Vannin' Home Forums General Discussion Electronics Deep Cycle Batteries and TVs (2 separate questions)

Hi all, I am in the market for a pair of group 31 AGM batteries to add to my van for shows and camping and have some questions.

For reference, we are not living in this van, and most of our adventures are at most for a 3 day weekend, but do often include shows that can last all day (we can usually plug in at night, but not always and want to be prepared)

Question 1: What AGM group 31 batteries do you recommend or have personal success with? I understand the importance of keeping the charge topped off as soon as we get home, but I want solid batteries that can take the abuse of running lights, stereo, 12 volt fridge, and possibly a TV for several hours at a time. Emphasis on amp hours and overall lifespan. Obviously I'd rather not spend my entire budget on batteries but I understand they are expensive.

Next thing.. I have laid the groundwork as far as wiring goes. I have a battery switch to isolate the starting battery if the others go dead, and I have an on board Guest dual bank charger (planning on 1 bank for the starter battery and 1 bank for the other 2).

My question here is will setting the dual bank charger up to charge the starting battery with 1 bank, and the pair of house batteries with the other bank work? Or would I be better off to charge the house batteries on their own individual banks, and rely on isolating the starter battery so that I'd shouldn't need to be charged (except while driving)?

My last question is about TVs. I plan on adding a flat screen TV to the big wall inside the van. I have found TVs around 30-32" that are made to be used in campers or RVs and will run off of 12 volts. Obviously this seems ideal for my van, however, I have heard from more than 1 source that those TVs will only really work with a bare minimum of 12 volts but really like closer to 14 volts like when the engine is running and alternator is providing power. Supposedly under that ideal voltage they will just shut down.. Instead it had been recommended to me to run an inverter and a normal 110v TV. I am no electronics expert, but I feel like that may deplete the batteries much faster? Are there truly issues with using a 12v TV? I need some guidance here.

WRC68 is truly the guy you want to speak with ….

https://www.vanning.com/threads/ubbthreads.php/users/4697/wrcsixeight.html

I figure he will probably chime in, but wanted to make a public thread for people to reference later

This is excellent and relevant to my interests as well. I’m in the process of planning some wiring out now

The best G31 AGMS in my opinion are Lifeline/Concorde and Odyssey and Northstar.
Northstar is rebranded at batteries + as X2 power.

These 3 AGMS really enjoy huge recharging currents and are better off for them. When deep cycled Lifeline specs no les sthan 20 amps per 100Ah of battery, and Odyssey spec no less than 40. Believe it. I've seen how too little charging current of deeply cycled agms suntts their lifespans and performance
Do dismiss the 'trickle charge' mentality one often reads about concerning lead acid batteries. AGMs especially can be tickled to death with too little charging current.

If one cannot meet the high amp recharge requirementsd then one needs to hold extend the charging afterawards to help negate premature capacity decline from too little recharge current.

Lifeline has a very good tech manual about how to treat batteries.

If you cannot meet the high charging amp requirements then you will not get the benefits from spending top$ on the Lifeline northstar or Odyssey AGMS, and are likely better off just getting whatevers most easily available. Even the UPG 121000 availabal on amazon for under 160 can give adequate service for less than half the price of Lifeline.

There is little point in getting the best battery, if you can't meet the charging specs. Even the cheaper AGMS which will say no more than 33 amps per 100Ah of capacity, still enjoy recharge currents upto those limits, and i have exceeded them by a factor of 5 without any mushroom cloud or degrading the battery.

The East penn/deka AGM battery is likely the most rebranded AGM battery for autromitive starting use, they say deep cycle on them, but they have performed poorly in deep cycle duty when tested by practical sailor magazine.

Full river makes a pretty good AGM, of you can find them.
Avoid Optima AGMs for deep cycle duty, they have 1/3 less capacity than a rectangular AGM and have not been a good agm battery since 2004 or so.

As far as 12v TV's, I have a 13.3 inch RCA 12v tv for about 6 years now, and it works fine at 9.5v, perhaps less, and upto as high as 15 volts, and likely would be OK with more. I can;t say for sure about other 12v TV's but most devices seem to have pretty wide voltage tolerances.

Lots of pewople advocate for powering a TV with an inverter, but I find an inverter to be electrically wasteful and electrically noisy, it will knock out some strong tv stations broadcast in the VHF-Hi spectrum. It is certainly an option though.

I cannot recommend any chargers and despise their marketing and their ignorant fanboys who think a green light is indicative of a true full charge. I use an adjustable voltage power supply capable of 40 amps at any voltage between 13.12 and 19.23 volts for battery charging. It is NOT automatic, but it is capable of fully charging a battery, something few automatic chargers are capable of, especially on a hard working battery.

Fully charging a battery take a lot longer than one thinks, much longer,when held at higher voltages, and there is NO shortage of complete arrogant ignorance regarding the proper care and feeding of lead acid batteries online. So much so I have stopped replying to most requests for info or correcting poorly parrotted incorrect info.

Ideal, and what you can get away with are two very different things.

The highest capacity g31 agm is the lifeline gpl -31XT at 125 amp hours.

I just got a g31 northstar agm at 103ah capacity. The thin Plate pure lead agms by odyssey and northstar are more dual purpose agm. Starting and cycling.
My northstar has 1150cca while the lifeline gpl31xt is 720, iirc. Lifeline is more.purpose built deep cycle with thick plates.

While i can carry 3 g31 batteries with 2 dedicated for house loads. I only use one battery for house and engine starting. I got over 1300 deep cycles over a period.of 6 years from my previous group 27 northstar, which i was impressed with so i bought another.

Its all about proper recharging. But some will claim complete ignorance is just fine too.

"Its all about proper recharging." Yes. What he said! Rinse. Repeat.

We've always used the cheapest batteries we can find at Wally World but make sure to "properly" charge them and have never had a problem.

When we started out we had two supposedly 'dead' batteries out of Dad's bass boat. Once we topped them with water and began 'properly' charging them on solar they lasted us nearly four years while full-time living in the van (We never plugged in).

As for using the batteries for a weekend without charging them; the only thing we found that might would drain your non-charging batteries over the weekend would be the fridge (I think it depends on the compressor or something like that). But we don't run a fridge except when we are provided government electricity so never tried any of the 12 volts just heard others experiences and they all use solar to keep a fairly strong re-charge daily.

Wow! As always great info! Thank you guys!

I'm going to digest that a bit before diving in head first. I definitely don't want to waste good batteries without the necessities to maintain them properly. I'm sure I'll be back with more questions, but I have a lot to consider now.

Digesting is wise indeed.

If one finds a good deal on a desirable TV which requires 19vdc instead of 12, there are many products out there which will take battery voltage and step it up. These are called boost converters or step up converters and even upto 10 amps of rating, they are inexpensive.

I use them for controlling fans and lights, mostly buck/step down converters, but I also have boost/step up converters for some 24v fans and have also used them for charging 18v and 24v power tool battery packs.

Laptops are generally 19.5v DC, and those that have a simple + and - wire barrel plug can also use these step up converters. If one is willing to slow boat from china they can get them ridiculously cheap.

There are also combo step up/step down converters, though one loses some efficiency by using these.

Here's an example of a step up converter.

https://www.amazon.com/Gowoops-10-3...+converter&qid=1577424223&sr=8-3

step down converter:

https://www.amazon.com/DROK-90483-V...converter&qid=1577424330&sr=8-10

Combo step up step down converter

https://www.amazon.com/Converter-Au...converter&qid=1577424386&sr=8-10

note those are examples of products, not specific recommendations of products or sellers. They do appear to be very similar in appearance though.


These will make some electrical noise, but not as much as an inverter which is essentially taking 12.xx vDC battery voltage, stepping it upto 115vAC, then the powerbrick/wall wart which comes on tv/laptop powercord brick/wallwart which then converts 115vac to 19.5vdc. They will also save some wattage over using an inverter.

One other thing to note is the power brick/wall wart will say something like 19.5v and 4.5 amps dc output.

volts times amps = watts and this example the power brick would be able to supply no less than 87.75 watts.

Do note that the TV will not always draw that much wattage, that is the maximum it can draw, say at full volume with a white screen on max brightness, volume turned all the way up, and perhaps spinning a DVD too. Average consumption can be half of the maximum listed output on the powerbrick, and perhaps even less.

My 5+ year old 13.3 inch TV says something like 25 watts but averages about 14.