Why not get the biggest battery possible?

[Dragos28]

It needs a higher voltage to charge, and if you use an external charger, you cannot use one that desulphates or whatever it is called that is sometimes done to lead-acids.
So, I'd check the specifics of the battery you're thinking of buying and then measure how much voltage the alternator puts out before even thinking about it I'm not so sure a mixed environment is what I'd do, even with a solenoid.

I'm going to give the company a call tomorrow and see what they suggest.

I have a buddy who runs his 12v fridge off his Lithium ion battery, but he charges it while driving from a 110v inverter.... so thats another option..
but in my mind it seems a bit wasteful taking 12v to 110v then back to 12v... lol... but i'm sure there's more to it than that.
ideally the solenoid setup would be the best as it would be a "hands-off" setup but if thats not possible then i would be ok with manually charging it.
either way the weight and size savings using the lithium battery would be worth the hassle.

 

[IdaSHO]

I'm going to give the company a call tomorrow and see what they suggest.

I have a buddy who runs his 12v fridge off his Lithium ion battery, but he charges it while driving from a 110v inverter.... so thats another option..
but in my mind it seems a bit wasteful taking 12v to 110v then back to 12v...

Not wasteful if the vehicle charging system isnt smart enough to properly charge a "special" battery.

 

[Dragos28]

Ok, just got off the phone with the battery company and the lithium ion battery can be used directly with the alternator provided that the alternator does not put out more than 14v and more than 40amp current,
I was looking at a battery without a controller that cost 240. but the guy suggested this battery http://www.batteryspace.com/Custom-LiFePO4-Prismatic-Battery-12.8V-40Ah-512Wh-30A-rate-with-PCM.aspx as it has a controller built in that will control charge and discharge


think this will be my new battery

 

[Pilat]

Yup, it sometimes pays to ask a manufacturer/reseller directly rather than trying to learn all sorts of intricate details and principles. I'd go for something with either a more rugged casing or build a case for it to protect it against penetration/breakage.

 

[LeishaShannon]

I'd ditch their BMS and use a Victron BMV 702 with midpoint monitoring. It'll tell you exactly how much energy is in the battery at any time and can monitor for cell failure without complicated and unnecessary balancing.
Most (all) resellers have 0 clue when it comes to these batteries, as evidenced by claims of them being direct replacements for lead. That might be the reason they're only warrantying these things for 12 months

Please take the time to read all 2 pages of http://www.pbase.com/mainecruising/lifepo4_on_boats before embarking on the lithium journey, your batteries will last longer for it.

(not sure how cold it gets where you are but i'd also read up on the temperature range of these things)

 

[Dragos28]

ok, reading all 3 pages of that has me scared to even attempt to use a Li-ion battery now...

 

[LeishaShannon]

Hehe. They're definitely not plug and play replacements for lead but if you need low weight and high discharge they're an excellent alternative. We use ours for all our cooking (induction hotplates, oven, microwave, pressure cooker, etc) which just wouldn't be possible without a ton of lead, but for a fridge i'd probably recommend sticking to a good AGM like the full river DC series unless weight is an issue.

 

[Dragos28]

Hehe. They're definitely not plug and play replacements for lead but if you need low weight and high discharge they're an excellent alternative. We use ours for all our cooking (induction hotplates, oven, microwave, pressure cooker, etc) which just wouldn't be possible without a ton of lead, but for a fridge i'd probably recommend sticking to a good AGM like the full river DC series unless weight is an issue.

problem with an AGM is that it doesnt like to be discharged below 50% so i'll need a really high Ah battery to run my fridge... with a Li-ion i can easily get 14 hours out of a 40ah

My only concern now is do i get the $240 battery and a $50 Li-Ion charger and keep it super simple, just charge the battery from my inverter when my truck is on.
or do i spend $400 on the same battery with the charge/discharge controller... the charge/discharge controller is only $40 by itself so i'm not even sure why they are charging $100 extra...

I really would only use the battery once every few months when I'm out camping.. other than that it would just sit next to the fridge in my garage.

weighing the options.. do i spend $300~400 on a 2nd battery
or do I just run the fridge off my main battery, start my truck and let it run for 20 min before i call it a night, and start it early in the morning to make sure it doesnt discharge too much..
I know that this will cause some wear on the battery.. but like i said, i only go out once every month or so, and its for 2~3 nights when we do go out....

hmmm......

 

[Pilat]

Buy another lead acid as a house battery, a good case and do the solenoid thing and run the fridge from that house batttery. With so little use, I don't think a lithium is worth it. You could also insulate the fridge some more, making it use less power.

 

[Chazz Layne]

Separate charge controller. No sense replacing a perfectly good battery because a built-in charge controller dies, or a perfectly good charge controller because a built-in battery dies.

 

[jeep-N-montero]

If available space under the hood was not an issue, why wouldn't someone just get the biggest battery they could fit? Bigger dimension wise, cold cranking amps, reserve capacity? I have bunch of extra space under the hood in my 4runner, and if there's no negative consequences, I'd like to get a bigger, stronger battery...

Also FWIW , I've had two Optima red tops die on me in the last 4 years...

yes , my biggest concern was my puny alternator not being able to keep the battery topped off, but perhaps this will motivate me to do that alt. upgrade ...

Read up on premature Optima failure due to insufficient charging, I am not at all surprised that you had two failures based on the fact you admitted to having an alternator that couldn't keep up.

 

[jeep-N-montero]

Put the biggest one in my tundra. Love it. All other info above is to funny. Make it sound like its rocket science. I have die hard platinum in both my trucks.


Sent from my iPad using Tapatalk

If you look at his location it might explain how/why he gets away with it.

Umm- it's not rocket science, it's Electrical Science and Chemistry. If you care about how often you have to replace your batteries, and you care about having that reserve capacity when it's 20 below or in an emergency, then how you charge/discharge and the type of battery itself does matter.

Sent from my Passport

 

[PirateMcGee]

FYI for those looking at LiFePO4 batteries order from these guys: http://www.electriccarpartscompany.com/ they have great prices.

I use LiFe batteries daily at work and have interacted with many of the sellers/products out there. Batteryspace sells decent batteries but the controllers they put on packs are not very good, I would order individual cells from them but not packs.

Remember Li is different than LiFePO4. In general LiFePO can be interchanged with Pb Acid.

 

[Pilat]

Actually, a LiFePo4 is ALSO a lithium battery. "lithium" is an umbrella term for all sorts of chemistry that includes lithium.

The LiFePo4 batteries are Lithium-Iron-Phosphate batteries, but you're right, they should not be confused with Lithium-Ion (no typo) batteries.

 

[Chazz Layne]

Hmm... 1/3rd the weight, about the same size, and theoretically the same capacity as an Odyssey G31: http://www.electriccarpartscompany....BMS-br-Can-Be-Paralleled-Up-to-48V_p_281.html

So at three times the price the question is: Can a LiFePo4 really deliver "up to 5 times" longer life versus an AGM under the same conditions?