Charging Improvement

[crockitt]

I would like to think that our van battery would be fully charged after travelling for 3 or 4 hours but I know that will not be the case. I am interested in the ctek D250S unit would this achieve full charging? I hope someone can advise if it would be aworth while addition Dave

[John M]

I would like to think that our van battery would be fully charged after travelling for 3 or 4 hours but I know that will not be the case. I am interested in the ctek D250S unit would this achieve full charging? I hope someone can advise if it would be aworth while addition Dave

There are a number of major impediments to "fully charging" the batteries the first is the depth of discharge/ available rate of charge, the second an major one is the time limitations, if you use a direct alternator charger, or similar (around 80 amp hour or so), you will be able to put a large charge quickly, depending on the size and type of batteries and whether they can absorb this much charge, assuming you have the normal lead acid, gel or AGM type batteries then if they are at the state where they will absorb that much charge then you are not going to have sufficient time anyway, the other and even larger problem is the charging regime employed by most battery chargers, that is assuming that you are running a standard type of charger that has Bulk, Absorb and Float levels of charge, the battery charger initially goes to boost charge as soon as it is turned on, that is, the charger puts in maximum volts (14.7 V or so) and as many amps as the batteries will absorb,until the voltage of the batter reaches certain value (often around 0.3V below the boost level) then the battery charger then will change to the absorb mode, where the charger will input a regulated charge, normally for a set time, usually around 10 times the time required on bulk charge, after this time the charger will revert to a float or maintenance charge, at which time the battery can be called fully charged.
If you use a direct alternator charge system usually the battery will come up to 80% fairly quickly, however the standard alternator will not charge much beyond this point without modification, and even then, in my belief, not much more.

If you use a battery charger, either a 240v run from an inverter or a Dc/Dc charger such as a Redarc or ctek. the main constraint is time, in that even if you achieve the absorb stage you will not progress much past it unless you are going to be driving for extended times.

All of the above are my own observations and deductions, are purely my own opinions, there will be some who disagree with me, I further believe the same time constraints are in place when employing solar panels, particularly if the batteries are well discharged, as if the batteries require say 4 hours on bulk charge then they require another 40hrs on absorb, to be "fully charged" In my experience this is the case, with my own solar setup the batteries are normally maintained to around 96%, and the xantrex meter never resets or reaches 100% charge. except when external power is employed, then the meter resets at around 8 pm.

I understand that Lithium type batteries, ease this as they do not require the absorb state of charge

[Wilbor]

John, I have a xantrex battery monitor and my solar reaches 100% as per the monitor most days. How much solar and batteries do you have?

[John M]

John, I have a xantrex battery monitor and my solar reaches 100% as per the monitor most days. How much solar and batteries do you have?

Hi Wilbor,
I have 520w of Solar charging 4 x 100 ah AGM Batteries through a Stand alone MPPT regulator, my daily usage averages around 80 ah running two compessor type fridges plus TV, Computers and the usual LED lighting, my usage was determined by removing the solar and all inputs at midday with the batteries fully charged, using all items as per normal, and then taking the reading from the xantrex meter at midday the next day. I believe part of my trouble is the compressor fridges, they use quite a lot of power and even though the solar is producing in excess to my usage from quite early in the day, peaking in excess of 25a, possibly the current drawn by the fridges, confuses the readings at the xantrex meter.

[BruceS]

80ah for 2 compressor fridges for 24 hours?
Can you tell us the outside temperature and the size/make/model of the fridges?
Seems a little light for everything for 24 hours but I'm not questioning your ability to measure it!!!

[Newcastle George]

Depends on the size of the compressor fridges, how often they are opened and whether we are talking 12 or 24V.

George

[John M]

80ah for 2 compressor fridges for 24 hours?
Can you tell us the outside temperature and the size/make/model of the fridges?
Seems a little light for everything for 24 hours but I'm not questioning your ability to measure it!!!

We are currently parked with family at Toolangi (Vic). The house fridge is a 150l waeco the beer fridge is a 35l Ybere chinese version of a waeco, both fridges are stocked to near capacity, with the house fridge and freezer being near full, the beer fridge at the time of doing the check was almost full with 2 doz stubbies and half a dozen soft drink, I have found that this fridge uses a lot less power if taken out of the car and stored under the awning, the ambient temp was in the low to mid thirties, the beer fridge is set at, and maintains 1 deg, and the house fridge is switched to 3, as the bus is parked in almost total shade, I did not pull the fuse on the solar though the input was negligible less than 1 amp the couple of times I checked, we were away from the bus for most of both days only returning to sleep and watch a video, (which both of us slept through) and neither fridge was accessed at all during the day.

[BobnBev]

Thoes chineees waecos use a good 5 amps when running,( wankool compressor) the smaller waeco with a bd35 Danfoss only uses 3.5 max, but 5 if a resister is used to speed the compressor up .....
Bob....

[John M]

Thoes chineees waecos use a good 5 amps when running,( wankool compressor) the smaller waeco with a bd35 Danfoss only uses 3.5 max, but 5 if a resister is used to speed the compressor up .....
Bob....

I have found the chinese fridge can use anything from 2.6a through to as much as 6a with the same amount of beer on board, they do not like being in a hat environment, if it is under the awning in a bit of a breeze the current draw is greatly reduced as is the run time if it is in the back of the Suzy even with the back door open then it can use 5a (or more to the point where it wont work), and will run almost continuously.
I believe the problem with my xantrex meter not resetting is due to the fridges cycling, towards the end of the day the current can drop to 12.8 or so with either fridge running, consequently the meter does not see the full voltage, (I know what I am trying to say, but cant seem to make the words work).

[T1 Terry]

My Xantrex meter in the Mazda gets to 100% and that's it, the battery was still charging but 100% was as far as it read. The Plasmatronics stuff will read up to 128%, this lets you know you need to rest the 100% because the meter and battery have gone out of sinc, the Xantrex doesn't have such a feature, the 100% reading could be way off 100% fully charged, the fact the battery is still accepting reasonable current yet the meter reads 100% is a good indicator that it's lost the plot and needs to be rest, once the battery really is fully charged, as in, it will accept no more current at a charge voltage of 13.8v.