car battery/starting battery system, DIY?

[regis101]

Greetings. I have a phobia about having the house battery system tied in with the car battery system.
Just my hang up.
I do not have the alternator tied into the house system.

That being said, I've been doing some research on car battery solar chargers.
These are generally small, maintaining type, < 10 watts, that keep it topped off. Sounds great.
Our van sits in the driveway for extended periods of time.

It seems easy enough to just pick up one of the numerous choices from the internet, lay it on the dash, plug it into a (constant hot) ciggy socket and walk away.

But... Most do not provide output control. So, to jump ahead of that part of the convo, what are some thought(s) about building/having a small stand alone dedicated system to charge and maintain the car battery.

In my case the battery is a simple flooded starting battery.
Perhaps having a 30w panel and ten dollar pwm controller would be fine? Or the typical +/- 10 watt panel, as advertised but add a low cost PWM.?

I do not know how to maintain a car battery using solar. Is it any different from FLA deep cycle?
Probably not need to equalize a car battery?

In closing, I thought it'd be nice to have a small system dedicated to the car/starting battery.

I'll stop here before too many questions appear.

Thanks,

 

[DLTooley]

I’ve read you can use a 15 watt panel without a controller due the low power output. I’m not sure where, maybe here. 10 watts without a controller seems like a reasonable claim.

 

[XERTYX]

A lot of sail boats near me have a 5-10w panel wired directly to the deep cycle battery to make sure the bilge pump will always have power. But then again bilge pumps do regularly turn on. Especially after a rain. The rear deck ls drain runs directly to the bilge. So maybe those batteries get more of a workout and need the more wattage panels to keep them topped off.

 

[regis101]

Doing some more browsing. This is cheap enough. The controller specs show 14.4 over voltage protection.
https://www.amazon.com/ECO-WORTHY-P...lar+panel+kit&qid=1564527983&s=gateway&sr=8-8

I'm pretty sure the Vans charging system is set around 14.

One thing I'd have to remember is to assemble and disassemble correctly and in proper order.
Could also upgrade to a 30w panel. It'd be almost like having a redundant back up charging system to either the car or the house battery(ies).

I'll keep looking .

* edit. Saw this . https://www.amazon.com/ECO-WORTHY-I...KVPP5656RQ1&psc=1&refRID=5A3HYT1G5KVPP5656RQ1

My reason for this inquiry is that after a long rest period , the Van battery was at 11.6. It still started up just fine but made me wonder.

Off topic a bit but same train of thought. Perhaps I can just connect the van electrical system with the house solar via the van ciggy socket during these driveway episodes.
The more I think about it, it should do the trick.
So here I am contradicting myself.

 

[highdesertranger]

I have a 15 watt battery maintainer. I used to run it without a controller but it would fry the batteries over a long period of time. now I have it run through a cheap Morning Star PWM controller(sub 20 buck) I haven't fried a battery since. if you don't have a controller you have to be there to disconnect the panel when battery voltage gets to high or your batteries will not last long. highdesertranger

 

[regis101]

Copy. Thanks HDR. It’s the fine print with the small so called car chargers that state no over protection. One vendor said to keep an eye on it. What the....?
I will end up getting a small matched system to maintain the starting battery with a little wiggle room to spare.

 

[regis101]

Yep. Still at it. I'm on a quest to know how to properly maintain the car battery, especially if the vehicle sits for long periods of time.

The ~140 pages in this forum seem to cater to the House battery side of life. I'm curious if there are any similaties between the two.

My main question is if a car battery needs the equalization mode. Or should a FLA car batt be charged on GEL, using lower voltages. Or should I have a programmable SC like the Victron 75/10 to set charging parameters.

Anywho, I found this link about car batteries. https://www.powerstream.com/car-battery-faq.htm
I was able to pick out similarities between it and what i think I know about Deep Cycle Batt charging.

I'm not too keen on the 5-10 watt solar panels that merely plug in. There are a couple low watt solar panels that come with a controller, presumably PWM style. But don't trust that yet due to my lack of education.

This link is from the same site as above. Interesting that this can have parameters set thru dip switches.
https://www.powerstream.com/z/7112Manu.pdf

 

[Harry-O]

I’m pretty interested myself for future reference, Boondocking for 14 days never know.

 

[regis101]

What I do not know is how to maintain a starting battery vs the house battery.
The former is of different makeup.
Are long term solar maintenance charging parameters different?
Maybe it doesn't need equalization. Maybe a starting battery is maintained on GEL setting.
Maybe I'm trying too hard. Maybe I shouldn't worry about it.
I don't want to charge off the house solar setup since it has AGM's. Different resistances between it and FLA.
I think if I understood the charging parameters of a 120v battery tender, then I would probably mimic that with solar.

 

[tx2sturgis]

You can use a 5-10 watt solar panel to directly maintain a starting battery, no controller needed.

That's the simple answer.

Yes there are a few things to be aware of...

If the power windows, power door locks, interior lights, etc, are being operated as when camping and in and out of the vehicle, it is almost plug and play simple: You can hardwire the panel to the battery posts or use the power port if it is always powered on. Put the panel where it receives several hours of sun exposure daily, but don't move it to track the sun.

If the vehicle is stored, not used at ALL...nothing is ever powered on during storage...then place the panel where it receives a few hours of sun per day, and check the battery water levels often.

Either of these options requires a blocking diode, and most solar battery maintainers have a blocking diode built in. 

I have a 10 watt panel (closer to 2-5 watts in real world use) on mine right now, as we speak...its keeping the starter battery topped-off.

 

[regis101]

Thanks for the real world info.
I'm starting to feel more at ease about charging/maintaining the Van's starting battery while it sits in the driveway or campground or forest. I'm aware that its physical make up is different than a deep cycle and wanted to find out proper charge techniques. But don't really think it's all that different.
I keep referring to the GEL setting due to lower voltage. I also think to not equalize . I was able to dig up some info on BatteryTender. I've had one of their 021-0128's from back in the motorcycle days.
I now see that it can maintain but isn't recommended as a car charger. I've been playing with that and a spare/core starting battery from the van. Seems to work . This link has a chart that is helpful with their products.

https://www.amazon.com/Battery-Tend...9Y2xpY2tSZWRpcmVjdCZkb05vdExvZ0NsaWNrPXRydWU=

 

[regis101]

Ok, so, I'm still having fun researching. I've been wondering about having a 5-10 watt panel tied into the ciggy socket with out a (programable) controller. This link from Samlex is loaded with info on their product that eases my mind. One important point is to note that they say this style of "maintainer" is to be used with a fully charged battery. They state it can be a set it and forget it thing. That's nice. I understand also previous postings in this thread about hooking a panel to the battery/ciggy and keep an eye on it. Works, yes, but not what I'm after.
https://www.samlexamerica.com/documents/manuals/11023-SC-05-10-0618_Hrez.pdf
This leads me to want to increase the multitask ability of a small 50< watt system. I'm wondering if maybe something like the Victron 75/10 w/bluetooth could be used it all three charging stages were set to 13.5 and let 'er rip? Then if the need arises to charge some other battery, the parameters could be readjusted to suit.?

 

[B and C]

OK. You need to make your connections clearer. You have a spare unused 50 watt panel and want to stick a small charge controller on it to keep your starting battery maintained? If this is the case, why not just set it to what your battery wants depending on state of charge (like solar is normally used)?

 

[regis101]

That's exactly what I want to do.
My dilemma is that damn near all the solar charging info is for deep cycle. I find zero info about how to maintain a starting battery with solar. The cheapy dash mounted low watt panels that plug into the cig socket scare me.
Samlex was the first one that showed any sign of intelligence, to me. I could buy the SC-10 and walk away but thought I could multitask this.
I don't think I need to worry about 3 stages, let alone 4. I want to think 2 stages should be fine. Maybe I could program all three stages for 13.5, turn off equalizing and be good?
The starting battery , by default from driving, is considered fully charged at any given time. Except when said vehicle sits for long periods of time. Case in point, the battery in the van is at 12.1 today. I had had a reading of 11.6 a short time ago from lack of use and vehicle phantom loads.

I'm just trying to find charging parameters for a starting battery. It's make up is different from a deep cycle. Do the same charging parameters still apply? Do I really want to equalize a starting battery? Not sure how the vehicle electronics would handle the increased voltages.
The vehicle electrical system is up around 14 volts when running according to the dash gauge.

I'm not overthinking this. I'm looking for a either ciggy panel that is designed as a set n forget, hence the Samlex, or design a small system with a panel and a programable charger to "maintain" the starting battery and yet be able to charge a deep cycle is someone needs.
Just my hang up.

 

[B and C]

Here is what I am using on my Geo and motorcycle trailer: https://www.amazon.com/ECO-WORTHY-P...ttery+charger&qid=1566096037&s=gateway&sr=8-3

Float on these are 13.8 but the amperage is very low and has no equalization. A 10 amp PWM controller is all you should need with a 50 watt panel. If your starting battery is already fully charged, the controller would go straight to float, no bulk or absorbtion.

 

[highdesertranger]

I just treat the starting battery the same as any other lead acid. the only thing that needs setting is flooded, AGM or SLA. highdesertranger

 

[regis101]

Yep. Thanks guys. See how easy that was. I required education. This is one of many links that explain differences. So I wondered if charging is different.
https://www.batterysystems.net/deep-cycle-vs-starting-battery/

I looked at the same Ecoworthy system; may have even posted the same link a few posts back. At least it has a controller.

I can find charging specs for most any Deep Cycle all day long. Don't really think AutoZone is going to have charging specs for a group 78 battery for a 2011 Chevy van.

I didn't know that if a battery is basically full, the solar side would quickly go to float. That just might be the key I am looking for.

I kept the first battery from the van as purchased to use as a spare. Maybe I'll pick up a programmable controller and along with a 30w panel from my stash and try it.

Thanks again.

 

[highdesertranger]

Autozone should have the specs if they are charging batteries. but like you said I wouldn't count on it.

but the battery manufacturer has the specs.

highdesertranger

 

[regis101]

I wouldn't be so sure about any FLAPS. Take a battery to them and they put a load test on it.
If they did try to charge one, my guess is with an ordinary bulk charger.
Anyway, I'm feeling more confident about charging a starting batt vs a house batt.
I penned an email to Samlex asking about their small PWM's and small wattage cig socket maintainers.
I've learned a lot from reading any of their owners manuals as well as the real time info within the CRVL forum pages.
Thank you thank you

 

[wayne49]

Samlex tech support is pretty cool. Not offshore. Not a bot. They actually read what you wrote and respond to what you asked. At least the one fellow with whom I was communicating. He inferred that the rest of staff was also not the usual corporate types.