Thread: solar battery maintenance

Originally Posted by DiscoMick

If it helps I'm mounting my 80 watt panel across the front of a Rhino Rack platform and the bars of the platform are thicker than the height of the panel so I will still be able to lay long items on top of the bars and they won't touch the panel below them.

Thanks DM you gave me a lot of food for thought, in fact a whole afternoon's worth

I looked at this yesterday from the perspective of putting it on top and wrote it off but your message got me to reevaluate the options. I've uploaded a couple of photos to illustrate the issues

There's is room to fit panels under the rack

• but the depth of the frame would have to be reduced, not a problem

• for a large single panel the rack would need to come off for the installation

• multiple smaller panels could be fitted with the rack in place

• cells would be partially blocked by the cross bars

• it would be a semi permanent installation & not possible to demount the panel(s) in camp

• A permanent, non demountable install means the vehicle has to be parked in full sun. I have to do this 99.9% of the time any how but in other parts of the world .....

• the rack would have to be unloaded to expose the panels

• because of the rack's design removable flooring would have too be used to protect the glass

• the panels would lay flat at all times, angling towards the sun would not be possible

None of the above are impossible but I can't help feeling that having to unload the rack to expose the panel(s) means its going to get a lot less use that it otherwise would

A twist to the under rack would be to lay a raised ply floor and inlay the panel, the floor would need to be 50mm thick and most of the other issues would still exists

Dave's idea with the frames is more obtrusive, (remember this is a da Vinci rack), but far more practical. However if a panel was to be carried under a frame it wouldn't be ready for instant use and would never see the sun unless demounted and assembled. Its likely that it could only be accessed from the side of the vehicle because of the shark fin antenna on the rear

It seems like a suitcase panel would require a lot less messing around.

But as Dave has suggested if a panel was to be carried on top of a frame it would be ready for instant use, constantly visible to the sun and it could be angled. It could also be made demountable. A frame that went over the accessories instead of the other way around would provide the accessories with security and protect them from UV allowing for permanent carry.

An example might be a shallow full width frame at the the back. The frame might house maxtrax and rope which because of their shape could be accessed from the rear of the vehicle. The top of the frame would support an 80w across the width of the vehicle. The panel would overhang the rack 3cm on each side but not the overall vehicle width

But it still seems to me like a suitcase panel would require a lot less messing around and when required easily fixed to the roof for as long as required ...... I'm just saying

Originally Posted by DiscoMick

.... with 60 amp fuses both ends

Why fuses at both ends?

Originally Posted by DiscoMick

..... 80 watt panel .... a 120 amp AGM
..... an Evakool 30 litre fridge-freezer ..... three days ... out of this battery setup, so ... at least 5 days, plus driving

DM is this a work in progress or have you had a chance to give it a good spanking in real time?

Originally Posted by DiscoMick

I don't see any need for a DC-DC charger with this setup.

From what I've read most of the guys who truely know the 'magic? of the traxide install agree with you. I am not one of those who "truly know" so no taking me to task over it

Originally Posted by DiscoMick

So this is vagely similar to your plan, I think. Hope that helps.

Indeed it is mate and many thanks for sharing. If you haven't already run it let us know how your system performs in real time

100Ah sufficient for 48 hrs?

Originally Posted by Blknight.aus

yes based on new batteries

Awesome

Originally Posted by Blknight.aus

I'm guessing a little here and I'm going to go with about 2 hours which would more or less double for the extra battery

Awesome, most of my recreational journeys require a minimum of 3 hours each way. Might be a bit sketchy for my last project which was 1.5 hours each way but next time I'll have panels with me

Originally Posted by Blknight.aus

for a 20w panel those numbers are pretty good

Wow, perhaps they are genuine then. It'll be interesting to see what the voltage settles at

Originally Posted by Blknight.aus

Of just as much interest is what you're doing as part of your experiments.

Well the only other thing that might be of interest is that I split the feed from the panel. I ran a cable with a watts up on it that's conveniently located for charging the car and another longer cable to the work shop with another watts up on it to use with the batteries I have stored there. It'll make keeping every thing up together some more convenient.

What I'm looking forward to seeing is what happens if I connect the D3 and a workshop battery at the same time. I'm guessing it'll work in the same way and be effective but at a lesser and slower rate.

I haven't connected the work shop cable to anything other than the watts up and won't until all testing with the D3 has been completed otherwise I won't have a base line to work from. It'll be interesting to see what the D3 float voltage ends up at. What I did notice is that the watts up on the longer cable gets a very slightly higher voltage at the battery read out at .01 difference. [edit: I checked this morning and the 5m cable reads 13.39 while the 15m cable reads 13.97v]

1 fridge for 48 hrs stationary = an additional 50Ah battery, stand alone if necessary
1 fridge for 1 week stationary = 80w portable plus the same additional 50Ah battery
2 fridges for 1 week stationary = 80w plus 80w portable plus the same additional 50Ah battery
[QUOTE=Blknight.aus;2609812] That should work ... might be marginal depending on if you have any other parasitic loads

Dave, lads thanks so much for all of this I now have a logical plan to work to and a much improved, if still fairly shallow, understanding of the subject. I'm extremely grateful for every one's input & patience.

My next search will be on panel wiring and third battery installations

Battery connections

I forgot to ask about the correct way to connect a panel or a reg to the D3

I understand that incorrect connections interfere with the D3's battery monitoring system and that accessories should not be connected directly to the negative terminal but to an earth stud instead.

Does this also apply to panel and regulator connections?

My vehicle system is a work in progress, but it is based on experience with our camper trailer, which has an Engel 40 litre fridge, a 105 Ah AGM and an 80 watt folding panel, so with a smaller fridge and larger battery in the vehicle, I am confident it will work.
We have camped for a week with the camper OK. After running the fridge overnight the solar has usually replaced what was used by mid-morning and then you just need to keep it charging for as long as possible.
The main disadvantages of a folding panel are you have to actually set them up and they can be stolen. An advantage is the panels can be moved several times a day to maximise solar input.
Having the panel on the roof should be similar to laying a panel on the ground. The angle might not be perfect, but up on the roof it should get some sun all day.


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Originally Posted by DiscoMick

Having the panel on the roof should be similar to laying a panel on the ground. The angle might not be perfect, but up on the roof it should get some sun all day.

DM What was the reason for installing 2x 60amp fuses at both ends of the cable?

Drove today for three hours, 1.5hrs each way. Just before home I stopped for fuel. When I got home, before connecting the solar I measured voltage at the crank battery and it was only 12.3V.

Is this normal or do I have issues?

That's a bit low. It should be between about 12.6 - 12.8v. Was everything off? Headlights, stereo? How old is your crank battery?

1998 Disco 1 300tdi no edc no abs
1995 Disco 1 v8i dual fuel RIP

It's not leaking oil, it's bleeding power.

Originally Posted by Magnet6x6

I measured voltage at the crank battery and it was only 12.3V.

Hi Magnet, if that was the voltage just after turning off your motor, say within a few minutes, and you had nothing turned on, then you definitely have an issue.

All lead acid batteries, even when they are stuffed, will have a surface voltage reading above 12.7v, straight after turning the motor off.

Try starting your motor and then measuring the voltage at your cranking battery.

This should be anything above 13.5v.

If it is not above 13.5v, then you have a problem and it is most likely your alternator, but it could also be one of your batteries on it's way out.