Solar Charging of Starting Battery

Submitted: Monday, Jul 02, 2012 at 16:16
ThreadID: 96638 Views:6225 Replies:6 FollowUps:13
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Hi all, Think I have read the answer to my question somewhere but unable to remember, can somone help please.
I have dual batts. in the vehicle starting batt.- isolator then 2nd batt. with an Anderson plug at rear to charge Camper Batts. When in camp I connect a 160w solar panel to Camper to top up batts. My question is - after getting a flat starting batt. at home if this occurs while camping can I plug the Solar panels into the Anderson plug at the rear of vehichle and charge the 2nd batt. then through the isolator to charge the starting batt. The Solar panels have a PV Charge Controller attached at end of 6mm cable near Anderson plug to get it closer to the batts. to lose less charge or should I make up a set of leads with jumper lead clamps to attach to the starting batt. only.
Thanks for your replies in advance
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Reply By: escapesilv - Monday, Jul 02, 2012 at 16:46

Monday, Jul 02, 2012 at 16:46
Hi Tony Z

Can't you connect your solar directly to your starter battery, I have done it that way, but I don't have a set up like you have.

Cheers
Rob
AnswerID: 489964

Follow Up By: Member - Rob K (VIC) - Monday, Jul 02, 2012 at 17:16

Monday, Jul 02, 2012 at 17:16
Hi Tony,

Is there anything stopping you from using the auxiliary battery in the vehicle to help the cranking battery turn the motor over? I assume the auxiliary battery is under the bonnet and still has charge? Just need some jumper leads.

Otherwise, if that's not possible, I don't believe you can go "backwards" with the charging process via the isolator switch. The isolator needs the charge in the 1st battery (cranking) to be above a certain voltage before it opens up to allow charging of the auxiliary battery, at least that's is my understanding of the way it works. Others will know better than I (Derek Bester from ABR Sidewinder might be able to help here).

Failing that, direct connection of the solar panel to the cranking battery will do the job, but you'd better hope for a sunny day and a 12 hour wait to get the voltage up in the cranking battery as it might take some time to recharge.

Cheers

Rob K
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Follow Up By: Member - Tony Z (NSW) - Monday, Jul 02, 2012 at 19:38

Monday, Jul 02, 2012 at 19:38
Hi Rob K, I tried to jump start from the 2nd batt. but as the starting batt. is dead there has been no charge flowing over to the 2nd batt it's a deep cycle not for cranking. And don't care if it takes 2-3 days to charge so long as it starts
Thanks
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Follow Up By: Nomadic Navara - Monday, Jul 02, 2012 at 20:05

Monday, Jul 02, 2012 at 20:05
Tony, just because a battery is a deep cycle unit it does not mean that it will not start a motor (unless of course you have run it down more than you should have.) Just use your jumper leads to start the motor with our deep cycle battery. If your leads are not too light it will work, make sure you carry a quality set of jumper leads and not K-mart specials.


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Follow Up By: Member - DOZER- Tuesday, Jul 03, 2012 at 22:43

Tuesday, Jul 03, 2012 at 22:43
Be very careful if your motor is computer controlled (efi) as a spike will render the computer dead. The best option is to jump the aux to the main,+ to + and neg to the motor, then remove the earth from the main, so it is not dragging extra current from the aux when you start the motor, and once the motor is running put the earth back onto its post with the jumpers still attatched and let the motor run for 5 minutes that way to charge the main. Stop motor, disconnect auxiliary jumper leads and start straight away. If there is not enough charge, your battery is stuffed it should fire straight up after 5 minutes of charging.
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Reply By: Member - Josh- Monday, Jul 02, 2012 at 17:10

Monday, Jul 02, 2012 at 17:10
Seeing that you have a 2nd battery in the car, can't you just jump start it off that battery. That's all I used to do???? I know that doesn't answer your question, sorry.

Josh
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Reply By: Member - John and Val - Monday, Jul 02, 2012 at 17:24

Monday, Jul 02, 2012 at 17:24
Hi Tony,

I see 2 options

1) Simply plug the solar controller into the anderson plug leading to the vehicle. That should apply the solar output to the in-vehicle auxilliary battery. To get it all the way through to the cranking battery you will need to put a jumper across the isolator in the engine bay.

2) Probably better, and avoiding the jumper on the isolator - provide an anderson plug right at the cranking battery so that you can plug the output of the solar regulator directly to the battery. (Bearing in mind that any connection to any battery should be through a fuse that is connected right at the battery.) This might be a semi permanent connection, or maybe just make up a lead consisting of a couple of battery clips one end, an anderson plug the other.

Cheers

John
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Follow Up By: Member - Tony Z (NSW) - Monday, Jul 02, 2012 at 19:46

Monday, Jul 02, 2012 at 19:46
Thanks John & Val, looks like No (2) thats what I thought of but do I require a fuse on the leads with battery clips one end and anderson to solar panel on other that the question ?
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Follow Up By: Member - John and Val - Monday, Jul 02, 2012 at 20:14

Monday, Jul 02, 2012 at 20:14
Hi Tony,

I confess, my battery clips to anderson plug cable, and battery clips to cigarette lighter socket do NOT include fuses. (I use cigarette lighter plugs for lots of gear such as chargers for phones, camera batteries, torch batteries, laptop supplies, soldering iron, etc. They are a horrible, crude device, but are universally available in any vehicle, so something of a standard.)

Any permanent wiring such as an anderson plug connected permanently to a battery should include a fuse. Why? There's a lot of energy stored in a battery and it can come out fast and can damage wiring, even cause fire, if something goes seriously wrong. A fuse is a cheap way of disconnecting the battery from everything if disaster does strike.

If I were mounting an anderson plug permanently to the sidewall, and permanently connecting it to the battery I would certainly include a fuse in the positive line. If just a temporary connection using clips, I would not include a fuse, but remain mindful of the risks.

Cheers

John
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Follow Up By: Member - John and Val - Monday, Jul 02, 2012 at 20:31

Monday, Jul 02, 2012 at 20:31
Tony,

Forgot to mention - I've fitted an inline fuse holder linking input (cranking battery) to output (Aux battery in your case) across the under-bonnet isolator. On the rare occasions when I might need to link the two, I simply insert a fuse. For normal operation no fuse is in place, but it's easy to insert one should you need to feed current into your cranking battery from further back, as you could do with your solar panels through the rear mounted anderson plug.

Cheers

John
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Follow Up By: Member - Tony Z (NSW) - Wednesday, Jul 04, 2012 at 18:56

Wednesday, Jul 04, 2012 at 18:56
Thanks for all the help, as we only travel remotely a couple of time a year I will go with the Solar Panel and clips if required for now and look at fitting a better 12v charging system in the near future
again thanks
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Reply By: Stewy1 - Monday, Jul 02, 2012 at 20:06

Monday, Jul 02, 2012 at 20:06
Hi Tony

When I had my dual battery set up, the auto electrician installed a button that deactivated the isolator switch. So if I have a flat battery, I can push the button and start the vehicle from the 2nd battery. Very easy, and no mucking around with jumper leads!
I charge the 2nd battery via a solar panel and Anderson plug.
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Follow Up By: philip t jones - Wednesday, Jul 04, 2012 at 08:41

Wednesday, Jul 04, 2012 at 08:41
Ditto
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Follow Up By: PJR (NSW) - Wednesday, Jul 04, 2012 at 10:18

Wednesday, Jul 04, 2012 at 10:18
Same here.

We actually have three batteries under the bonnet, with two isolated as the auxiliary "battery" to run our two fridges, lights and all the other junk we use when camping through outlets at the back of the cabin. The isolator is the 200 amp one with the over-ride switch in the cabin with the red status led for the redarc. The switch allows me to temporarily add the two extra batteries to the cranking battery if needed to assist with cranking.

I cannot see how the main battery should get flat unless I muck up and leave the radio, lights and everything that runs off the start battery, switched on. Or it goes crook.

Maybe I missed something.
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Follow Up By: Member - Tony Z (NSW) - Wednesday, Jul 04, 2012 at 19:01

Wednesday, Jul 04, 2012 at 19:01
PJR the starting battery ran flat at home as I was working under and around the vehicle all day Saturday with radio and interia lights on did not think they would flatten the batt. but only been doing short trips to work and back, so not fully topping both batts.
Thanks
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Follow Up By: PJR (NSW) - Wednesday, Jul 04, 2012 at 19:37

Wednesday, Jul 04, 2012 at 19:37
Aaahhh Tis a trap Tony. And not topping up does not help.

With your isolator, can't you switch the auxiliary batteries to cranking?

To get the motor running and put bit of charge in the cranking/start battery for next time.
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Reply By: ABR - SIDEWINDER - Monday, Jul 02, 2012 at 20:21

Monday, Jul 02, 2012 at 20:21
Hi Tony

Your other option is to fit a Bi-directional isolator that works both ways, when the aux battery is charging via solar it will kick in and charge the main battery. That way you should always have a charged starting battery. Redarc used to make one called a SBi12D which has 2 black boxes, we now make one called a Bi-150 that does the same thing.

Regards

Derek from ABR
AnswerID: 489984

Reply By: GT Campers - Tuesday, Jul 03, 2012 at 09:22

Tuesday, Jul 03, 2012 at 09:22
It's good to be ready for any and all situations - but what makes your start battery flat?

AnswerID: 490021

Follow Up By: Member - Tony Z (NSW) - Wednesday, Jul 04, 2012 at 19:04

Wednesday, Jul 04, 2012 at 19:04
GT had radio on all day Saturday will working on the 4x4 also rear interia lights I found were on
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