Solar controller upgrade on a budget

Interesting.
Reading the splurge they suggest that the controller will increase sub 12v panel voltage to be able to charge batteries.
Do all MPPT controllers do this?
 
Markd said:
Interesting.
Reading the splurge they suggest that the controller will increase sub 12v panel voltage to be able to charge batteries.
Do all MPPT controllers do this?
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Interesting. Not heard of that feature in any Solar Controllers.
The Victron controllers certainly will not. (They turn off if the PV voltage is less than 1V > than the battery voltage).
 
Basically an mppt controller gets what ever is possible from the incoming feed both watts and amps by " mixing " them where as a pwm basically only uses the current is incoming 25 v 3amp to battery 12v 3amp
 
I've re-read it and they actually say "boost up the current".
This I realise I knew on the basis of pv in = pv out with higher voltage in meaning higher current out.

Genasun do make "buck" controllers that step up the voltage - but they are much more expensive.
 
Landyseverywhere said:
Basically an mppt controller gets what ever is possible from the incoming feed both watts and amps by " mixing " them where as a pwm basically only uses the current is incoming 25 v 3amp to battery 12v 3amp
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It's my understanding that if we had 25v 3A input that output would be 12v 6.25A or more likely 14v 5.4A with MPPT.
PWM would be nearer the numbers quoted?
 
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Roughly correct from an mppt controller but it is sufficient to know that an mppt will deliver apx 30% more power to battery than pwm,so in a motor home where space for panels is limited then a mppt is like having 30% more panels a no brained if you need more power and can workout cheaper than addind 30% more panels even if space is available
 
I'm looking to trickle charge my starter battery and while Renogy talk about a separate low current load I didn't spot any specific outputs unlike the 1A max of the Votronic kit.
 
No split charge on the 60 amp and fairly sure not on the other one I've ordered ..but I will fit a 2 way switch so solar can charge either battery..just means switching periodically or something like the voltronic battery to battery 2amp controller can be fitted to automate this at apx£30
 
I'm still minded to get a Votronic 165 which does have trickle and is under £80 on Amazon.
 
Looks to be good IF claims are true ,but does appear physically small and lacking heat sink also no LCD or battery temp sensor( couldn't find it on amazon but found on eBay)
 
There is a temp sensor on the 250 model, is the smaller one different? The 1amp trickle works well for me
 
You're quite right remote displays and temp sensors are extra and quite pricey.
But the same goes for all controllers doesn't it?
I'm not that fussed about watching batteries charge - I'm generally too busy keeping an eye on the paint 😀😀
If I had a major power station on the roof and several batteries in the van I might worry about temperature fine tuning - I can always add later when I find I'm wrong.
 
The renogy I have comes with both temp and LCD.but my main concern would be the voltronic does not look right for true mppt
If I were you I would google it for reviews,also if your controller over or under charges it will at best shorten battery life the same applies if the battery overheats due to no overheat shutdown to say nothing for an abundance of hydrogen gas !.Having said all that IF it is as good as it claims and proves reliable great for a M/H,except for the lack of a screen old saying "information is key" you will have no idea what is happening until its too late...may be resulting in sitting in the dark to knackered battery or ?
 
It's my understanding that Votronic is designed for the motorhome market - it doesn't have an LCD screen because they expect it to be installed near to the hab battery probably in a cupboard or under a bed where having a screen is a waste of time.
They also have a dedicated trickle charge for the starter battery.
They all have connection for temp sensor and if one wants to see what is happening they do a remote "computer"
The larger models have cooling fans rather than relying on heatsink alone.
The reviews and technical assessments that I've seen are pretty good.
 
Sounds ideal. Give it ago and review it here in a year or so and if it's as good as it says it is you will have helped a lot of people
 
I've been thinking about cooling of MPPT controllers and convinced myself that heat losses must be low.
They claim to be 98% efficient at conversion of input to output so on a few watts to go in heat for the small ones.
Even if they waste 5% that's only 25w on a 500w controller - or have I got completely the wrong end of the stick?
 
***** said:
We have the Schaudt LRM 1218 Mppt and it simply plugs into the Schaudt charge controller
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Something to bear in mind with the Schaudt controllers ... they have a fairly low input voltage as MPPT Controllers go. Because of that limitation, you can NEVER connect multiple panels in series and only ever in parallel; plus you cannot use higher wattage single panels (say typically a 200W or larger panel) as they will usually have a voltage greate than the Schaudt can support. (They are also very pricey for what they offer beyond a convenient connection).
 
Something to be said for convenience for first time diy installation or it mates directly with existing kit.
I've just taken delivery of my Votronic 165 and it should be a very quick swap over from existing PWM.
Unfortunately it's an Xmas present so I'll have something to do on boxing day 😀

I'm contemplating running additional wires to the the leisure battery to reduce voltage losses as the cable run must be 7-8m.
Any views on this?

Also thinking about pitting another feed from alternator via a D+ relay - thoughts?
 
I used a Votronic MPPT controller on my old Dethleff with a single 130 watt solar panel which worked very well and never gave us any trouble.

Regards,
Del
 
***** said:
Yes it is expensive but as you say very convenient to just plug in and in our case it charges both the leisure and engine battery. From memory, I think it also has a little internal fan to keep it cool
We are not power hungry, only have one 100watt panel, but it does the job for us and works well
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yup. Shows there is not a single right/wrong/bad/good solution. All depends on the users requirements. :D
 
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