OEM Battery Life

newRVer · 03-25-2017, 02:06 PM

Before we set out this season I'm doing some battery maintenance and have a question. How long did your original batteries last? Right now it would appear that mine are not in very good shape. After deinstalling and charging both batteries with a standalone charger and then letting them sit for a few days indoors, both register about 12.75 volts but the average specific gravity across all cells is only 1.17. According to all the data that I read, that's not good. My charger does have a repair mode that I will try tomorrow to see if I can improve the SG readings, but at this point I'm wondering if I should just toss in the towel on this pair and start with a couple of new batteries.

PS - I thought I might run into this issue as both this winter and last my RV has been on a dealer lot for weeks or months at a time for warranty repairs with probably no charging occurring except when they were troubleshooting electrical items.

wahoonc · 03-25-2017, 02:17 PM

Are you charging them as a pair or individually?

In general the batteries that come with the RV are not the best quality, not to mention you have no clue on the history of them or how many times they have been deep discharged or otherwise abused. If I get 2-3 years out of a battery from the RV dealer I figure I have done well.

Aaron

grumpy0374 · 03-25-2017, 02:19 PM

Have two 12 volt deep cycle in our 2012 Lexington. The no name oe batteries were good till last November, so almost 5 years. One started to show signs of going bad, so I replaced them both.
Grumpy

newRVer · 03-25-2017, 03:06 PM

Quote:

Originally Posted by wahoonc

Are you charging them as a pair or individually?

In general the batteries that come with the RV are not the best quality, not to mention you have no clue on the history of them or how many times they have been deep discharged or otherwise abused. If I get 2-3 years out of a battery from the RV dealer I figure I have done well.

Aaron

Charged individually.

They have already gone through two cycles of deep discharge (this winter and last) without much time on the charger. Going forward it will not be much of an issue since the warranty period is now over (and hopefully the problems will be as well) and I'll be able to take the batteries out for the winter before putting into storage. Additionally, once I install the solar panel on the roof, they should stay charged during the season.

newRVer · 03-26-2017, 10:44 AM

OK. I ran the repair cycle on both batteries this morning but I'm not optimistic that it will help much so I'm now trying to find a good replacement now. Unfortunately since the OEM batteries are generic with no labels I have nothing to really compare a replacement with. For now I'm just going by the battery type (27), dimensions and weight to see what might be a good fit. Seems that Trojan batteries get good recommendations so in that lineup they have a flooded battery 27TMX which is similar in size, only 4 pounds more per (55 vs 51), have a a discharge rating of 175 minutes at 25A and run about $155-$170 ea online. Also, we are not going to be doing a lot of boon docking so adding capacity is not a big consideration. However, I am thinking that it may be tough to find someone that ships a flooded cell battery so I may be stuck with whatever I can buy locally. ???

Another consideration might be that I will be also installing a solar panel on the roof for the sole purpose of maintaining the batteries. If that is the case, should that now affect my choice of replacement batteries?

Finally, since I'm already somewhat weight constrained in the RV, whatever is the solution probably needs to not add significant weight. A few pounds for each battery is probably not a big deal but 15-20 pounds per battery would probably not work.

Suggestions?

SeaDog · 03-26-2017, 11:19 AM

Before you to the the expense of buying new batteries why not run a load test on them? If they test go use them until they no longer fit your use. For me a load test is the only way to truly test a battery

WI nomad · 03-26-2017, 04:05 PM

The acid/water levels are critical. If the lead plates are exposed to air the battery can't maintain a charge once the load is introduced. In high end cars (deep cell style, 12v) battery life is 5 years. In the RV with limited use it could fall to 4. If the battery is weak, odd electrical things can begin to seem overwhelming. These may begin as mirrors not working, steps not retracting, and lights flickering.

newRVer · 03-26-2017, 04:23 PM

Quote:

Originally Posted by SeaDog

Before you to the the expense of buying new batteries why not run a load test on them? If they test go use them until they no longer fit your use. For me a load test is the only way to truly test a battery

Good idea SeaDog, but don't you need to know the AH rating of a battery to do a load test? That seems to be the rub here on these generic battery's. There does not seem to be any AH rating on the battery nor are there any labels with manufacturer/model for me to look it up.

newRVer · 03-26-2017, 07:37 PM

Quote:

Originally Posted by WI nomad

The acid/water levels are critical. If the lead plates are exposed to air the battery can't maintain a charge once the load is introduced. In high end cars (deep cell style, 12v) battery life is 5 years. In the RV with limited use it could fall to 4. If the battery is weak, odd electrical things can begin to seem overwhelming. These may begin as mirrors not working, steps not retracting, and lights flickering.

The acid solution is full.

The label on top says "27MDP" which stands for Group 27 "Marine Dual Purpose". I guess they use dual purpose to enable the starting of the engine if the cab battery should fail? That should not be an issue for me as I will typically be staying in locations where getting a jump, if I need it, wont be an issue. However, having true deep cycle batteries would be nice for tailgating and some places which limit generator use.

newRVer · 03-28-2017, 04:59 PM

Quick Update. The repair cycle I ran the other day seems to have improved the specific gravity just a little. I.e. there were solid red and now they are just at the red line. So today I took my batteries over to Northeast Batteries in Bristol PA. These guys are a big battery distributor that also do consumer sales. The guys there helped me with the batteries into the warehouse where we first tested the specific gravity. Interestingly enough they were getting different readings than I was so much so that some of the cells were in the green. There also did a load test on both batteries which passed. His initial diagnosis was the batteries were not charged all the way even though they measured 12.6 volts. So for now they are both hooked up to some industrial smart chargers overnight and I will pick them up tomorrow.

I think I will invest in the same hydrometer they use instead of the tube type I have which is a bit hard to read.

https://www.amazon.com/E-Z-Red-SP101...red+hydrometer

Then I will have to investigate why my brand new Noco Genius G15000 apparently did not charge the batteries all the way up.

PS. Apparently these Generic Batteries are actually made by Exide. The tech was able to tell just by looking at the case. He also had the same model Exide sitting nearby and they looked the same to me.

wahoonc · 03-29-2017, 05:31 AM

I use a Refractometer to measure specific gravity. The bubble ones, as you have found can vary a bit. The only way to be more accurate would be to get a lab involved.

tAaron

SeaDog · 03-29-2017, 07:22 AM

Tool for two uses check your batteries and then your orange juice

wahoonc · 03-29-2017, 11:17 AM

Quote:

Originally Posted by SeaDog

Tool for two uses check your batteries and then your orange juice

Margaritas!

Believe it or not that is where I first learned to use a Refractometer. Worked for Chi-Chi's Restaurante way back in the day. One of my jobs was to "brix the mix" for their famous margarita's to make sure it was done correctly.

Aaron

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