Hank the Tanks Dodgy battery and solar system

merl said:
You can't argue with the laws of physics, not even if you're an 'Expert' from Vanbits or Off-grid solutions🤣.
My guess is that Hank1 reported a slightly higher voltage than Hank2 would have done with the same battery swapped between the 2 vans, this would be simply down to inaccuracies of whatever you are getting the readings from. What did you experience that would contradict my idea Baz? I've read every post🥱and can't find anything, in fact it would explain everything.
The old display panel in my van reads nearly 200mv higher than it should, another van (or plug in voltage display) could easily read 200mv low, that's nearly half a volt difference between the 2 vans more than enough to completely throw you off target WRT operating efficiency.
Tell you what, fully charge your battery, switch on the telly, lights etc, and anything that you can plug into the 12v side that'll take a constant current indefinitely ( not a laptop or phone charger because that will slow down/stop taking current when it's full). Note how long they've been running before you reach the point where the voltage readings would suggest to you that you would have to be conservative with usage going forward (You seem to suggest 12V?) and then continue to run the equipment as before. I reckon you'll get considerably longer than you think before you go flat.
Yep, it'll be 1 full discharge cycle down to nearly zero but it won't kill the battery and you'll now have a much greater knowledge re your actual battery capacity.
Hey! If you owned a DC clamp meter you could actually measure the current at the same time and get a much greater insight into what's going on and what to expect going forward 🥱🥱🥱.
Click to expand...

All I used on the old van was the MPPT controllers screen which told me the current voltage on the old van. All I know is that when we swapped from a 120ah lead acid to a 120ah AGM it made a world of difference and Im talking about when the lead acid was in good fettle. I was told up thread that a 120ah AGM would make no difference and would discharge at the same rate as a 120ah lead acid and that does sound logical. After all its 120 amp hours so its usage is measured in time right? No, not right. It most definitely lasted longer. This new 120ah I would say replicates the usage of the original 120 lead acid I had but as you suggest it could be two things. It could be there is more draw on the new van and it could be that the two methods to measure the voltage are not the same. Dunno.

I don't think the controller is the issue. (if there is an issue). Its holding the charge for long enough once its charged hence the idea of trying just a second battery.
 
So why don't you "just bite the bullet" and get a second battery Barry? That will be the only way to resolve the issue of, will this work, should I do this, that or something else!!! If it doesn't work as you want/think it should you can always add solar, change to MPPT etc, etc What I would suggest is to make sure you have hookup when you fit another battery so that it/they will be fully charged without hoping for sunny days and then "take it from there"!!
Best wishes
 
Wightman said:
So why don't you "just bite the bullet" and get a second battery Barry? That will be the only way to resolve the issue of, will this work, should I do this, that or something else!!! If it doesn't work as you want/think it should you can always add solar, change to MPPT etc, etc What I would suggest is to make sure you have hookup when you fit another battery so that it/they will be fully charged without hoping for sunny days and then "take it from there"!!
Best wishes
Click to expand...

Yep. Thats likely what ill do. Just need to figure out what cables I need and make sure I wire it up correctly, hence the reason for resurrecting the thread but of course its brought up further debate. Im not in a rush to do it. We are going away for Christmas but on hookup for three weeks. I would of course charge it / them fully at home first on EHU anyway.
 
barryd said:
Yep. Thats likely what ill do. Just need to figure out what cables I need and make sure I wire it up correctly, hence the reason for resurrecting the thread but of course its brought up further debate. Im not in a rush to do it. We are going away for Christmas but on hookup for three weeks. I would of course charge it / them fully at home first on EHU anyway.
Click to expand...

Don't talk to me about cables Barry. I reckon mine are gonna cost more than my Victron boxes by the time I've finished!

I do tend to go for overkill though.
 
Just go thick on the cables, (too late ;) ;) ) I'd suggest 16mm2 at least, bigger willn't do any harm at all, just cost more, there are calculators on line to work out the mega fuses etc if you decide to fit them, and it is only two cables one red & one black, Wiring Products sell good stuff, one thing you need to do is make sure they are secured from moving about, think of speed bumps and rough roads.
 
Wightman said:
So why don't you "just bite the bullet" and get a second battery Barry? That will be the only way to resolve the issue of, will this work, should I do this, that or something else!!! If it doesn't work as you want/think it should you can always add solar, change to MPPT etc, etc What I would suggest is to make sure you have hookup when you fit another battery so that it/they will be fully charged without hoping for sunny days and then "take it from there"!!
Best wishes
Click to expand...
Cos Barry likes asking for advice and then spending the next gazillion pages telling everyone that they're wrong 🤣. Have you encountered his 'Cork' thread yet? 🥱🥱🥱
 
Pudsey Bear said:
Just go thick on the cables, (too late ;) ;) ) I'd suggest 16mm2 at least, bigger willn't do any harm at all, just cost more, there are calculators on line to work out the mega fuses etc if you decide to fit them, and it is only two cables one red & one black, Wiring Products sell good stuff, one thing you need to do is make sure they are secured from moving about, think of speed bumps and rough roads.
Click to expand...

Funny you should mention that. There are two clamps in the battery box. @yeoblade could not get the one on the left off. The threads are knackered under the van I think (marked with the arrows). Not sure how to tackle that. Also Ill need a battery bag I think like the one the current battery is in.

new battery screen shot with arrows.jpg
 
Pudsey Bear said:
Just go thick on the cables, (too late ;) ;) ) I'd suggest 16mm2 at least, bigger willn't do any harm at all, just cost more, there are calculators on line to work out the mega fuses etc if you decide to fit them, and it is only two cables one red & one black, Wiring Products sell good stuff, one thing you need to do is make sure they are secured from moving about, think of speed bumps and rough roads.
Click to expand...

16mm2 Kev? I'm going 95mm2 on some of my cables, but yeah quite a lot of 16 as well. (did I say I like overkill?)

And yeah, Mega fuses on me Busbar.
 
Pudsey Bear said:
WTF wired that up, RED wires going to negative, very helpful if you remove them both, I notice the battery clamp is next to the neg post which is okay, but if you DIY it make sure the positive is nowhere near the clamp.

View attachment 137344


Calcylter https://www.rapidtables.com/calc/wire/voltage-drop-calculator.html
Click to expand...

HaHa! @yeoblade Julian who I believe is a qualified commercial electrician wired those cables in! They are the two 12v trailing sockets I put in which have been really useful. I think though your eyes are deceiving you. I think the negative ones are coloured black and red (I think) will have a look later. Anyway they work perfectly.

This is what I bought. Great these.


screenshot_774.jpg
 
I can't even see a black wire, I've used red on neg myself but never with back shrink sleeving.

And no disrespect intended towards Julian at all.
 
Pudsey Bear said:
I can't even see a black wire, I've used red on neg myself but never with back shrink sleeving.

And no disrespect intended towards Julian at all.
Click to expand...

No I know! :D Its how they come if you look at the Amazon link. One red wire has a black line through it I think. Bit daft really but they are good sockets.

Anyway. A meeting has been held and we are going with the additional battery to start with and possibly another panel if its not enough. Im leaving the existing controller unless I can find an MPPT with two outputs for the cab battery. Ill probably wait until after Christmas now when we have been away. I think ill need help removing that clamp.

However I think ill revisit the weighbridge first. We had 700kg free on the back when the van was empty out of over 1000kg I think of payload so we should be fine but Ive added the scooter and rack and all our stuff since then. Will be interesting to see where we are at. I did the calculations but never actually got it weighed after. :D
 
Battery clamp strip is plastic.
Battery clamp M6 nuts are rivnuts into the plastic battery box which have started to spin due to corroded bolts. As they are recessed from underneath they will be a barsteward to replace, they were on mine, stainless St. fitted now 🤗.
Strangely the flying leads off the ciggy sockets are both RED 🤔😀😀. Well actually they're not but when the 2 cores are separated there is a lot of red on the black insulation, poor production of cable.
 
I hope this is on topic . . . . . .
With reference to putting a fuse in between solar controller and batteries I was just browsing a Victron supplier yesterday and saw that Victron do a 'special' solar - controller - to - leisure battery cable, (price £69) and it contains an in-line fuse. I can't remember what the current rating was though . .. .
 
One red wire has a black line through it, Ah, like speaker cables, dumb idea for 12v though, I've used 12v twin flex but it's always been red/black.

I have an MPPT that does the VB and LB Barry, made in the UK I believe.

1731594189845.png
 
barryd said:
........ One red wire has a black line through it I think. :D
Click to expand...

You can't have a mixture of red electrons and black electrons going down the same wire. Everyone knows that red electrons go down a red wire, and black electrons go down a black wire. . . . . . .



Too many years ago to think about, in A level physics at school we were learning about cathode ray tubes. A 6.3 volt coil heated the cathode which was connected to -ve supply. The grid was connected to a variable voltage source. The anode was connected to the +ve of the same supply as the cathode. The phosphorescent ? (not sure) screen showed the trace of the sine wave that was the input signal. Teacher explained that electrons were being transmitted from the cathode to the anode, accelerated by the voltage on the grid, and then they hit the inside of the glass screen and made it glow green. He increased the voltage of the sine wave and the sine wave got bigger on the screen. He than asked what we can conclude from how it works.
Bright Spark (junior) stuck his hand up and said "Electrons are green"
I have remembered that ever since. From then on in Physics electrics classes the buzz of conversation around the classroom was always "Remember, red electons go down the red wire and black electrons go down the black wire".
 
trevskoda said:
Or you could buy of temu, wonder if its real mppt or just a rebadged pwm. :unsure: View attachment 137330
Click to expand...
I bet "MPPT 100A" is a name they have given to the product, it has nothing to do with multiple point power transfer electronics inside the box. Possibly. You would have to strip it and deconstruct the components and circuitry inside to find out. Or set up a lab of test equipment and a variable sun to test it.
 
You must log in or register to reply here.

Users who viewed this discussion (Total:0)

Back
Top