for deep cycle.

I think the modern batteries accomplish more surface area in starting batteries by making the plates porous, like a cheese puff. This would lend me to believe it would be harder to get any substantial life from reconditioning a starting battery over a deep cycle.

Hi Rodney!

I live in Charleston, SC and came across your post while doing a search for ReNu batteries. I bought two Rolls Suratte T-12 250AH(20hr) batteries from ReNu batteries back in 2011 and they are still going strong... at 1.265s/g and 12.7V.

The guy was real from ReNu was real friendly and he explained how he had found the two Rolls batteries abandoned under a truck trailer and had

How long did your 2 - 8D batteries survive?

Of the two that I originally got with the coach one died after two years. I bought a refurbed one from the same guy for 80 bucks if I remember right and that last until I sold the coach. The 6v that I bought from went bad right after I sold the coach. But the verdict is still up in the air if they got over charged or discharged to much. I think it was the latter. The guy is really a great guy. He even delivered for me and installed for free even though he started charging for that stuff. I guess because I brought him some business and I was a repeat customer.

I was writing my last message from my phone. Let me clarify a few things. He refurbed my two 8D's after they were dead. So I thought. He took some measurements on the acid and voltage and said that he could recover them. Not 100% but about 80%. Of those only one died. Those two 8D's were pretty old too.