Starter battery drain

[Huyrob]

Apologies for lengthy post but here goes.
Last summer my old starter battery was letting me down so bought a new platinum heavy duty 60ah.in nov 2019. After about 3 weeks this let me down , showing under 11v. Took it back to the factors and they confirmed 2 cells were duff and they replaced it confirming they’re had very few problems with the make and sold many.
Put new battery on in December and since then I am still getting a constant problem with drain.
When I had the bus mot’d in March I asked them to check for a parasitic drain and they found none.
Still having problems I charged it up and took it back to factors who said it was showing 100%.
Still problems so,
Last week I had a mobile auto electrician come out to check and he found no drain.think he said less than 3 milliamps
Some info :-
1. Had a new loom fitted last March
2. My regulator throws out about 14.5volts
3, I have a sergeant power source thingy for lights , leisure etc.which also charges leisure battery, I have a permanent 240 v connection to keep leisure battery topped via the Sergeant unit.
4. Earth straps , battery terminal clamps all sound.
5. Starter battery only serves engine, lights and one plug in socket that is only live when ignition is on.
6. I have a durite split relay switch.

My auto electrician was not able to confirm but thought it was another faulty battery and suggested I get a Varta,
I did some tests over the last couple of weeks:-
After charging up to 13.85 v AND DISCONNECTED
Day 1 ...13.85
Day 2...13.22
Day 3....13.09
Day4.....13.02
Day 5...12.97
Day 6.....12.92
Day 7...12.89
Day 8...12.84
Day 9....12.80
So all appeared good

I then reconnected terminals
Day 11...12.68
Day 12....12.6
Day13....12.5
Day14...12.3
Day15...12.16
Day16...12.01
So problems showing.
I then recharged to 13.5 v and put a load tester on (just acquired) and it read Good
Connected terminals
Day 1....13.04
Day 2....12.99
Day3....12.7
Day 4....12.54
Day 5....12.50
Today 12.42. Put load test on and it was, as expected, just into the weak zone.

I am baffled, clearly there is a drain ,though 2 different people have said no or negligible drain.
The battery seems ok when disconnected.
Everything seems to point to the battery but it is fine under load when charged
Any suggestions would be much appreciated.

 

[67panel]

Last bus I had with that fault it was the radio memory intermittently drawing excessive amps

 

[vwsunseeker]

Hi, 12 v at the battery is fine to engage the starter motor, does the starter engage and cranks slowly or does the solenoid just click or is there nothing when trying to start?

Voltage drop is very common in our old busses when trying to engage the starter motor due to the way the current travels

check out your ignition switch and fusebox wiring and measure for voltage drop you may also need a hard start relay kit


https://www.heritagepartscentre.com/uk/ac9112917-hard-start-relay-kit-12v.html

cheers

 

[Huyrob]

Hi 67
Will take out radio to see, but is 3 milliamps going to drain in such a short time?
Grateful for your input .

 

[Huyrob]

Hi 62
No problems with starting , starter motor works great. My problem is why is voltage dropping when connected yet holds when disconnected and ...
drops voltage when no discernable parasitic drain.
Surely a battery fully charged and healthy with 3 milliamps max drain should hold charge of 12.6 or above for more than 7 days...or am I wrong ?
Thanks for your input much appreciated.

 

[vwsunseeker]

Hello,

3 milliamps is to much............what modern stuff do you have in the bus ? i would start by connecting amp meter over negative pole and pull fuses power supplies ect to see amp draw reduce as you isolate stuff.

cheers

 

[ozziedog]

I’d start by putting an in line switch in the power cable to the radio or just take the fuse out then do the tests over a period of days. Or possibly disconnect the battery and test that over a period of days but charged fully but disconnected. It does sound a bit weirdo weirdy don’t it. Makes you wonder if the first N ew battery realLy was as bad as they said or if the person or the equipment wasn’t testing properly and just did a nice PR for the company trying to please a customer and just swap the battery . A simple check without getting tooooo complicated, pop the earth off the battery, connect an indicator bulb or similar in a bulb holder between the earth lead and the earth terminal, if you can see it light up “”at all “” then your drain is too much and you can then remove fuses one at a time to narrow it down and track your fault that way. Similar to above but more primitive.

Ozziedog,,,,,,,, I mostly do primitive :mrgreen:

 

[Huyrob]

Thanks 62 and Ozzie
I will try all the suggestions. I hadn’t gone down the route of pulling fuses as I accepted at face value what the garage and auto electrician man said ie. no drain.Will do now though.

 

[ozziedog]

Thanks 62 and Ozzie
I will try all the suggestions. I hadn’t gone down the route of pulling fuses as I accepted at face value what the garage and auto electrician man said ie. no drain.Will do now though.

As suggested above by Davi (67panel) you may be unlucky enough to have an intermittent fault, because it’s ever so hard to track down a fault when it’s not there.

Ozziedog,,,,,,,,,,,keep us in the loop taaa :mrgreen:

 

[Huyrob]

So.
Put a light on between -ve clamp and -ve battery post and there was quite a bright light. Pulled fuses out and eventually found pulling the fuse for the R Front headlight had an effect, the lamp lit less brightly and the Durite relay clicked.Put the fuse back in the light remained on but no clicking. ( should say I had a new loom and fuse box with blade mini fuses fitted last year by Iain Burns )so felt connections would be good.
Decided to check the Durite relay.Took it’s main fuse out and there was a tiny glow on the light, with fuse in the glow was slightly more.
Took Durite cover off and found both connections weren’t even finger tight, the nuts that are supplied with the unit are far too large and makes it virtually impossible to get a spanner on ...obviously the PO or installer didn’t bother. Put smaller nuts on and put it back.
Checked with the light again and with fuse in or out I got 15 small pulses of light then light went off. Took probe off and then back on same number of pulses. Did this several times.
I had then planned to recharge batteries and see how it went.
In the meantime got Ozzies message reiterating what Davi Panel 67 had said so took the detachable front off radio and checked the light...
No light at all!
So not sure whether it is radio/ intermittent fault/Durite loose bits. Have put on charge and will see what happens when I connect charged battery up.
Oz did mention about charging and leaving battery disconnected, I had done that as mentioned in my OP and the battery held a good charge.

 

[ozziedog]

At least you can take the front off to eliminate the radio, I’m wondering if the pulses might be to park an electric Ariel or similar, any evidence of an alarm in there ? And how many live feeds have you got to the radio?

Ozziedog,,,,,,, Bmy the way ,, I knows nuffink bout them leckertricks :mrgreen:

 

[Huyrob]

No elec aerial Oz and I took of the hi tec alarm last year.No other modern bits that I know of.
Battery charged up last night to 13.22 and left disconnected.Today 13.07 so that’s ok?
No light showing so hopefully no drain.
Connected battery so will see how it goes over next few days.Hoping it was the loose Durite fittings but don’t know enough to know if that could have caused the drain.

 

[ozziedog]

If it stays reasonable then maybe we can assume it’s something to do with your radio, are there any other functions on it that might cause it to scan every so often? Like Bluetooth or a phone hookup etc. Maybe just live with taking the head unit front off when you pull out the ignition key and put them back in together as a habit. Wondering if the alarm at some point made the headlamps flash ?

Ozziedog,,,,,,,,,,,Lots of ifffs buts and maybes

 

[67panel]

Its the permanent live feed to radio memory that stays live even with front off, disconnect radio completely to test.

 

[ozziedog]

Its the permanent live feed to radio memory that stays live even with front off, disconnect radio completely to test.

As Davi says above, but maybe a switch so you know it’s disconnected, I guess you could group the lives then switch all of them off at a master stroke but you’ll loose your memory function and clock and stuff.

Ozziedog,,,,,,,,,sounds like you’re close! :mrgreen: