Dual-Purpose Batteries

[Manfred]

Does anyone have any experience with dual purpose batteries?

I was in Batteries Plus yesterday and they have a battery brand called Xtreme that has both a starting battery and a deep cycle battery in one.

I believe Optima has the same thing called a yellow top.

I was thinking these would save on space and weight. Also not sure if they need separate wiring to recharge.

http://www.batteriesplus.com/product/33 ... up-31.aspx

http://www.optimabatteries.com/optima_p ... /index.php

[Amskeptic]

Does anyone have any experience with dual purpose batteries?

I was in Batteries Plus yesterday and they have a battery brand called Xtreme that has both a starting battery and a deep cycle battery in one.

I was thinking these would save on space and weight.

Tell us about your space and weight issues. Then tell us about your needs. Do you camp? Refigerator? Do you have an insane stereo rig?
Colin

[Manfred]

Does anyone have any experience with dual purpose batteries?

I was in Batteries Plus yesterday and they have a battery brand called Xtreme that has both a starting battery and a deep cycle battery in one.

I was thinking these would save on space and weight.

Tell us about your space and weight issues. Then tell us about your needs. Do you camp? Refigerator? Do you have an insane stereo rig?
Colin

I know where you are going with this Colin. I'm on to you. I have read several posts about adding additional batteries and there is some debate if another one is needed. A lot of people say they camp all the time and use their battery quite a bit and never needed another battery. Point taken. I know you are a minimalist from what I've read of your posts. More crap...the more things go wrong. While I too would like to me a minimalist, I know deep down in my heart that I am not and never will be. I have an VW westy. Who needs one? I live in a city. All I need is a bus pass and a bicycle....and this thermos I found.

Counter argument specific to my needs: My number one reason is purely psychological. I have my pride and I don't want to lose credibility. I don't want to be the guy at the campsite, Comiskey Park parking lot, or on the beach that ran down his battery and the old bus won't start. If my bus craps out because of the battery, I will never hear the end of it from friends, girl friends, what have you. It won't matter the reason..."it left us stranded and now you and your bus suck forever." I usually have to convince that who ever is going with me that the bus won't break down. Also, out in tailgating land there are guys the roll up in full RV's that bring their own chefs. Never will I be the guy with the VW bus that wouldn't start in the parking lot because my radio ran it down. When the guys that bring their lifted F250's and 10k dollar stereos that can blow you ear drums out and have more than one battery start right up. I just don't want to take that chance. And why should I, if I don't need to?

Another need: You never know. I do plan on building the biggest sound system I've ever built, which in my case means wiring an amp and 4 speakers and a bass box (not sure what the kids call it these days). I do plan on running GPS and a laptop. Not all the time, but I would like using these things if I need to. I know a laptop will drain a second battery if used for a long time. But you never know what you may need to charge, plug in...blah blah blah. I like to be the guy that is always prepared.

Battery life: I've also done quite a bit of research on the interwebs. And in my vast research of 30 minutes, I've read that draining your starting battery on a regular basis will reduce battery life because it's not built to be drained and recharged, while a deep cycle battery is.

Space Issues: The PO of my bus (78 Westy) hooked up the spare battery under the rear bench seat. I Like to use the space for storage when camping. I guess I could always hook up the second battery in the engine bay, saving me space.

Weight issue: Why have another 20 pounds in your bus if you don't need to? We would all like to carry around a spare engine and we all would if you could fold up and put it in the glove compartment. But we don't because the bleeding thing weighs like a 100 pounds or something like that....anyway engines are really really heavy.

I believe, I have built an air-tight case here, Colin. There is no need break my logic down with a one sentence answer and reveal my shallowness, lack of self-esteem, and lack of electrical knowledge. Because you aren't that guy Colin. You aren't the type guy to do something that terrible to a fellow air-cooled VW owner.

So now tell me all your experience and testing and word of mouth and rumors and drunken conversions that lasted all night, debating about the dual-purpose battery.

[airkooledchris]

, I've read that draining your starting battery on a regular basis will reduce battery life because it's not built to be drained and recharged, while a deep cycle battery is.

That's why if you are going to run stuff that drains it down over and over, get a yellow top optima or bite the bullet and install a real deep cycle.

if you go the Optima route and tell yourself it's no biggie if you drain it way down, carry something like this:


I got one for xmas last year, and it's perfect. you can jump start a car, plug in regular household plugs or cigarette adapter devices. it has a built in rechargeable LED flashlight and an air compressor. the best part is that it weighs about a third of that deep cycle battery and does much more.

I use it also as my portable 12v source when testing shit in the garage. I never knew I needed one till I had it...

that said, I DO have a deep cycle battery from my old camper and I will eventually put it into the bus. I don't use all of the complicated isolators and dual battery relay kits/yada yada.... I just have one of those big red marine switches that toggles between battery A/B/AB/OFF - then I run all power to the switch and the switch to the batteries. Rotate switch to battery A (Starting) most of the time, then switch it to B when you get to your campsite. Toggle back over to A before you start it up and head back home. When you want to charge B back up, just switch it to B and try to start it. If you can't start it on B, start it on AB, then switch it to B once it starts.

[pb24ss]

I just purchased a new group 31 AGM battery to replace the 5 year old group 27 axillary battery. I would definitely recommend a house battery to run your toys. I don't know about dual-purpose batteries. I use a starting battery to start the bus and a deep cycle AGM battery to power the stuff.

[Manfred]

That's why if you are going to run stuff that drains it down over and over, get a yellow top optima or bite the bullet and install a real deep cycle.

if you go the Optima route and tell yourself it's no biggie if you drain it way down, carry something like this:


I got one for xmas last year, and it's perfect. you can jump start a car, plug in regular household plugs or cigarette adapter devices. it has a built in rechargeable LED flashlight and an air compressor. the best part is that it weighs about a third of that deep cycle battery and does much more.

I use it also as my portable 12v source when testing shit in the garage. I never knew I needed one till I had it...

Chris,

Thanks for the tip. That sounds like a must have for the bus and the garage.

As for the batteries I mentioned. The Yellow Optima does indeed look like one battery. But the Xtreme battery I saw at Batteries Plus looks like two batteries complete with 2 posts (neg and pos) for each battery fused into on.

I know for a fact that 12v batteries are getting smaller. I had to buy a 12v battery for my 84 BMW motorcycle. I bought the best battery they had that fit my bike and it is half the size of the original battery with twice the cold cranking amps.

So if the Xtreme battery has the deep cycle hooked directly to the cranking battery, but is still a separate battery (unlike the optima)...I wonder if you even need a switch to charge the deep cycle. I tried to ask more questions about the Xtreme battery but the person at the story didn't seem too knowledgeable. I thought I could do some research online, but I can only find these batteries on the Battery Plus website and they don't get too technical as the the charging setup.

My hope is that the Xtreme battery charges the deep cycle as well as the cranking battery without any additional wiring, since they are one battery. You wouldn't need to do anything but run your accessories to the deep cycle half of the battery and that's it. You wouldn't need to set up a A/B charging switch at all.

[Manfred]

Just called Batteries Plus. You don't need a separate charging loop to charge the dual purpose battery. I'm going to pick one up and see how I like it. What a headache saver. He said he gets very few returns and over all quality is good.

[airkooledchris]

let us know what you find out. id run the 'deep cycle' side totally dead and then verify it really does have plenty of amps left on the starting side before using it in a real world application (unless you have a little jumper like I show above)

[Manfred]

let us know what you find out. id run the 'deep cycle' side totally dead and then verify it really does have plenty of amps left on the starting side before using it in a real world application (unless you have a little jumper like I show above)

I'll get all the specs on it and report back. I'm interested to know the Amp Hours on the deep cycle side.

[Manfred]

Hey everyone. I thought I would follow up on my "research" of dual-purpose batteries.

I recently bought an Odyssey battery, which they call a dual purpose. I bought the PC680 model for a 1984 BMW r80rt, which is a BMW air cooled twin cylinder motorcycle for those of you you that are not familiar.

The idea of a dual purpose battery is this: it gives you the cold cranking amps of a standard battery to start your bus. It also gives you the ability to use the battery as a deep cycle, meaning discharging and recharging the battery. Discharging and recharging a standard battery frequently will kill a standard battery.

The BMW r80rt inherently has a charging problem. The alternator does not charge the battery at idle. The Germans apparently didn't account for Chicago rush hour traffic. I know some maybe thinking, just turn up your idle speed. Not a good idea for an air cooled motor sitting in traffic. But buying this battery is a great solution. Because it is made to slowly discharge for a longer period of time than an standard battery. I don't have to worry about it not being charged while it's running my turn-signals, head light, tail light. Also, I don't have to worry about wearing out the battery once I do get up to speed and the recharging can kicks in. And it will still have enough CCA to start the bike without being fulling recharged.

In point of fact, when I first bought the bike I went out a bought a standard battery. Then promptly got stuck in a huge traffic jam. It took me 1.5 hours to move 1.5 miles. I'm not joking and there was no place to go. Well, the battery was toast. It stopped taking a charge because I had drained completely. My bike wasn't charging it while standing still. I bought an Odyssey battery because all the guys with old air heads gave them rave reviews. Problem solved. I haven't been in that kind of traffic jam since, but I have been in traffic sitting at idle for a long spell and notice that the lights do not dim as before. I've even started keeping my high beam on during the day which is standard practice for motorcycle riders and have had no issues.

So why am I talking about motorcycles in a VW Bus forum? I think the application translate quite nicely to VW bus because a lot of us like to camp and run all kinds of electrical gadgets. I think these types of batteries are worth looking into. I intend on buying one for the bus. I think these types of batteries are going to completely eliminate the need to run two batteries IMHO.

Here is a link to how Odyssey batteries are made and how the dual purpose battery works. There are a number of other dual purpose battery manufacturer out there.
http://www.youtube.com/watch?v=3P-wqckJ ... r_embedded

[Opus]

On my truck I run a 3,000 watt inverter. My sleeper is wired for 110 and runs coffee maker, microwave, fridge, cell phone charger, computer charger, TV, sattellite dish etc. I tried al kinds of expensive batteries including Optimas and could only get 12-14 months out of a set of 4. Found a good dual purpose battery at my Cat dealer. Just replaced all 4 batteries after 54 months. They cost in the neighbourhood of $100 each..