Charging twin lesure batteries

[Deleted member 71915]

when I put a thread on called inverter I had a reply about this but I cant find a proper answer.
When we get the campervan I plan to wild camp, so a solar panel and 2 110ah batteries will be fitted, is it right I need a dual battery controller for the solar panel, and also how to charge the 2 batteries with a smart charger.
thanks for any help

 

[yeoblade]

when I put a thread on called inverter I had a reply about this but I cant find a proper answer.
When we get the campervan I plan to wild camp, so a solar panel and 2 110ah batteries will be fitted, is it right I need a dual battery controller for the solar panel, and also how to charge the 2 batteries with a smart charger.
thanks for any help

Generally, the two batteries will be connected together in parallel and appear, electrically, as one large battery to the solar battery controller, so a dual battery controller isn't needed, unless maybe you want this feature to charge the leisure batts and then the engine battery.
Ditto for smart charger, it will need to be able to charge 220Ah batt

 

[Obanboy666]

when I put a thread on called inverter I had a reply about this but I cant find a proper answer.
When we get the campervan I plan to wild camp, so a solar panel and 2 110ah batteries will be fitted, is it right I need a dual battery controller for the solar panel, and also how to charge the 2 batteries with a smart charger.
thanks for any help

No expert by any means as only been motorhoming 4 years but I was in a similiar position as you.
Fitted an additional 110amp battery giving me 220amps in total.
Basic factory fitted Sargent Controller / charger unit only rated to 115amps so hard wired in a Ctek intelligent charger solely for the leisure batteries.
So when on drive at home I put van on ehu with the Sargent unit charging the vehicle battery and the Ctek charging the leisure batteries 24 hours before setting off out, this ensures the leisure batteries are 100% charged. I also have a 100 watt solar panel again for the leisure batteries, on reflection I should have had this charging the vehicle battery as well as the leisure batteries but to be honest my van can be stood on my drive for 2 weeks without ehu and the vehicle battery has always been ok and starts the vehicle first time.
Since fitting the above I have never once required ehu when out on my travels, just returned from Cumbria on a CS farm site and only drove 20 miles in 4 days and batteries never went below 12.5 volt. I probably do 50/50 wilding and on CS sites and checking my diary I have done 44 nights this year on sites without ehu so my setup has saved me £4.00 x 44 nights = £176.00 saving to date. The extra battery and solar panel will pay for itself in no time at all and well worth the spend imho.

 

[GWAYGWAY]

Do not forget that two 110ah battery hold, Just that 220 AMPERE-HOURS, 1 amp for 220 hours or 220 amps for 1 hour or until the wiring melted. It is the potential capacity that we are talking about. 220 amps at 12volt would start a diesel train engine. Cranking current is a different beast, that is high load for a few seconds. The takeoff we need for our little cabins on wheels is nowt to worry about it is the time you can run the lights, television etc. I have three 90's on mine to keep the lights on when the clouds gather.

 

[Deleted member 71915]

still confused

1st, will a 220amp battery charge up fully with the built in charger
2nd as a 220ah battery got the same hours of say tv & lights as 2x 110ah assuming all are new
3rd I have just looked at a 12v tv on e-bay it says its 12watts does that sound right and if so does that mean it will use 1amp per hour or have I got it wrong ie the tv will run for 220 hours?
hope this sounds ok, remember iam was a car body repairer and now a wood turner whilst retiered so if you need help on these points I`am yer man

 

[Admin]

1st, will a 220amp battery charge up fully with the built in charger
2nd as a 220ah battery got the same hours of say tv & lights as 2x 110ah assuming all are new
3rd I have just looked at a 12v tv on e-bay it says its 12watts does that sound right and if so does that mean it will use 1amp per hour or have I got it wrong ie the tv will run for 220 hours?
hope this sounds ok, remember iam was a car body repairer and now a wood turner whilst retiered so if you need help on these points I`am yer man

1) Yes

2) Yes

3) Yes and No. 12w / 12v = 1. 1Ah is correct. But you should aim to use no more than 60% of your battery capacity, so you will have 132Ah (132 hours at 1Ah).

 

[wildebus]

12W sounds a remarkably low power consumption for a TV.
Are you sure that is the operational consumption or possibly standby power use?

 

[KuyaAndAte]

12W sounds a remarkably low power consumption for a TV.
Are you sure that is the operational consumption or possibly standby power use?

I agree... partially.

I have a TV brand that is renowned for being low power and its operating power is 23W (max), but less than 0.5W in standby. 12W sounds like a tiny TV or misleading data.

 

[Obanboy666]

Have you a manual for the charger ? If yes it should tell you the recommended maximum battery bank.
I contacted Sargent regarding my charger as the manual stated max 115amps and I was going to have 220amps.
They said yes it would charge the batteries but it would take an eternity and as my Sargent charger was a basic type I fitted a Ctek intelligent charger rated for more than 220amps.

 

[Deleted member 71915]

16w

I agree... partially.

I have a TV brand that is renowned for being low power and its operating power is 23W (max), but less than 0.5W in standby. 12W sounds like a tiny TV or misleading data.

thanks for the reply the 12w was only a 16in tv
e-bay item no. 172832471427 16w 20in

 

[KuyaAndAte]

ObanBoy, I am struggling to understand your comments about battery chargers being measured in the regions of 100's of Amps.

Are you talking about solar charge regulators or mains battery chargers?

For solar regulators it is all to do with the maximum current that the charger can handle, and is normally 10, 20 or 30 Amps. You can calculate (or read the instruction manual if you have one) the maximum number of Watts the solar panel array can be for the amount of Amps your regulator can handle.

For mains battery chargers I have only ever seen them listed in relation to their power, i.e. in Watts - normally 150W, 200W, 300W, etc.

It doesn't matter how many AHrs your leisure battery bank is your regulator or charger will still work, regardless of its size (in terms of power). The only effect of a higher power charger is that it will put the Amps into the battery bank quicker. Think about it, from the solar panels on my van's roof, on a bright sunny day, I can get over 10A going into my batteries. However, on a dull, miserable day I could be getting only 1A or 2A going into the batteries. The batteries are still getting charged but it will take a lot longer to put back in the same number of Amps that have been taken out of the batteries through normal use. The same applies for a mains charger, a 150W charger will still charge your batteries compared to a 300W charger, but will take twice as long to do it.

 

[Obanboy666]

ObanBoy, I am struggling to understand your comments about battery chargers being measured in the regions of 100's of Amps.

Are you talking about solar charge regulators or mains battery chargers?

For solar regulators it is all to do with the maximum current that the charger can handle, and is normally 10, 20 or 30 Amps. You can calculate (or read the instruction manual if you have one) the maximum number of Watts the solar panel array can be for the amount of Amps your regulator can handle.

For mains battery chargers I have only ever seen them listed in relation to their power, i.e. in Watts - normally 150W, 200W, 300W, etc.

It doesn't matter how many AHrs your leisure battery bank is your regulator or charger will still work, regardless of its size (in terms of power). The only effect of a higher power charger is that it will put the Amps into the battery bank quicker. Think about it, from the solar panels on my van's roof, on a bright sunny day, I can get over 10A going into my batteries. However, on a dull, miserable day I could be getting only 1A or 2A going into the batteries. The batteries are still getting charged but it will take a lot longer to put back in the same number of Amps that have been taken out of the batteries through normal use. The same applies for a mains charger, a 150W charger will still charge your batteries compared to a 300W charger, but will take twice as long to do it.

My mistake, meant maximum size of battery bank the charger is suitable for. The Factory fitted Sargent controller / charger in my pvc would charge my 220 amps of batteries but would take an eternity and isn't an intelligent charger.
The Ctek charger I fitted is an intelligent charger for battery banks up to 200 amps and charges at 10 amps.
I have to say my battery bank appears to last longer since I started using the Ctek, may be to do with the intelligent charger ensuring the battery bank is as near to 100% charged as possible.

CTEK MXS 10 12v Car Battery Charger

 

[wildebus]

He would have been referring to the Ah rating of the battery.
Sargent in their literature say the maximum size of battery recommended for their integrated charger is 110Ah. I very occasionally used the Sargent charger with my 220Ah Battery Bank, but it wasn't my main form of charging, my solar panels were, followed by the B2B charger. IF it were, then I also would have bought a more hefty charger.

I think there is an assumption that people use the batteries they have in their campers/Motorhomes. so if they have 100Ah, they will use it (50Ah anyway, if sensible). but if they have 400Ah, it is because they want and need 400Ah (really around 200Ah as we all know). so if they need that amount of power, there is a follow-up assumption that they need to recharge those batteries in a timely way, so a charger which is designed for a 110Ah max battery won't be ideal for a 200Ah bank and really wouldn't cut it for a 400Ah battery bank if the vehicle is being used in a typical way.
Yes the batteries will recharge eventually, but eventually often is not quite enough, is it? If Sargent said "sure, our battery charger will charge any bank of batteries you fit, but it could take a couple of days" I don't think it would go down to well with their customers.
Setting expectations is the name of the game, especially when if comes what you can do with a 12V battery in a motorhome (and why so many people aren't told what they can REALLY do and why so many people are disappointed after they go away for the first time)

 

[wildebus]

My mistake, meant maximum size of battery bank the charger is suitable for. The Factory fitted Sargent controller / charger in my pvc would charge my 220 amps of batteries but would take an eternity and isn't an intelligent charger.
The Ctek charger I fitted is an intelligent charger for battery banks up to 200 amps and charges at 10 amps.
I have to say my battery bank appears to last longer since I started using the Ctek, may be to do with the intelligent charger ensuring the battery bank is as near to 100% charged as possible.

CTEK MXS 10 12v Car Battery Charger

I am sure you are right about why your batteries are lasting longer. The Sargent just puts a constant voltage (13.6V?) onto the battery. No conditioning or intelligence, whereas the CTEK will be truely managing them.
When I get my new 12V setup installed in my conversion, if I use the Sargent PDU, I won't be bothering with the Sargent charger at all this time as will be moving to 3 times the useable capacity compared to my old 220Ah bank, so it won't be close to adequate to charge that (will be fitting a 20A Smart Charger)

 

[trevskoda]

Or you could use a numax 20ah smart charger.
I have fitted to some vans a 200ah relay with thick leads as hairydog states which will charge from eng alt at its output which is regulated.
If you go down the solar route then i would be looking at 200 watts min for your bank of batteries and possibly 400w would be better.

 

[trevskoda]

A caution: don't replace the split charge relay with a 200A one and fit heavy cables unless you also fit a charge regulator.
Start the engine and the alternator will try to get the engine battery to 14v. Join both batteries with a hefty cable and the starter battery will "top up" the aux battery as if it were starting an engine. This won't do either battery any good.
A battery to battery charger is the correct solution. You could devise some simple charge current limiter (that's why the wires are "too small" in the first place), but as soon as you increase the charge current, it becomes important to provide proper multistage charge regulation.

In truth you will as you say get a big boost from battery a to bat b along with alt but it will regulate down after about ten mins,remember this happens to low car batts to and we did this after jump starting cars in yard when i was in motor trade.
And yes a b 2 b charger is by all accounts the best way but price is the thing here for some,my van cam with a split diode charge regulator from new to recharge the tail lift battery so i used that for service batts,4 years now with no probs.

 

[Deleted member 71915]

i`am i missing something

A caution: don't replace the split charge relay with a 200A one and fit heavy cables unless you also fit a charge regulator.
Start the engine and the alternator will try to get the engine battery to 14v. Join both batteries with a hefty cable and the starter battery will "top up" the aux battery as if it were starting an engine. This won't do either battery any good.
A battery to battery charger is the correct solution. You could devise some simple charge current limiter (that's why the wires are "too small" in the first place), but as soon as you increase the charge current, it becomes important to provide proper multistage charge regulation.

sorry if I`am not just grabbing this but as already said the reason for using a smart charger is its a plug & forget. so does that mean you need to attach it direct and not using the EHU lead as this would be also charging it using the inbuilt charger, its all a bit mind boggling.

 

[wildebus]

Devices such as the Sargent DO have an inbuilt charger, but if you chose to fit a better and/or bigger one, then it is simply a matter of turning the inbuilt one off. In the Sargent, there is a big red switch to do just that

The separate mains charger you would wire up to an outlet from the CU so it is connected up whenever you are on hookup, and if you wanted to turn it off, you would just flick the breaker for that outlet down to turn off the circuit.
Most good smart chargers can be left on continuously without a worry in the same way as solar panels are always on (at least in daylight). The programming in them takes care of the voltage levels.