Need your help and advice: Adding electrical stuff...does this make sense?

#31
The 5 hour charge need is pretty common to lead acid batteries that are deep cycled. If you are only out for a few days, you can just plug in when you get home.

Sounds like you can go with a 75-100AH flooded marine/hybrid battery under the hood. A portable battery (or box if you desire), can be plugged in the back. Batteries that are different ages, or different types/sizes should not be connected in parallel (except when charging/driving). So you would need a isolation/charge relay that can handle your expected load. This would be pretty beefy if you are splitting winching loads between two batteries.
 
#32
OK, so now I'm looking at stuff. This site below suggests having the two different type batteries is "fine":
https://www.arkportablepower.com/bl...reezer-and-battery-life-what-you-need-to-know

Then, same company, naturally, has this battery box that include the ability to be recharged via alternator:
https://www.arkportablepower.com/products/arkpak-730-portable-power

I'll assume that you've seen this before, and you likely know of a cheaper alternative to that ark item. Does this idea make sense? Also known as...what's wrong with this idea, having a starter and a deep cycle box that I add as needed?
 
#33
Those portable power packs (ark, goal zero etc) are a conveniently packaged group of components. They have distinctive downsides, usually relating to slow charge rates, and limited output current (20A in some cases).

It is okay to mix battery types in parallel as long as they are disconnected when not charging (such as with an isolation relay). Some of those powerpacks use a direct charging method, so the vehicles electrical system directly connects to the packs battery. The more advanced ones use a DC-DC charger. This charger takes power from the vehicles systems, and convert it (usually boosting the voltage) to charge the packs battery. This can allow for more complete charging, possibly faster (not always!).


There is nothing wrong with using a lead acid deep cycle portable power pack for a fridge etc. If you like those pre-made packs, they can be a good option. Just read the fine print on charge rates, capacity, etc. A lithium pack has some advantages. They are lighter, and don't need to be fully charged for longevity. I don't see that as a big advantage, as you don't do long trips.

I personally feel that if you have a modest amount of skill, its possible to make a portable pack with more capacity for less money. Given your short trips, I think something like this would work.

100AH lead acid battery, hybrid or true deep cycle. 100-150$
50A isolation relay (higher if you plan to supplement your starting battery for winching) 25$
anderson 50A connector with ~1awg wire connected to vehicle electrical system 35$
4-6 ATC fuse block 20$
ANL 40-60A main fuse 30$ (breaker optional)
rotary on/off switch (if desired) 30$
USB charging ports 20$
300W inverter (if desired) $25
12V powerports $15
accurate volt meter $19
Amp meter (if desired) $10
Wire and misc connectors ??

So around 400-450$ depending on options. Depending on your alternator voltage, you would want to plug the pack into a shop charger after a trip to top it back up to 100%. With appropriate sized wiring, this pack could start your engine unaided, and can run or supplement your winch. With something like the ark pack, you would need to remove the battery from the pack, or rig something up with jumper cables.

The ark pac is about the same without a battery, so add that on top. The ark pack only charges at 6a max as well. That is 10 hours or more to get from 50% to full.
 
#34
I wondered about the small size of that ArkPak charger; I couldn't see how it could charge something quickly. I wonder if it would make more sense to have a beefier cable direct to the batt terminals as opposed to that little charger...assuming that this could even be done with the ArkPak, or any cognate.
 
#35
I wondered about the small size of that ArkPak charger; I couldn't see how it could charge something quickly. I wonder if it would make more sense to have a beefier cable direct to the batt terminals as opposed to that little charger...assuming that this could even be done with the ArkPak, or any cognate.
Some of the packs offer a direct style external connection. Usually limited to 30A-50A for safety. This could be used for direct charging. If your alternator is low voltage (less than 13.6V), then the DC-DC charger may be faster than the direct method. Lots of variables though.
 
#38
Lots of folks seem to think they need an AGM. The reality is, that unless you are doing an equalize cycle (15v+) there is very little hydrogen or odor production in a flooded battery. A vehicle is not really a sealed space either, with plenty of air venting locations in the pillars etc. A flooded battery will last longer and cost lest. So just make allowances to check the water/electrolyte every 30-60 days (depending on how often its used).

Here is a good read on choosing true deep cycle batteries.
https://marinehowto.com/what-is-a-deep-cycle-battery/

For light duty, a marine type "deep cycle" starting battery can be a good value, especially the flooded type.

That battery box looks a bit weak. If you bought one, plan on spending many hours beefing up the case with some epoxy and glass fabric, adding backing plates. Generally making it safe. Remember, a short circuit, or high resistance connection can cause a fire. Even the smoke released can make a vehicle reek for years. Buyer beware.


That DC charger is only 2A. It also only reaches 14.4V, which is okay for some AGM batteries, it is not high enough for ideal charging of flooded batteries. This type of charger is useful for keeping a starter battery topped up from a house battery that has a full time float charger.
 
#39
Lots of folks seem to think they need an AGM. The reality is, that unless you are doing an equalize cycle (15v+) there is very little hydrogen or odor production in a flooded battery. A vehicle is not really a sealed space either, with plenty of air venting locations in the pillars etc. A flooded battery will last longer and cost lest. So just make allowances to check the water/electrolyte every 30-60 days (depending on how often its used).

Here is a good read on choosing true deep cycle batteries.
https://marinehowto.com/what-is-a-deep-cycle-battery/

For light duty, a marine type "deep cycle" starting battery can be a good value, especially the flooded type.

That battery box looks a bit weak. If you bought one, plan on spending many hours beefing up the case with some epoxy and glass fabric, adding backing plates. Generally making it safe. Remember, a short circuit, or high resistance connection can cause a fire. Even the smoke released can make a vehicle reek for years. Buyer beware.


That DC charger is only 2A. It also only reaches 14.4V, which is okay for some AGM batteries, it is not high enough for ideal charging of flooded batteries. This type of charger is useful for keeping a starter battery topped up from a house battery that has a full time float charger.
Thank you for the advice. Do you have any recommendations for a pre made box or should I just make plans to make my own? Also any recommendations for an adequate dc to dc charger?
 
#40
Thank you for the advice. Do you have any recommendations for a pre made box or should I just make plans to make my own? Also any recommendations for an adequate dc to dc charger?
I am assuming you are talking about a provide-your-own battery type? I am not up to date on all the current offerings. But there are a couple options from goal zero, ark, etc. None are perfect, and they can't be all things to all people anyways. The primary issue seems to be charge rates (GZ does offer a direct higher current port for their lead versions).


So it really comes down to your budget and needs. For the DIY savvy, you can build a pretty nice power pack with bare components. It won't be as sleek or user friendly as the more expensive options though.


For a DC-DC charger, CTEK makes a good DC-DC unit. This can also double as a solar controller which makes it a decent value. 25A output, can be combined with the smartpass unit for 50A. Not cheap though.
https://amzn.to/2L1e75u

For lead acid batteries on vehicles that have alternators in the 13.8v+ range, a direct low resistance charging circuit can work quite well. Especially when combined with a quality shore power charger (2-15A) after each trip.

For those a bit more DIY savvy, a basic boost converter could be used with good effect. Use a relay triggered by the ignition to power the converter, and set its output to the absorb voltage of the battery in question (14.4-14.6V). Yes its a dumb single stage charger, but unless you drive crazy large amounts (6+ hours days in a row) it won't be a problem. A small fan may be needed to cool the heatsinks. Some of these converters will also do step-down. Which would allow a cheap laptop power supply to be used a shore charger. With a laptop type charger, you would need to watch the pack, and disconnect once full, as the 14.4V is not suitable for float charging.
https://amzn.to/2UdYdZD

There are also some trolling battery DC-DC chargers. Never used them, but the prices aren't bad. This unit is rated at 10A. No indication of voltages, so you would need to contact the MFG for details.

https://amzn.to/2PmAXoC
 
#41
I was browsing some DC-DC chargers and powerpacks and found some interesting stuff.

The first up is a charger unit designed for radio systems. It is a DC-DC charger that accepts solar or alternator inputs. Can be programmed via usb? Doesn't look able to boost alternator votlage though.
https://powerwerx.com/west-mountain-radio-epic-pwrgate
http://www.westmountainradio.com/product_info.php?products_id=epic-pwrgate

This particular power pack looks like a decent deal (never used myself). I am not sure what the charge voltages are for the internal pack, but it is possible that it can be chared from the jump start output plug via the alternator. Some care would be needed to make sure the max charge rate is note exceeded. However most lithium iron phosphate packs can be charged for extended periods at 13.9-14.1V without issue. Otherwise the provided charger is an anemic 90W.
https://www.bioennopower.com/collections/mobile-power-station/products/400-w-hr-power-pack-bpp-m400
https://powerwerx.com/bioenno-bpp-m400-power-pack
 
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