FarmerFrederico
Adventurer
Great discussion guys. Thanks! I went with the UPG battery shipped $525 to my door. I think I've got everything I need now and will hook it up entirely separate from my chassis batteries for now and see how it performs!
Batteries? Start and House
- Thread starter FarmerFrederico
- Start date
mgmetalworks
Explorer
I just got two of the Odyssey beauties you linked for my starter batteries. First step was to reproduce them in CAD so I can start on a custom battery box. I think I'll mount them along the frame approximately as shown because there is a pretty nice pattern of holes for mounting in this area.
Bikersmurf
Expedition Leader
Chris recently posted a nice box he made for a row of batteries mounted to the frame... There'd be an advantage to separate boxes for repairs/maintenance... I'd hate to try and lift two of those batteries from under the truck without some form of hoist 
mgmetalworks
Explorer
Chris recently posted a nice box he made for a row of batteries mounted to the frame... There'd be an advantage to separate boxes for repairs/maintenance... I'd hate to try and lift two of those batteries from under the truck without some form of hoist
What about one big assembly but individual battery lift/lowering capability? I'm thinking lift/lowering assist of some sort too.
Bikersmurf
Expedition Leader
X2 on way down on my list is more batteries... Low down would be best for space and COG... Can never have too big a battery bank. I wish mine had more spots like some other Ambos I've seen. 2 house are barely enough more is better.
mgmetalworks
Explorer
I am designing with the intent to sell, yes. It won't be a universal application though...I'm designing for group 65 batteries.
Bikersmurf
Expedition Leader
I'm running 4 65 series.
Market might be better for a more universal box or one that'll fit deep cycle batteries.
I can take pictures of Crestline's design which will house 2 batteries of most sizes height/width/length. It held deep cycle 27, 31, & 65 series.
Market might be better for a more universal box or one that'll fit deep cycle batteries.
I can take pictures of Crestline's design which will house 2 batteries of most sizes height/width/length. It held deep cycle 27, 31, & 65 series.
FarmerFrederico
Adventurer
Wow, I somehow missed a bunch of posts to this thread! Looks great, MG! I did end up getting the Odyssey's for my two chasis batteries - one under the hood and one on the frame rail. Installed them within 30 minutes of finding them on my porch after getting the kiddo to bed! I kept my ARB twin compressor directly hooked up to the one on the frame rail and will double check next week that it is getting a good charge from the alternator.
I ended up going with the UPG 8D battery at 250Ah. Should work well for my needs. I decided to leave it entirely separate from the chasis batteries for now and address that down the road.
As I'm starting to wire everything up though, two questions.
If my battery doesn't get here for another few days, is it OK to leave my solar panel mounted on the van in direct sun for a few days? I would just zip tie some plastic bags around the two loose MC4 connectors and zip tie them so they don't roll around.
Also - I realized I bought 4AWG and 6AWG welding wire rated for 600V instead of battery wire for 12 and 24v systems. Did I make a mistake here and buy the wrong kind of cable?
Thanks!
I ended up going with the UPG 8D battery at 250Ah. Should work well for my needs. I decided to leave it entirely separate from the chasis batteries for now and address that down the road.
As I'm starting to wire everything up though, two questions.
If my battery doesn't get here for another few days, is it OK to leave my solar panel mounted on the van in direct sun for a few days? I would just zip tie some plastic bags around the two loose MC4 connectors and zip tie them so they don't roll around.
Also - I realized I bought 4AWG and 6AWG welding wire rated for 600V instead of battery wire for 12 and 24v systems. Did I make a mistake here and buy the wrong kind of cable?
Thanks!
FarmerFrederico
Adventurer
Good to hear on the cable Verkstad. That's what I figured. So I can leave the panel unplugged from anything for a few days up on top of the van in the sun? I know I have to hook my solar charger up to my battery before I connect it to the panel.
DiploStrat
Expedition Leader
At the risk of being really pedantic, a few clarifications are in order here:
-- Your point about how much you can expect from a X sized alternator is spot on. The actually amount provided will be the lower of the alternator's maximum output as limited by cable resistance or the ability of the lead acid battery, lithium is different, to take a charge, typically determined by the battery's internal voltage. As the voltage rises, the voltage differential drops and with it, the amp flow.
-- Lead acid batteries do need to be charged quickly, that is, not left discharged, and fully, that is "100%." While most lead acid battery life tables are given at 50% DOD, there is nothing wrong with designing a system for a lower DOD; your batteries will simply last longer. Similarly, you might plan to run a 75% DOD and simply replace the batteries more often.
-- The ability of your vehicle's alternator to do this is determined by its output voltage. Mercedes Benz and Toyota typically suffer from low charging voltages of around 13.9v. Chevrolet, on the other hand, is temperature compensated and will charge at up to 15.5v when required. I don't have data for Ford, but I would suspect that it charges at 14.5v or so. The real issue is not the voltage, although this is important, but rather the simple fact that you rarely run the engine long enough to complete the absorb/acceptance charge. N.B. Lifeline (Concorde) for example, calls for about two hours of charge AFTER you reach 100%. This is why solar or shore power is so important to complete the charge.
-- There is no reason not to use a bidirectional sensing intelligent relay like the Blue Sea ACR. Indeed, if you have shore or solar charging, a bidirectional sensing relay has the advantage of keeping your starter battery happy without the additional expense of a trickle charger.
-- You can assess the impact of different wire sizes and lengths on your charge voltage with this tool: http://www.calculator.net/voltage-drop-calculator.html?material=copper&wiresize=1.296&voltage=14&phase=dc&noofconductor=1&distance=10&distanceunit=feet&eres=100&x=62&y=10
Do note that, as a practical matter, most of your charging will take place at 50A or less. Bigger wire pays off in the first stage of bulk charging.
luthj and I are agreeing on the essentials; I would merely note that I suspect that is low opinion of alternator charging is based on his experience with his Sprinter. It was precisely to cope with these low charging voltages that companies like Sterling Power, CTEK, and Redarc market their various battery to battery and alternator to battery chargers. For Chevrolets and, I suspect, most US pickup type trucks, these devices are of minimal utility.
luthj
Engineer In Residence
I actually have had great luck with alternator charging on my Sprinter (as part of a complete charging regime). :sombrero: I have just seen to many ruined batteries due to chronic undercharging. If your alternator is getting to 14.4+ volts at 70-80F then it may be suitable for absorb charging (many vehicles don't). For temperature regulated alternators, there is always the concern of the temperature drift between chassis and aux batteries. The other concern with higher voltage alternators is that they can overcharge some AGM batteries (electrolyte loss). Of course do you drive often enough? As mentioned, it usually takes 1-4 hours after reaching the absorb voltage to fully charge a battery. My outback system monitors the charge current via a shunt, and terminates the absorb cycle when return current drops to 0.5% of capacity. The other issue is when you start charging at the absorb level, you want to have temperature compensation (with a sensor on the battery case). Which most alternators do not have (those that due just use air temps).
Lithium batteries have much lower internal resistance, and thus charge much more quickly (even at lower voltages). They also do not need to be returned to 100% SOC (compared to lead acid). In fact they will last longer if they are floated at around 90% SOC. Like all batteries, Lithium chemistries age more quickly at higher temps, so keeping them cool during charging and usage is important.
All that being said, the alternator is great source of amp hours. There is no reason not to use it in most cases. :ylsmoke:
The reason I suggested a uni-directional battery separator is because the OP is using a Bogart solar controller which will occasionally exceed 16V. Some vehicle electrical systems do not like voltages this high.
Most batteries will provide more cycles at lower DOD. It is exponential once you start getting below 50% DOD. However, there is no reason that you can't regularly cycle to 80% DOD. It will reduce your batteries total cycle life, but the total cost per AH/cycle will be fairly similar. The main reason I suggest 50% DOD for the design stage, is that many people overestimate the available charging, and underestimate their consumption. The 50% number provides some additional overhead for that long night, or cloudy day.
Lithium batteries have much lower internal resistance, and thus charge much more quickly (even at lower voltages). They also do not need to be returned to 100% SOC (compared to lead acid). In fact they will last longer if they are floated at around 90% SOC. Like all batteries, Lithium chemistries age more quickly at higher temps, so keeping them cool during charging and usage is important.
All that being said, the alternator is great source of amp hours. There is no reason not to use it in most cases. :ylsmoke:
The reason I suggested a uni-directional battery separator is because the OP is using a Bogart solar controller which will occasionally exceed 16V. Some vehicle electrical systems do not like voltages this high.
Most batteries will provide more cycles at lower DOD. It is exponential once you start getting below 50% DOD. However, there is no reason that you can't regularly cycle to 80% DOD. It will reduce your batteries total cycle life, but the total cost per AH/cycle will be fairly similar. The main reason I suggest 50% DOD for the design stage, is that many people overestimate the available charging, and underestimate their consumption. The 50% number provides some additional overhead for that long night, or cloudy day.
DiploStrat
Expedition Leader
"complete charging regime" is exactly correct. And it is a point that some fail to grasp.
Less of an issue these days as many (most?) OEM starter batteries are AGM Chevrolet, for example, uses Lead-Calcium. In any case, There is almost always enough extra resistance between the starter battery and the camper battery to reduce the chances of this. Certainly I have driven the odd 14 hour day with no obvious ill effect. (Of course, as with all things battery, check back with me in a few years!)
Not an issue with the Blue Sea as it opens at 16v. Actually, the controller that I use, a Magnum SBC opens at 15v; I have to use a manual override in extremely cold weather.
We are definitely on the same page! As I said, I am just being a bit pedantic.