12v Aux Battery Replacement

[arsharpe]

Hi,

It looks like I need to replace my 12v Aux battery.

Because the 12v battery only supplies the auxillary components I assume that any car battery of the right size and connectors will do.

Anyone tried to match a cheap (less than the £75 quoted by Halfords) normal car battery and had a result ?

Regards,
Rob

[ChrisB]

Got mine from a motor factors Rob for £35

ChrisB

[arsharpe]

Thanks Chris.
What model did you ask for ?

[ChrisB]

TBH I can remember all I did was take the old battery in and told them to match it, as its not the standard Berlingo one from memory.

ChrisB

[Flying John]

I should look up your nearest motor partsco and go down there with the Van and get one that fits. Shouldn't cost more than £40. I ran my old one on an old aircraft battery for 9 months. The Aux battery is not subject to those large starting current loads that there would be in an ICE car.

[Alan Ward]

I was interested that Paul mentioned a 1-year life for 12 V lead-acid leisure batteries used as auxiliary batteries. Sadly, I can confirm this! - I have had had to buy 3 in 3 years, but I got one replaced free as it failed so quickly. I am interested that the sequence over the 3 years is: open top; maintenance free; now open top again - all from the same local garage.

The present one is a NUMAX 75 Ah open-top leisure battery and in desperation I bought a NUMAX charger. Too early to say what success.

I am still trying to decide between a dc to dc 14 volt converter from the traction battery ( 30 of mostly-old TS 200 Ah cells ) or a separate add-on 2 volt lead-acid cell or a separate AlCad cell. Some years ago I saw a friend's Enfield where he had managed to get a large separate 2 V lead-acid cell which he fitted in series with his 12 V auxiliary battery and which gave excellent headlights. I'd appreciate any advice, now that we do a lot of evening driving in our old Fiesta with headlights and wipers, total 18 amps. Alan

[GregsGarage]

Hi Alan,

How often do you charge your aux battery? The reason I ask is that your lithium traction pack probably doesn't require charging every day and it is better for the life of the battery if you don't keep it fully charged all the time. On the other hand a pb battery will last longer if it is kept in a state of full charge, so if your letting it sit partially discharged that will shorten its life. If this is the case try charging your aux battery every night.

A 2volt cell to boost your voltage to 14 volts will give you brighter headlamps, but also make sure that you are using a brand name bulb (Osram or Bosch to name a couple). Many people fit cheap bulbs but they don't give out as much light, bulbs are NOT commodity items, also make sure your headlamps are clean and properly adjusted.

Another option would be to get a DC convertor that outputs 14 volts. this should keep your aux battery charged or you could replace the battery with a supecapacitor. Peter Perkins used this in his Solar Van, look at number 6 on the link. The main thing to look out for is that your DC convertor is isolated, some aren't and that would tie you traction pack earth to the chassis earth which it shouldn't be.

Greg.

P.S. Your Noalox is on the way to you.

[EVan]

I tend to buy used batteries from a scrapyard - £10. If it's got a reasonable voltage when you get it, chances are it's fine for a few years use in a Berlingo.
I think they die from chronic undercharging in this application. If you want it to last a bit longer than charging it with a mains charger once a week would probably help.

[ChrisB]

I think they die from chronic undercharging in this application. If you want it to last a bit longer than charging it with a mains charger once a week would probably help.

mmmm interesting as mine sits at 14.4 volts with the DC-DC running which in theory should be fine, even loading it hard it only drops to 13.6v.
My Aux 12v was I think the original Citroen unit which meant it must have been coming on 7yrs when I changed it

Must admit I normally buy all my batts from the scrappy I think 75% of them that are junked are acutally only in need of a good long charge.

I didnt use a scrappy one on the blingo for fear of damaging the DC-DC if and when the the battery died.

ChrisB