12 volt "upcharger"?

[jacobconroy]

I finally have all my 12 volt parts installed for Overlanding...only to find that the Jeep won't charge my AGM fully. It is not a daily driver and I need a way to keep the batteries in shape and ready to use.

I have an NL Power Pack with a VMAXtanks SLR125 battery. Amazon had good reviews for the battery, and the manufacturers' website said it will charge will on alternators (up to 14.7 volts). I metered the Jeep and found 14.3 at the Power Pack when running at idle. In the week or two of testing I've done, the battery is rarely in the "green" on the Power Pack, and seems to drop below the green after sitting a night or two (with no load other than the Power Pack sensing gear).
[h=1][/h]Surely there must be some sort of "inverter" or "shore power" device that I can permanently install in the Jeep. My plan is to leave the Jeep plugged into 120v while at the house to keep the batteries in primo shape (with smart charging, floating, etc.). My hope is, that the same device will take incoming 12 volt from the alternator and step it up to 12.7 at lower amperage (or whatever) to keep it topped off until I reach camp.

All I'm running of this battery is an NL Weekender. Has anybody found a magic device that will take care of all battery maintenance issues? I don't care what it costs if it works.

Thanks.

 

[Ducky's Dad]

Solution will depend partially on which AGM you have.

 

[coop74]

sounds like you need a DC to DC Charger. Check out Ctek stuff, i think you will find some combo there that will do what you need.

 

[AndrewP]

Sounds like it's a matter of checking the battery voltage. Likely it's fine. Don't get lost in proprietary meters, they are often wrong/inacurate/misleading. What is the resting voltage of the battery itself. If above 12.7, it is likely you are good.

A battery that sits a day or two, especially if exposed to parasitic loads, will read slightly less than 12.7. But if it's above that, your charging system is good and doing what it should.

Use a good meter, measure the voltage an know for sure. I'll bet you are fine.

With that said, the NL is a known weak link with lots of failures, so don't rely on it.

 

[jonyjoe101]

There are many different RC type chargers that charge all types of batteries including lead acid. Many of them are ac/dc and will give your battery a good charge.

I use a triton charger that I bought for 20 dollars to top off my agm batteries that I rarely use, it does a very good job. I also charge lithiums and my nicad power tools with it. It max output is 6 amps, but that is good enough to maintain a battery. Once topped off, the battery if it is good will maintain the charge for months.

On agm batteries, as long as your getting 14.4 volts to charge it, thats good. You can keep it at that voltage all day long. Once fully charge you can float it at 13.7 volts, but not really need to lower the voltage. Connected directly to your alternator is fine, it wont overcharge, even if your alternator puts out 200 amps, the battery only accepts what it needs. The more full the battery the less amps it will accept. The alternator will quickly charge the battery to about 80 percent, but then the remainder 20 percent will take hours to fully charge. Thats why people never get a full charge from driving.

 

[Ducky's Dad]

What is the resting voltage of the battery itself. If above 12.7, it is likely you are good.

Not for all batteries. An Odyssey AGM should be at 12.85OCV or higher to be at 100%. Optimas should be at 13.1 or 13.2, depending on whether it's a starting battery or a dual purpose battery. Others will vary. Battery Lives Matter.

 

[e60ral]

Is the 14.3V at idle (and presumably a little more when running) really not enough for your battery? I would double check the battery specs, I know my East Penn/Deka battery wants 13.8V-14.6V for Charge/Absorption/Equalize.

My 4Runner is 13.8 max, its usually 13.3-13.5, so I use an on-board charger to occasionally top-off the battery to prevent sulfation. NOCO makes on-board chargers that you can permanently mount, they charge at 14.4V which doesn't sound better than your vehicle already, but would be good if you are worried about it sitting
https://no.co/products/charging/onboard

 

[jacobconroy]

Wow, lots of good infos. I will look over NOCO and Ctek as well as go over the battery specs again and report back. Thanks everyone.

 

[jacobconroy]

So, I trickle-charged it last night (with a regular-old charger that I've had forever), and it's reading 13.28 volts at the battery now. I guess that's good. When I get to my destination this weekend, I'll take a reading after a 3 hour drive in the Jeep while running the fridge. This should give me a good idea of what the alternator can keep it at.

Still going to research a good charging/maintenance solution though.

 

[GoodEnoughforGabe]

Get a NOCO Genius and then just leave a hangoff terminal hookup hooked up to the battery. When you get home you can plug the Noco right in and it will do its thing, if your really that worried about it. I have a Northstar AGM and my Gen 1 Tundra seems to keep it well charged.

 

[e60ral]

.

 

[mep1811]

I use this marine dual bank charger on my FJ-60 keep the batteries charged and maintained.

https://www.amazon.com/gp/product/B00BGIBOLE/ref=oh_aui_search_detailpage?ie=UTF8&psc=1

 

[dwh]

So, I trickle-charged it last night (with a regular-old charger that I've had forever), and it's reading 13.28 volts at the battery now. I guess that's good. When I get to my destination this weekend, I'll take a reading after a 3 hour drive in the Jeep while running the fridge. This should give me a good idea of what the alternator can keep it at.

Still going to research a good charging/maintenance solution though.

While charging or discharging, electrons build up on the surface of the lead plates. This is called a "surface charge". To get an accurate reading of the battery's true voltage, you have to wait for the surface charge to dissipate. The commonly recommended rule of thumb is to wait four hours without power flow in or out and then take the measurement.

But that's if you are trying for pinpoint accuracy when measuring what is basically a chemistry experiment.

If you're going to measure immediately after, or during charging/discharging, then you have to keep in mind that the readings will be off, possibly far off, from the true "resting voltage" of the battery.

You might get a better feel for what's going on with your battery if you take a few readings, say one per hour for a few hours.



Another option on your quest is Sterling:

http://www.sterling-power-usa.com/

 

[DiploStrat]

... I metered the Jeep and found 14.3 at the Power Pack when running at idle. ...

I'll add my usual, contrarian view on B2B. If your Jeep charges at 14.3v, the you have no reason to add a B2B, unlike the poster whose Toyota runs at 13.9v or less. (Although there are easy ways to boost the voltage on the Toyota.)

Use the relay isolator of your choice, key control, automatic, or even a manual switch, and pay attention to your wiring - size matters; larger wires mean a faster charge, up to a point of diminishing returns.

You can play with this to get an idea: http://www.calculator.net/voltage-d...ce=10&distanceunit=feet&amperes=100&x=62&y=13

Change the numbers as appropriate.

This, of course, relates to charging from your vehicle's alternator while driving. If you don't have solar, then a good shore power charger would be a good investment.

 

[e60ral]

I'll add my usual, contrarian view on B2B. If your Jeep charges at 14.3v, the you have no reason to add a B2B, unlike the poster whose Toyota runs at 13.9v or less. (Although there are easy ways to boost the voltage on the Toyota.)

i have seen the diodes for the voltage regulator but haven't seen any evidence that they actually work, have you seen any reviews that show them working successfully on a 5th gen 4Runner or other 120 platform vehicle?

and i don't think your view is contrarian, i don't know why a system that could do 14.3V at idle wouldn't be sufficient