12V Battery question

[Leadbouncer]

Originally Posted by James Jake

Hey Folks
Its me again A couple of things I would like to report in on since you all were kind enough to advise.


Well, I decided to remove the old dead batteries and put the new ones in and of course usually that is a quick job but its still 2020


I called around and 12v AGM batteries

I did not check the voltage on my new batteries when I got them so they could have been completely drained, again I dont know.


If they were even almost drained how long would it take for my 100W solar panel with a 30A controller to recharge them to an acceptable voltage?


Facts I do know - I measured by output from my solar panel and it was about 13.8V

I dont want to take anything for granted, here.

These are deep cycle batteries?

Are they maintenance free or can you add water?
If you can add water, check the level.

Can you verify that the correct leads are connected to the positive and negative posts?

Did you wire the batteries in Parallel? + to + and - to -

you should connect a regular volt meter to the batteries to check the voltage. set it on volts NEVER OHMS and set it on 12v.
A test light only checks available current.

When charging dead batteries, if they have been depleted or discharged, they take extra time and may need more than 13 to shock them back to live. Some larger chargers have quick charge settings. they may have a setting for 40 volts for example. Shop models are common.

Secondly, batteries consume more voltage in the beginning and less and less as the battery fills up. Many battery chargers have 2 or 3 stages and some have an automatic setting that reduces the charge going to the battery. its best to charge them separately. That way if you have a dead cell, it will more clearly show up in the results.

I had 2 12volt wired for my 24 volt minkota. I also bought a second charger that was not as beefy as the first and its always been a dissappointment. So I shock the battery and then use a weaker charger to finish it. I had a week usually between fishing trips.

I dont think some high powered shop charger is needed.

Deep cycle are purposely made for drastic swings of voltage. Car batteries are injured by draining them.

If you need to buy a volt meter, the same basic features are contained in most units. no need to spend more than 30 bucks. If you are not doing home electrical panels etc, dont pay for it.

[tomkatb]

Two batteries are 160 to 200 amps capacity. Thus you need likely 250 amps put into them.

A 100 watt solar panel on its best day during the summer produces 25 amps per day. So, I would expect one panel 20 days to recharge a battery set. Maybe forever.

In this situation the great thing about a 100 watt panel is its ability to maintain a battery over the winter storage.

You just have to plug the rv in for two days and it would fully recharge.

Get a battery monitor installed. If you never let the batteries get below 12 volts they might last 4-5 years.

[HiTech]

My factory 100 watt system is producing 2-4 amps for the peak output period of the day this time of year. Call it 4 amps for 6 hours. So roughly 25 amp hours a day. The old batteries were 100 amp hours and there were two. So 8 sunny days to fully recharge destructively dead batteries.

Hopefully the batteries you bough were not sitting on the shelf dead or they are junk. But they might have been sitting at 12.4 or 12.6 volts if they were not maintained in inventory properly. So a few sunny days to recharge.

Also, being PWM instead of MPPT, the lower your voltage batteries are, the less power the panel produces.

EXCEPT, the factory puts globs of Dicor on the panels when they install them, and it runs over 6 of the cells, cutting the solar output in half on mine. If you warm the Dicor and gently but firmly push it back off the cells (but leave it covering the screw heads!), then clean off any residue and clean the panel (no harsh cleaners - follow the GoPower directions), your system will charge twice as fast.

[HiTech]

Originally Posted by Duckogram

Group 27 batteries are 85-105 amp hour. That is what FR installs. The OP might be able to go to Group 31 which are 95-125 amp hour but that recommendation would be predicated on the model the OP has. And no, there are no ratings on the OEM battery. FR used Exide Nautilus Marine 27MDP which are 100 amp hours @ 20 hour rating.

Is the current install with solar these batteries? Mine have a smooth top and look like AGMs. This Nautilus Marine looks like a FLA battery with caps. I am struggling to find a data sheet on them - not all AGMs like their charge curves at the same voltage, especially float voltage.

[Duckogram]

Originally Posted by HiTech

Is the current install with solar these batteries? Mine have a smooth top and look like AGMs. This Nautilus Marine looks like a FLA battery with caps. I am struggling to find a data sheet on them - not all AGMs like their charge curves at the same voltage, especially float voltage.

My response was for the OP’s 2018 unit. As for what FR is using today, Wedontknowdis.

[HiTech]

Originally Posted by Duckogram

My response was for the OP’s 2018 unit. As for what FR is using today, Wedontknowdis.

I really want to know. No useful markings on top that are Google friendly.

[TitanMike]

Originally Posted by HiTech

Hopefully the batteries you bough were not sitting on the shelf dead or they are junk. But they might have been sitting at 12.4 or 12.6 volts if they were not maintained in inventory properly.

When I retired and ran out of things to do around the house I took a part time job in an Auto Parts House (Nationwide brand name). After working in a corporate structure for 17 years I wanted a job where I could work the hours I wanted, punch a time clock, and utter the phrase "sorry, above my pay grade".

This A/P chain was great for maintaining the freshness of their battery stock. The main computer would send the store a weekly list of which batteries (ID'd by a coded sticker) needed to be pulled from the display rack and put on a battery maintainer until the maintainer incidated a full charge. No battery sat uncharged more than a month.

When batteries sat on the rack too long (according to the main computer) they were returned to the warehouse where the chances of them being sold at a higher volume store was greater. From the warehouse "stale" stock was returned to the manufacturer but usually only a few a year with the hundreds of outlets being served by the warehouse.

If you purchase a battery off the rack at an RV Store or small auto repair shop, it's anyone's guess how long the battery has sat there un-maintained.

FWIW, the Deep Cycle (not marine starting) batteries we sold had to be ordered from the warehouse and the ones I saw had factory date codes showing their "Birthdate" was only 1-3 months earlier.

[HiTech]

Originally Posted by TitanMike

When I retired and ran out of things to do around the house I took a part time job in an Auto Parts House (Nationwide brand name). After working in a corporate structure for 17 years I wanted a job where I could work the hours I wanted, punch a time clock, and utter the phrase "sorry, above my pay grade".

This A/P chain was great for maintaining the freshness of their battery stock. The main computer would send the store a weekly list of which batteries (ID'd by a coded sticker) needed to be pulled from the display rack and put on a battery maintainer until the maintainer incidated a full charge. No battery sat uncharged more than a month.

When batteries sat on the rack too long (according to the main computer) they were returned to the warehouse where the chances of them being sold at a higher volume store was greater. From the warehouse "stale" stock was returned to the manufacturer but usually only a few a year with the hundreds of outlets being served by the warehouse.

If you purchase a battery off the rack at an RV Store or small auto repair shop, it's anyone's guess how long the battery has sat there un-maintained.

FWIW, the Deep Cycle (not marine starting) batteries we sold had to be ordered from the warehouse and the ones I saw had factory date codes showing their "Birthdate" was only 1-3 months earlier.

Exactly right!

[LittleBill]

Originally Posted by TitanMike

When I retired and ran out of things to do around the house I took a part time job in an Auto Parts House (Nationwide brand name). After working in a corporate structure for 17 years I wanted a job where I could work the hours I wanted, punch a time clock, and utter the phrase "sorry, above my pay grade".

This A/P chain was great for maintaining the freshness of their battery stock. The main computer would send the store a weekly list of which batteries (ID'd by a coded sticker) needed to be pulled from the display rack and put on a battery maintainer until the maintainer indicated a full charge. No battery sat uncharged more than a month.

When batteries sat on the rack too long (according to the main computer) they were returned to the warehouse where the chances of them being sold at a higher volume store was greater. From the warehouse "stale" stock was returned to the manufacturer but usually only a few a year with the hundreds of outlets being served by the warehouse.

If you purchase a battery off the rack at an RV Store or small auto repair shop, it's anyone's guess how long the battery has sat there un-maintained.

FWIW, the Deep Cycle (not marine starting) batteries we sold had to be ordered from the warehouse and the ones I saw had factory date codes showing their "Birthdate" was only 1-3 months earlier.

Thanks for the info as good to know. Will check out Auto Parts next time I need a battery.