Yet more battery charge confusion

So,I’ve reconnected the B2B - next morning after a day of 104% it has dropped to 90.

Same the next day, it charged from the solar, then discharges again

I’ve disconnected for 2 days now with no ill effects

It’s being removed and sent back for a refund, pile of sh..
 
When I first fitted my B2B I accidentally bypassed the separation relay, which caused some problems. Quickly resolved but it did demonstrate the importance of separation.
 
SimonM said:
So,I’ve reconnected the B2B - next morning after a day of 104% it has dropped to 90.

Same the next day, it charged from the solar, then discharges again

I’ve disconnected for 2 days now with no ill effects

It’s being removed and sent back for a refund, pile of sh..
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Could it be the actual solar panel at fault? (Or had you just disconnected the Starter Battery +ve Input and found all ok and then put that back and it dropped again overnight? which would suggest some kind of reverse drain to the starter battery?)

But anyways .... other B2Bs ;)
 
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Yes as you’ve just said, I disconnected the B2B +ve cable and it was then all OK. Reconnected and it goes wrong, disconnect and it’s all ok again.

I don’t “need” a B2B, I just wanted one for belt and braces. I don’t need the fuss, so I’ll remove it. In hindsight I wish I’d read up more of the info available on here first before diving in head first with both feet ?
 
SimonM said:
Yes as you’ve just said, I disconnected the B2B +ve cable and it was then all OK. Reconnected and it goes wrong, disconnect and it’s all ok again.

I don’t “need” a B2B, I just wanted one for belt and braces. I don’t need the fuss, so I’ll remove it. In hindsight I wish I’d read up more of the info available on here first before diving in head first with both feet ?
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It is handy to be able to use that spare altenator power though :)
I've just done a setup for someone and we discussed the pros & cons of VSR vs B2B approaches for Split-Charging. Later today I will be delivering his kit, which includes a basic VSR Relay and a Victron 75/15 MPPT controller. Not quite as good as an all-singing all-dancing B2B/MPPT integrated controller but it is a whole load cheaper!

As you have all the wiring in place, you could slap in a VSR at little cost and get back some of the benefits.
 
That sounds interesting. Can you direct me to the product to see what you’re talking about please as I’m not sure what it is.
 
SimonM said:
That sounds interesting. Can you direct me to the product to see what you’re talking about please as I’m not sure what it is.
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Basically it is just the Relay Part of a simple split charge system.
So for example my kit here ...
https://wildebus.com/store/index.php?route=product/product&path=69&product_id=110
This is a complete Split Charge system. But you have all the cabling already as you have a starter battery connection to the RING B2B.
So you just need just the Relay part, so without the battery watch part, all the cabling, the fuses (if that was separate to the ring - I am assuming so?), mounts, etc, Just the relay.
The Relay in that kit is this one available from Amazon for £30 -
https://amzn.to/2Ly3qeB

Or you could go for this unit -
http://www.onboardenergydirect.co.u...20a-intelligent-battery-combiner.html#SID=200
which is still a VSR, but with a little more intelligence and a 5 year warranty for a fiver or so more.

You just disconnect the Battery in and Battery out off the Ring and attach them to the VSR and jobs done! (VSR needs a little ground wire connection as well)
 
We found with the display showing so many errors in it's calculations (as what's seemed to been experienced here), we dropped the NASA panels and have stuck with Victron ever since, for many reasons like battery types, Peukert's law etc. What is also great about Victron is the ability to process battery banks by using Midpoint voltage monitoring (BMV-702/712 only)
to save grief, I've copied and pasted the blurb;
"This feature, which is often used in industry to monitor large and expensive battery banks, is now for the first time made available at a low cost, to monitor any battery bank.
A battery bank consists of a string of series connected cells. The midpoint voltage is the voltage halfway along the string. Ideally, the midpoint voltage would be exactly half of the total voltage. In practice, however, deviations will be seen, that depend on many factors such as a different state of charge for new batteries or cells, different temperatures, internal leakage currents, capacities and much more.
Large or increasing deviation of the midpoint voltage, points to improper battery care or a failed battery or cell. Corrective action following a midpoint voltage alarm can prevent severe damage to an expensive battery."
The Victron will give you a more accurate read-out of the state of batteries and help care for them better as explained above.

Battery ratings...………. well that's a whole different argument and will go on till the cows come home!!
Everything that needs to be explained has been explained beautifully, so no need to add to it. On a personal level, I have always worked on 45% SOC of the rating of a lead acid battery as a safety buffer (till I started using lithium). I know a lot of manufacturer claims well exceed this percentage, but by having a safe figure to work with, you know in your own mind that you won't take the battery to a level where repeated discharge doesn't put it down to the path of no return.
Going back to some the OP's original posts and issues surrounding the B2B draining power, who's was it that you had fitted?
Personally I much prefer the use of B2B technology, especially with connecting your battery bank and the battery ratings higher than that of the engine battery they are connecting it to. Having a good make of B2B is like having a good 3-4 stage charger powered by the engine, so for long term battery heath (and the fact that most B2B's now have Li profiles, so future-proofing your install), but has been proven to charge your batteries 5-20 times faster. I've loved having one fitted, as I tend not to relay on solar during the colder months, where we hit the batteries harder than that of the summer months and want a speedy recovery after a few hours driving.
 
So, Nick, is the inference here that perhaps it’s the BM2 having reporting issues rather than a faulty B2B? Incidentally the past 2 mornings it is reporting fully charged.
 
SimonM said:
So, Nick, is the inference here that perhaps it’s the BM2 having reporting issues rather than a faulty B2B? Incidentally the past 2 mornings it is reporting fully charged.
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Sounds plausible, as NASA equipment from memory misses out so many variables when it monitors the Battery capacity.
I had the small compact white NASA BM, in the end working from the amp hour counter rather than the percentage capacity (based on the way I was using it on my lead acid batteries which on the one of the last M/H's about 5 years ago). The 2 110ah batteries I had I knew would be good for say 100ah, so never allowed the AH counter to measure -100ah before say starting the engine and popping a bit of power in using the B2B.
Since then, I haven't strayed to the BMV's from Victron (Now using the 712). Well impressed with it, as the app you can put on the iPad is great for looking over the last 30days and the bloody thing even sees the withheld AH on the Li I have that isn't included in the rating the battery that's given :ROFLMAO::ROFLMAO:. Cost wise, yup there are cheaper units out there, but I think it's worth the extra bit to get a more accurate read-out.
 
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It does seem, the more I read on here that perhaps my selection of manufacturers for the MPPT etc. could have been better considering the iPad monitoring facility available? ?
 
SimonM said:
It does seem, the more I read on here that perhaps my selection of manufacturers for the MPPT etc. could have been better considering the iPad monitoring facility available? ?
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True that the MPPT with Bluetooth is a good thing, but I much prefer how the batteries are actually performing rather than just the efficiency of the solar, so would see more value from a Battery Computer to that of a solar monitor or display.
 
I find the Victron BMV iPad/iPhone app so good I haven't bothered to mount the fixed display where I can see it. I have left it in the battery compartment next to the battery, saving wiring and mounting it in the habitation space. Same app for my inverter too, which I switch on by bluetooth only when I need it but without having to bend down and fiddle in a locker.
 
Well I’ve kept an eye on the numbers morning and night for the last week, and since removing the B2B it has been showing full all the time.

I think, for now, I’m going to simply leave well alone configured the way it is now, and add a B2B or VSR or whatever later in the year if it’s needed.

Thanks for the input ?
 
Well I’ve been away for nearly a week and kept an eye on things while we’ve been taking out the amps and seen how they’re going back in so far.

Quite clearly watching TV of an evening is a heavy usage, it’s rated at 54w/4.5a, all my lights are LED, and overnight is supping out to 80%.

We’ve had rather a lot of rain ☔️ and so the 220w of solar has struggled in the gloom. It did sunny sunny on Tuesday quite nicely, and I saw this on the computer ?

It’s been back up to fully charged for each evening so all in all it’s looking OK. The VSR suggested previously is looking a good option in readiness for the next outing. BC62239A-1402-4A49-819B-1E136B060AF9.jpeg
 
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