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Split Charge Relay

Dabber

Active member
Messages
256
Location
Aylesbury
Hi

Will a split charge relay provide all of the battery power required to work on a daily basis or will there be occasions when you might need to charge the  wfp battery through other means.

thanks

Dabber

 
Hi

Will a split charge relay provide all of the battery power required to work on a daily basis or will there be occasions when you might need to charge the  wfp battery through other means.

thanks

Dabber
Yeah, this is the thing - it’s gotta be trial & error. Would do my nut in I think. 

 
Hi

Will a split charge relay provide all of the battery power required to work on a daily basis or will there be occasions when you might need to charge the  wfp battery through other means.

thanks

Dabber


Truthfully, no.

If your 8000 miles includes hours and hours in stationery traffic queues with your engine running, then you might get away with the ocassional charge.

My van does around 6k annual mileage and I put my leisure battery on charge every other night in summer and every night in winter. My Numax leisure battery charger will take several hours each time to fully recharge the battery. There are two of us and 95% of our work is within a 6 mile radius of home. Usually the drive home takes 10 to 15 minutes tops.

When son in law worked with us his trip to work was 10 miles to work and 10 miles home plus the days work. His 85 amp leisure battery was flat after about 3 weeks. Often he had to return home after a couple of hours as his battery died on him. So in all due honesty, the last 25 or so miles gave him a couple of hours work. He was just too lazy to recharge his battery more often.

A leisure battery doesn't like to be charged quickly. After a days work my leisure battery will reach a peak charging rate of about 22 amps for a few moments and quickly drop down to around 7 - 8 amps within a couple of minutes. (Numax advised that a leisure battery shouldn't be charged at more than 10% of its rating. So my 110 amp leisure battery shouldn't recieve a charge of more than 11 amps.) As the battery gets more and more fully charged the charge it will accept reduces. So if I run my pump for an hour and take 4.5 amps from my fully charged battery, it will take my alternator much longer than an hour to put that charge back as the battery will only be accepting a charge of 2 or 3 amps.

 
Truthfully, no.

If your 8000 miles includes hours and hours in stationery traffic queues with your engine running, then you might get away with the ocassional charge.

My van does around 6k annual mileage and I put my leisure battery on charge every other night in summer and every night in winter. My Numax leisure battery charger will take several hours each time to fully recharge the battery. There are two of us and 95% of our work is within a 6 mile radius of home. Usually the drive home takes 10 to 15 minutes tops.

When son in law worked with us his trip to work was 10 miles to work and 10 miles home plus the days work. His 85 amp leisure battery was flat after about 3 weeks. Often he had to return home after a couple of hours as his battery died on him. So in all due honesty, the last 25 or so miles gave him a couple of hours work. He was just too lazy to recharge his battery more often.

A leisure battery doesn't like to be charged quickly. After a days work my leisure battery will reach a peak charging rate of about 22 amps for a few moments and quickly drop down to around 7 - 8 amps within a couple of minutes. (Numax advised that a leisure battery shouldn't be charged at more than 10% of its rating. So my 110 amp leisure battery shouldn't recieve a charge of more than 11 amps.) As the battery gets more and more fully charged the charge it will accept reduces. So if I run my pump for an hour and take 4.5 amps from my fully charged battery, it will take my alternator much longer than an hour to put that charge back as the battery will only be accepting a charge of 2 or 3 amps.


Do you use a split relay @spruce ? This is something I've been wondering too. I have a Pure Freedom van system and was told as long as I give my van a decent run out quite often I should be OK to let the split relay charge my leisure battery. Was wondering if I need to bring it in to give it a good charge. Each morning my battery is reading 13.9/14.0. When I start cleaning it's dropping to around 12.7-12.2

 
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Do you use a split relay @spruce ? This is something I've been wondering too. I have a Pure Freedom van system and was told as long as I give my van a decent run out quite often I should be OK to let the split relay charge my leisure battery. Was wondering if I need to bring it in to give it a good charge. Each morning my battery is reading 13.9/14.0. When I start cleaning it's dropping to around 12.7-12.2


Yes I do. Its a bog standard 140 amp Durite equivalent. It was supplied with 75 amp cables which will be upgraded to 110 amp in the next van. My current van has plenty of excess charging capacity with a 90 amp alternator. When it comes to charging you can only put in a charge equivalent to what the battery will accept. If that battery will only accept 5 amps at 14.4 volts then putting on a bigger alternator isn't going to charge that battery any quicker.

The expert state that you will only get an accurate state of charge your leisure battery is after its been at rest (after charging and before use) for around 4 hours. A fully charged leisure battery will show a voltage of 12.8/12.9v.

I'm afraid all sorts of people make all sorts of claims with regard to leisure battery charging. Just to get this in perspective, an RV motor home magazine reported that a motor home's alternator would need a trip of 750km to fully recharge a flat 85 amp hour leisure battery using a split charge relay.

I don't know what effect these Stirling battery to battery chargers will have on charging rates. I've seen a video of them putting a very high amperage into a leisure battery, but again, according to Numax, they will be ruining the battery with faster charging. They were using a BB1260 putting 60 amps into the battery, 6 times more than Numax recommend.

I prefer to keep my leisure battery between 75% and fully charged. My current leisure battery will be 4 years old in January 2019.

We, as an industry have greater continual demands on our leisure batteries than any leisure application does. A battery to battery charger in a motor home will have much longer to charger the battery/batteries than we do. When they get to their destination they usually have hookup power. Very rarely do they do wild camping. This heavy demand we have is the reason why Numax refuse to give us warranty on a leisure battery used for window cleaning.

 
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All my work is local and my split charge doesn’t provide enough power to kept my battery top up and I have to charge my battery every night, I won’t bother with another split  charge when I change my van. 

 
I have a split charge relay on mine.I do a small amount of miles and most days the van is parked up running the pump all day.

I never have to bench charge my battery infact I don't even have a charger.

It's important to buy and use the right split charge for your van.

 
All my work is local and my split charge doesn’t provide enough power to kept my battery top up and I have to charge my battery every night, I won’t bother with another split  charge when I change my van. 


Yes, you are probably right making that decision.

The first leisure battery I had failed unexpectedly. It happened when we were half way through a large clean we had. We were also a long way from home. The split charge relay 'saved' us as we were able to continue and finish the job running the engine of the van. So for me, that split charge relay paid for itself that day.

I have an upgraded relay now and again its not necessary but its good to have the 'comfort' of knowing that if the battery should fail I have a backup.

The closest caravan outlet from us is 20 miles (40 miles round trip) away. Most of the local motor factors do not keep leisure batteries in stock so order as required.

I could buy a battery from Halfords off the shelf, but according to their recent grading listings that they have signed up to (NCC), their £95 (reduced from £105) 115amp leisure battery is only a class C rated. The specs list it's charging cycles as 80.

https://www.halfords.com/camping-leisure/caravan-motorhomes/electrical-power/halfords-leisure-battery-hlb681

Thats a pretty poor show for a window cleaning battery.

I would rather go for a Numax for £5 more and get a battery with a 500 cycle rating. (Numax doesn't apear to have signed up to NCC rating, but I have had very good service from Numax batteries and would recommend them even although Numax won't warranty their batteries when used by window cleaners.)

https://www.tayna.co.uk/leisure-batteries/numax/xv31mf/

I'm glad Halfords have signed up the the NCC rating. Even their class B 100 amp leisure battery doesn't measure up that much better with 200 cycles

https://www.halfords.com/motoring/bulbs-blades-batteries/leisure-batteries/halfords-leisure-battery-hlb700

Even their top of the range AGM battery doesn't seem to 'cut the mustard.'

https://www.halfords.com/motoring/bulbs-blades-batteries/leisure-batteries/halfords-leisure-battery-hlb800

NCC =

https://www.thencc.org.uk/our_schemes/ncc_verified_leisure_battery_scheme.aspx

 
I have a split charge relay on mine.I do a small amount of miles and most days the van is parked up running the pump all day.

I never have to bench charge my battery infact I don't even have a charger.

It's important to buy and use the right split charge for your van.
I would love to know why some seem to be able to do this and most of us don't, even with a variety of different vans.

For us we take between 20 and 30 amps a day from our battery. For us never to need to recharge it we have to replace exactly what we take out everyday. Our to work and return home takes us on average 15 minutes each way. There could be another 15 minutes traveling between jobs/engine running during the day.

If so I would need to replace that 20 to 30 amps in 45 minutes. That means I would have to charge my leisure battery at between 26 and 40 amps an hour. My volt/amp meter gauge will only tell me I'm charging my battery on the way home at 7 or 8 amps. Even if I take the ride back to work the following morning I'm not putting back what I took out the previous day.

Numax once told me that Its not recommended to charge a leisure battery at more than 10% of its capacity. So the maximum I should be charging my battery is 11 amps.

The other 'negative' is that the fuller a battery gets the lower the charge rate it will accept. So if I draw 4.5 amps for an hour from my fully charged leisure battery, it will take much longer for the van's alternator to replace the current drawn as that battery will only accept a small charge of 2 or 3 amps on recharging.

.

 
I would love to know why some seem to be able to do this and most of us don't, even with a variety of different vans.
 
For us we take between 20 and 30 amps a day from our battery. For us never to need to recharge it we have to replace exactly what we take out everyday. Our to work and return home takes us on average 15 minutes each way. There could be another 15 minutes traveling between jobs/engine running during the day.
If so I would need to replace that 20 to 30 amps in 45 minutes. That means I would have to charge my leisure battery at between 26 and 40 amps an hour. My volt/amp meter gauge will only tell me I'm charging my battery on the way home at 7 or 8 amps. Even if I take the ride back to work the following morning I'm not putting back what I took out the previous day.
 
Numax once told me that Its not recommended to charge a leisure battery at more than 10% of its capacity. So the maximum I should be charging my battery is 11 amps.
 
The other 'negative' is that the fuller a battery gets the lower the charge rate it will accept. So if I draw 4.5 amps for an hour from my fully charged leisure battery, it will take much longer for the van's alternator to replace the current drawn as that battery will only accept a small charge of 2 or 3 amps on recharging.
 
.
I've never had to charge my battery so far. It's a 110 Numax and I work 7 hours a day, (albeit on my own) and it's 18 months old.
I do about about 10/20 miles per day and a 40 mile motorway run at weekend (gives the DPF a blast).
Access to the battery is a bit of a pain so it's more of a disincentive to charge it regularly, so I'm just going to see how it goes until it dies.
If I get 2/12 to 3 years out of it I'll be happy.
If it dies tomorrow I'll have to pull my finger out and charge it more often.

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I have a 110AH Bosch leisure battery I bought from Euro. I bought a split charge but I haven't bothered fitting it just yet.... It's on the long list of adaptations I want to make to the van.

My battery is under the passenger seat, i've got a new dispatch so the passenger seat springs up which is a cracking space for the battery. I got chatting to an AA bloke who was recovering my old van, he told me how his mate down in Bristol is a window cleaner and was having trouble with his battery, where he bench charged it every day the battery sometimes ran too low and caused damage. He had just installed a split charge with him but he removed the relay thing. He said he removed the relay because modern alternators kick out far more power than one battery needs, there should be no need to have it only charge your leisure battery when the van battery is full.

I wonder if the guys not doing much mileage but never charging their battery have a faulty relay which means they are constantly charging the battery 100% of the driving time.

 
I have a 110AH Bosch leisure battery I bought from Euro. I bought a split charge but I haven't bothered fitting it just yet.... It's on the long list of adaptations I want to make to the van.

My battery is under the passenger seat, i've got a new dispatch so the passenger seat springs up which is a cracking space for the battery. I got chatting to an AA bloke who was recovering my old van, he told me how his mate down in Bristol is a window cleaner and was having trouble with his battery, where he bench charged it every day the battery sometimes ran too low and caused damage. He had just installed a split charge with him but he removed the relay thing. He said he removed the relay because modern alternators kick out far more power than one battery needs, there should be no need to have it only charge your leisure battery when the van battery is full.

I wonder if the guys not doing much mileage but never charging their battery have a faulty relay which means they are constantly charging the battery 100% of the driving time.


This is all about those new vans with smart alternators and regenerative braking. These alternators, when they are instructed to charge the starter battery kick out higher voltages than an ordinary leisure battery is designed to tollerate. They will also never fully charge a leisure battery because they don't know its there even if its in circuit. That's when a battery to battery charger works, but they are expensive.

These split charge relays are basically just a relay or switch. They just switch a current on when the engine is running and off when it isn't. (My first split charge relay failed and even although I don't do much mileage it didn't take long before I realised there was a problem. Now I have a volt/ampere meter connected up I can immediatlely see if I have a charging problem with my relay.) The rest is down to the alternator. Alternators are not very good battery chargers as they don't need to be. All they need to do is put back the little power taken from the battery when starting the engine. (If your engine starts in 3 seconds then you have drawn the same amount of power your Shurflo pump uses in an hour. A starter battery just needs to deliver a very high current for a brief moment.) Alternators are good at keeping all the electrical goodies in the car/van supplied with current when you need them - the battery doesn't do that.

On new diesels with regenerative braking, things are different. The battery is more involved with supplying current for the onboard equipment, especially when the battery is more than 80% charged.

 
 
This is all about those new vans with smart alternators and regenerative braking. These alternators, when they are instructed to charge the starter battery kick out higher voltages than an ordinary leisure battery is designed to tollerate. They will also never fully charge a leisure battery because they don't know its there even if its in circuit. That's when a battery to battery charger works, but they are expensive.
 
These split charge relays are basically just a relay or switch. They just switch a current on when the engine is running and off when it isn't. (My first split charge relay failed and even although I don't do much mileage it didn't take long before I realised there was a problem. Now I have a volt/ampere meter connected up I can immediatlely see if I have a charging problem with my relay.) The rest is down to the alternator. Alternators are not very good battery chargers as they don't need to be. All they need to do is put back the little power taken from the battery when starting the engine. (If your engine starts in 3 seconds then you have drawn the same amount of power your Shurflo pump uses in an hour. A starter battery just needs to deliver a very high current for a brief moment.) Alternators are good at keeping all the electrical goodies in the car/van supplied with current when you need them - the battery doesn't do that.
 
On new diesels with regenerative braking, things are different. The battery is more involved with supplying current for the onboard equipment, especially when the battery is more than 80% charged.
Glad I never followed his advice now dude.

Another thing I thought about was the cold. All these chaps not removing the battery in the cold will risk frost damage I guess. Also doesn’t the battery lose some of its charge overnight during the winter months?


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Glad I never followed his advice now dude.

Another thing I thought about was the cold. All these chaps not removing the battery in the cold will risk frost damage I guess. Also doesn’t the battery lose some of its charge overnight during the winter months?


Sent using the Window Cleaning Forums mobile app


https://windowcleaningforums.co.uk/topic/22375-split-charge-relay/

Our batteries are never removed from the vans. But they sit on a thick piece of conveyor belt rubber that insulates them from the cold steel van floor. The starter battery in the engine compartment just sits on a steel battery mount base.

I have never heard of a lead acid battery freezing up, even in the depths of a winter polar vortex in middle America. But the colder the battery gets the lower its capacity or ability to provide power. A boarderline battery working through summer will fail when the first frost of winter strikes. This is why the motor trade always stock up with batteries as winter approaches.

Cold temperature increases the internal resistance and lowers the battery's capacity. A battery that provides 100 percent capacity at 27°C (80°F) will typically deliver only 50 percent at –18°C (0°F). The momentary capacity-decrease differs with battery chemistry. It doesn't necessarily mean that that battery will not work as before when temperatures are higher.

We add another facet to this situation. We require more power to start an engine when its freezing than when its warm - oil is thicker etc. I believe that our batteries in our vans loose about 25% of their capacity in our just above freezing vans in winter. So my 110 amp leisure battery is good for about 25 amps, hence the reason why it gets plugged into the charger every night in winter.

Our pumps require a little more power to push cold water to the windows than it does in summer when the water is 10 or 12 degrees warmer. On the same controller flow setting the flow through my jets was much greater when the water was at 35 degrees C compared to when it was at 9 degrees C.

Have you also noticed that starter batteries are finding their way into the driver's and passenger areas of the vehicle more and more. Not only does this free up space in the engine compartment, but it also protects the battery from high engine temperatures. Batteries don't like heat either.

.

 
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https://windowcleaningforums.co.uk/topic/22375-split-charge-relay/

Our batteries are never removed from the vans. But they sit on a thick piece of conveyor belt rubber that insulates them from the cold steel van floor. The starter battery in the engine compartment just sits on a steel battery mount base.

I have never heard of a lead acid battery freezing up, even in the depths of a winter polar vortex in middle America. But the colder the battery gets the lower its capacity or ability to provide power. A boarderline battery working through summer will fail when the first frost of winter strikes. This is why the motor trade always stock up with batteries as winter approaches.

Cold temperature increases the internal resistance and lowers the battery's capacity. A battery that provides 100 percent capacity at 27°C (80°F) will typically deliver only 50 percent at –18°C (0°F). The momentary capacity-decrease differs with battery chemistry. It doesn't necessarily mean that that battery will not work as before when temperatures are higher.

We add another facet to this situation. We require more power to start an engine when its freezing than when its warm - oil is thicker etc. I believe that our batteries in our vans loose about 25% of their capacity in our just above freezing vans in winter. So my 110 amp leisure battery is good for about 25 amps, hence the reason why it gets plugged into the charger every night in winter.

Our pumps require a little more power to push cold water to the windows than it does in summer when the water is 10 or 12 degrees warmer. On the same controller flow setting the flow through my jets was much greater when the water was at 35 degrees C compared to when it was at 9 degrees C.

Have you also noticed that starter batteries are finding their way into the driver's and passenger areas of the vehicle more and more. Not only does this free up space in the engine compartment, but it also protects the battery from high engine temperatures. Batteries don't like heat either.

.
Far too much science there for me dude. My logic was simple... In winter if you leave your lights on the battery goes flat quickly, in summer you would have a good few hours. I was once told the battery drains faster in cold weather. ?‍♂️

 
Far too much science there for me dude. My logic was simple... In winter if you leave your lights on the battery goes flat quickly, in summer you would have a good few hours. I was once told the battery drains faster in cold weather. ?‍♂️


@spruce is way too clever for us plebs mate. It's straight over my head as well. I'm just a simple windy ?

 
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