Leisure battery not charging

[pusd]

Hi, I've been adding a few bits & bobs to make my Mk7 transit into an occasional weekend camper while keeping the practicality of a van (temporary beds et).....

I fitted a new leisure battery, the 'biggest' that would fit under the drivers seat - 60AH I think along with an 'itelligent' split charge relay - which is working and only opens when the engine is running.
I have fitted the van with a fusebox & sub harness and just fitted a new Eberspacher D2 heater.

This weekend the leisure battery flattened overnight with the Heater & a small portable coolbox.

When we drove the van the next day, an electrical burning smell became apparent, I pulled over,checked the electrics under the seat & all appeared ok. Set off again, & again a smell of burning electrics, the split charge relay was a bit warm so I replaced the fuse (between master battery & charge relay) with a lower rating - 10A just to be safe.
This seemed fine, the fuse never blew & no smell.
I later replaced the 10A fuse with the stock 20A fuse & all is fine except that the battery is not charging or not holding charge, the relay is opening & closing correctly & there is a healthy 14.2 - 14.5v at both batteries when the vehicle is running. The vehicle has been run for 7-8 hours or more since the weekend but the leisure battery still has little charge?

Am I doing anything wrong or have I missed something, does the leisure battery just need a good charge at home??

By the way the (Brocott) split charge relay is rated at 30 Amp, has 25Amp cable from both batteries to the relay and there are two fuses of 20 Amp between each battery & the relay (as supplied) So why the burning smell??

Any comments welcomed,
cheers, Phil

[dachre]

A Leisure battery takes a trickle charge to charge it up so it can take a long time to charge via the engine. Thats why you are only using 25Amp leads.

But it should of been charged (or you should of chrged it up before) when you put it on and i cant see why it discharged overnight with the heater and cool box.

Is the battery ok?... is it holding charge if left unconnected?

The smell means to me its the relay or too much current/draw throught the cables.

can you find out where the smell is comming from exactly?... might be loose or shorted wires.

[pusd]

A Leisure battery takes a trickle charge to charge it up so it can take a long time to charge via the engine. Thats why you are only using 25Amp leads.

But it should of been charged (or you should of chrged it up before) when you put it on and i cant see why it discharged overnight with the heater and cool box.

Is the battery ok?... is it holding charge if left unconnected?

The smell means to me its the relay or too much current/draw throught the cables.

can you find out where the smell is comming from exactly?... might be loose or shorted wires.

Hi & thanks for the reply.

The battery appeared to be fully charged when I received it (12.5v), I fitted it all a couple of months ago but it has only been powering an 8w flourescent light (on all night) but without problems.

As I say the cables supplied are 25Amp and are fitted with 20 Amp fuses, upon closer inspection, the relay internals look a bit black & scorched which is odd as it is rated at 30A but the 20A fuses never blew?
Would the battery really draw nearly 20A to charge it up from a discharged state?

I have since contacted Brocott, who (while not giving any reason or explanation for this) said to send it back and they will replace it & cover the cost of my postage.
Top service but I'm still baffled.

Phil

[Kerunk]

....Would the battery really draw nearly 20A to charge it up from a discharged state?...

Phil

Your battery will draw as much as it can from the source to get itself back up to full capacity. Therefore when you start up the engine and the voltage rises sufficiently to trigger the split charge relay, the flat leisure battery will draw as much as it can (disregarding technical internal resistance calculations) from the "source" (which in this case is the alternator AND your main battery).

So, the answer is yes it can draw an awful lot of current.

Cheers,

Rob

[pusd]

....Would the battery really draw nearly 20A to charge it up from a discharged state?...

Phil

Your battery will draw as much as it can from the source to get itself back up to full capacity. Therefore when you start up the engine and the voltage rises sufficiently to trigger the split charge relay, the flat leisure battery will draw as much as it can (disregarding technical internal resistance calculations) from the "source" (which in this case is the alternator AND your main battery).

So, the answer is yes it can draw an awful lot of current.

Cheers,

Rob

Ok, great stuff, thanks.

BUT why is the leisure battery still flat?
Is there any preference for charging a leisure battery - high or low Amps, a friend said they need lots of current or they don't charge fully, is this right or just crap?!

Cheers, Phil

[Kerunk]

BUT why is the leisure battery still flat?
Is there any preference for charging a leisure battery - high or low Amps, a friend said they need lots of current or they don't charge fully, is this right or just crap?!

Cheers, Phil

You say that you leave a light on all the time? An 8W light left on for say 10 hours will use around 6 amps over that time but not enough to flatten it completely if it is recharged every day. Cold weather can cause a battery in a poor state to fail (my leisure battery has died over the winter). Get it sent back and ensure that you are charging the new one enough.

When your friend says they need a lot of current he is partly right, look at current as "the content" of your battery and volts as "the pressure". Apply enough volts and the current gets forced into the battery, a 60A/H battery will hold (surprise) 60Amps! and will deliver this as required eg. 60Amps for 1 hour or 1Amp for 60 hours or any combination in between.

Leisure batteries are different to the battery you use to crank the engine and special rules apply, have a look at this link: http://www.a-tconsulting.co.uk/caravan_ ... ttery.html It gives a lot of good information.

Cheers,

Rob

[pusd]

You say that you leave a light on all the time? An 8W light left on for say 10 hours will use around 6 amps over that time but not enough to flatten it completely if it is recharged every day. Cold weather can cause a battery in a poor state to fail (my leisure battery has died over the winter). Get it sent back and ensure that you are charging the new one enough.



Cheers,

Rob

Thanks Rob, I understand the basic principles of vehicle electrics - watts/volts/amps etc.
Since the battery discharged over the weekend, there has been no drain on the battery, previously the light was only on overnight (my wife works nights & takes the dog to work!), I'm just not sure why is hasn't charged, when I had a look the other day the leisure battery voltage was only 9v!

I'll take it out, give it a full charge & give it a try when we get the replacement split charge relay (this one is a bit burnt inside despite 30 A rating & fused at 20 A)

Thanks again, Phil

[100 T280]

This weekend the leisure battery flattened overnight with the Heater & a small portable coolbox.

Eberspächer D2 will use negligible amount of power, mine has run constant for 5 days without flattening the batteries.
However, those electric peltier system cool-boxes draw an incredible amount of power, and mine will completely flatten two fully charged 110Ah leisure batteries within 24 hours.
By using a cable with a relatively small cross-sectional area, you'll get a voltage drop commensurate with length, and as it's the potential difference between power source (in this case, alternator) and battery which creates charge current, you'll in effect, reduce the charge rate by using sub-standard cable.
I've used an "intelligent" split-charge relay to actuate a 120A relay between the van batteries and leisures, with an 80A fuse at EACH end of the positive cable. Even so, after fully discharging the leisures, it'll take maybe 200 miles to fully replenish them.

[pusd]

This weekend the leisure battery flattened overnight with the Heater & a small portable coolbox.

Eberspächer D2 will use negligible amount of power, mine has run constant for 5 days without flattening the batteries.
However, those electric peltier system cool-boxes draw an incredible amount of power, and mine will completely flatten two fully charged 110Ah leisure batteries within 24 hours.
By using a cable with a relatively small cross-sectional area, you'll get a voltage drop commensurate with length, and as it's the potential difference between power source (in this case, alternator) and battery which creates charge current, you'll in effect, reduce the charge rate by using sub-standard cable.
I've used an "intelligent" split-charge relay to actuate a 120A relay between the van batteries and leisures, with an 80A fuse at EACH end of the positive cable. Even so, after fully discharging the leisures, it'll take maybe 200 miles to fully replenish them.

Ok, thanks, maybe it was the coolbox that has a lot of current draw - I assumed that it would be negligable!

The leisure battery is on charge tonight and the damaged relay has been sent back for replacement.

Is 20A enough to recharge the battery or should I go bigger?
Using the intelligent relay to operate a conventional relay is a great idea!

Cheers, Phil

[darkbluevanman]

This weekend the leisure battery flattened overnight with the Heater & a small portable coolbox.

Eberspächer D2 will use negligible amount of power, mine has run constant for 5 days without flattening the batteries.
However, those electric peltier system cool-boxes draw an incredible amount of power, and mine will completely flatten two fully charged 110Ah leisure batteries within 24 hours.
By using a cable with a relatively small cross-sectional area, you'll get a voltage drop commensurate with length, and as it's the potential difference between power source (in this case, alternator) and battery which creates charge current, you'll in effect, reduce the charge rate by using sub-standard cable.
I've used an "intelligent" split-charge relay to actuate a 120A relay between the van batteries and leisures, with an 80A fuse at EACH end of the positive cable. Even so, after fully discharging the leisures, it'll take maybe 200 miles to fully replenish them.

Ok, thanks, maybe it was the coolbox that has a lot of current draw - I assumed that it would be negligable!

The leisure battery is on charge tonight and the damaged relay has been sent back for replacement.

Is 20A enough to recharge the battery or should I go bigger?
Using the intelligent relay to operate a conventional relay is a great idea!

Cheers, Phil

I agree, was using one of those types of cool boxes at a trackday, was on (after parking up) for about 3 hour, came to start van, could deffo tell the battery was towing, good job was a good starter!...

jumped someone off the other day, I have intelligent split, used the 2nd batt' with the engine running, you could hear the thing tripping in and out like a good 'un, thinking on now, I wonder if this has done damage (was a lot of cranking going on!), I still have to fit a couple of led voltage readouts (one for each batt'), then can monitor what's going on...

[pusd]

Leisure battery is fully charged & held a steady 13.4v for 5 mins. I'll check again in the morning.

I also checked the coolbox instructions - ratedat 48w, not massive but I guess 4A drain overnight is 40A or so, added to the 32w max (drain) of the D2......

I'm still unsure why the smell the following day (why the relay rated at 30A but fused to 20A started to melt....) and why the battery never took any charge, despite the albeit damaged, relay was still working - increased internal resistance perhaps???

Thanks for your replies all, Phil.

[transititus]

hi, having had similar problems with intelligent relays in past i now run a 70amp intelligent relay and only use standard batteries as leisure batteries cannot cope with voltage transfer as relay opens?? i think you need a charge regulator to do what you want??

[100 T280]

Leisure battery is fully charged & held a steady 13.4v for 5 mins. I'll check again in the morning.

I also checked the coolbox instructions - ratedat 48w, not massive but I guess 4A drain overnight is 40A or so, added to the 32w max (drain) of the D2......

I'm still unsure why the smell the following day (why the relay rated at 30A but fused to 20A started to melt....) and why the battery never took any charge, despite the albeit damaged, relay was still working - increased internal resistance perhaps???

Thanks for your replies all, Phil.

The 48W draw is constant, the Eberspächer D2 will only draw 32W whilst initially firing with the glow-pin operating. Power draw is much lower when running, max. 22W and as little as about 5W if just ticking over on low.