Best approach retro-fit Lithium batteries in existing set up

Submitted: Tuesday, Mar 07, 2017 at 17:37
ThreadID: 134424 Views:6116 Replies:6 FollowUps:9
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We would really appreciate some help on how to best retro-fit an improve an existing setup, we are considering a move to Lithium (in a slide-on camper we are very weight sensitive), apologies in advance for the amount of information but I thought it would help people get a good understanding of what we think we are trying to do. If anyone knows any good people to talk to in the Melbourne please PM me (we are located in the inner North West suburbs)

The Pro Power LiFeP04 100ah Battery or similar seems to fit our spec but there is not much information about that I can find and we also need to find some way to get BMS information of how the system is performing (amps in/out etc) which we do not have today. This spec seems too good to be true: Life cycles 1500-5000, Internal cell balancing, Can be charged using most standard lead acid battery chargers (Set for agm/gel cells), can be used in series or parallel meaning we could add more later if needed and has a 1.5 Years Warranty. I am not sure if Pro Power has an Australian presence or not by the look of the website

Our 200 amp hours (2 batteries) of AGM has worked pretty well for us so far. Our electrical devices are at the bottom of the post. We prefer not to use “powered sites” and are typically un-powered, the slide-on is used a several months each year and has NO good spot for permanently mounted solar panel so I will need a better maintenance charging regime that I have had on the past to keep batteries healthy.
• We need to be able to charge from Solar (we go bush for up to a couple of weeks at a time, at this point we usually get low on food/drinks/fuel but not power)
• We need to be able to charge from Ranger alternator to re-charge on route but also this is our diesel generator is case of no sun, to hot etc. In the current config we charge the in vehicle Thumper 75ah battery a lot while we are exploring our destination and then plug back into the Trayon Anderson Plug and let the batteries find there level (I assume this has not shortened the life of the batteries). We leave the Solar Panel on the camper while we are away. This use case may support 2 smaller lithium batteries or just replacing the current AGM as otherwise we would be wasting all that charging time while driving around doing things like fishing etc or moving the lithium about occasionally as its light enough.
• If we move to lithium, I would keep the 75Amp Hr Thumper as a spare and I assume this could only be connected if any “new” Lithium Battery was unplugged. We would be a lot more reliant on the solar panel as the slide-on camper is typically left standalone (battery in camper) and we would no longer be charging a second battery other than the cranking battery in the Ranger.

We are thinking a 100 amp hour lithium with a better solar panel and faster recharge times (even if cranking the engine) may allow us to stay within the required parameters to optimise the life of the battery. We also need better information and battery management info and potentially be able to set parameters to improve the configuration over time if needed. All we have now is voltage meter on either battery that isn’t really accurate as the fridge is usually drawing when I take readings. We also need to find good solar charging balance or wait for technology improvement. We don’t really want a fixed solar as in our case the roof of the camper when closed faces the ground when the camper is open, at this stage our preference when travelling is to rely on the alternator. We need something to be reliable and handle off-road travel and varied climatic conditions. Ideally if we can head towards 7-10 years it would be great. Vendor Warranties and maintenance will be important. I would be hoping at least initially to keep the Thumper 75 ah as a backup and be able to charge it somehow as required. This would address the issue of a single battery failing in the short term until we have full confidence in any new system.

Current Setup. Ford Ranger Cab Chassis with Trayon 1980 Slide on camper on the back ( ). Single Circuit as I understand is that has an isolator built in somewhere to isolate the cranking battery and the Trayon circuit that can be joined as required by an external Anderson plug (joined most of the time when the vehicle is near the camper). In Ranger is a Redarc BCDC1225 (12v 25a) charger under vehicle bonnet. (I didn’t think my model did solar or had MMPT but by the documentation it looks light it might). Ours was installed December 2014. Thumper 75 Amp hr AGM, this is a portable unit that sits on the floor behind the passenger and connect via an Anderson plug on the rear of the console. This was repacked with 5 x Century PS12120L 2 years ago.

In Trayon Camper is a 120 Amp hr Lion HZB-EV12-120 AGM VRLA (FAILED after 2.25 years which has started us considering Lithium). Voltage gauge. External Anderson plug to connect to ranger and solar panel. I use a “Y” cable to connect the 2 batteries and solar panel together at times. Projector Battery charger (12v, 15 amp, 7 stage) which runs off 240v only (typically used at home for maintenance purposes)

Portable folding 100w Solar Panel with regulator about 5 years old (any suggestions as to what to do here are welcome). The was purchased from Low Energy Developments in Melbourne. The distance from vehicle is important. Cable with panel is about 5 metres and connects to an Anderson Plug on camper or Ranger. Occasionally when chasing the sun, I connect another 5 metres of cable with dual Anderson plug.

Our devices: Novacool R3800 Fridge/Freezer. Info from a website: Apparently the R3800 draws only 2.1 amps @ 12 Volts DC - less than 0.5 amps on the 120VAC option. Average power use will vary depending on ambient temperature and how often the door is opened etc. but you can expect the R3800 to use less than 20 amp hours per day at 30C ambient temperature. Volume: 100Liters Total Internal Fridge Volume. 87.5 litres of fridge space plus a 12.5 litre freezer box at the top.
• The rest of our charging requirement is USB chargeable devices like Bluetooth speaker, Bluetooth fish finder, iPad, Smartphones, Telstra Hotspot is also a wi-fi hub that creates a LAN when we need to. AA and AAA rechargeable batteries for head torches, computer mice
• 12v Cig socket recharging for: 2 GME 5 watt handheld UHFs, Sangean Radio (has recharging battery) & Laptop x 2, AAA/AA battery recharger, Ryobi Lithium 18v Batteries for 18v Ryobi Drill we use to set up camp, Versa light (used rarely for short periods). Tyre compressor and inflatable boat pump (these could easily be run from Ranger cranking battery as they are used occasionally)
• We don’t buy anything that is not rechargeable in some way as per the above. We don’t have an invertor to get to 240v and at this stage don’t intend to get one. Apart from the fridge a lot of stuff is non-critical, if we get short of power when tend to reduce their usage.

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Reply By: HKB Electronics - Tuesday, Mar 07, 2017 at 19:13

Tuesday, Mar 07, 2017 at 19:13
"The Pro Power LiFeP04 100ah Battery or similar seems to fit our spec but there is not much information about that I can find and we also need to find some way to get BMS information of how the system is performing (amps in/out etc) which we do not have today."

The inbuilt BMS is only a protective device, it disconnects the battery if you attempt to over charge, or over discharge it. The cutoff voltage is way to low, you don't want to go below 20% SOC so you will need a separate low voltage cutout.

"Can be charged using most standard lead acid battery chargers (Set for agm/gel cells)"

Lithiums don't like being kept at a fully charged state, according to many you'll need to turn off the charger once the battery is fully charged and preferably not fully charge it, and cycle it once charged, float charging is bad If your cycling daily then maybe this won't be such an issue. They like to be stored around the 50% SOC level. The general consensus these days is don't charge above 13.8V to 14V so most chargers are to high, but it is a moving target and up to you what you do.

Personally I would go for a battery built up form cells, that way if one cell goes faulty you can replace it.

Lithiums have a higher terminal voltage than lead acid so you can't have the two connected together.

I would aim at not discharging below 20% and not charging above 95% so that gives 75 useable Ah.

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Follow Up By: Sam39 - Tuesday, Mar 07, 2017 at 20:24

Tuesday, Mar 07, 2017 at 20:24
Thanks, if I understand what you are suggesting.

It sounds like I need some cells to build up the amp hours into an array and a charger for management etc. Any suggestions as to what would be reasonable to fit my brief? I am having a challenge heading in the right direction with this one or finding something online is similar to our scenario online to investigate. I went to the Caravan show in Melbourne recently and talked to a few suppliers I have dealt with in the past and generally they we not doing much at all with people in my situation.

Are you saying that I can have my existing AGM and potential Lithium battery connected at the same time without issue? This would be really good if I can as I had assumed this would not be possible.
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Follow Up By: HKB Electronics - Tuesday, Mar 07, 2017 at 22:17

Tuesday, Mar 07, 2017 at 22:17
No you can't have the AGM and Lithium connected together, the Lithium will discharge into the AGM.

The battery your looking does not have an inbuilt charger, it is upto you to decide on how your going to charge it.

You can buy a made up battery from evpower with integrated cell balancing, they also have their on BMS. You can also make your own using their components. Cells, cell balancing and BMS are also available from other suppliers, the evpower batteries are a very neat setup though. See also EVWORKS

Enerdrive make a user settable charger for lithiums if you need a charger, as I already wrote you should also have a low voltage cutout independent of the BMS as the BMS is the last line of defence to protect the battery.

In my setup I'm not using a charger for charging off car, I'm just using a VSR to see how it goes, I would not suggest you do this unless you have some idea as to what your doing and can monitor the charging.

For other charging I'm using my existing solar and ac chargers set to gel. As my batteries will be cycling daily I don't think the float setting will be a problem.
Time will tell.

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Follow Up By: Sam39 - Wednesday, Mar 08, 2017 at 17:20

Wednesday, Mar 08, 2017 at 17:20
Thanks, those websites are a wealth of information that I hadn't found before.

This may be more suitable if it saves the need to additional low voltage switch but I suspect you are saying add this either way as an additional safeguard. EV Power LifeP04 100ah and not sure what this means "Not suitable for connection in parallel for higher capacity (use BCU-PPAK)" or if our existing chargers can be used to charge it?
I do like the idea of potentially adding a second 40-60ah Li battery in the Ranger and end up with 60-80ah in slide-on camper as there doesn't appear to be much of a price penalty to do this (instead of just 1 100ah battery)

RE: charging while using the camper. This would be either by solar or with existing Redarc BCDC1225 (12v 25a). A very long drive for us would be 8-9 hours with breaks, not sure if this is the sort of overcharging that could cause issues.

In storage, most likely I could put the Projector Battery charger (12v, 15 amp, 7 stage) on an appropriate cycle managed at the power point by a timer. When we prepare the camper for travel 240v it is never left connected overnight.

Out of interest, what is VSR?

I checked out the Enerdrive chargers, they appear to be full of useful features. Could the display panel on these chargers also be used to provide the battery monitor information I am likely to need to monitor the batteries ongoing? (as in no other battery monitoring required).

I think I am capable of assembling most of the system if its kept simple enough and this can help it be a cost effective activity, I may need to get an electrical qualified person or similar to double check the install is a good enough job or do the bits I can't do.
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Follow Up By: Sam39 - Wednesday, Mar 22, 2017 at 08:28

Wednesday, Mar 22, 2017 at 08:28
The more I research this the more it sounds like I need a VSR whether i go lithium or not.

What VSR are you using and how long have you been running this?
Is it a programmable one that can do both upper (over charging) and lower (complete battery drain)?
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Follow Up By: Frank P (NSW) - Wednesday, Mar 22, 2017 at 22:07

Wednesday, Mar 22, 2017 at 22:07
VSR is Voltage Sensitive Relay.

I have a lithium conversion from EV Power and couldn't be happier. It came with the necessary add-ons (a battery management system, or BMS) to prevent over charge and over discharge - in effect a voltage sensitive relay, but way smarter.

Rod Dilkes, the proprietor of EV Power, advised me that my AGM chargers would be ok in a camping environment where daily cycling occurs PROVIDING that they had suitable voltage selection. In the case of my pack, that is 14.2 volt, which my chargers could be set to.

As HKB says, I rarely charge to 100%. In my camping environment the batteries cycle between about 90% and 30% with the occasional full charge to 100% to ensure cells are balanced. They are the best thing since sliced bread. Twice the useable power, half the weight. If you can afford the up-front cost which is substantial, go for it.



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Follow Up By: Sam39 - Thursday, Mar 23, 2017 at 06:59

Thursday, Mar 23, 2017 at 06:59
Thanks Frank,

I am slowly getting my head around this but it is a journey and certainly time consuming.

I will check out the EV Power BMS.
Does it protect from over charge and over discharge from any incoming charge source and is programmable, as in you can set upper and lower thresholds? (solar, vehicle and mains chargers)

Will it do low voltage cutoff or do you do this with something else?
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Reply By: PhilD - Tuesday, Mar 07, 2017 at 22:21

Tuesday, Mar 07, 2017 at 22:21
I have Winston cells in a 400 Ahr pack from EV Works in Perth, which I have found to be a lot cheaper than some suppliers of lithium batteries. I use a Zeva BMS and relay rated at 350 amps/750 volts. I am charging at 14.2 volts using a Sterling 100 amp charger and a GSL 60-2 MPPT controller for the solar. I can also charge through my inverter chargers if needed from mains or generator. The system works a treat but has required an investment in the setup, and the cable sizes have to be big where appropriate as the Sterling gets the 100 amps by converting DC current to AC current. I have a 180 amp alternator.
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Reply By: Keith B2 - Tuesday, Mar 07, 2017 at 22:24

Tuesday, Mar 07, 2017 at 22:24
Maybe have a yarn with Phil at Solar4RVs in Melbourne. He could specify and supply an entire system for you. I think there might be some wisdom in getting everything from the one source.
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Follow Up By: Sam39 - Wednesday, Mar 08, 2017 at 17:38

Wednesday, Mar 08, 2017 at 17:38
Thanks website looks good, other side of town but could well be worth a chat at some point very soon.
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Reply By: Malcom M - Wednesday, Mar 08, 2017 at 13:08

Wednesday, Mar 08, 2017 at 13:08
I don't know how the costs work out but if you want a system that you don't have to be a rocket scientist to figure out, maybe something like this-
125ahr battery (200 agm equiv)This has all the BMS stuff built in and talks statistics to smart phones.
Charge that via a Redarc BCDC1225D charger which supports lithium and auto switches between solar and alternator (there's a 40 amp version out soon).
Add in a suitable low voltage cutout and you are in business.
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Follow Up By: Sam39 - Wednesday, Mar 08, 2017 at 15:47

Wednesday, Mar 08, 2017 at 15:47
I like the "Enerdrive" battery and its features. The issue for me seems to be that the "warranty" requires a specific charger with a Lithium profile and if possible we want to use our current gear for charging if possible. It also says that I can't run in series or parallel which I think means that if we needed to at another 50ah at some point down the track that I might have an issue. This is what led me towards Pro Power mentioned above: Life cycles 1500-5000, Internal cell balancing, Can be charged using most standard lead acid battery chargers (Set for agm/gel cells), can be used in series or parallel meaning we could add more later if needed and has a 1.5 Years Warranty. Does anyone know anything about them e.g. have they been around a while etc?
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Follow Up By: Malcom M - Thursday, Mar 09, 2017 at 06:20

Thursday, Mar 09, 2017 at 06:20
You have to use a charger with a lithium profile to charge lithium batteries.
You are going to pay a heap of dollars for a battery and then shorten its life by charging it incorrectly.
Doesn't make sense to me...

Perhaps you could read the manual for a charger that does have a lithium profile such as the Redarc unit I mentioned. Look at the different voltages used for the different style batteries. There's good reasons why they are different.

Your AGM charger will try and float charge the battery. Very few battery manufacturers will tell you this is a good idea. You cannot take shortcuts with lithium.
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Reply By: Member - Andrew W14 - Wednesday, Mar 08, 2017 at 20:42

Wednesday, Mar 08, 2017 at 20:42
If you want to save literally thousands on the install and have a fully protected and monitored system stay well away from the various 'drop in' systems.
Contact Terry at T1 Lithium in Mannum as he is the recognised expert in this area. No connection other than a very satisfied customer with a foolproof system that saved me $1000's.
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Reply By: kcandco - Wednesday, Mar 15, 2017 at 21:10

Wednesday, Mar 15, 2017 at 21:10
I also use agm batteries at the moment and use a projector 7 stage smart charger to recharge at home. I have been looking at a dc - dc charger and was told by the seller that on agm setting, it is suitable for lithium. However when searched for more info on charging lithiums, I found info that said they required a different charging regime to agms etc and that a non specialist charger would damage the battery. So in summary I would be cautious as to method of charging and only use a charger designed for lithiums unless they can be proved safe.
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