Chassis batteries DOA.

[Smitty77]

I've started researching replacement for my single 8D CAT Maintenance Free battery. (Drained down pretty bad for the third time in it's life of ~6 years now (Fog lights left on for about 19 hours!), and thought I've got it charged back up now, not sure how much more life I took out of it.

I want to go to AGM for the next Starter Battery, as I'm pretty sure we'll change the house over to Lithium at next change over. So I want to close off the egg crate grill at the bottom of the battery compartment.

Here are some of the batteries I'm considering for replacing the CAT (And by the way, the CAT 8D Maintenance Free battery is 1500 CCA. And I pretend to top it off with maybe 1 1/2 oz of water, twice a year... In our application, it just does not out gas that much at all... A very good battery, IMO!)

CAT 8D Maintenance Free (wet) Starter Battery (Current Starter Battery)

L20.47 X W10.8 X H9.76 WT132LBS CCA1500

Lifeline GRP31Starter

L12.9 X W6.74 x H9.27 WT67LBS CCA 810 (X's 2)

Lifeline GPL-4DL RV

L20.76 X W8.7 X H8.64 WT124 CCA 1100

Lifeline GLL-8DA RV

L20.76 X W10.89 X H8.64 WT156 CCA 1350

I've also got the spec's for the GRP31's Trojan Overdrive as well as the Full River too. Just from reading the internet, so it must be true, I'd rank these as Lifeline #1, Trojan #2 and Full River not much further down from the Trojan. IMO, the best bang for the buck would be the Full River between these batteries. But, I'm a fan of extra contingency when it comes to batteries, and will likely go with the Lifeline's. Spend more up front, hopefully get some more life out of them, and having a bit extra reserves is not bad too. And good chance I'll go with the 8D. The GRP31 are easier to manhandle, but frankly hope not to need to do so too often! And, it will be a drop in replacement for the CAT 8D (Which replaced OEM Deka Wet Cell 8D's.)

The ISL in our coach, spins very nicely with a single 8D.

Just info sharing here, and wish you the best of luck on your search!
Smitty

[Matt D]

Our Entegra chassis are currently designed for (2) Group 31s arranged in tandem. The length and height of an 8D would likely work fine, but the width would create a need to reengineer the battery tray.

With the after treatment on the inside of the battery tray rear wall, this would be complicated.

-Matt

[Craneboy302]

This is late but have a question. A friend of mine changed his coach battery with Agm batteries but not the engine batteries. Then the charging system would overcharge his engine batteries. Is this true do you have to change all the batteries?? Thanks b.

[Mr_D]

My rig had no maintenance starting batteries (4 925 CCA) and four 8D AGM's. The inverter was set to AGM charging profile. Both sets were original when we bought the rig although I have changed all of them out.
Due to an ordering mistake on my part I got regular wet cell starting 8D's rather than deep cycle house batteries. Will be replacing them this summer with Lifeline AGM's.

[Matt D]

Originally Posted by Craneboy302

This is late but have a question. A friend of mine changed his coach battery with Agm batteries but not the engine batteries. Then the charging system would overcharge his engine batteries. Is this true do you have to change all the batteries?? Thanks b.

In order to answer your question, we would need to know the friends coach make and model, and yours.

I only know about two different brands of coaches, Tiffin and Entegra. So take everything I say with a large dose of sodium.



This is the simple version..

In both cases, the engine driven alternator charges both the chassis batteries, and the house batteries when the engine is running (generator off and shore power disconnected.)

While the alternator and chassis batteries have a very simple relationship, the house batteries are a little more complex. In fact, the alternator provides power to the Inverter/Charger that can then recharge (or maintain) the house batteries.

The Inverter will have a charging profile that is user selectable. However, this only applies to the house batteries. The chassis batteries are charged according to the Voltage Regulator, which manages the Alternator output.

Obviously if both the Chassis, and House batteries are depleted, the Alternator will struggle to recharge both simultaneously. This is why many manufacturers incorporate forms of managing which batteries get charged first, and for how long before charging the other bank of batteries.

In short, changing house batteries to AGM should only require updating the charging profile within the Inverter. If the chassis batteries are being overcharged, something else undesirable is happening.

I hope this helps,

-Matt

[twinboat]

Originally Posted by Matt D

In order to answer your question, we would need to know the friends coach make and model, and yours.

I only know about two different brands of coaches, Tiffin and Entegra. So take everything I say with a large dose of sodium.


In fact, the alternator provides power to the Inverter/Charger that can then recharge (or maintain) the house batteries.


-Matt

That not how the engine alternator charging works.

The alternator charges the chassis batteries. Once they are satisfied, the house batteries are paralleled in, thru the isolation relay and control ( IRD, BIRD ) control, when conditions are met.

The inverter/charger only charges while the shore or generator power is available.

[Matt D]

Originally Posted by twinboat

That not how the engine alternator charging works.

The alternator charges the chassis batteries. Once they are satisfied, the house batteries are paralleled in, thru the isolation relay and control ( IRD, BIRD ) control, when conditions are met.

The inverter/charger only charges while the shore or generator power is available.

Yup, you’re right Twinboat, thanks for the correction. Sorry, I’m not sure what I was thinking there. The Inverter/Charger only charges when on shore or generator.

The Tiffin charged the Chassis batteries, then a solenoid paralleled the house batteries.

I’d bet Entegra does something similar, but I’m not 100% sure of how they get that job done.

Either way, while running down the road (without the generator running) our Entegra Alternator will do a fine job of keeping the house batteries topped off, in addition to the chassis batteries.

-Matt

[757driver]

Originally Posted by Craneboy302

This is late but have a question. A friend of mine changed his coach battery with Agm batteries but not the engine batteries. Then the charging system would overcharge his engine batteries. Is this true do you have to change all the batteries?? Thanks b.

Depending on the coach your friend has and the way it is wired that may be true but on an Entegra (diesel models) you do not have to change the chassis batteries to match the house batteries. While on shore power or generator the chassis batteries will only get a charge for 1 hour and only if they are 12.6v or below.

[classicalgas]

Originally Posted by Matt D

Yup, you’re right Twinboat, thanks for the correction. Sorry, I’m not sure what I was thinking there. The Inverter/Charger only charges when on shore or generator.

The Tiffin charged the Chassis batteries, then a solenoid paralleled the house batteries.

I’d bet Entegra does something similar, but I’m not 100% sure of how they get that job done.

Either way, while running down the road (without the generator running) our Entegra Alternator will do a fine job of keeping the house batteries topped off, in addition to the chassis batteries.

-Matt

Matt, there are probably no other people who know so little as me who are willing to go so deep in the weeds to try to understand those of you who DO understand what you're talking about... is that clear?

You guys are making me crazy I think. I have figured out that I have a battery problem, and that the likely solution is to change out batteries, but with what? My house batteries have been *DEAD* more than once but resuscitated with an industrial strength charger. I'm not sure how many times I can bring them back from the brink or how efficiently they're operating.

[brobox]

Originally Posted by classicalgas

You guys are making me crazy I think. I have figured out that I have a battery problem, and that the likely solution is to change out batteries, but with what? My house batteries have been *DEAD* more than once but resuscitated with an industrial strength charger. I'm not sure how many times I can bring them back from the brink or how efficiently they're operating.

Just my experience, but the factory installed Discover batteries in my coach did not take many DEAD cycles, and none since I have owned it They didn't make it past the warranty. Lots of good, long posts about battery replacement from the high $ Lifelines on down. Entegra replaced mine with East Penn's, first time I have been able to hold a charge overnight and make coffee in the morning since new. They work for me, they also just received the contract to make Duracell AGM now being advertised by Batteries Plus.

[Matt D]

Greg, sorry to confuse the issue. That was certainly the last thing I intended.

In regard to your problem, I believe Entegra was still using traditional wet cell lead acid batteries in 2016, is that correct?

If so, those types of batteries have little tolerance for a deep (or complete) discharge. If they’ve been discharged more than once, internal damage may have occurred.

My suggestion would be to have your batteries checked to quantify their performance. In your case, I wouldn’t be surprised to find one or more of the batteries testing poorly.

The general advice for a bank of batteries, is to replace as a group.

Obviously, the best solution from a maintenance perspective, and tempered by some degree of economy, is an AGM.

However, in our last coach we had wet cells and when they went bad I went back with wet cells again primarily as I didn’t feel the periodic battery maintenance was worth the increased cost.

In this aspect, I feel each user is unique. Some abhor watering their batteries. Some applications require water quite often. Others like us didn’t have to water very often, and when needed it wasn’t a big deal.

Should you choose AGM, one benefit is the ability to tolerate deep discharges better than lead acid batteries. While I certainly don’t intend to deeply discharge my batteries, it’s nice to know one accident won’t likely cost me $1200.

Changing to a different battery may possibly require replacing your battery cables. This shouldn’t be the case in going from one specific frame to another battery with the same frame, but it happened to us.

Sorry for the confusion,

-Matt

[brobox]

Originally Posted by brobox

Just my experience, but the factory installed Discover batteries in my coach did not take many DEAD cycles, and none since I have owned it They didn't make it past the warranty. Lots of good, long posts about battery replacement from the high $ Lifelines on down. Entegra replaced mine with East Penn's, first time I have been able to hold a charge overnight and make coffee in the morning since new. They work for me, they also just received the contract to make Duracell AGM now being advertised by Batteries Plus.

MY bad! I was thinking coach batteries not chassis batteries, sorry, it was too late to delete the post after have my second cup of coffee and waking up.

[wa8yxm]

Revisiting this thread I noticed a statement:

Join Date: Jan 2016
Location: Spring, TX (Home Sweet Home)
Posts: 1,347
Chassis batteries DOA.
All it takes is one good discharge to kill a flooded battery.

Not entirely true

All it takes is one good discharge to kill a STARTING battery, does not matter if it is flooded wet cell or AGM or what.

DEEP CYCLE batteries on the other hand often will recover if not left sitting dead for long periods of time.. And again does not matter if Flooded, Maintence Free or AGM

MARINE?deep cycle are primarly starting and MIGHT recover from one "opps" but... Well.. Don't count on it,.

But I'v erun deep cycle flooded wet cell batteries (GC-2 class) down below 10 volts multiple times and they lasted 9 years.