Ntnl Luna PPP / Diehard Platinum problems

[Superu]

Hope everyone had a great weekend and someone is in the mood to offer some helpful advice to my most recent issue.

Here's the setup:

03 Chevy Suburban 5.3l V8
Not sure if the alternator is the stock 105 Amp or the 145. Will check VIN and update post.

Starting battery is stock lead acid Group 34.
Second battery is a Group 31 Diehard Platinum in a National Luna PPP.
PPP is located in the rear of the truck and is wired with the NL kit including heavy gauge cable and anderson connectors.

Here's the problem:

After installing a brand new DH Platinum 4 weeks ago and running my Engel MT45 loaded with containers of water and Gatorade I started to notice that the battery level indicator on the PPP would drop overnight from 100 to 75 and sometimes even to 50% charge. This seemed excessive considering the Engel was set to fridge, was maintaining temps in the high 30's and the ambient temps were in the 80 - 95 degree range.

I had read about these DHP's having issues so I called Sears and they said it sounded like a bad cell. Brought it back last week, got a new one from a different Sears location and the issue appears to be recurring this week.

So, before I make a bad assumption about this battery, I thought I'd better post up for some wisdom here. :ylsmoke:

BTW, the NL PPP appears to be working as designed. It lights up, waits the standard 5 minutes before starting the charge cycle and looks as though it's charging as designed. On 7/4/10, I had a 220 mile round trip that I would think would have been enough to top it off. (full disclosure: we did have the AC running, the Engel plugged in and a laptop going the entire time.)

So, if I am running a 105 amp Alt; is it not enough? What about a 145?

Would it make any difference if I replaced my starting battery with the Optima Yellow Top that used to be in the PPP? I took that out because it was exhibiting similar issues but I assumed it was due to it's small size and lower capacity and I wanted a bigger battery for upcoming multi week trips.

Is there something else I am overlooking? When I plugged in a little LCD voltage meter to the front cig outlet, it showed 13.6 - 13.8 while underway.

Thanks!

 

[wrcsixeight]

It is normal, while under load, for the voltage of the battery to drop. With a compressor fridge, by the time the battery voltage starts rebounding after the compressor switches off, the compressor switches on again.

This is why using voltage as a gauge of remaining battery capacity is inaccurate at best.

Alternator ratings are very misleading. A 105 amp alternator is not capable of delivering that when hot, and at low engine RPM's. It is possible the 140 amp alternator might even produce less amperage at lower rpm's than the 105.

I am not familiar with how NL is wired up. The weak link in any dual battery system is using the Vehicles stock charging circuit. It is designed to power only the stock accessories, and recharge a slightly depleted starting battery.

You can significantly improve charging by running a properly fused heavy gauge cable directly from the alternator to the engine battery side of the Solenoid. You can leave the stock wiring in place.

There could be issues with newer vehicles and with NL's set up when doing this. You might just have to upgrade the OEM wiring to get the amps to the Diehard. Those more familiar with your vehicle and NL should chime in.

Also make sure the Diehard battery has a big thick ground wire and all the battery to engine/ frame grounds are clean and tight. Any thin wiring in the charging circuit is like breathing through a kinked cocktail straw after running many flights of steps.

13.6 to 13.8 is a little low. I usually only see that after my batteries have reached full charge, or well before that, at idle speeds. But the ciggy plugs have notoriously thin wiring over many connections and is not usually very comparable with true battery/ alternator voltage tested at the battery.

 

[Superu]

Thanks for the feedback. I'm trying to get some info on your proposed wiring from the alternator to the PPP, but will have to wait until I can reach them. Their site appears to be dead in the water at the moment.

I've checked all the connections and they look good. The heavy gauge wiring runs straight back from the main battery to the NL PPP as described in the instructions that came with the unit.

Maybe I need to take the DHP out and charge it on the charger in the garage to be sure it's fully charged and then start this cycle over with it installed in the PPP.

 

[Plantdriver]

Two different batteries?

I've always heard that one shouldn't mix batteries in a dual-battery setup - even to the extent that mixing a Yellow Top and Red Top Optima is not a good idea. Sears makes a battery that's a rebadged Hawker Odyssey, but less $ - I'd use two of those, or at least buy a Die Hard to match the existing Die Hard.

 

[Plantdriver]

Diehard Platinum Group 31

I just checked and the Diehard Platinum Group 31 is the re-badged Hawker Odyssey Group 31 - I'd just buy another. Even if that's not the source of your problem (mis-matched batteries) it could become a problem later.

Good luck!

 

[Superu]

I have a Group 34 Optima Yellow Top that I'm planning to swap in as my starting battery so both batteries with be AGM.

 

[dzzz]

The diehard platinum is primarily a starting battery. It doesn't hold the amp hours like a true deep cycle. The Odyssey/platimum as the starting battery and a deep cycle like an lifeline would be a good camper setup.
The platinum isn't a bad choice, however.
A bad cell brings a battery down two volts. If it's charged and over 13 volts it's probably fine.

 

[dzzz]

I just checked and the Diehard Platinum Group 31 is the re-badged Hawker Odyssey Group 31 - I'd just buy another. Even if that's not the source of your problem (mis-matched batteries) it could become a problem later.

Good luck!

All RV's are "mismatched batteries". It's not a problem.

 

[Superu]

The diehard platinum is primarily a starting battery. It doesn't hold the amp hours like a true deep cycle. The Odyssey/platimum as the starting battery and a deep cycle like an lifeline would be a good camper setup.
The platinum isn't a bad choice, however.
A bad cell brings a battery down two volts. If it's charged and over 13 volts it's probably fine.

I should have been more specific. I have the DieHard Platinum PM-1 which is an AGM Dual Purpose battery.

•Longer off-season storage time - ideal for boats
•Deep discharge recovery - ideal for marine & deep cycle applications
•Plates made of 99.99% pure virgin lead
•High purity grade acid held safely in place by glass mats; non-spillable design
•Absorbed Glass Mat construction provides mounting flexibility & guarantees longer service life

 

[ThomD]

I'd guess it is time to get the vehicle charging system checked.

Just so nobody misses this, the NPP comes with some very heavy gauge cables and the OP said he checked the connections, so the connection to the NPP is not likely to be the source of any problems.

 

[Superu]

Just verified the RPO code: KG3 GENERATOR 145 AMP 145 AMP(KG3)

Should think that's enough to top this battery up and keep it there. Going to pull the battery and fully charge it before trying it in the PPP again.

 

[wrcsixeight]

Your 145 amp alternator can only produce that in lab situations. Low temps, high rpms, with power hungry devices and depleted batteries that can ask for that much. You will be lucky to see 10 amps making it to the additional battery after the engine and alteranator are hot. Get that 145 amp number out of your head, it is meaningless at recharging your battery.

It is okay but not ideal to use 2 different makes of batteries, while they are being charged. They should not be left together while discharging, or resting, but it is not the end of the world if they are.

Again I am not familiar with how NL want's their system wired. Is your solenoid in the back, or closer to the engine battery?

Some vehicles have a dashboard ammeter. Sometimes this alternator amperage is routed through this dashboard ammeter. Over thinner wire, through multiple connections. Resistance, voltage drop, poor recharging. Then there is the fact that most modern vehicles have the voltage regulator inside the engine computer. It is safer to undercharge a battery, so that is how they are programmed. When an additional battery is added, the recharging performance is just not designed to bring an additional depleted deep cycle battery back up to snuff.

I have added very thick wiring between alternator and battery switch. It has not improved hot idle speed amperage, but at any higher rpm I am seeing 40 to 140% improvement in amps. (I have a battery monitor/ amp hour counter which will read alternator amperage)

You should always top off the battery with a 3 stage automatic charger before and after an outing. Unless you have solar, you basically cannot rely on your vehicle to ever fully recharge a battery, unless significant improvements are made to the OEM charging circuit, or lots of driving at higher engine/ alternator rpms.

BTW you cannot rely on those lights on the NL system for state of charge. I doubt your Engel actually brought your battery down to 50% in 12 hours unless it was left open, or the battery was only at 65% to start the night.

 

[dzzz]

I should have been more specific. I have the DieHard Platinum PM-1 which is an AGM Dual Purpose battery.

I have 3 of the 31M. If you look at an Odyssey spec sheet the difference between a group 31 and a 31M is just a an extra set of terminals. (There's no sears version of the straight group 31). The 31M is used on electric fishing motors because it can put out high current, yet not be ruined by deep discharge.
It may be the best "deep discharge" battery Sears sells, but it's not constructed like a dedicate true deep cycle battery. It's not a wasteful purchase as a house battery, just probably not the best choice. It is likely a better deep discharge battery than the ones Walmart sells for RVs at a similar price.

Both Sears and Odyssey's marketing people "position" their products into niches. But if you look at Odyssey's engineering documents they make only one fundamental battery type.

 

[wrcsixeight]

Wally world's flooded ever starts, if they are labelled rv/trolling/rv/deep cycle, are just dual purpose batteries of dubious quality. I have had poor luck with them, even when I babied them.

Supposively they make a flooded group 31 which is labelled only deep cycle. Some have said they work great for them.
Does wally world sell AGM batteries now? I heard in some parts they are no longer offering warrantiess past 90 days on batts due to the extremely high number of returns.

Due to the weight of batteries, I doubt they are all made for wall mart by the same johnson controls or US battery manufacturing plant, and are probably pretty variable in quality in different parts of the country

 

[Superu]

Update and NL question

Charged up the battery and re-installed it in the PPP. Will give it a workout this weekend with the Engel MT-45 and see how it holds up. Reading 12.8v at rest with no load.

On a side note, does anyone know what's going on with National Luna? Their website has been dead in the water for at least 3 days.