So I'm ready to install the dual battery setup. I really wanted to go with AGM's but found out they have different charging requirements than regular flooded batteries. I was specifically looking at the Die Hard AGM's. Now I don't know what to get anymore. The AGM batteries are supposed to do both high current starting or winching and low current deep cycle and have much better vibration resistance. I plan on running camp lights and water pump and such at camp so I suppose I will need to deep cycle at least one of them but I'm new to this so don't know for sure. My 2000 G500 has a group 48 battery right now in the tray which is in a bad shape so I can't do any testing on it to see how long it will run everything. Also I read somewhere that it's not recommended to mix different types of batteries so that idea is out the window. What kind of setups do you guys have and what batteries do you use? I guess you can do anything if you are happy with batteries lasting only 2 years but I'd like to get this right and get a long and reliable service out of my batteries.
Dual batteries
- Thread starter ILIAN
- Start date
burquedoka
Adventurer
I run a National Luna dual battery system, and I love it. It has the ability to link the two batteries in parallel if needed to jump the truck or run a winch. The system is very non-invasive to the stock electrics and can be easily removed. As far as batteries, I still have my stock lead acid MB battery running the truck and then I have the big boy diehard platinum marine battery running all the accessories. System is bulletproof as far as I'm concerned.
LocoCoyote
World Citizen
And here I thought they were in the refrigerator business....
dwh
Tail-End Charlie
You can look at the charging requirements of 10 different flooded batteries and see 10 different sets of recommendations. Same with 10 different AGMs. But the variations are minor - basically, what works on flooded will work on AGM and vice versa. In other words, take it up above 14v, and hold it there long enough and it will get charged.
Made by the same company that makes Odyssey. Most people think they are identical, but I'm not sure that's exacty true. Still, close enough - both are dual-purporse (cranking and deep cycle).
Most batteries are not dual-purpose - so the right way is to use a cranking battery for cranking, and a deep cycle for running aux loads. You can find cranking AGMs and deep cycle AGMs - just like you can with flooded or GEL.
That idea has spread because of solar systems getting so popular, and lots of "solar lore" being parroted on the 'net.
But it only applies if the batteries are tied together into a permanent battery bank. If they are only tied while being charged (normal setup in a vehicle), then they don't have to be the same - they only have to have basically the same charge requirements, and all flooded and AGM do have basically the same charge requirements.
If only tied during charging, you can mix and match cranking and deep cycle, flooded and AGM all you want. GEL is a different beast and shouldn't be mixed with flooded or AGMs.
My truck has a "dumb split-charge relay" (a.k.a., solenoid-type isolator, which is different than the diode-type isolator you'll see in auto parts stores with a big heat sink).
A typical split-charge relay is done like this:
http://www.expeditionportal.com/for...ke-a-cheap-isolated-dual-battery-setup-for-50
It was on my truck when I got it, and it just works - day in and day out, it just works. I think it was first invented by the the Egyptians to charge up pyramids or something.
If I wanted to spend a few bucks on this truck (I don't), and "do it up right", I'd go with an "ACR".
An ACR (automatic charge relay) like the National Luna recommended above, is basically the same "split-charge" setup, but with a little computer brain added to control the solenoid with a bit more smarts. ACRs are also made by other companies as well, like Blue Sea, Samlex, SmartGauge, PowerStream, Merlin, Victron...in other words, an extremely common way to add a second battery to a vehicle or boat and get some charge into it while the engine is running (but the engine might have to run a long time (8-24 hours) to get a heavily drained deep cycle *fully* charged).
McBride
Adventurer
I see your point. I could have been more accurate and said they are into battery based systems and accessories (lighting and refrigeration, battery management and perhaps other stuff)... It was perfectly clear in my mind
Thank you all for the replies. I have the National Luna setup. I've also read about AGM's drawing too much power when charging after a deep discharge and overloading and possibly frying a regular alternator. Do you recommend Marine batteries? Are they really built better to resist vibrations?
dwh
Tail-End Charlie
Possible, but unlikely, and besides, AGMs don't magically draw more power than any other battery. Most AGMs do have a slightly lower internal resistance than the same size flooded battery (it is the resistance of the battery and the wire which determines how much power will flow from the alternator though the battery), but it's not really enough to make any big difference.
Alternators are "current limited" - they won't produce more than they are rated at. They also usually have a "duty cycle" rating and are generally not intended to put out their full power 100% of the time or they'll overheat. That problem of potentially overheating the alternator can happen with any deeply drained battery - not just AGM. It pretty much won't happen with just one aux battery. Now if you had 4 aux batteries rigged into a single full-time battery bank, and that was deeply drained, you might have to worry about overheating your alternator because that battery bank would draw a lot of amps for a long time to get recharged.
Typically, cranking batteries have lots of thin lead plates. They are very good at dumping a boatload of amps in a bloody big hurry. But not for long. 600 or 900 amps for 3-5 seconds to start an engine is just about all they are good for. Draw too much for too long, and you've got to start worrying about those thin plates overheating and warping, then touching and shorting and bye-bye battery.
Deep cycle batteries typically have less number of plates, and the plates are thicker. They are very good at supplying less amps, but for a long time, and are far less likely to have the plates warp and touch.
You can use a deep cycle to crank an engine. You won't get as many max amps all at once as you would get with a cranking battery, but you won't hurt it. You can NOT use a cranking battery for deep cycle use however - you'll ruin it.
Typically, "marine" batteries are a compromise between the two. They have a medium number of medium thickness plates. They don't crank quite as well as a cranking battery, but they'll do the job. They can't handle deep cycling as well as a deep cycle battery, but you won't ruin it quite as fast that way as you would deep cycling a cranking battery.
AGM is just a lead-acid battery, but with fiberglass fabric sandwiched in between the plates. That is how Odyssey can make a "dual use" battery. They make a battery with a bunch of thin lead plates, which can crank really well, but that fabric prevents the plates from warping and touching, so you can also use it for deep cycling without having to worry about ruining it. Diehard Platinum - same deal.
Also, that fabric helps to keep the plates from moving, so an AGM battery is more resistant to vibration. Not that it would make any difference unless you spent a whole lot of time hauling *** down the Tanami Road (notorious washboard road in Australia). Even a regular old flooded battery has plastic separators to keep the plates apart - warping is an issue, vibration usually isn't. A flooded "marine" battery will have the same plastic separators. An AGM "marine" battery will have the same fiberglass fabric. So just because it says "marine" doesn't automatically mean that it can handle vibration any better.
In practical terms, the main advantage of having the fiberglass between the plates, is that it will usual allow you to pump a lot more amps through the battery - recharging it a lot faster - without worrying about warping the plates and ruining it. But normally, you need a really good battery charger to do that. A normal voltage regulated alternator is just going to charge it the same as it would any other battery.
nuclearmonkey
Observer
Where are you guys putting the second battery in the 463's? Thanks in advance!!
dwh thank you for taking the time to explain this stuff so well. Unfortunately they don't make the die hard platinum AGM batteries the size I need any more or at least Sears dosn't carry them. Sears now has a line of Die hard gold AGM which are not made by Oddesey. People say they are not as good. Since you know batteries so well can you please recommend an AGM battery thats good below the $250 price? If this is not possible then can you please recommend a good lead acid deep cycle battery? I've read a lot on the web about the Optimas not lasting very long, seems like their quality is not the same any more so I'm going to avoid them and they need a different way of mounting which is not possible in my car.
My G500 has the battery in the left rear fenderwell so I'm going to make a bracket to hold the second one on top of the main battery. I will start a build thread for my car soon so you will see it in there.
I think in this thread you will find a good solution for using the National Luna second battery box on a later 463.
http://www.expeditionportal.com/forum/threads/78051-O-erlanderwagen-build
dwh
Tail-End Charlie
I don't really have any recommendations for AGMs at a certain price point. In the camper I have now, I prefer flooded batteries.
I replaced both batteries in my truck last year, with a matched set of group 31s - one cranking and one deep cycle - that I got at O'reilly. They were made in USA by Exide but have the SuperStart brand name on them. O'reilly also had the same batteries, but made in Mexico by Johnson controls (same factory where they make Optimas nowadays). I had to do a bit of sleuthing to figure out how to get the ones I wanted.
For AGMs I wouldn't feel bad with Trojan, Lifeline, Interstate, Odyssey, Exide, Enersys.
I replaced both batteries in my truck last year, with a matched set of group 31s - one cranking and one deep cycle - that I got at O'reilly. They were made in USA by Exide but have the SuperStart brand name on them. O'reilly also had the same batteries, but made in Mexico by Johnson controls (same factory where they make Optimas nowadays). I had to do a bit of sleuthing to figure out how to get the ones I wanted.
For AGMs I wouldn't feel bad with Trojan, Lifeline, Interstate, Odyssey, Exide, Enersys.
nuclearmonkey
Observer
Any way you can post a pic of the location inside the fender well? (or pm me if not and I can shoot you over an email address). I've heard of this location before as well, but I think at some point they changed to in the floor of the back seat. I'm thinking that maybe the fender well may be a good spot for the second.
I saw Jeremy's build, and he's using a power pack. I'm not crazy about losing precious space in the cargo area for the second battery - I'd much, much rather manage a spot that won't take from storage space.
Thanks!!