Taking care of my vehicle battery

chenderson1965

chenderson1965

Free Member
Joined
Aug 3, 2019
Posts
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Location
Nottingham
Funster No
62,953
MH
N+B Arto 79R A Class
Exp
10 years with hires, Newbie owner
Hi.
This year I fitted an extra solar panel in the hope that this would keep my leisure and vehicle batteries topped up. I also upgraded my solar controllers to MPPT and already have a battery master fitted.

As the days have got shorter and the sun has got lower, overnight the vehicle battery drops to 12.0v and then recovers to about 12.6/12.7v if the weather isn’t too gloomy. I guess it will get better than that from here but that seems like quite a lot of discharge.

The van is parked outside the house but it isn’t easy to get a mains cable out to it because it’s in the street so I have to cross a pavement etc.

I have a couple of questions, therefore:-

1) Will it be damaging the vehicle battery to be constantly charging and discharging it to that degree?

2) Would I be better off finding a solution to keep it trickle charged via mains cable (either permanently or periodically)?

Thanks
Chris
 
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12 volt is a bit low I think?? What is drawing the power?? Is it just the parasitic drain on engine??
Is it both engine and leisure batteries??
 
Sundowners said:
12 volt is a bit low I think?? What is drawing the power?? Is it just the parasitic drain on engine??
Is it both engine and leisure batteries??
Click to expand...
Don’t know what’s draining it. Combination of self discharge and electronic security devices I guess. Seems a lot but I don’t have the knowledge to track it down myself or the appetite to pay for diagnostic work. The leisure batteries don’t discharge much so they quickly get to the level where charge is diverted to the vehicle battery by the battery master to top it up.
 
Your vehicle battery shouldn't drop overnight to 12 v unless there is some major draw in it .
I think the vehicle battery may be damaged already ,well ,past it's useful use by date.
.
 
Trickle charger is definitely the answer we use this charger.

Amazon product ASIN B00DW6RHN2​

We use one of these and it's brilliant keeps both Hab and Engine battery fully charged.

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Jimbohorlicks said:
Your vehicle battery shouldn't drop overnight to 12 v unless there is some major draw in it .
I think the vehicle battery may be damaged already ,well ,past it's useful use by date.
.
Click to expand...
I've had the battery tested and apparently it's fine.
 
robnchris said:
Trickle charger is definitely the answer we use this charger.

Amazon product ASIN B00DW6RHN2​

We use one of these and it's brilliant keeps both Hab and Engine battery fully charged.
Click to expand...
Thanks. The van has a trickle charger fitted already (in the form of the battery master) . The issue is getting a cable to it.
 
It sounds like your battery is on its way out if it drops that quickly, how much solar and what’s the battery amps... age of battery..?
 
chenderson1965 said:
I've had the battery tested and apparently it's fine.
Click to expand...
How was it tested..? If it was a drop discharge by a garage it will probably show ok... but a normal amp discharge in the van will show up a bad battery...
 
12V = very low = no capacity left
12.6V = fully charged
It would seem that the battery's capacity is very much reduced, especially if it can recharge in a day of today's solar.
Which battery gets so low? Do you know how old it is?
You could, perhaps, bring the habitation battery in for the Winter, to keep it warm and charged-up.

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Just smiffy said:
How was it tested..? If it was a drop discharge by a garage it will probably show ok... but a normal amp discharge in the van will show up a bad battery.
Click to expand...
Not sure. They put it on a machine at the car parts place and it came up fine.
 
two said:
12V = very low = no capacity left
12.6V = fully charged
It would seem that the battery's capacity is very much reduced, especially if it can recharge in a day of today's solar.
Which battery gets so low? Do you know how old it is?
You could, perhaps, bring the habitation battery in for the Winter, to keep it warm and charged-up.
Click to expand...
According to my research, 12.0v is only about 50% discharged.

I agree that either the battery capacity is reduced, or there is too much drain.

What I really want to know is the answer to my original question. Will repeated discharge to 12.0v and then recharge damage the battery?
 
It sounds like the solar and controller is doing it’s job ok on the leisure batteries and trying to charge the vehicle battery during the day but it’s dropping at night because it’s not holding its charge... the voltage you see during the day i suspect is the solar charge on the vehicle battery
 
chenderson1965 said:
According to my research, 12.0v is only about 50% discharged.

I agree that either the battery capacity is reduced, or there is too much drain.

What I really want to know is the answer to my original question. Will repeated discharge to 12.0v and then recharge damage the battery?
Click to expand...
In truth... no, probably because it’s already knackered, sorry, go buy the van a Christmas present ..👍🏼😊

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chenderson1965 said:
According to my research, 12.0v is only about 50% discharged.

I agree that either the battery capacity is reduced, or there is too much drain.

What I really want to know is the answer to my original question. Will repeated discharge to 12.0v and then recharge damage the battery?
Click to expand...
12V (in my book) is empty for all practical purposes.
Still don't know which battery (or type) you are referring to.
Batteries have a finite number of cycles, so exercising one this much is not going to be good. Sounds like it's on its last legs.
 
chenderson1965 said:
Thanks. The van has a trickle charger fitted already (in the form of the battery master) . The issue is getting a cable to it.
Click to expand...
If it's one of EddieVanbitz Battery Master then that isn't a trickle charger, that will send a small charge to your Engine battery but the main battery needs to be on a charger to do so.

I wouldn't be trusting the van's charger hence me mentioning the Trickle Charger, I realise you have a problem getting 240v mains electric to the motorhome but somewhere you are going to have to find a way.

I have two Vehicles and 6 motorcycles all hooked up to their own trickle chargers all winter and never have any battery problems, a trickle charger can also bring your battery back to good condition.
 
chenderson1965 said:
Not sure. They put it on a machine at the car parts place and it came up fine.
Click to expand...

Just smiffy said:
Thought so... Lenny HB will be able to explain in more detail then me...👍🏼
Click to expand...
There aren't any testers that can test a leisure battery all they will have done is a CCA test which is a starter battery test, I've had batteries pass that at 80% but totally useless for leisure use only supplying 10 a/h on a small load.

The only way to test a leisure battery is with a slow discharge at the C20, rate i.e. 5amps on a 100 a/h battery.
 
two said:
12V (in my book) is empty for all practical purposes.
Still don't know which battery (or type) you are referring to.
Batteries have a finite number of cycles, so exercising one this much is not going to be good. Sounds like it's on its last legs.
Click to expand...
You may well be right, but before I start shelling out cash, I’m hoping someone can give me some authoritative information.

Even if I replace the battery, I still need to know the answer to my original question so I don’t damage the new one.
 
Lenny HB said:
There aren't any testers that can test a leisure battery all they will have done is a CCA test which is a starter battery test, I've had batteries pass that at 80% but totally useless for leisure use only supplying 10 a/h on a small load.

The only way to test a leisure battery is with a slow discharge at the C20, rate i.e. 5amps on a 100 a/h battery.
Click to expand...

I’m talking about the vehicle battery rather than the leisure battery....

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Almost certain your vehicle battery is at end of life.
With a battery master, the cab/starter battery should be adequately protected while the habitation battery remains good. Battery master ensures that the cab battery does not drain, so long as the hab battery is strong.

Fully cycling batteries reduces their lifespan. Yours appears to have so little capacity left that it is being cycled once a day, which will kill it before long. A new one should not drain and hence cycle so much.
If you cannot get enough charge into the hab battery from solar, take them out and charge them up inside once in a while. Or get a rubber strip to lay over the cable while you bring them back. Charging up once every so often (4-8 weeks) is better than leaving them on continuous trickle.
 
Last edited:
chenderson1965 said:
Hi.
This year I fitted an extra solar panel in the hope that this would keep my leisure and vehicle batteries topped up. I also upgraded my solar controllers to MPPT and already have a battery master fitted.

As the days have got shorter and the sun has got lower, overnight the vehicle battery drops to 12.0v and then recovers to about 12.6/12.7v if the weather isn’t too gloomy. I guess it will get better than that from here but that seems like quite a lot of discharge.

The van is parked outside the house but it isn’t easy to get a mains cable out to it because it’s in the street so I have to cross a pavement etc.

I have a couple of questions, therefore:-

1) Will it be damaging the vehicle battery to be constantly charging and discharging it to that degree?

2) Would I be better off finding a solution to keep it trickle charged via mains cable (either permanently or periodically)?

Thanks
Chris
Click to expand...
Don't know whether you live in a house beside the pavement or whether you have garden between the house and the pavement, but, how about.

Place hook on wall of house, say 3 mts. in the air and park van so that the EHU is road, (not pavement side) of house.
Then hook EHU on hook on house, over the roof of van and into socket. No chance of peeps strangling themselves (in fact, I doubt they'd notice.)

If you have a garden, a pole near the pavement would do to put EHU on before it crosses pavement.

Play Hovis advert.
When I were (sic) a boy, the ladies would install the washing line half way up the side of the terraced houses by means of a clothes prop and a pulley. That wasy, no washing was in the way of vehicles, (admittedly not many of them in those days) dirtying the washing as they drove under.
 
chenderson1965 said:
1) Will it be damaging the vehicle battery to be constantly charging and discharging it to that degree?
Click to expand...
When batteries discharge, the plates become coated with a paste-like lead sulphate. As it recharges, that turns back into the original chemicals (lead, lead oxide etc.). If left for a long time, the lead sulphate turns into hard crystals that can't be turned back into the original chemicals by charging. So the battery loses some capacity.

It's best to keep a lead-acid battery topped up to 100%, or at least make sure it gets to 100% every few days, if not every day.
chenderson1965 said:
2) Would I be better off finding a solution to keep it trickle charged via mains cable (either permanently or periodically)?
Click to expand...
An arrangement I've used is to have a spare battery, a small charger and a small inverter. Charge the battery in the house. Then take it to the MH and connect the inverter, plug in the charger, and leave it to charge the starter battery.

It works best if just topping up a not-very-discharged battery, so you may need a few round trips to fill up the batteries initially. I used a 150W coke-can-shaped inverter, and a CTEK MXS5.0 charger, but any small charger/trickle charger would be OK. If you get a new battery you can use the old battery as the 'spare'.
 
If I understand correctly???
The leisure batteries are holding their charge ok??
But it is just the engine battery that is struggling??
We had this same issue---- that battery master thing was not putting enough into the engine battery to cover all the alarms/trackers and whatever else is running off the engine battery.
If you have an inverter what about a small intelligent charger ( like the one we just bought from lidl)------ they maintain the battery intelligenty and are big enough to cover all that parasitic draw!------ we are using this same principle in our off grid house as the main battery bank is 48volt but we need 12volts for lights water pump etc.
You wouldn't have to run it 24/7---- just work out how long works for you--- and obviously keep an eye on leisure battery state
 
If there are too many 'parasitic' drains on the starter battery for a BatteryMaster to sustain, switch some to the leisure battery (or ditch them altogether).
 
Sundowners said:
If I understand correctly???
The leisure batteries are holding their charge ok??
But it is just the engine battery that is struggling??
We had this same issue---- that battery master thing was not putting enough into the engine battery to cover all the alarms/trackers and whatever else is running off the engine battery.
If you have an inverter what about a small intelligent charger ( like the one we just bought from lidl)------ they maintain the battery intelligenty and are big enough to cover all that parasitic draw!------ we are using this same principle in our off grid house as the main battery bank is 48volt but we need 12volts for lights water pump etc.
You wouldn't have to run it 24/7---- just work out how long works for you--- and obviously keep an eye on leisure battery state
Click to expand...
That’s a good idea. I might give that a go. Thanks
 
I think that's an inefficient way of dealing the effect rather than treating the cause.
If the starter battery is not at end of life, I'd investigate why it is being depleted so quickly. It's not right.
 
two said:
I think that's an inefficient way of dealing the effect rather than treating the cause.
If the starter battery is not at end of life, I'd investigate why it is being depleted so quickly. It's not right.
Click to expand...
I suspect you’re right and the battery may well need changing. This will do as a stop gap though until I get round to looking into that properly and/or changing the battery.

i still don’t understand why the load test would show it’s ok if it’s actually gone though. Can someone explain?

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