Battery vent?
Submitted: Wednesday, Aug 08, 2007 at 07:45
ThreadID:
48520
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4180
Replies:
6
FollowUps:
7
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gilghana
Folks I have two questions that I need an eleccy guru to answer! First one is that in my troopy I am rigging a second battery in a home made box (removable) that will be
well secured. The battery I intend to use has a small vent pipe (solid cell caps) that I intend to attach a hose and put through a grommet in the floor, with a u bend and maybe a small filter like a diff breather... Should be okay or? Second question is where I live I have
no access to a deep cycle battery, so a regular cranking battery (100ah) will be used, running a 40L National Luna fridge. Would be topped up by a Sterling 4 stage battery to battery charger and a solar panel (65w). Anyone have any rough guess how long the battery would be good for, bearing in mind the set-up would be used for running the fridge only once a month (solear panel and sterling would then keep it okay when parked up) and then really only overnight before being topped up... with a longer two week trip every year. Way I see it a cheap cranking battery might even be the logical choice?
Don#t want to start a battery war :-) please bear in mind a fancy AGM type battery for me means airfreight (or three months to wait for cold beer which is not possible) to west africa, and that buys a fair few cheap wet lead acid batteries!
Cheers guys,
Gil
Reply By: Robin Miller - Wednesday, Aug 08, 2007 at 08:17
Wednesday, Aug 08, 2007 at 08:17
I don't think will have any problems with what your doing Gil,
hard to make any more than the most general estimate of your
batteries life but I don't think you will kill it in under two years.
Just limit the deep discharges where you can and you should be fine.
Robin Miller
AnswerID:
256362
Reply By: Member - Mike DID - Wednesday, Aug 08, 2007 at 08:54
Wednesday, Aug 08, 2007 at 08:54
What's a Sterling 4 stage battery to battery charger ?
Where will it get its power from ?
AnswerID:
256367
Reply By: Mainey (WA) - Wednesday, Aug 08, 2007 at 11:17
Wednesday, Aug 08, 2007 at 11:17
Gil,
use the largest capacity (cranking) battery you can find to fit you container if you can't get a genuine AGM Deep Cycle battery.
Another secret is to use the heaviest battery available in a given size (footprint) as it will have thicker plates and/or more of them, giving you more available 'power' per sq cm.
The down side of this is it will be much slower to charge than a AGM battery and will not be able to be constantly discharged to low levels safely, but as you say you have to get the best performance for your fridge as possible with the equipment available to you.
If you can find out the internal resistance to each battery you are interested in, definitely get the battery with the lowest resistance number available, as it will recharge faster than a high resistance battery and with a solar system that is paramount as you have limited sun-hours per day.
See if you can source a 'sealed' Cranking battery as you won't have to worry about the breather system and their technology is normally superior to wetcell batteries.
Calcium grids offer advantages over just lead composite grids also.
AnswerID:
256379
Reply By: Seagecko - Wednesday, Aug 08, 2007 at 18:00
Wednesday, Aug 08, 2007 at 18:00
Gil,
You are on the right track.
Just make sure your charger is smart enough.
The Sterling charger is very expensive, have a look at the Arrid Twin Charge. (arrid.com.au)
I have an Arrid battery to battery charger, and an Arrid solar regulator. No probs.
Cheers,
Seagecko.
AnswerID:
256451
Follow Up By: disco1942 - Friday, Aug 10, 2007 at 02:00
Friday, Aug 10, 2007 at 02:00
Naturally the Sterling is more expensive. It is a multi stage charger - the Arrid model is not. It has the battery isolator built into it where you would have to add one to the Arrid unit. The Arrid twin charge has a constant 14.5V output - I have one and I blame it for the demise of my battery after 20,000km of towing. I would prefer to pay double the price which would have been cheaper than the combined cost of the twin charge and the replacement battery. I now have the twin charge disconnected but keep it there in case I strike too many cloudy days and do not get enough solar charge.
PeterD
FollowupID:
517734
Reply By: gilghana - Thursday, Aug 09, 2007 at 04:23
Thursday, Aug 09, 2007 at 04:23
Thanks a lot for all the replies everyone! As usual a wealth of info available. I bought the sterling in the uk so probably saved a bit over Oz prices, so this weekend it is out with the cables... Big ones!
Cheers,
Gil
AnswerID:
256546
Follow Up By: Member - Mike DID - Thursday, Aug 09, 2007 at 08:42
Thursday, Aug 09, 2007 at 08:42
I don't see the point in having a Battery-to-battery charger - you are just increasing the sulphation in one battery to reduce it in another.
The money would be better spent on more solar cells.
FollowupID:
517598
Follow Up By: disco1942 - Friday, Aug 10, 2007 at 01:51
Friday, Aug 10, 2007 at 01:51
If you go to the link provided in FollowUp 1 of Reply 2 you will see a link at the bottom that takes you to
this page This will explain how they work. The Battery-to-battery charger only comes into action when the alternator is putting out an out put in excess of 13 volts so it does not drain the starting battery.
PeterD
FollowupID:
517733
Follow Up By: Member - Mike DID - Friday, Aug 10, 2007 at 07:25
Friday, Aug 10, 2007 at 07:25
If this is to be used to charge a battery in the vehicle while the engine is running, then the money would have been better spent making sure the Alternator puts out the correct voltage and the wiring is the correct size.
Voltage-boosting devices are only cost-effective with really long wiring e.g. to a Trailer where there are other loads which prevent the battery eventually rising to the Alternator voltage.
FollowupID:
517741
Follow Up By: disco1942 - Friday, Aug 10, 2007 at 15:00
Friday, Aug 10, 2007 at 15:00
Mike
Vehicle alternators are not designed to charge deep cycle batteries quickly. They are designed to maintain the cranking battery. In fact texts like
Bill Darden's site infer that an alternator is not an effective way to recharge a flattened cranking battery - they even go to the trouble of reminding you that you should use an external battery to do the job. Very few vehicle alternators fail to maintain the battery to the design specifications.
Vehicle alternators output voltage is not high enough to recharge deep cycle batteries quickly. If the output was high enough to do so it would boil the cranking battery dry in quick time. Multi stage battery chargers monitor the input current to the battery so that when the battery is nearly completely charged and the current drops to a low value these chargers detect that and switch to a float voltage output. Vehicles alternator do not have this feature, they simply have an output voltage that only varies with the under bonnet temperature (temperature compensation.) Because of this simple regulation the output voltage can not be set high enough to recharge any battery quickly - remember they are only designed to maintain a cranking battery.
If you wish to quickly recharge a battery, you need a device to boost the alternator voltage. Remember Gil wants to do this in a few hours of driving. The TwinCharge will do this but it does not have the same regulation that the multi stage chargers do. The Sterling battery-to-battery device does. Most of the other battery boosters only boost the voltage to 13.8V which is insufficient to recharge quickly.
PeterD
FollowupID:
517797
Follow Up By: disco1942 - Friday, Aug 10, 2007 at 15:03
Friday, Aug 10, 2007 at 15:03
The 4th line in 4ollowUp 4 should read:
that you should use an external battery charger to do the job.
PeterD
FollowupID:
517799
Reply By: gilghana - Friday, Aug 10, 2007 at 01:24
Friday, Aug 10, 2007 at 01:24
As I understand it the sterling basically tries to keep the cranking and the 'house' battery in as good a state of charge as possible. For me what is important that it is easy to fit and also that I am running a normal wet cell battery as a house battery, To be honest when reading the specs as
well as various reports on the unit I cannot see how it would really increase sulphation in the cranking battery at the benefit of the house battery. Every 20 mins it stops the charge to the house battery and reverts to the cranking battery. In fact it is set up to prioritise the cranking battery. More solar cells would not be pratical as they are as scarce as hens teeth in Ghana, and most of my trips are a few days - almost all driving and
parking in the evening. At most I would get about two hours decent charging in. This is why I went that route, as
well as really not wanting to interfere with the original alternator/cranking circuit at all.
Gil
AnswerID:
256662