Lord Lucan
If no, or poor solar, which hookup battery charger is good to use?
MPPT vs PWM - The Solar Controller Test!
- Thread starter wildebus
- Start date
RAW
Forum Member
Fridge is OFF in Sylvia unless plugged into 240V as OLD Electrolux 3 way Job
Since we are posting some history and yesterday was quite a dark day Vs Today (so far anyway)
Here is my yield yesterday
So from TODAY 27/10/2019 Yield will be less all over UK due to the clocks going back so would be interested to see Today's Yield Vs Yesterday's longer Day yield
Since we are posting some history and yesterday was quite a dark day Vs Today (so far anyway)
Here is my yield yesterday
So from TODAY 27/10/2019 Yield will be less all over UK due to the clocks going back so would be interested to see Today's Yield Vs Yesterday's longer Day yield
RAW
Forum Member
I am looking at a Victron Charger for a Van build, one that could report on 240V Consumed and Power Used in that process.
I am quite Taken with the Victron Multiplus units but sadly they are likely out of budget.
wildebus
Forum Member
There are lots of options of course.
A few pointers ...
Capacity. Get one suited to your battery. So for a 125Ah battery, something along the lines of a 20A or so would be sufficient. There is a general rule of thumb that a charge rate should around 10-20% of the battery capacity, so a 125Ah battery would typically want no more than a 12.5A-25A charger. Get bigger and you could be wasting your money on the higher rate that never gets used. Check your own battery specs for the recommended charge rate.
Noise. If you want to use this overnight, get one that is nice and quiet. Some chargers can be very noisy and you end up having to turn them off, which makes them pointless during the main time you want to use them.
Control. You need a way to check the status and turn the charger on and off. If you fit the charger tucked away that can be hard unless you have remote control. If you fit the charger in an easily accessible location then you can have direct control.
Charge Profile. Avoid a charger that just puts out a fixed voltage charge (many Motorhome Power Distribution Systems do this when plugged in). Get a 'Smart' Charger that has the various charge stages that a Lead Acid battery needs for optimum charging.
Rpbert, Victrons Mains chargers are very good and tick all the boxes in the list in the reply to Lord Lucan, but .... they won't do what you want in terms of reporting UNLESS you get one of the new IP43 models (which is, at least at the moment, rather pricey!). The IP22, IP65 and IP67 models have no VE.Direct Port so will not talk to the Venus OS system. You can of course get 'moment in time' data via bluetooth on all of those products though
The Multiplus Charger/Inverters are very nice and if something is looking for a mains charger AND an inverter, the Multiplus', especially from the 12/800 upwards offer some great extra features that are only possible by having the Charger and Inverter combined. They do also provide a connection to the Venus OS system.
RAW
Forum Member
Would it be OK to get a Larger one if the battery bank were to be upgraded in the future ?
So as it stands 230AH = 23Amp to 46AMP
Future possibly 800AH = 80Ampt to 160Amp
So if I got https://www.cclcomponents.com/victr...2v-1600va-70a-16-230v-ve-bus-inverter-charger
That would probably do the Job I would think
SquirrellCook
Forum Member
One thing I've thought about with big chargers, is the power required to run them. Ok the multiplus can limit the loading on an external power source, but it can still be a lot of amps if you rely on external charging. I remember using 3 7.5amp chargers with a 1kva silent smart generator. Poor thing reved it's nuts off, and was not silent coping with that loading.
RAW
Forum Member
I would not rely on External Power or EHU but rather have decent Solar as the primary power source; split charge relay as secondary power source; and then EHU as an optional third Power Source. EHU would be used at home when parked for top up in Winter and to send 240V to a few sockets in the Van for works etc. Make sense ?
wildebus
Forum Member
Firstly, I assume that is just a link to the product and you don't intend buying at that price?! (Victron have a New-Style Multiplus in the 500-1600VA range size which are much more keenly priced - Have a look here at info on the new range.
To answer the question, typically the batteries will only take what they will take, so in general terms should be ok to go bigger.
With regards to the Victron Chargers, they have a 'low' setting so you can typically halve the standard maximum output to limit the charge current.
And with regards to the Victron Multiplus Chargers, you can specify precisely the maximum charge current you wish to allow.
As an example, I have the 12/3000/120 - which is a Charger/Inverter with a maximum charge capability of 120A. I set the limit to 95A when I had 4 x 95Ah(@C20) Leoch AGM Batteries as those batteries had a recommended charge rate of no more than 25% (so 95Ah*25% * 4 batteries = 95A).
When I changed to the North Star Batteries they have a 'no limit' charge rate so I changed the limit to the maximum possible 120A.
wildebus
Forum Member
I am surprised it had such an effect there - are you talking 7.5A@12V? 3 x 12V 7.5A Chargers only adds up around 2.5A so should be well within what a 1kVA Generator could provide? Sure, not silent, but better a bit more noise and power but for a shorter time?
I find it handy to have the option of a high current charger when the situation allows, and throttling the input when it does not. Which is why the Multipluses are so handy - you can set the current input to whatever is permitted. So for a standard hookup, leave at 16A; if on a generator, set at whatever is suitable for it (I set my input to 6A, so approx 1400W for my P2000 Generator. If the charger delivers 120A@12V, that is still under 6A @240V); and if on a limited site hookup, set at that limit. It is not just the charging aspect but utilizing the mains for general usage - with the power assist, you can use something like an electric kettle without tripping the breaker as the battery makes up the difference.
wildebus
Forum Member
RAW
Forum Member
Just PM'd you LOL
wildebus
Forum Member
OK. The PWM vs MPPT test is over and the (my) conclusion is that MPPT has a definate advantage, but it will take a season of use to pay for itself over the cost of PWM.
Yes you can fit more solar to cover the waste that PWM creates but most people are limited in their roof real estate when it comes to adding solar - so getting more from what you have has got to be the better option
I thought what I would try with the setup I have while it is there is another test ... What does the charging profile look like? I know the Victron MPPT Controller has the 'perfect' profile when it comes to charging a Lead Acid Battery (I have logged the evidence) but what about the other MPPT I have and the PWM Controllers?
So first on the bench is the P2420 20A PWM Controller. I am not having to use the battery monitors for this as I can connect the Victron MPPT on the battery terminals and use that as a Battery Voltage logger with the Victron Portal and see precisely what is happening for all the controllers in turn and have a good comparision between them all.
I am using the 27V 2.15A Power Supply setup again for this for reliable constant power. Not bothering about logging voltage inputs or current rates - this test will be purely about how long each controller takes to get the battery fully charged (or if it even does!) and what that profile looks like (how kind is it to to the battery?). I have no load on the battery other than a LED Voltmeter and illuminated LED Switch, so pretty minimal
Yes you can fit more solar to cover the waste that PWM creates but most people are limited in their roof real estate when it comes to adding solar - so getting more from what you have has got to be the better option
I thought what I would try with the setup I have while it is there is another test ... What does the charging profile look like? I know the Victron MPPT Controller has the 'perfect' profile when it comes to charging a Lead Acid Battery (I have logged the evidence) but what about the other MPPT I have and the PWM Controllers?
So first on the bench is the P2420 20A PWM Controller. I am not having to use the battery monitors for this as I can connect the Victron MPPT on the battery terminals and use that as a Battery Voltage logger with the Victron Portal and see precisely what is happening for all the controllers in turn and have a good comparision between them all.
I am using the 27V 2.15A Power Supply setup again for this for reliable constant power. Not bothering about logging voltage inputs or current rates - this test will be purely about how long each controller takes to get the battery fully charged (or if it even does!) and what that profile looks like (how kind is it to to the battery?). I have no load on the battery other than a LED Voltmeter and illuminated LED Switch, so pretty minimal
trevskoda
Forum Member
Thank you so much wildebus for all the proper info,i shall soon as pos fit my mppt regulator,mind you the we so called one you tested same as mine is keeping the battery up,but im thinking that once the fridge goes in the mppt unit will by miles use and make a better job of keeping batts up and faster to,cheers.
wildebus
Forum Member
I got my money back for that small controller. TBH I think it is a nice unit and good value for money for a PWM (but it was described as MPPT!)
But yes, I think with your 200W of Panels, the difference between PWM and MPPT in the summer months will actually be what your Fridge uses, so it will be like running your fridge for free
SquirrellCook
Forum Member
It could just about cope with the fridge kicking in, but sounded heavily loaded. That said it runs for about 6 hours on very little fuel so good for emergencies.
Finally I returned home to find Murky's leisure batteries fully charged, funny what a little sun will do.
This morning I switched on the inverter and fired up 2 of the 7.5 amp chargers to bring up the engine start batteries.
20 amps drain from the two chargers, not the most efficient.
This one of the down side of the bigger mercs, their is a current drain I've never been able to track down. They provide an isolation switch for the batteries, but then the alarm or powered doors don't work. Odd characteristics, it draws more current in winter than it does in summer. Also when connecting the supply there is a current serge just like a big capacitor is in the circuit somewhere?
SquirrellCook
Forum Member
