WOW this went on for a while LOL. Glad the family on here are helping you out Steve.

We left England 3 years ago with an 100Ahc geltec, Engle, 40w panel and a electronic split charger.

We now have 210 Ahc in 2 Gel btys 1 engle 40 ltr fridge, 1 engle 21ltr set up as a frezer, morningstar 30A controler, 2 90w sunpower solarpanels, 40w Kyrocera panel through a 7A controler, victron 350w pure sine wave, waterpump, lights and now a Cetec xs25000 charger. all monitored by a Victron BVM 602.

We are finally satisfied the btys only get down to 85% capacity over night so are getting looked after and we try to plug the cetec in once a week to look after the btys.

The final thing we will fit is a Bty to Bty charger in place of the split charger Cetec will be releasing one soon had our hands on the protatype but it looks good and will be cost effective, basicly unafecting the starter bty but doing the same as their smart chargers when the engine is running.

The BVM 602 can also be conected to a PC to download the last 40 days of usage in to an excel doc to help monitor bty state and usage.

Forgot to mention I was alwayd told look after your earths. lots of them and take them off clean with sand paper the put back. If earthing is not good then you will draw more current to push it through, did mine and noticed the drop couldnt belive it the fridges used .5A less dosent seem much but in the long run.

But now you have power enjoy the ride mate

__________________
www.landroveradventure.co.uk
Land Rover Discovery 2, Yamaha Super Tenere

Thanks Q. I've got the manual, and have been connecting/disconnecting as specified.

I emailed Steca through their website Wednesday last week, but they haven't responded yet. It's a bit frustrating, stuck here with no idea what's wrong and no response.

I've had a look inside to see if there is an obvious culprit. One of the MOSFETs has some discolouration on the back, so I'm thinking perhaps that's blown. That's the only thing I can see that could be the problem. Code on the MOSFET is IRFZ48N. From what I can see online it's rated at 55V / 64A... I really don't think I've put anything close to this into the regulator, so if it is blown, I have no idea how it happened.

I've taken 2 of the MOSFETs off. Tested the one with discolouration, and the drain is conducting all the time... blown. Tested the other to make sure, and it's working as expected. How on earth did I blow that MOSFET?

Now just gotta find a new MOSFET somewhere here. Naturally, 3 days ago I left Nairobi! Aaaargh! I do have a glimmer of hope - spoke to a guy who has a solar company here in Nakuru and he reckons he has MOSFETs - we'll see about that tomorrow. Wish me luck!!

I hope Steca isn't reading this forum - don't think they'll honour my warranty when I'm busy desoldering their circuit board!

Blimey Steve talk about being born under a bad sign!

I assume the MOSFETs are used as simple swiching devices. If the worst comes to the worst you'll have to wire in a switch to stop the system back-discharging to the panels at night and basically dump the Steca unit. As your panels are so small perhaps this isn't quite the disaster it might be (careful monitoring of the battery voltage will be needed though) and in the end, as an alternative you might have to abandon using the solar side altogether.

Good luck!

Q

Q, as they say - when it rains, it pours! Boohoo!

I'm really loathe not to have the panels - the current they produce is enough to keep the freezer running indefinitely, plus some. (Freezer takes about 2Ah, Panels produce between 4A and 7A during the day.) Without them, and the fact we're heading out into the boondocks in the near future, well - don't want to have to sit and run the truck all the time just to keep the LBs charged up.

Anyway, I had an idea, and it's looking like it may work.

The Steca has 3 connectors: for the panels, batteries and load. The way mine is wired up I don't use the load - all the consumers are connected directly to the battery bank, so I just have the batteries and panels connected to the solar regulator.

The regulator allows you to turn on and off the load at will - ergo, there must be a similar transistor that is used for the load. I had a look at the circuit board and found a transistor where the drain was connected to the load's negative connector. I swapped that transistor with the blown one on the module input, and voila, it's working! Well... sort of. Since the transistor now on the load is blown, its drain is always transmitting, so I can't turn off the load. Nothing is connected, but I'm not happy with the electronics thinking it's off, yet it's actually on. Tomorrow morning I'm going to experiment with taking the blown transistor out of the system, and thereby disallowing the load function of the regulator altogether.

I'll let you know how I get along. I really hope I can get this thing going again, coz as previously mentioned, I want to try connecting the alternator's 24/12V converter to the regulator. I haven't tried that yet, coz the regulator blew (here's hoping I don't get the regulator working, then connect the alternator and blow it up!)

I've got a 2-way 24V relay which I'll have the ingnition switch between the panels when the truck is off, and the alternator when the truck is on. I'm worried about having both the panels and the alternator transmitting into the regulator at the same time. Shouldn't cause a current overload, but the voltages will be different (panels are about 16V, alternator will be at about 13V) - I don't know if that will have an affect - am thinking the higher voltage panels will prevent the current from flowing out of the alternator and into the regulator... can anyone confirm if this is correct, or if not, what would happen?

Cheers
Steve

www.overafrica.org
www.overlandcamperforsale.com

Steve (this is beginning to get like a 2-way conversation!) I use exactly the same relay-controlled set up in G4. When the ignition is switched on the Sterling B2B is livened up charging the LBs and the solar side isolated and when the ignition is off the solar side does the charging and the Sterling is off. I would have thought this is the way to go because aside from anything else, if you wire up the dropper output directly into the input of the Steca regulator, you're going to discharge the truck batteries through the panels unless the dropper is itself swithed by an ignition-controlled relay. See what I mean?

V clever of you to cannibalize the transistor though. V impressed!

Good luck!

Hi again Q. Yes indeed it is almost a 2 way conversation!

The dropper is actually already wired up to a relay switched by the ignition. It's a simple (and therefore not very good) solution - truck batteries connected via a relay to the dropper, which is connected to the leisure batteries. Obviously without the relay the truck batteries would permanently power up the dropper and soon go dead if we don't keep the alternator running.

Now I'm going to have a 2nd 2-way relay that will take the output of the dropper and the output of the panels and switch between them for the input into the solar regulator (no power to the relay switch, the panels are connected to the regulator - when the relay switch is powered up (ignition) then the dropper is connected to the regulator)

Why do you bother to turn off the solar side when the truck is running, if each has its own "smart" charging sytem? I'm thinking the answer is going to be something like what I was alluding to in my previous post, but if you could elaborate I'd appreciate that.

Cheers
Steve

Sure Steve. Basically I wanted to keep the two systems separate and simple. I did reckon that mixing the inputs (which inevitably would be at a potential difference-i.e. different voltages) would be likely to 'confuse' both the Sterling unit and the Solar regulator.. So I have exactly the system that you're proposing-ignition off: solar on etc.

Q

What happens when you plug in mains?

Hi guys,

Just so its not a 2 way conversation i have a few questions regarding my own set up. I dont want to hijack your thread as it has been incredibly informative and has raised questions about my own set up that i am having a few problems with..

I have just built an MAN camper. The truck is 24v and i have used an IBS 24v split charger to charge 24v LBs (2 x 12v65amh exide gel) that uses a relay and has battery monitors.(showing the starter bat and LBs seperatly ) Also charging the LBs is an 85w solar panel with 24v regulator.
From the 24v system there is an engal fridge, an erberspacher heater and a 24v-240v inverter.
There is then a 24v-12v dropper and the interior lighting and cig lighter for computer from the 12v side.

I thought i would have enough juice to use the fridge and a light in the evenings and the computer , but the LBs seem to drain very quickly.

Should the dropper and the inverter be on switches so that they are only on when in use ?
Also the solar is on all the time, the IBS allowing it to charge the Starter batteries when the LBs are full, only they are never getting full?

Even after driving 5 hours they dont seem to get fullycharged, and if the led shws they are as soon as you use a light it drops.

Am concerned the batteies are not good as when i first set it up i didnt charge them up fully and then used them for a while with just the solar as i wasnt driving any where..

I am in germany trying to get it sorted before heading south, i have bought a ctek 24v charger to try and get them in shape, but need to know if i should alter the set up, and maybe get another set of 24v batteries to increase the AHrs( The problem with this set up is that its based on 24v so i will have to get another 2 batteries)

Anyway, help appreciated and hope you get yours fixed steve, your a brave man de soldering regulators!

Cheers

Stan

I'll try do a brain dump here that may be a help. I'll probably ramble for a lot of it, so try bear with me!

After all the help I've been receiving on this and other forums, I found this excellent overview of using multiple charging systems. I would highly recommend reading it: Multiple Charging Sources to the Same Battery Bank - Cruisers & Sailing Forums

Using just the alternator's 24V output to charge your LBs will only charge them to about 50% of capacity. The alternator generally works for starter batteries because all they have to do is deliver a high current to turn over the starter motor before the alternator takes over. Leisure batteries are used differently (slow discharge over time), and as such we're more concerned over the state of charge of the batteries. Really you need a smart charging system which alters the current and voltage output according to the state of the batteries it is charging. My solar regulator does this, does yours? (what is the make / model?)

As you will see from reading this thread, and from the above link, it would probably be pertinent to use a relay to switch between your panels and your alternator, depending on a signal from your ignition. To be honest it's probably worth finding a good 'smart' charger that can be driven off your alternator, and then use a 2-way relay to switch it on when driving, and the panels on when not. That way you'll get your batteries charged up properly when driving.

Certainly I would put a switch into the 24V input line to your inverter, alowing you to remove it from the system when not needed.

Another thing to look at is the power usage of your system, as this will determine how large your batteries should be.
What power rating is your inverter? Now you can work out the amps the inverter is using (P = IV, so I = P/V where V = 24V) Remember that an inverter is quite inefficient, generating a fair amount of heat when converting to AC. If you use a very high power inverter, when you're consuming only a low amount power, you'll be wasting a lot of battery power needed. The inverter won't always consume the full power it can produce (ie: if a 300W inverter is on but the AC is not being used, it won't be consuming 300W of power), however, a higher power inverter will use more power producing AC than a lower power inverter will - so try match the inverter to your needs.
How many amps does your Engel use? (will be in the technical docs supplied with it)
How many amps does your Eberspacher use?

Basically, what you want to do is work out how many amp/hours each thing uses - how many amps, and for how many hours - that will give you an indication of total amp hours you use per day.

Now, in an ideal world, you don't want to discharge your batteries more than 1/3rd - so if you're using, for eg, 16amps and you want to use them for 2 hours a day - then that's 32Ah you're consuming - you want to have 100Ah of battery life to be able to supply this, and over the course of the day you want to put back 32A into the batteries.

In ideal sun conditions your panels will produce 3.5A. Let's say you average half that over a day, of say 8 hours. That's 28Ah you're putting back into the batteries - which means that every day you're actually taking 4Ah out of the batteries you're not replacing (consuming 32Ah, producing 28Ah) - that means you can sit parked up, relying on only your solar panels, for a maximum of 8 days before you want to think about charging your batteries from another source (100Ah battery, you want to discharge it to a maximum of 1/3rd (ie: 33Ah), you're taking out 4Ah a day, so 33/4 = 8 days)

Steve you've got it absolutely right in that last post. Sorry for silence but the world of work........

Stan, looking at your system Steve has identified the design deficiencies though I could add that your IDS device has the wrong priority: it should charge the starter battery first then turn to the LB. You need a smart chager powered off you charging systen like the Sterling B2B device (honestly I haven't got shares!). There is one that takes 24 volts and charges at the LBs at 24. You must have the inverter off when its not in use as it'll waste loads of power just doing nowt. I imagine the dropper is less than efficient too.

As Steve has shown you almost certainly haven't got nearly enough battery capacity Stan. In the winter you won't be getting a great deal out of your panels yet the demands (save possibly by the fridge) will be higher. Remember the key is to work out your power needs, minimise them as much as possible e.g. use LED lamps etc, and basically as a rule of thumb, have 3 times this battery capacity. Frankly without a smart charger driven off the vehicle charging system and some more capacity you'll be struggling. With a fairly low wattage solar system you're reliant on the vehicle side to charge your LBs-just regard the solar as a adjunct.

Oh and Steve my mains system is totally separate from the leisure side. I have mains lights for example only used when the mains input or generator is doing it's stuff. I do have a mains smart 12V charger but I found that the generator had the habit of killing off mains chargers.

Q

Welcome back Q, you were missed!

Re the voltage dropper: These days most people use a switch-mode converter for their voltage dropper which is very efficient, so you don't have to worry too much about the power consumption for that Stan.

To report back on the changes I've made to my system:

I have a 24V 2-way relay, normally closed line connects the solar panels to the solar regulator. The normally open line is switched with the ignition, and connects the output of the 24/12V dropper to the solar regulator instead (so alternator takes precedence when driving)
I also have a 24V 1-way relay which is switched on the ignition - this connects the 24V truck batteries to the dropper - ie: they're only connected and therefore the dropper only runs, when the truck is on.
I then have a 12V 2-way relay - normally closed line connects the output of the previous relay (ie: either solar or alternator (aka: 24/12V dropper)) to the solar regulator. The normally open line is switched by the 12v output of my mains charger, and connects the main's 12V output to the solar regulator (so mains takes precedence when on shore-hookup)
That means mains is always 1st precedence, then alternator, finally solar.

I've made a bit of a stupid mistake, and that is that when the 12v output of the mains charger signals the 12v 2-way relay, and connects the mains 12v output to the solar regulator, even when mains turns off, the solar regulator input continues to energise the 12v switch of the 2-way relay. Tomorrow I'm going to hunt down a diode to put in the output line of the relay, to prevent the solar regulator's charge returning through the closed line of the relay and energising the switch (switch and 12v line input to normally-open are attached together)

I think this will work. Any comments? I'll let you know how it comes along.

So long and thanks for all the fish.
Steve

I don't know if your leisure batteries are AGM such as the Odyssey range but I have just found out that they need to be charged at 14.7volts. 14volts will only charge to 60% and will lead to premature failure of the battery. I had this problem and found that my alternator regulator was only 14volts - I have ordered a 14.7volts one and will see what happens but hopefully i'll be able to charge my new battery properly. I'll let you know.

Thanks to all the contributors to this informative thread btw.

__________________
Chris
-----------------
"Never have a stupid argument with an idiot - he gets a lot more practice than you"
there I go again
not too hard really

Thanks for the info guys, its been massively helpfull.

Due to costs of redoing the system i will have to stick with it as it is, but i will increase the 24v Battery amphours. ~If i change anything i may add 12v solar totally seperatly and just run the 12v stuff- interior lighting and toilet flush off this. This will reduce the AHrs needed on the 24v side and not require as many batteries.. ?

Can you use the lights etc when a mains (ctek) charger is plugged in? As i dont have 240v so if hooked up to mains it is just to charge batteries. I have unplugged the solar when using this charger.

Thanks

Stan