Recharging leisure battery - how long?

[BongoGog]

Hi All, newbie question for you,

How long should you have to charge a leisure battery to full capacity, either from mains and or from battery charger? I have trawled through many threads, but cant find the answers to my questions, only too much detail for my understanding. Well one thread reckoned a full day - really that long? Im concious of overheating the battery.

I've only camped in the bongo a couple of times (had her a month now, and love it), but was curious to see how long the L batt would last so after last trip left the fridge on. My Zig CF9 has green (charged) and a red (low charge) lights only, no gauge. It powered the fridge for 5 days, still on green (which was really good i thought), had to switch off in the end, so i guess not much charge left?

I am going on another trip this week with a 4 hour drive, is that long enough to fully recharge the L batt you think??

Appreciate any views on this.

BTW I've a standard side conversion from JAL

[Velocette]

[quote="BongoGog"]Hi All, newbie question for you,

How long should you have to charge a leisure battery to full capacity, either from mains and or from battery charger? I have trawled through many threads, but cant find the answers to my questions, only too much detail for my understanding. Well one thread reckoned a full day - really that long? Im concious of overheating the battery.

I've only camped in the bongo a couple of times (had her a month now, and love it), but was curious to see how long the L batt would last so after last trip left the fridge on. My Zig CF9 has green (charged) and a red (low charge) lights only, no gauge. It powered the fridge for 5 days, still on green (which was really good i thought), had to switch off in the end, so i guess not much charge left?

I am going on another trip this week with a 4 hour drive, is that long enough to fully recharge the L batt you think??

I would be inclined to charge it from mains if mains is available. The increased load on the engine will cost extra diese,l wear and tea,r and waste heat and the mains is probably a cheaper way to get the energy. The battery amp/hours X percentage discharged will be equal to hoursx CHARGING RATE IN AMPs

so if you have a 100AH battery which is 80% discharged it would take 16 hours to charge at 5 Amps or 8 hours at 10A. Check the Leisure Battery Manufacturerers charging instructions to avoid damaging your battery.

Someone electrical will probably come and shoot me now, but this is my understanding and if I have got it wrong I will learn something.

[Dodgey]

Modern fast chargers won't "overheat" your battery - they sense the voltage at peak and stop. Trickle chargers, like the Optimate, charge your battery so gently that there is no chance of overcharging/overheating. You don't need to fret about damaging yoru battery unless you are using a charger from the dark ages.

If you flatten a 100Ah leisure battery and charge it with a fast charger you should allow 12-24 hours, depending on the charger and battery. If you use a low ampage charger like an optimate, allow a couple of days at the least, maybe 3 days.

As for charging whilst you drive - well, a one hour drive will put an aweful ot back in - alternators kick out a load of amps and charge really fast, although you want lots of extra time for the "topping off" - this is where the battery gets a large % of it's charge - the last "gentle" bit.

If you are not planning on camping for the next week or so, and you use your Bongo regularly, then assume it'll be recharged by the time you go away again.

(the cost of diesel used by charging on the go compared to using a mains charger is so small it's not worth worrying about)

[BongoGog]

Thanks for your replies.

My battery is a Numax Leisure 75Ah C20, so not that big.

I was considering charging from house mains, but this sounds riskier as no cut off?

I better invest in a charger then?

Cheers

[Velocette]

Thanks for your replies.

My battery is a Numax Leisure 75Ah C20, so not that big.

I was considering charging from house mains, but this sounds riskier as no cut off?

I better invest in a charger then?

Cheers

As said if you are doing long runs in betwen discharges you may not often if ever need to recharge from the mains, it depends on your pattern of use.

If you do buy one I can reccomend the Black and Decker 10A Charger sold by Argos. It is adequate for the Bongo starter battery too. I have only needed it for my motorbike battery so far but I bought one deliberately capable of handling all my vehicle batteries and it was a good price to. It also has a display I can read without hyaving to squint

Because of the analysis/cut out function it won't desulphate a totally flat battery that has been left discharged for too long, it will just say "REPLACE BATTERY" I have to dig out my 1970 Halfords one for those! A Ctek or Optimate would probably have a desulphating setting but I priced up a Ctek the correct capacity for a 2.5 D starter battery and it was too pricey for me.

[rita]

Thanks for your replies.

My battery is a Numax Leisure 75Ah C20, so not that big.

I was considering charging from house mains, but this sounds riskier as no cut off?

I better invest in a charger then?

Cheers

A charger is your best bet,saves blowing the a### out of the battery.

[scanner]

The deeper you discharge it and the faster you then recharge it, the quicker it will die on you.

[Dodgey]

Thanks for your replies.

My battery is a Numax Leisure 75Ah C20, so not that big.

I was considering charging from house mains, but this sounds riskier as no cut off?

I better invest in a charger then?

Cheers

If you really mean plugging mains wires into the battery with NO charger then stop! - you'll blow the battery up! you simply MUST use a charger.

...and scanner is right - avoid taking your battery below 11.5 volts - it'll kill it in short order. My mate kept letting his fridge and phone charger take his battery to 10 ish volts - it lasted two or three camping trips and then would not power the fridge for more than a few minutes, even when it "appeared" fully charged.

[stuc]

I am still trying to figure out how long mine will last it is an 85ah. But it only lasts about 10 min with just the dvd player on. The fuse blew on the cable from the split charge relay to the LB and hadn't realised till the battery ran out of power and the stereo/dvd went off. Will i need to take it off and give it a proper charge, I have a optimate and a normal charger.
The bit that is puzzling me is I read the battery and it was about 7.5V, started the car for a few minutes and measured again and it said 12.7V is this normal? When the meter is on you can see the voltage dropping quite quick.

[g8dhe]

If any Lead Acid battery has been completely discharged then it is best if it is fully charged from a mains charger, you will be able to put a reasonable amount of charge back in within a few hours, but unless you allow the battery to be fully charged then the life of the battery will suffer. I would suggest that you need at least 48 hours on a charger capable of supplying 8-10 Amps to start with, after the first few hours the charging current will fall to around 2-4 Amps and then this needs to be left in place for the 48 hours. Yes you will get away with less, it will seem to work, but the life of the battery will be reduced.

[Dodgey]

I am still trying to figure out how long mine will last it is an 85ah. But it only lasts about 10 min with just the dvd player on. The fuse blew on the cable from the split charge relay to the LB and hadn't realised till the battery ran out of power and the stereo/dvd went off. Will i need to take it off and give it a proper charge, I have a optimate and a normal charger.
The bit that is puzzling me is I read the battery and it was about 7.5V, started the car for a few minutes and measured again and it said 12.7V is this normal? When the meter is on you can see the voltage dropping quite quick.

To give you some perspective - my good condition 70Ah battery will run a fridge that draws around 3.5amps, on and off, of course, for two days without any charging. a 12v DVD player and screen should draw nothing like that much.

You don't need to take your battery "off" the car, or disconnect any leads to charge it. Just plug your charger onto it in situ and close the bonnet on the lead (leaving the charger under the bonnet too, or under the car). There is loads of space for the cable at the front and back of the bonnet. I use a mains extension lead and put it under the car to keep it dry. I make sure the mains lead drops to the floor before rising again so water can't run into the plug.

Your battery reading 7.5v is very very bad, but if it's the 1st time you may well get away with it. It would be normal for it to jump to 12.7 when running the engine as the car's alternator will be ramming current into it immediately, although, as you discovered, stopping the engine results in the voltage dropping very quickly. It needs A LOT more charging than that! You need to really charge it up to 100% full and then see how it holds it's charge.

As suggested above - plug it into your normal charger for a day or two, then I'd switch to the optimate to let it give the battery a really thorough topping off. The last stage - to get "green" on the optimate, may take a couple more days.

[BongoGog]

Dodgey wrote: If you really mean plugging mains wires into the battery with NO charger then stop! - you'll blow the battery up! you simply MUST use a charger.

What I meant was connecting (somehow) house mains to electric hook up connector on van. Thinking about it this is just the same as hooking up on campsite? Or are they regualted somehow?

Ive borrowed a battery charger from a mate and its been charging for about 8 hrs - still going. Checked before charging and it was 12.05, starter battery only read 12.5. Cant believe its taking so long as almost full power, right?

[g8dhe]

You probably have a mains charger built into the conversion and yes, when plugged into the EHU you will be charging (assuming the charger has been turned on!).
Getting a Lead Acid battery fully charged does take a some hours (typically 48 hours from totally flat ≈ 11.0 volts), some of the small chargers available from Lidl/Aldi etc. are only rated at 3.6-4 Amps Max. and are really only intended to "top up" and maintain the battery, not to really charge the battery from flat (despite what the Marketing material might suggest!).

[Dodgey]

Also bear in mind that full - as far as charging is concerned, is more like 14.5 volts. When you stop charging it'll settle to 12.6volts after about an hour.

You hookup lead can indeed be used at home though you'll need to buy a UK plug adapter to it'll plug into a normal mains socket. It's just mains power - nothing special or regulated. If you do this then either the built in charger that you "may" have will charge your battery, or you can plug in your mains charger to one of the mains sockets in your van!

You can tell if you have a built in charger in your van. Plug in teh hookup and see if the battery voltage climbs, pretty instantly.