Split charge relay

[craig at pure]

has any one used a split charge relay? pros and cons please.

 

[Green Pro Clean Ltd]

Always.

Pros: Charges your battery.

Cons: None for me.

FYI. New Water Genie Digital Controllers have built in split charge relay.

 

[craig at pure]

thats good for me, do you have a link for this?

 

[Green Pro Clean Ltd]

Water Genie Pump controller Built in Batt Charger

 

[spruce]

As I've mentioned before I have a 110 amp h leisure battery on a split charge relay. Our pumps on the van draw around 4 to 4.5 amp an hour each.

If I manage a 6 hour day on my own and my pump actually works for 3 hours of that day actually on the glass then I can presume I have used 12+ amps from my battery. If my battery was fully charged the previous night, then at the end of the day I would estimate that I have approx 98 amps left in the battery.

On my way home I see that my alternator is charging the battery by about 6 amps. At that rate I would theoretically need to drive for 2 hours to replace the charge I had used that day. However if it only takes 15 minutes to get home, then I have only replenished the charge in the battery by 1.5 amps. If I drove back to the same area the following morning I would put a further 1.5 amps into the battery. So I took 12 amps but only replaced 3 amps.

I know its a lot more complicated than that as a discharged battery will accept a higher charge rate. As the charged battery gets 'fuller' then the rate it will accept a charge reduces. My battery when nearly fully charged on my intelligent battery charger will only accept about 0.5 amps from the alternator.

It was once stated in an Australian Motor Home magazine that it would take a journey of 750km to fully recharge a discharged (flat) leisure battery. I can vouch for that on a trip I did in my van to London. I started off with a 75% charged battery and it was fully charged by the time I got to London - a distance of 250 miles. It took that distance, around 5 hours driving time, to put back about 35 amps.

My van alternator will supply the leisure battery with exactly the same charge rate, whether its traveling down the motorway or idling at traffic lights. So taking it slowly saves fuel and gives your battery a longer charge, but the results aren't big numbers.

Remember, alternators don't make efficient battery chargers. They just barely do the job. They are there to power all the accessories in the vehicle and whilst doing so also replenish the little power taken by the starter motor from the starter battery. (The latest generation of smart alternators controlled by the ecu are a little different now. The starter battery is also used to power accessories.)

So you may rightly ask why I bother with a split charge relay or a VSR (voltage sensing relay) which is more popular now.

It just gives a bit of peace of mind. On both occasions the leisure battery had failed we were able to let the engine of the van run on idle which provided sufficient current to power both pumps to finish the job. Without a VSR we wouldn't have been able to do that.

When I had the wfp trailer often the battery would end up flat during the working day. My little Suzuki used to idle in the street quite often whilst I finished the last couple of houses to keep the pump going.

When son in law did window cleaning he had a round trip of 18 miles and then whatever running around he did. I estimate it would have been another 10 to 12 miles.

He also used his van as everyday transport. He had an 85amp leisure battery in his van and he had to charge it about every 3 weeks or so.

If you have a new model van, especially from 2015 a split charge relay or voltage sensing relay probably won't work on your van.

Grippatank have a few pointers on their website detailing why these will not work on vans with regenerative charging systems and what will work. However, the solution is expensive.

FULL KIT - 12v 30AMP Smart Battery to Battery Charger | GrippaTank Ltd

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[Green Pro Clean Ltd]

My battery stays comstantbat 12.7v andI dont do 700km a day.

TEC 3M - SCR (£12 off flea bay) and the Water Genie controllers arent wired to your alternator they go straight to the battery.

I bow to your superior technological knowledge Spruce but all I know is my SCR does keep my battery charged. (I also use a 110mah batrery)

 

[spruce]

Some windies seem to get SCR's to work and others don't @Green Pro Clean Ltd , even using the same vehicle.You have the added power draw from your electric hose reel.

My son had a Peugeot Partner and we were unable to run his leisure battery without bench charging the battery every couple of days. We also tried to run the pump off his van battery but that flattened in 4 days. We replaced the van battery and tried it again with the same results.

Yet another cleaner had the same van in the south and he only every used his van battery with no issues.

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[mufcglen]

i bought one of the durite intelligent split replay kits 2 years ago and fitted a new 110ah leisure battery at the same time, never touched it or taken it to charge since.

i'd definately recommend getting one of these kits from this seller on ebay rather than the cheap car relays that people fit, they tend to burn out over time,seen it from my days as a grease monkey!

1mtr Split Charge Relay Kit, 140a Voltage Sense Durite Relay with 110amp Cable | eBay

 

[craig at pure]

Thank you all for you feed back.