starting problems after installing 2nd battery and switch

[beubanks]

here's the issue:

installed a second battery (deep cycle) and a perko marine switch between this and the starting battery. How I did it was simply take all the wires that were connected to the starting batteries positive terminal and connect those to the perko switch common post. Then off the perko one wire to starting battery (1) and one wire to the rv battery (2); and they share the ground.

this has worked fine until about 2 weeks ago when the van wouldn't start. had the wiring re done from starter to battery, and things were fine. later noticed that the mechanic in the town I was passing through at the time had rewired this battery set-up too. He essentially made it not a switch, but an on-off for the second battery where the starting battery is always connected (with it's bundle of wires) and then there is a second wire which goes to the perko common post.

yesterday I switched this back since when wired as above both batteries drain when the deep cycle is on. however, I just got a call from girlfriend, on her way to western washington, that the van wouldn't start after stopped after driving a couple of hours. after a sit it started again.

so, I"m wondering is the issue the starter (which is apparently fine, pulling 12v)? or my novice wiring? should some of those wires stay connected to the starter battery? or something else?

weird thing is this was fine for about 4 months and I'd like to be able to use the second battery as a back up starting option (which is the idea of a switch).
never a starting problem until very recently. fuses all seem fine too....but I've read on other posts that it's sometimes worth changing ignition fuses even if they look fine..

edit: this has only happened after long drives (2 + hours)....


thanks for any thoughts

[beubanks]

okay...

I've figured that there is a slight voltage drop occurring at the switch... not sure if this the total issue, but has anyone experience with having a second battery for appliances/electronics in their vans and what they use for this?

thanks

[Reducto]

The mechanic wired the battery correctly. Running the starter through the switch and the extra length of wires is likely to cause problems and wear out the switch.

I have a dual battery setup that has worked very well. I left the existing van wiring untouched - the big wires going to the frame and starter are intact. I ran a big 4ga wire from the marine battery through a fuse, to the switch. All of my rear electronics (fridge, laptop, lights, water pump, fan) are connected at this point. Another big wire goes from the switch to another fuse then to the starting battery. This way, when the switch is turned off the car operates as normal. When the switch is on, the alternator charges the rear battery and if necessary the rear battery can be used to assist in starting. The switch is an electronic one which operates off the "rear" button in the dash such that it only turns on when the car is running and the rear button is lit. That was a little tricky to wire up but I could give details if you like.

What are you using the marine battery for, exactly?

[beubanks]

Thanks so much for this info. I thought that was the problem. funny though, it worked fine for almost 4 months. I'm using a marine switch (perko) pretty heavy duty, supposedly made for 12 and 24 volt batteries.

the second battery is for very basic cooking, computer, and listening to music. sometimes used for onsite recording.

please send details about fuses used how you wired this up as I'd like to have this set up correctly so I can use the car to recharge the deep cycle. What I liked about this was that I could almost drain the deep cycle, then start with the car battery, switch over the deep cycle and drive for a few hours to recharge.

When you say the alternator charges the 2nd battery, are you keeping the car running when your using things?

I'm not sure I've got a 'rear' button :)



thanks,
bryan

ps_ I'll be in SF in October...

[Reducto]

Not sure why it only became a problem after 4 months - maybe carbon buildup on the switch from running too much juice through it during starting?

The fuses were 60 amp ones I got a Fry's - they are designed to be used with big car amplifiers. They are mostly there because the switch and wiring is running through the side wall and could get shorted in an accident. I mounted them as close to the batteries as possible.

The rear button used to turn on the rear heater before I removed it, I guess you won't have one of those if you never had a rear heater.

I only keep the car running if my rear battery is dead, which I try not to do very often because it reduces the life of the battery. When I say the alternator charges the battery, I mean when I'm driving.

Wiring is fairly simple. Just put all the stock wiring back in place, then run a wire from the marine battery to the switch, then from the switch to the main battery. 4 gauge is slight overkill, but bigger is better. Definitely don't go smaller than 8.

I'm actually not in SF anymore, I just drove cross country :) Here are pictures of my crazy rig: http://www.toyotavantech.com/forum/showthread.php?879

[beubanks]

your van looks great. I should post some photos of what were driving in. just crossed the country from nyc.... heading back in november...

anyhow.... are the fuses necessary? It seems like I should just put the wiring back as it was a few days ago. I can't wrap my head around how that won't just drain the car battery as well (say if I'm running car stereo for a while with car off)..but, this will work for my needs of course since the inverter is hardwired to second battery. I think I'll poke around the switch some more and see whats happend on the inside. Thanks again for the help.

b

[Reducto]

Fuses are recommended, but if you want the risk you can go without them.

I think I misunderstood your wiring a bit - so when you're driving you set the switch to "both" and when you're stopped you set it to only use battery 2?

Yes, if you run the car stereo with the car off it will drain the starting battery the way I recommend wiring it. The proper way to avoid this is to have anything you want to run with the car off connected to the second battery. I don't use my car stereo except for when I'm driving so I haven't run into that problem. All my non-driving stuff is in the back.

There probably is some elegant solution to what you're trying to do but I'm not sure I feel comfortable trying to do it remotely on a van I haven't seen.

Good luck!

[RawbSpear]

here are some professional dual battery set up products that are automatic.

i did a bunch of research a few months ago and these came up the best:

http://www.dfna.info/bsr-isolator.html
http://www.perfectswitch.com/isolators/dual-rectifier-isolator/
http://www.jamestowndistributors.com/userportal/show_product.do?pid=11993&familyName=Blue+Sea+Systems+Dual-Battery+Dual+Circuit+Plus+Panels#