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Tech heads - battery advice

Green Pro Clean Ltd

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8,103
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Nottingham & Derbyshire
Perhaps someone knows, maybe @spruce.

My battery seems not to be charging as quick as usual still, nice and green on the indicator, but where it is usually 12.5 -12.7 topped up by the SCR it is now 12.1 to 12.2

At present I am hoping I can attribute it to the drop in temperature. I have taken it out for the night and got it on the trickle charge to max it up again but normally I do not have to take it out and put it on charge.

Any advice.

 
He means charge cycles green,

Generally the more charges it's had the worse it'll get lol

 
Never been on a charger, stays topped up from the SCR
How many miles are you doing to keep it charged? I don't do a lot of miles, mine charges through the van battery as I drive, but I still put my leisure battery on charge twice a week.

 
These split charge relays, do they reduce the current you're chucking into the battery? Or is it basically coming off the alternator? 14v ish? Should they have some sort of charge controller?

 
Perhaps someone knows, maybe @spruce.
My battery seems not to be charging as quick as usual still, nice and green on the indicator, but where it is usually 12.5 -12.7 topped up by the SCR it is now 12.1 to 12.2

At present I am hoping I can attribute it to the drop in temperature. I have taken it out for the night and got it on the trickle charge to max it up again but normally I do not have to take it out and put it on charge.

Any advice.
I would leave it on charge tonight and see what happens. Unfortunately, after it comes off charge it will need to stand for a couple of hours before you read the voltage across the battery. Fully charged voltage should be 12.7 to 12.8v. It might also be a good idea to check and see if the split charge relay is working. You can do this with the van running and putting a volt meter across the battery terminals. It should read somewhere between 13.8 to 14.5v. (Some of the newer vans charge at a slightly higher voltage of 14.8v)

A battery at 12.5v is 75% charged. (12.4v is 50% charged so there isn't much margin for error.)

Most batteries fail during winter. Lower temperatures mean that the battery has to work harder (or is less efficient) to do the same job. Our pumps are going to work harder as the water is colder and so more difficult to push through the hose. The hose is also more stiff which adds to the pump's labours.

The green of the magic eye isn't a good guide for a battery's state of discharge, especially if you look at it after you have completed your journey. Your van will probably be charging your battery at around 14.1 to 14.3v at 75% charged. In this situation my leisure battery will still be registering about 13.8v after 5 minutes, so the magic eye will show the battery as fully charged. When my first 110 amp leisure battery failed, the green eye was still green even although the battery didn't have the power to drive the pump.

I usually boost charge my leisure battery every 2nd day in the summer. In winter I usually do it every night (unless the battery hasn't done much work) as I put a heater in the back of the van. Adding the battery charger to the socket takes very little addition effort to plug it in.

I also have the 1/2 thick piece of rubber under the battery to isolate it from the freezing van floor.

 
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These split charge relays, do they reduce the current you're chucking into the battery? Or is it basically coming off the alternator? 14v ish? Should they have some sort of charge controller?
You are right. Alternators don't make good battery chargers. But they are excellent at supplying all the accessories the vehicle has. So a battery in a modern vehicle does a lot less work that one fitted to a vehicle with a generator.

Alternators are better than the old generators ( showing my age here) vehicles were fitted with before alternators become popular in the mid to late 1960's.

The ideal answer is special controllers supplied by companies such as Sterling. But these control units are expensive. I couldn't justify spending between £250 and £500 (depending on application) for these state of the art units. I don't need to power equipment like an ambulance does.

A leisure battery doesn't like to be fast charged anyway. A rule of thumb is that it should never be charged at more than 10% of its capacity. So the maximum amperage a 110 amp leisure battery should receive is 11 amps.

I haven't read anywhere that charging at a higher voltage itself will damage a leisure battery. But higher voltage charging means that a high amp of charge can be driven into the battery, and its the amps that do the damage to a leisure battery.

In time we may see improvements to VSR (Voltage Sensing Relays.) My current VSR intelligent relay cuts in at 13.3 volts and cuts out at 12.8 volts. Could we see another circuit added that restricts the VSR at 14.5 volts? My 230v intelligent charger only reaches 13.9v when charging. So maybe I would be better off using the VSR to power a pure sine inverter and then coupling my 230v charger to my leisure battery. It definitely does a better job charging my leisure battery than the van's alternator does.

 
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Great stuff. I had a wind turbine once (12v DC) that allowed the voltage to be limited, for battery life. Noisy thing.

Would wiring two batteries in parallel more than double their lives? So you're just dipping into 200 amp hours. Know what I mean?

I've only ever known one leisure battery freeze up, a posh £700 quid one. That was only after minus ten for several days.

Off grid batteries are getting better so I guess we'll all have smarter kit in a few years.

 
take it in house bench charge it on saturday night and leave to sit for around 6 hours before use

scr r great but every now again take the battery in to fully charge it as a 6 month old battery should have lots life in it yet

 
It's certainly safe on older vehicles. Not sure about fancy new ones. Can't see why not, that's all that happens to it while the engines running. However, manufacturers normally say take them out and charge in a safe place, with screws out of the top etc.

If you leave leisure battery in, you'll be charging that at the same time (maybe).

 
Well just found out that if the vehicle battery i am using drops below 13 the TECH 3 scr i have fitted doesnt kick in and charge tye leisure battery.
Is it safe to charge the vehicle battery whilst its still wired in place?
I disconnect the terminals linked to my system on my leisure battery when I charge it. Dunno if that makes any difference, but I do it anyway.

 
Well just found out that if the vehicle battery i am using drops below 13 the TECH 3 scr i have fitted doesnt kick in and charge tye leisure battery.
Is it safe to charge the vehicle battery whilst its still wired in place?
The idea behind the intelligent relay is that it gives priority to charging the vehicle's battery. In reality, the relay will kick on very soon after the vehicle has started, even if the starter battery is low on charge. An alternator is very good at pushing out more than enough current to charge both batteries together.

An intelligent VSR will disconnect the batteries when the voltage of the vehicles battery drops to 12.8 volts. So it will not be an issue to charge the leisure battery with all terminals connected.

In fact the vsr that I now have is bi-directional, so when I put the leisure battery on to charge the van battery will also get topped up.

 
@spruce 3mtr Split Charge Kit Durite Intelligent VSR 110amp Pro Ready Made Leads T4 T5 is the the sort of set up you are using? Does this one need wiring to an alternator or just vehicle battery to leisure battery?
Also (just curious) why does a battery need to stand for a couple of hours after charging?
I'm using the M Power VSR. The Durite is also the same. Its a 140 amp unit and is also bi-directional. I have wired in an on/off switch into the earth wire of this vsr so I can switch it off if I want to.

The battery doesn't need to stand for a couple of hours before charging. What I meant was that after you have get home, the leisure battery needs to rest (no charging or discharging) for a couple of hours (4 is recommended) before putting a volt meter or multimeter across it the read the voltage and hence the actual state of charge of the battery.

Your VSR just needs its feed wire from the starter battery.

Things are going to get more difficult for us in the future with stop/start vehicles becoming more popular to meet emission regulations. (I read somewhere that the US FED is requiring all small vehicles to be stop/start by 2018.) Various manufacturers are doing different things, but battery charging is set to change from the norm today. The ECU is given control over when to charge the battery and when not to. So the ECU will monitor the starter battery's condition, not that of an auxiliary battery connected to it. If the starter battery is fully charged then a second battery will get no charge even if its flat.

Some cleaners on the forums have already experienced issues with new Ford Custom.

I'm not sure how this will effect the motor home market as most of these units use leisure battery banks to supply on board accessories which will need charging by a vehicle on the move. For us we may end up having to charge our leisure batteries from a power point at home each evening and not have an alternator charging option at all.

 
How many miles are you doing to keep it charged? I don't do a lot of miles, mine charges through the van battery as I drive, but I still put my leisure battery on charge twice a week.
Someone on an Australian motor home forum once said that it will take a journey of 750kms to fully charge a flat leisure battery.

A few years ago my leisure battery was about 75% charged when I set off on a trip to the south coast. My leisure battery was fully charged at around the 250 mile mark. This is always difficult to translate as the fuller a battery gets the less charge it accepts. So much of the latter phase of the charging cycle was on minimal charging. The battery continued to be charged at 1/3rd of an amp for the next 250 miles, so I decided my battery was fully charged once the alternator voltage was a 14.4 volts and the battery was accepting 1/3rd of an amp. (It took just under 5 hours traveling time to reach this point of being fully charged.)

 

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